Microbiology #3

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Which group of drugs includes nystatin and amphotericin B and cause cell lysis by forming channels in the cytoplasmic membranes of fungal cells

Polyenes

Which group of drugs includes nystatin and amphotericin B and cause cell lysis by forming channels in the cytoplasmic membranes of fungal cells?

Polyenes

Alteration in the structure of which of the following are an important aspect of Gram-negative bacterial resistance to antimicrobial drugs?

Porins

Drugs that selectively target bacteria because of a smaller and structurally different ribosome

Tetracycline and Chloramphenicol

What group of drugs can become incorporated into the bones and teeth of a fetus?

Tetracyclines

Mutualism is a relationship...

That provides benefits for BOTH members, sometimes to the point that one cannot live without the other.

What effect do enterotoxins have?

They affect the gastrointestinal system...Enterotoxins affect the cells that line the gastrointestinal tract, often causing stomach cramps, vomiting, and diarrhea.

What is the value of the McFarland No. 0.5 turbidity standard?

To assure that you have enough microbes in broth and to standardize the numbers of microbes being spread on the plate.

Drug that binds to ergosterol in fungi cell walls

Amphotericin B

What antibiotic disrupts cytoplasmic membrane function?

Amphotericin B

Match the following descriptions of cellular structures with the type of cell in which they are found.

Archaea- hami, protein cell wall Bacteria- peptidoglycan cell wall Eukaryotes- organelles, 80s Ribosomes in Cytosol Both Eukary and Prokary- Cytoskeleton, DNA, Glycocalyx Prokaryotes (Archaea and Bacteria)- Fimbriae, 70s Ribosome in Cytosol

Medications which block viral entry into cells include __________________ antagonists

Attachment

Which antimicrobial drugs inhibit ergosterol synthesis?

Azoles and Allylamines

A particular microbe gains resistance to gentamicin. You might also expect this microbe to exhibit resistance against __________. A. chloramphenicol B. streptomycin C. clindamycin D. vancomycin

An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition indicates that the microbe being tested is __________ to the drug. A. susceptible B. resistant C. synergistic D. intermediate

An antimicrobial drug that blocks the transport of NAG and NAM from the cytoplasm is targeting which of the following cellular processes? A. nucleic acid synthesis B. cell wall synthesis C. protein synthesis D. cytoplasmic membrane synthesis

Antimicrobials that block protein synthesis by binding to the mRNA are A) aminoglycosides. B) antisense nucleic acids. C) macrolides. D) beta-lactams. E) nucleic acid analogs.

Bacillus licheniformis secretes a compound that inhibits the growth of other Gram-positive bacteria. This is an example of a(n) A) analog. B) antibiotic. C) chemotherapeutic. D) porin. E) toxin.

Beta-lactam antibiotics such as penicillins, have an effect on which of the following types of cells? A) animal cells B) bacterial cells C) fungal cells D) virus-infected cells E) both animal and fungal cells

Chloramphenicol blocks the action of the large (50S) subunit. This essentially _____. A. changes the shape of the large subunit B. prevents the formation of peptide bonds C. prevents a large subunit from attaching to a small subunit D. prevents the attachment of tRNA to a ribosome

How does resistance to drugs spread in bacterial populations? A) Exposure to drugs causes mutations in bacterial genes. B) Horizontal gene transfer between bacteria spreads R (resistance) plasmids. C) Genetic recombination during sexual reproduction. D) Exposure to drugs induces immunity. E) Exposure to drugs alters gene expression in bacteria.

Methicillin is an example of the beta-lactam class of drugs that A) disrupts cytoplasmic membranes. B) inhibits cell wall synthesis. C) inhibits nucleic acid synthesis. D) inhibits metabolic pathways. E) inhibits protein synthesis.

Most broad-spectrum antibiotics act by A) inhibiting the synthesis of the cell wall. B) inhibiting protein synthesis. C) inhibiting nucleic acid synthesis. D) inhibiting metabolic pathways. E) disrupting the cytoplasmic membrane.

A class of drugs that contain a ring that irreversibly BINDS TO ENZYMES to produce NAM-NAM cross bridges

Beta-Lactams

Which of the following is NOT a direct mode of action of antimicrobial drugs? A. inhibition of protein synthesis B. inhibition of cell wall synthesis C. inhibition of flagella formation D. inhibition of nucleic acid synthesis

Which of the following is a primary advantage of semisynthetic drugs? A) They are less stable and consequently have fewer side effects. B) They work faster. C) They are more effective than the unmodified natural antibiotics. D) They must be administered intravenously. E) They are not readily absorbed.

Which of the following mutations would not result in antibiotic resistance? A. Missense mutation B. Nonsense mutation C. Silent mutation D. Frameshift insertion E. Frameshift deletion

Which of the following statements is relevant in explaining why sulfonamides are effective? A. Sulfonamides attach to sterol lipids in the pathogen, disrupt the membranes, and lyse the cells. B. Sulfonamides prevent the incorporation of amino acids into polypeptide chains. C. Humans and microbes use PABA differently in their metabolism. D. Sulfonamides inhibit DNA replication in both pathogens and human cells.

Who proposed the concept of chemotherapy, that compounds might selectively kill pathogens without harming people? A) Gerhard Domagk B) Alexander Fleming C) Paul Ehrlich D) Selman Waksman E) Joseph Lister

Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug? A. Bacteria are especially sensitive to these compounds. B. The drugs also work against DNA gyrase. C. Humans and other animal hosts lack peptidoglycan cell walls. D. They are less expensive that other chemotherapeutic agents.

Why do antimicrobial agents active against mycobacteria have to be administered for months or years rather than the typical 10-30 days prescribed to treat other infections? A. They are too toxic to be used on a more rapid administration schedule. B. Mycobacteria do not have cell walls. C. Mycobacteria reproduce very slowly. D. The only available agents are relatively ineffective drugs.

_______________ are chemicals that are released by leukocytes at the site of infection, that attract Phagocytes

Chemokines

What is meant by selective toxicity?

Chemotherapeutic agents should act against the pathogen and not the host.

What is meant by selective toxicity? Chemotherapeutic agents should work on certain types of pathogens. Chemotherapeutic agents should have only one mode of action. Chemotherapeutic agents should work on many different targets on a pathogen. Chemotherapeutic agents should act against the pathogen and not the host.

Chemotherapeutic agents should act against the pathogen and not the host.

The ribosomes of bacteria differ significantly from our own, making them a prime target for antimicrobial drugs. Which commonly prescribed antimicrobial for eye infections blocks the formation of peptide bonds in prokaryotes?

Chloramphenicol

The antimicrobial polymyxin A) inhibits protein synthesis. B) inhibits nucleic acid synthesis. C) blocks a metabolic pathway. D) disrupts cytoplasmic membranes. E) inhibits cell wall synthesis.

An exotoxin that has the ability to kill or damage host cells is a...

Cytotoxin

AZT and Valaciclovir are antiviral nucleoside analogs that interfere with A) protein synthesis. B) cell wall synthesis. C) cell membrane component synthesis. D) nucleic acid synthesis. E) viral attachment.

Antimicrobial drugs are selectively toxic. This means _____. A. the drugs will not have toxic effects on a patient B. the drugs are reactive within a specific part of the patient's anatomy (for example, the inner ear) C. the drugs will affect only a particular type of pathogen D. the drugs are more toxic to the pathogens than to the patient

Cross resistance is____. A. the deactivation of an antimicrobial agent by a bacterial enzyme B. alteration of the resistant cells so that an antimicrobial agent cannot attach C. the mutation of genes that affect the cytoplasmic membrane channels so that antimicrobial agents cannot cross into the cell's interior D. resistance to one antimicrobial agent because of its similarity to another antimicrobial agent

Diffusion and dilution tests that expose pathogens to antimicrobials are designed to determine _________. A. the spectrum of action of a drug B. which drug is most effective against a particular pathogen C. the amount of a drug to use against a particular pathogen D. both b and c

Drugs that act against protein synthesis include ____. A. beta-lactams B. trimethoprim C. polymyxin D. aminoglycosides

Infection of the ________ would be the hardest to treat with antimicrobial drugs. A) heart B) kidneys C) liver D) brain E) colon

It is inappropriate to prescribe antibacterial agents to treat colds or flu because A) the microbes involved can develop resistance rapidly. B) these diseases are transmitted by endospores, which are difficult to kill. C) these diseases exhibit cross resistance. D) these diseases are caused by viruses. E) these diseases can act synergistically with each other.

PABA is _________. A. a substrate used in the production of penicillin B. a type of β-lactamase C. molecularly similar to cephalosporins D. used to synthesize folic acid

Pentamidine is an example of an antimicrobial A) used to treat bacterial infections. B) effective against helminths. C) used to treat viral infections. D) effective against eukaryotes, especially protozoa. E) used to treat both bacterial and fungal infections.

Quinolones and fluoroquinolones act against what bacterial target? A. Bacterial ribosomes B. Metabolic pathways unique to bacteria C. Cell walls D. DNA gyrase E. Cell membranes

Quinolones and fluoroquinolones act against what bacterial target?

DNA gyrase

Quinolones and fluoroquinolones act against what bacterial target? Cell membranes Cell walls Bacterial ribosomes DNA gyrase Metabolic pathways unique to bacteria

DNA gyrase

_________ discovered the antimicrobial effects of penicillin. While, ________ work resulted in the discovery of arsenic compounds, one of which worked against the bacterial agent of syphilis.

Flemming: penicillin Ehrilch: arsenic compounds

Match the type of point mutation with the type of damage it is most likely to produce.

Frameshift- Match the type of point mutation with the type of damage it is most likely to produce. Silent- No change in gene product. Missense-Small change in gene product which may or may not alter function. Nonsense- Premature termination of gene product with probable loss of function.

Label the structures of this bacterial cell. Drag the appropriate labels to their respective locations.

From Left to right DNA, Ribosome, Glycocalyx, Cell Wall, Cytoplasmic membrane

__________ cells would be expected to be the most susceptible to the action of polyene drugs such as amphotericin B, while __________ cells would be the least susceptible.

Fungal; bacterial

cells would be expected to be the most susceptible to the action of polyene drugs such as amphotericin B, while _____ cells would be the least susceptible.

Fungal; bacterial

Scientist who discovered the first antimicrobial widely available to the general public?

Gerhard Domagk

Which scientist was responsible for discovering Sulfanilamide, a class of antibiotic drugs that would save countless lives in world war 2?

Gerhard Domagk

Basophils (granulocyte) are involved in...

Inflammation

What drug specifically targets cell walls that contain arabinogalactan-mycolic acid?

Isoniazid

A drug that disrupts mycolic acid formation in mycobacterial specials. Also Inhibits cells wall synthesis

Isoniazid and Ethambutol

The process of diapedesis is important because .....

It allows white blood cells to leave the vessel system and attack pathogens in the tissue

Why is polymyxin only used on the skin?

It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead.

Virulence factor that digests bloods clots

Kinase

Determining the susceptibility of pathogens using the filter paper disk agar diffusion method.

Kirby bauer method

Use filter paper discs impregnated with an antibiotic on a Mueller Hinton agar plate that has been covered with organisms. View this diffusion method after 12-24 hours of growth and look for the zone of inhibition.

Kirby-Bauer

Antimicrobials that block protein synthesis by binding to the mRNA are ________________

antisense nucleic acids

Which category of drug is complementary to mRNA of the pathogen?

antisense nucleic acids

antimicrobials that block ribosome attachment altogether by forming a complementary strand to the mRNA

antisense nucleic acids

Synthetic antimicrobials that block protein synthesis by binding to the mRNA are Select one: a. beta-lactams. b. antisense nucleic acids. c. aminoglycosides. d. macrolides. e. nucleic acid analogs.

b. antisense nucleic acids.

What major cellular feature that might be targeted by antimicrobial drugs is found in both bacteria and fungi but not in human cells?

a cell wall

Etest

a non-diffusion-based technique that employs a preformed and predefined gradient of an antimicrobial agent immobilized on a plastic strip The plastic strip contains a gradient of the antimicrobial agent of interest. The MIC is estimated to be the concentration printed on the strip where the zone of inhibition intersects the strip.

Which type of antimicrobial drug is produced entirely in a lab?

synthetic microbials

What is the function of tRNA during the process of translation?

tRNA brings amino acids to a growing chain of amino acids in ribosomes.

Which of the following activities can be shown to increase resistance among microbial populations?

taking antibacterial drugs for viral infections

External infections can be treated by (surface/topical) administration, in which a drug is applied directly to the site of infection.

topical

External infections can be treated by ____________ administration, in which a drug is applied directly to the site of infection

topical

Selective (toxicity/action/treatment) means that a given antimicrobial agent is more toxic to a pathogen than to the host being treated

toxicity

Selective ____________ means that a given antimicrobial agent is more toxic to a pathogen than to the host being treated

toxicity

The process of acquiring antibiotic resistance by means of bacteriophage activity is called

transduction

The process of acquiring antibiotic resistance by means of bacteriophage activity is called

transduction.

The process of acquiring antibiotic resistance by means of bacteriophage activity is called transduction. R-plasmid acquisition. point mutation. transformation.

transduction.

efflux pumps

transmembrane pump that removes antimicrobial drugs from a cell or from the periplasm

Hospital personnel can also act as reservoirs of infection and most often act as a link for ____.

transmission

Bacterial resistance to antibodies has developed to the use of antimicrobials (not antibiotics) like ____ in soaps and other products.

triclosan

In the past decade, the number of MRSA infected patients has ___.

tripled

The dairy creamer used in restaurants is usually treated by autoclaving. lyophilization. ultra-high-temperature pasteurization. ionizing radiation. filtration.

ultra-high-temperature pasteurization

Which of the following types of antimicrobial agent has the narrowest spectrum of action? Select one: a. azoles b. antivirals c. erythromycins d. Both azoles and erythromycins have equally narrow spectrums of action. e. sulphonamides

b. antivirals

Lincosamides or macrolides

bind to the 50S subunit, preventing movement of the ribosome along the mRNA.

Bacteria within _____ resist antimicrobial drugs more effectively than free- living cells.

biofilms

Tetracycline

block the tRNA docking site (A site) on the 30S subunit, preventing protein elongation

Chloramphenicol

blocks enzymatic activity of the 50S subunit, preventing the formation of peptide bonds between amino acids.

Infection of the __________ would be the hardest to treat with antimicrobial drugs.

brain

Antibiotics are classified based on the range of different microbial types they affect. If they affect both gram - and gram + bacteria, they are called _____ _____ antibiotics.

broad spectrum

An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition indicates that the microbe being tested is __________ to the drug. a. intermediate b. synergistic c. resistant d. susceptible

What is meant by selective toxicity? a. Chemotherapeutic agents should work on many different targets on a pathogen. b. Chemotherapeutic agents should have only one mode of action. c. Chemotherapeutic agents should act against the pathogen and not the host. d. Chemotherapeutic agents should work on certain types of pathogens

In hospitals, the most important reservoirs of MRSA are ____ ____- those with the bacteria in or on the body but not causing disease.

colonized patients

Sulfonamide drugs inhibit microbial growth by disrupting metabolic pathways. What general mechanism do these drugs use?

competitive inhibition Sulfonamides bind to the active site of an enzyme in the metabolic pathway responsible for producing folic acid, a key step in nucleotide production.

How did the multi-drug-resistant strains of Mycobacterium tuberculosis, like those in the prison, arise?

conjugation and exchange of resistance factors located on plasmids

How did the multidrug resistant strains of Mycobacterium tuberculosis, like those in the prison, arise? -inclusion of histidine in the patient's diet -frameshift mutation -conjugation and exchange of resistance factors located on plasmids -point mutation

conjugation and exchange of resistance factors located on plasmids

There are several factors to consider when choosing a route of administration for antimicrobial drugs. Which would likely be the most effective route of administration when a patient has an infection that could result in death if not treated promptly?

continuous intravenous

Some bacteria develop resistance to groups of drugs because the drugs are all structurally similar to each other; this is a phenomenon known as (cross/multiple) resistance.

cross

Some bacteria develop resistance to groups of drugs because the drugs are structurally similar to each other; this is a phenomenon known as __________ resistance

cross

Prokaryotes contain _____ ribosomes. a. 30S b. 50S c. 80S d. 70S

Which of the following activities can be shown to increase resistance among microbial populations? a. developing second- and third-generation versions of antimicrobial drugs b. taking a combination of antimicrobial drugs c. taking an antimicrobial drug for the entire prescribed time d. taking antibacterial drugs for viral infections

Drug-resistant populations of microbes arise when ________________

exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells

Aseptic means sterile. clean. sanitized. free of all pathogens. free of all microbes.

free of all pathogens

An instrument coming into contact with the skin of an immunocompromised patient should be treated with which of the following? intermediate-level germicide low-level germicide high-level germicide surfactants

high-level germicide

Mix the E. coli culture and the ____ ____ until they reach their max turbidity.

mcfarland standard

Black hairy tongue," (flagyl) caused by the antiprotozoan drug

metronidazole

You must measure the diameter of the zone of inhibition in ____.

millimeters

definition: the lowest concentration of an antibacterial agent required to kill a particular bacterium

minimum bactericidal concentration (MBC)

The smallest amount of an antimicrobial drug that will inhibit growth and reproduction of a pathogen is expressed as the _______.

minimum inhibitory concentration

The size of this zone of inhibition depends on the sensitivity of the bacteria to the specific antimicrobial agent and the point at which the chemical's ____ ____ _____ is reached.

minimum inhibitory concentration (MIC)

definition: the lowest concentration of an antimicrobial drug that will inhibit the visible growth of a microorganism; the smallest amount of a drug that will inhibit a pathogen

minimum inhibitory concentration (MIC)

Macrolides inhibit protein synthesis by blocking (catalysis/binding/movement) of the ribosome.

movement

____ _____ agar, which has a pH between 7.2 and 7.4, is poured to a depth of 4mm in either 150mm or 100mm Petri dishes.

mueller hinton

A microbe resistant to a variety of different antimicrobials is said to have __________ resistance

multiple

A patient has been diagnosed with a disease caused by a drug-resistant strain of bacteria. What is a likely way that the bacterium initially acquired resistance?

mutation

A drug that is effective against a small number of pathogens is called a(n) _______ drug.

narrow- spectrum

Polymyxin is effective against only some Gram-negative bacteria; therefore, it is considered a __________.

narrow-spectrum drug

Ribavirin is an antiviral that interferes with ____________________

nucleic acid synthesis

Which of the following antimicrobial drugs would likely be useful to treat a methicillin-resistant Staphylococcus aureus infection because it effectively blocks initiation of translation?

oxazolidinones

antimicrobials that block initiation of protein synthesis by preventing the ribosomal subunits from docking properly

oxazolidinones

Which of the following antimicrobial agents has the fewest side effects? streptomycin chloramphenicol penicillin tetracycline erythromycin

penicillin

The first true antibiotic was __________, which was discovered by __________.

penicillin; Alexander Fleming

The ____________ is a defining characteristic of bacteria which is not found in eukaryotes and is therefore a good choice for chemotherapeutic agents.

peptidoglycan cell call

Which group of drugs includes nystatin and amphotericin B and cause cell lysis by forming channels in the cytoplasmic membranes of fungal cells?

polyenes

Which of the following antibiotics is recommended for use against gram-negative bacteria? cephalosporin polymyxin penicillin bacitracin polyenes

polymyxin

Second-generation drugs are semisynthetic drugs developed to combat (immunity/resistance) against an existing drug

resistance

Second-generation drugs are semisynthetic drugs developed to combat _______________ against an existing drug

resistance

What benefit would the presence of an R plasmid provide to a microbe that has this extra piece of DNA?

resistance to particular antibiotics

An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition indicates that the microbe being tested is __________ to the drug.

resistant

If there is no zone or a very small zone of inhibition around the disk, the organism is considered to be ____ to the drug.

resistant

Which drug for the treatment of tuberculosis inhibits RNA production and colors body secretions red-orange?

rifampin

Which drug inhibits RNA production and colors body secretions red-orange? rifampin polymyxin penicillin erythromycin

rifampin

Paul Ehrlich finally came up with _____ (salvation from syphillis); this compound contained arsenic and phenol.

salvarsan

What modern term best describes the property of an antimicrobial compound that lets it target bacteria while having little effect on humans?

selective toxicity

A compound is extracted from a microbial culture and is modified in the laboratory for use as an oral medication. This product would be a(n) ___________

semisynthetic antimicrobial

Ben's infection is treated with imipenem. A drug such as imipenem is chemically modified from penicillin. What are non-natural drugs developed from natural drugs called? protein inhibitors antimetabolites fungal enzymes semisynthetics

semisynthetics

Rank the following point mutations in order of least damaging to most damaging if they occur in the middle of the coding sequence of a polypeptide.

silent, missense, frameshift, nonsense

test (MIC):

smallest amount of drug that will inhibit growth and reproduction

Kirby Bauer Method: 1.____ method-must be performed as directed. 2. A ____ ____ agar plate is inoculated so that a lawn of the bacteria to be tested is placed on the plate. 3. A 0.5 _____ ____ is used to dilute the broth culture so that the number of bacteria placed on the plate is standardized.

standardized; mueller hinton; mcfarland standard;

Two important bacteria have become resistant to multiple antimicrobial agents.

staph aureus; enterococcus

oral administration method graph

start at bottom, goes a little higher in the middle, and goes back down

intramuscular administration graph

start at bottom, spikes high middle, then goes back down

continuous intravenous administration graph

starts at bottom, spikes very quickly, and stays there for the duration of the graph

More than half of the antibiotics we use come from a species of _____ filamentous bacteria found in soil.

streptomyces

A particular microbe gains resistance to gentamicin. You might also expect this microbe to also exhibit resistance against __________.

streptomycin

What was the first practical antimicrobial agent to be widely used?

sulfanilamide

Which of the following is NOT associated with the work of Paul Ehrlich?

sulfanilamide

A drudge is structurally similar to PABA and inhibits folic acid synthesis. It is most likely a(n) _________________

sulfonamide

Using a broad-spectrum antibiotic to treat an infection might seem like a good idea at first, but its use can allow unaffected members of the microbiome to cause what sort of infection?

superinfection

Using a broad-spectrum antibiotic to treat an infection might seem like a good idea at first, but its use can allow unaffected members of the microbiome to cause what sort of infection?

superinfection Superinfections are caused when some microbiota are unaffected by an antimicrobial drug and find themselves unchallenged by their usual neighbors who are affected. The sudden lack of competition for resources results in microbial overgrowth.

Secondary infections that result from the killing of some of the normal microbiota are called (antagonism/superinfections/resistance).

superinfections

Secondary infections that result from the killing of some of the normal microbiota are called __________________

superinfections

_____ (S) = antibiotic is useful against the bacteria. _____ (I) = antibiotic may be useful against the bacteria. _____ (R) = antibiotic is not useful against the bacteria.

susceptible; intermediate; resistant

The antimicrobial susceptibility testing of an isolated pathogen indicates: whether a pathogen is _____ or ____ to the antimicrobial agent.

susceptible; resistant

Consider a Kirby-Bauer disk-diffusion assay. If you put penicillin and streptomycin disks adjacent to one another, the zone of inhibition is greater than that obtained by either disk alone. This is an example of __________. antagonism synergism mutual exclusion RNA interference

synergism

Some antimicrobial drugs can work in tandem with one another to produce an enhanced antimicrobial effect. What is this process called?

synergism

The cooperative activity of drugs such a beta-lactam antibiotics and clavulanic acid, a beta-lactamase inhibitor, is known as __________

synergism

Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what? (a) PABA (b) sulfonamide (c) tetrahyrdrofolic acid (d) tetracycline

(a) PABA

Chloramphenicol blocks the action of the large (50S) subunit. This essentially _______________. (a) prevents the formation of peptide bonds (b) prevents a large subunit from attaching to a small subunit (c) changes the shape of the large subunit (d) prevents the attachment of tRNA to a ribosome

(a) prevents the formation of peptide bonds Without the formation of peptide bonds, amino acids diffuse away and protein synthesis ceases.

A compound is extracted from a microbial culture and is modified in the laboratory for use as an oral medication. This product would be a(n) _______________. (a) semisynthetic antimicrobial (b) synthetic antimicrobial (c) antibiotic (d) probiotic (e) analog

(a) semisynthetic antimicrobial

A particular microbe gains resistance to gentamicin. You might also expect this microbe to exhibit resistance against __________. (a) streptomycin (b) vancomycin (c) chloramphenicol (d) clindamycin

(a) streptomycin

The process of acquiring antibiotic resistance by means of bacteriophage activity is called ____________________. (a) transduction (b) R-plasmid acquisition (c) point mutation (d) transformation

(a) transduction

Which of the following is NOT a beta-lactam antibiotic? (a) vancomycin (b) penicillin G (c) methicillin (d) cephalothin

(a) vancomycin

Prokaryotes contain _____ ribosomes. (a) 30S (b) 70S (c) 50S (d) 80S

(b) 70S

If the MBC for a particular drug is 16 μg/ml, which of the following serial dilutions of the drug is likely to be the MIC? (a) 1.6 μg/ml (b) 8 μg/ml (c) 24 μg/ml (d) 32 μg/ml

(b) 8 μg/ml

Which of the following statements is MOST correct regarding the development of antibiotic resistance in populations of bacteria? (a) Exposure to antibiotics causes mutations which produce resistant bacteria. (b) Exposure to antibiotics selects for the members of a bacterial population which already have a resistant phenotype. (c) The bodies of people who take antibiotics become resistant to them. (d) Bacteria exposed to antibiotics alter their DNA to become resistant.

(b) Exposure to antibiotics selects for the members of a bacterial population which already have a resistant phenotype.

The tRNA molecule holding a growing polypeptide chain is at the _______________. (a) A site (b) P site (c) 50S site (d) E site

(b) P site

Which category of antimicrobial drug works by changing the shape of a ribosome? (a) tetracyclines (b) aminoglycosides (c) oxazolidinones (d) chloramphenicol

(b) aminoglycosides An aminoglycoside changes the shape of a 30S subunit causing the ribosome to misread the mRNA.

Which antimicrobial drugs affect the structure of the ribosome itself? (a) aminoglycosides, chloramphenicol, and lincosamides (b) aminoglycosides, antisense nucleic acids, and oxazolidinones (c) macrolides and antisense nucleic acids (d) tetracyclines and oxazolidinones

(b) aminoglycosides, antisense nucleic acids, and oxazolidinones Each of these drugs actually modifies or prevents the formation of the complete 70S ribosome.

Which category of drug is complementary to mRNA of the pathogen? (a) tetracyclines (b) antisense nucleic acids (c) oxazolidinones (d) macrolides

(b) antisense nucleic acids

Check all that apply. R-plasmids are most likely acquired via _______________. (a) transformation (b) bacterial conjugation (c) transduction (d) translation

(b) bacterial conjugation

Which of the following antimicrobial drugs would likely be useful to treat a staphylococcal infection? (a) praziquantel (b) erythromycin (c) streptomycin (d) isoniazid

(b) erythromycin

The ____________ is a defining characteristic of bacteria which is not found in eukaryotes and is therefore a good choice for chemotherapeutic agents. (a) phospholipid cytoplasmic membrane (b) peptidoglycan cell wall (c) carbohydrate cell wall (d) carbohydrate glycocalyx (e) protein cell wall (f) steroid lipid cytoplasmic membrane

(b) peptidoglycan cell wall

Antimicrobial drugs are selectively toxic. This means _______________. (a) the drugs are reactive within a specific part of the patient's anatomy (for example, the inner ear) (b) the drugs are more toxic to the pathogens than to the patient (c) the drugs will affect only a particular type of pathogen (d) the drugs will not have toxic effects on a patient

(b) the drugs are more toxic to the pathogens than to the patient

The cytosol of bacteria contain ____________ which has/have components different from those of the functionally equivalent structure of eukaryotes. (a) a nucleus (b) a nucleoid (c) 70S ribosomes (d) a cytoskeleton (e) 80S ribosomes

Disruption of the normal microbiota can result in infections caused by which of the following microbes? (a) Clostridium difficile (b) both Mycobacterium and Clostridium difficile (c) Candida albicans, Mycobacterium, and Clostridium difficile (d) Mycobacterium (e) Candida albicans

Membrane transport proteins are required for which mode(s) of antibiotic resistance? (a) beta-lactamases (b) modification of a porins (c) Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins. (d) modification of a metabolic enzyme (e) efflux pumps

Why do antimicrobial agents active against mycobacteria have to be administered for months or years rather than the typical 10-30 days prescribed to treat other infections? (a) They are too toxic to be used on a more rapid administration schedule. (b) Mycobacteria do not have cell walls. (c) Mycobacteria reproduce very slowly. (d) The only available agents are relatively ineffective drugs.

Which antibiotic is overcome by beta-lactamases? (a) Tetracycline (b) Sulfonamide (c) Penicillin (d) Tetracycline, Penicillin, and Sulfonamide are all affected by beta-lactamase.

What is meant when a bacterium is said to become "resistant" to an antibiotic? (a) The antibiotic kills or inhibits the bacterium. (b) The antibiotic is metabolized by the bacterium, providing more energy for growth of the cell. (c) The bacterium is neither killed nor inhibited by the antibiotic. (d) The antibiotic mutates in a way that benefits the bacterium.

Which of the following is NOT a direct mode of action of antimicrobial drugs? (a) inhibition of nucleic acid synthesis (b) inhibition of cell wall synthesis (c) inhibition of flagella formation (d) inhibition of protein synthesis

Which of the following is NOT a target of drugs that inhibit protein synthesis? (a) the shape of the 30S ribosomal subunit (b) the enzymatic site of the 50S ribosomal subunit (c) interference with alanine-alanine bridges (d) movement of the ribosome from one codon to the next (e) the tRNA docking site

Which category of antimicrobial drug essentially acts to stall a ribosome as it reads mRNA? (a) antisense nucleic acids (b) chloramphenicol (c) macrolides (d) tetracyclines

(c) macrolides Macrolides block the movement of a ribosome along mRNA, so the E site is never emptied and polypeptide formation is stopped.

Which of the following point mutations is most likely to alter a protein product without destroying its function? (a) frameshift (b) silent (c) missense (d) nonsense

Which of the following is NOT a possible side effect of antimicrobial therapy? (a) allergies (b) disruption of normal microbiota (c) resistance (d) toxicity

Which of the following mutations would not result in antibiotic resistance? (a) missense mutation (b) nonsense mutation (c) silent mutation (d) frameshift insertion (e) frameshift deletion

When a patient is treated with antibiotics, __________. (a) mutations occur in all of the bacterial cells (b) sensitive bacterial cells multiply uncontrollably (c) the drug will kill or inhibit the growth of all of the sensitive bacterial cells (d) the drug will kill or inhibit the growth of all of the resistant bacterial cells (e) mutations will occur in the sensitive bacterial cells, but not in the resistant bacterial cells

Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug? (a) The efflux pumps would not stop penicillin from blocking metabolic pathways. (b) There are fewer efflux pumps on the cell membrane. (c) The cell membrane is the target of penicillin. (d) Penicillin disrupts the cell wall, which is located outside of the cell membrane.

(d) Penicillin disrupts the cell wall, which is located outside of the cell membrane.

If a particular bacterial species is resistant to beta-lactam antibiotics, which of the following might you expect to find inside the bacterial cells? (a) porins (b) ergosterol (c) resistance pumps (d) R plasmids

(d) R plasmids

Which of the following will most likely contribute to the spread of a genetic mutation among bacterial species? (a) transduction (b) transposition (c) vertical transmission (d) transformation (e) sexual reproduction

(d) transformation

How might efflux pumps increase antibiotic resistance in bacteria? (a) Resistant bacteria may have a greater number of efflux pumps on their cell surfaces. (b) Some bacteria can decrease the specificity of their efflux pumps, increasing the number of different antibiotics the pumps can eliminate. (c) Some bacteria can change the chemical structure of the antibiotic. (d) Efflux pumps can never be modified to increase antibiotic resistance. (e) Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.

(e) Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.

Which of the following antibiotics disrupts cytoplasmic membrane function in fungi? (a) penicillin (b) streptomycin (c) tetracycline (d) erythromycin (e) amphotericin B

(e) amphotericin B

Granulocytes appear to be filled with granules, and end in ______

-phils

The following molecules are involved in the biosynthetic pathway that leads to the formation of DNA and RNA; what is their correct sequence in this pathway? a. PABA b. tetrahydrofolic acid c. purine and pyrimidine nucleotides d. dihydrofolic acid 1. a, d, b, c 2. a, b, c, d 3. a, c, d, b 4. a, b, d, c

Leukocytes (WBC) and Blood Plasma are part of which line of defense?

2nd

Put the following routes of administration in order, from the route that results in the highest concentration of drug in the bloodstream to the route that results in the lowest concentration: a. topical b. intravenous c. oral d. intramuscular 1. d, b, a, c 2. a, c, d, b 3. b, d, c, a 4. b, c, d, a

In one study, __% of nurses gloves get contaminated with MRSA

The cytosol of bacteria contain ____________ which has/have components different from those of the functionally equivalent structure of eukaryotes.

70s Ribosomes

If the MBC for a particular drug is 16 μg/ml, which of the following serial dilutions of the drug is likely to be the MIC?

8 μg/ml

Amoxicillin is very effective for treating infections with Gram-positive bacteria but rarely causes side effects in humans. This is an example of A) selective toxicity. B) narrow spectrum of action. C) a broad-spectrum antimicrobial. D) antibiotic resistance. E) altruism.

An antimicrobial that inhibits bacterial cell wall synthesis will result in which of the following? A) Bacterial cells become more susceptible to osmotic pressure. B) Bacteria cannot attach to their hosts. C) Cytoplasmic membrane proteins lose their function. D) The sterols in the bacterial cell wall become nonfunctional. E) No change in bacterial cell activity.

Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what? A. PABA B. Sulfonamide C. Tetrahyrdrofolic acid D. Tetracycline

Drug-resistant populations of microbes arise when A) exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells. B) exposure to drugs causes mutations that produce resistance. C) resistant cells become numerous in a population due to their greater vigor. D) the patient becomes immune to the drug. E) synergy between medications occurs.

If a particular bacterial species is resistant to beta-lactam antibiotics, which of the following might you expect to find inside the bacterial cells? A. R plasmids B. porins C. ergosterol D. resistance pumps

In a Kirby-Bauer susceptibility test, the presence of a zone of inhibition around disks containing antimicrobial agents indicates_________. A. that the microbe does not grow in the presence of the agents B. that the microbe grows well in the presence of the agents C. the smallest amount of the agent that will inhibit the growth of the microbe D. the minimum amount of an agent that kills the microbe in question

Membrane transport proteins are required for which mode(s) of antibiotic resistance? A. Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins. B. Modification of a metabolic enzyme C. Efflux pumps D. Modification of a porins E. Beta-lactamases

Most drugs that inhibit the synthesis of the cell wall act by A) preventing the cross-linkage of NAM subunits. B) blocking the secretion of cell wall molecules from the cytoplasm. C) preventing the formation of alanine-alanine bridges. D) disrupting the formation of the mycolic acid layer of the cell wall. E) preventing the formation of β-lactamases

Prokaryotes contain _____ ribosomes. A. 70S B. 80S C. 30S D. 50S

Put the following routes of administration in order, from the route that results in the highest concentration of drug in the bloodstream to the route that results in the lowest concentration: a. topical b. intravenous c. oral d. intramuscular A. b, d, c, a B. d, b, a, c C. a, c, d, b D. b, c, d, a

Some bacteria are resistant to erythromycin as a result of mutation of their ribosomal RNA. What type of resistance does this represent? A) alteration of the target of the drug B) inactivation of the drug C) change in the permeability of the drug D) overproduction of an enzyme in a key metabolic pathway E) removal of the drug via a pump

The first antimicrobial widely available for treatment of bacterial infections was a synthetic compound which A) was an antimetabolic analog. B) was a nucleotide analog. C) was an attachment antagonist. D) disrupted cytoplasmic membranes. E) interfered with bacterial cell wall synthesis.

The key to successful chemotherapy is ______. A. selective toxicity B. a diffusion test C. the minimum inhibitory concentration test D. the spectrum of action

The process of acquiring antibiotic resistance by means of bacteriophage activity is called A. transduction. B. R-plasmid acquisition. C. point mutation. D. transformation.

The tetracyclines interfere with A) protein synthesis. B) cell wall synthesis. C) cell membrane component synthesis. D) nucleic acid synthesis. E) folic acid synthesis.

Which of the following drugs inhibits nucleic acid synthesis specifically in most bacteria? A) fluoroquinolones B) actinomycin C) rifampin D) tetracycline E) 5-fluorocytosine

Which of the following is NOT a beta-lactam antibiotic? A. vancomycin B. cephalothin C. penicillin G D. methicillin

Which of the following is NOT a type of side effect exhibited by antimicrobial drugs? A. inhibition of host cellular enzymes B. disruption of normal microbiota C. damage to liver or kidney tissue D. allergic reactions

Which of the following is NOT associated with microbial mechanisms of resistance? A. denaturation of proteins B. beta-lactamases C. MfpA protein D. porins

Which of the following is most closely associated with a beta-lactam ring? A. penicillin B. vancomycin C. bacitracin D. isoniazid

Which of the following statements is false concerning antiviral drugs? A. Macrolide drugs block attachment sites on the host cell wall and prevent viruses from entering. B. Drugs that neutralize the acidity of phagolysosomes prevent viral uncoating. C. Nucleotide analogs can be used to stop microbial replication. D. Drugs containing protease inhibitors retard viral growth by blocking the production of essential viral proteins.

Who discovered the first antimicrobial widely available to the general public? A) Domagk B) Ehrlich C) Fleming D) Waksman E) Ehrlich and Waksman

Why are sulfonamides selectively toxic? A. Humans do not need to synthesize folic acid C. Sulfonamides are inactive in human cells D. Humans use different enzymes to synthesize folic acid E. At low concentration, bacterial enzymes are inhibited, but not human enzymes

Why is polymyxin only used on the skin? A. It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead. B. It can disrupt the metabolic pathways found in humans. C. It has no effect on bacteria that live in the GI tract. D. It is sensitive to degradation by acid, making oral delivery unsuitable.

What major cellular feature that might be targeted by antimicrobial drugs is found in both bacteria and fungi but not in human cells?

A cell wall

What major cellular feature that might be targeted by antimicrobial drugs is found in both bacteria and fungi.... but NOT in human cells?

A cell wall

Which of the following is an example of sanitization? -Heat is used to kill potential pathogens in apple juice. -A public toilet is treated with disinfectants. -An autoclave is used to prepare nutrient agar. -A nurse prepares an injection site with an alcohol swab. -A surgeon washes her hands before surgery.

A public toilet is treated with disinfectants

A reservoir is

A source of microbial contamination

One approach that is becoming more common in drug D&D is to search for antimicrobial-producing organisms in relatively pristine environments. A pristine environment is one that has been relatively unperturbed by humans and/or domestic animals. Your D&D team is searching for novel antimicrobials produced by bacteria in a remote area of a temperate rainforest in the Pacific Northwest. Which of the following terms would accurately describe your drug? A. antibiotic B. semisynthetic C. natural D. synthetic E. chemotherapeutic agent

A, C, E

Which of the following are NOT beta-lactam antibiotics? A. vancomycin B. ampicillan C. cephalosporins D. carbapenems E. streptomycin

A,E

Suppose you do this test on a hypothetical Staph species with the antibiotics penicillin and tetracycline. You record zone diameters of 20mm for the tetracycline disc and 25mm for the penicillin disc. Which antibiotic would be most effective against this organism? What does this tell you about comparing zone diameter to each other and the importance of the interpretive chart?

According to the chart, a zone of 25mm for Staph around a penicillin disk indicates resistance to the antibiotic. A 20mm zone around a tetracycline disk for same species indicates susceptibility. Therefore, even though the zone is smaller, tetracycline would be the more effective antibiotic against this organism.

Antibiotic used in cancer treatment, often used to disrupt DNA replication

Actinomycin

A Gram-positive bacterial strain is simultaneously treated with two different antimicrobials: Drug A, which targets a protein involved in cell wall synthesis, and Drug B, which targets ribosomes involved in translation. The bacteria continue to grow during the course of treatment, indicating resistance to both antimicrobials. What are all the possible resistance mechanisms this bacterial strain could have?

All of them

Based on the data shown, what are the possible resistance mechanisms of this patient's resistant strain of K. pneumoniae?

All of them

A particular drug works by interfering with cellular metabolism in Gram-negative bacteria. How might these bacteria become resistant in a way that Gram-positive bacteria never could?

Alter porin proteins in the cell's outer membrane

Zoonoses would be found in what type of reservoir?

Animal Reservoir

Natural antimicrobial agents produced by microorganisms.

Antibiotics

Antimicrobial X targets a specific protein in the cytoplasm of the bacterial cell, causing the bacteria to stop growing, but does not kill them. A few bacteria start to grow in the presence of antibiotic X. Analysis of the bacteria that can now grow shows that they have changed the shape of the target for antimicrobial X. What conclusion can be made?

Antimicrobial X is less effective against the new shape of its target

Virulence factor that prevent lysosomes from fusing with phagocytotic vesicles allowing pathogen survival Example: M protein produced by Streptococcus

Antiphagocytic Chemicals

When a nurse rubs your skin with rubbing alcohol prior to administering an injection, what process(es) is he carrying out? Select all that apply.

Antisepsis and degerming

What type of antimicrobial agent has the narrowest spectrum of action?

Antivirals

One aspect that must be evaluated during the development phase is the interaction of your drug with the host (i.e., what effect will the drug have on human cells?). There are several important factors to consider in this interaction, including the selective toxicity of your potential drug. Which of the following statements most accurately describes the principle of selective toxicity? A. Selective toxicity refers to the fact that antimicrobial agents target a particular microbial structure, molecule, or pathway to exert their effect. B. Selective toxicity refers to the ability of an antimicrobial to kill microbes with minimal damage to the host. C. Selective toxicity refers to the fact that the toxic effect of an antimicrobial varies depending upon the environmental conditions under which it is administered. D. Selective toxicity describes the fact that antimicrobials are more effective against certain microbes compared to others.

The antifungals known as polyenes interact with ________, a lipid unique to fungus membranes. A) cholesterol B) ergosterol C) mycolic acid D) phospholipid E) glycolic acid

The drug metronidazole is effective on both bacteria and some protozoa. It can therefore be described as a ________ drug. A) narrow spectrum B) broad spectrum C) full spectrum D) general spectrum E) specific spectrum

The mechanism of action of the antibiotic vancomycin is A) inhibition of protein synthesis. B) inhibition of cell wall synthesis. C) inhibition of nucleic acid synthesis. D) inhibition of a metabolic pathway. E) disruption of cytoplasmic membranes.

Understanding how resistance emerges is an essential part of this process. Which of the following statements is NOT true regarding the evolution of antibiotic resistance in bacteria? A. Due to natural genetic variation within populations, resistant bacteria will be present--even in the absence of antibiotic. B. The exposure of bacteria to an antibiotic causes the bacteria to produce resistance genes. C. Resistance can emerge due to mutations in chromosomal genes. D. Bacteria can acquire plasmids conferring resistance through horizontal gene transfer.

What is meant by selective toxicity? A. Chemotherapeutic agents should work on certain types of pathogens. B. Chemotherapeutic agents should act against the pathogen and not the host. C. Chemotherapeutic agents should work on many different targets on a pathogen. D. Chemotherapeutic agents should have only one mode of action.

Which antimicrobial drugs affect the structure of the ribosome itself? A. macrolides and antisense nucleic acids B. aminoglycosides, antisense nucleic acids, and oxazolidinones C. aminoglycosides, chloramphenicol, and lincosamides D. tetracyclines and oxazolidinones

Which category of antimicrobial drug essentially acts to stall a ribosome as it reads mRNA? A. antisense nucleic acids B. macrolides C. tetracyclines D. chloramphenicol

Which category of drug is complementary to mRNA of the pathogen? A. tetracyclines B. antisense nucleic acids C. oxazolidinones D. macrolides

Which of the following activities can be shown to increase resistance among microbial populations? A. taking a combination of antimicrobial drugs B. taking antibacterial drugs for viral infections C. taking an antimicrobial drug for the entire prescribed time D. developing second- and third-generation versions of antimicrobial drugs

Which of the following is NOT a target of drugs that inhibit protein synthesis? A) the shape of the 30S ribosomal subunit B) interference with alanine-alanine bridges C) the enzymatic site of the 50S ribosomal subunit D) movement of the ribosome from one codon to the next E) the tRNA docking site

Which of the following steps in the folic acid synthesis pathway is specifically inhibited by sulfonamides? A) the conversion of tetrahydrofolic acid to PABA B) the conversion of PABA to dihydrofolic acid C) the conversion of dihydrofolic acid to tetrahydrofolic acid D) the conversion of PABA to tetrahydrofolic acid E) the conversion of dihydrofolic acid to PABA

Which of the following tests does NOT provide information on the lowest concentration of drug effective on a pathogen? A) Etest B) diffusion susceptibility test C) broth dilution test D) both the Etest and diffusion susceptibility test E) MBC test

Why is it difficult to find good chemotherapeutic agents against viruses? A. Viruses infect both bacteria and human cells. B. Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected. C. There is no effective way to deliver the drug to the virus. D. Viruses are not cells, and therefore not sensitive to such compounds.

Why is penicillin regarded as the first true antibiotic? A. The sulfonamides were not effective in treating any bacterial infections. B. It is produced naturally by the fungus Penicillium. C. It is effective against a wide variety of bacteria. D. Ehrlich's arsenic-based compounds were produced after the discovery and mass production of penicillin.

Some antibiotics come from bacteria of the genus ____ and others from molds, mostly from the genera _____ and _____.

Bacillus, Penicillium, Cephalosporium

Drug that blocks transport of NAG and NAM from cytoplasm

Bacitracin

Beta-lactam antibiotics have an effect on what type of cells?

Bacterial cells

In what way are semisynthetic penicillins and natural penicillins alike? Both are based on β-lactam. Both are bactericidal. Both are resistant to stomach acids. Both are resistant to penicillinase. Both are broad spectrum.

Both are based on β-lactam.

What interferes with cell wall synthesis by blocking alanine bridge formation?

Both cycloserine and vancomycin

What antifungal works by inhibiting ergosterol synthesis?

Both fluconazole and tubinafine

How does resistance to drugs spread in bacterial populations?

Both horizontal gene transfer and the growth of biofilms spread drug resistance

What can result when antibiotic therapy disrupts the normal microbiota?

Both pseudomembranous colitis and thrus

The E-test determines what?

Both susceptibility and MIC (minimum inhibitory concentration)

Lysosomes

Break down cell wall/ peptidoglycan layers

What does lysosome do to a bacterial cell?

Breaks down polysaccharide chains in peptidoglycan layer

A compound is extracted from a microbial culture and is modified in the laboratory for use as an oral medication. This product would be a(n) A) antibiotic. B) analog. C) semisynthetic antimicrobial. D) synthetic antimicrobial. E) probiotic.

___ are becoming a serious problem. Gram neg rods resistant to carbapenem antibiotics, which have been used as drugs of last resort. Have a very high mortality rate.

CRE

A drug with a low therapeutic index... A. is associated with a high incidence of allergies B. is generally considered safe C. must be carefully dosed so as not to exceed toxic concentrations D. can cause organisms to quickly develop resistance E. is cheaper to prodcue than a drug with a high therapeutic index

Antimicrobials known as "attachment antagonists" are particularly useful for preventing A) bacterial protein synthesis. B) cell membrane synthesis. C) virus infection. D) nucleic acid synthesis. E) biofilm formation.

Clavulanic acid could be used to protect which of the following antibiotics in a drug formulation? A. erythromycin B. sulfanilamide C. penicillin D. bacitracin

Multiple-drug-resistant microbes _________. A. are resistant to all antimicrobial agents B. respond to new antimicrobials by developing resistance C. frequently develop in hospitals D. all of the above

R-plasmids are most likely acquired via A. transformation. B. transduction. C. bacterial conjugation. D. translation.

Some bacteria are resistant to antimicrobials due to the activity of ________, which removes many of them. A) plasmids B) porins C) efflux pumps D) lipopolysaccharides E) ribosomes

The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, a β-lactamase inhibitor, is known as A) cross resistance. B) antimetabolism. C) synergism. D) selective toxicity. E) chemotherapy.

The mechanism of action of ciprofloxacin is A) inhibition of protein synthesis. B) inhibition of cell wall synthesis. C) inhibition of nucleic acid synthesis. D) inhibition of a metabolic pathway. E) disruption of cytoplasmic membranes.

The tRNA molecule holding a growing polypeptide chain is at the _____. A. A site B. 50S site C. P site D. E site

The therapeutic range of an antimicrobial is the A) ratio of the dose a patient can tolerate to the effective dose. B) range of microorganisms the antimicrobial effects. C) range of concentrations at which the antimicrobial is both effective and non-toxic. D) ratio of the concentration of antimicrobial in the blood to the oral dose. E) length of time the medication persists in the body after a single dose.

Under which of the following conditions will penicillin be ineffective? A. At decreased body temperature B. At elevated body temperatures C. When bacteria are not actively growing D. If penicillin is administered intravenously E. If the concentration in tissues is too high

What is meant when a bacterium is said to become "resistant" to an antibiotic? A. The antibiotic kills or inhibits the bacterium. B. The antibiotic is metabolized by the bacterium, providing more energy for growth of the cell. C. The bacterium is neither killed nor inhibited by the antibiotic. D. The antibiotic mutates in a way that benefits the bacterium.

When a patient is treated with antibiotics, __________. A. mutations occur in all of the bacterial cells B. sensitive bacterial cells multiply uncontrollably C. the drug will kill or inhibit the growth of all of the sensitive bacterial cells D. the drug will kill or inhibit the growth of all of the resistant bacterial cells E. mutations will occur in the sensitive bacterial cells, but not in the resistant bacterial cells

Which antibiotic is overcome by beta-lactamases? A. Tetracycline B. Sulfonamide C. Penicillin D. Tetracycline, Penicillin, and Sulfonamide are all affected by beta-lactamase.

Which category of antimicrobial drug works by changing the shape of a ribosome? A. chloramphenicol B. tetracyclines C. aminoglycosides D. oxazolidinones

Which of the following antimicrobial drugs would likely be useful to treat a staphylococcal infection? A. isoniazid B. praziquantel C. erythromycin D. streptomycin

What causes thrush?

Candida albicans

What causes thrush? methicillin-resistant Staphylococcus aureus Penicillium notatum Streptococcus mutans Candida albicans

Candida albicans

Disruption of the normal microbiota can result in infections caused by what microbe(s)?

Candida albicans, mycobacterium, and clostridium difficile

Without ergosterol, a fungal cell's cytoplasms membrane does not remain intact. So what happens to the cell?

Cell death

Which among the following cell features of bacteria are potential targets for Dr. Ehrlich's "magic bullets" due to significant difference or absence from humans? Choose all that apply.

Cell wall, Ribosome

An antimicrobial that inhibits cell wall synthesis will result in what?

Cells will become more susceptible to osmotic pressure

Symptoms are

Characteristics of a disease only the person feels (Nausea, headache, fatigue, sore throat, etc)

Virulence Factor that causes blood to clot

Coagulase

Fibers in the Dermis tissue of the skin, that makes it both physically strong and flexibly

Collagen Fibers

Sulfonamide drugs inhibit microbial growth by disrupting metabolic pathways. What general mechanism do these drugs use?

Competitive inhibition

The following molecules are involved in the biosynthetic pathway that leads to the formation of DNA and RNA; what is their correct sequence in this pathway? a. PABA b. tetrahydrofolic acid c. purine and pyrimidine nucleotides d. dihydrofolic acid A. a, c, d, b B. a, b, d, c C. a, b, c, d D. a, d, b, c

The topical drug ________ inhibits protein synthesis in Gram positive bacteria by preventing loading of isoleucine onto tRNA. A) Amphotericin B B) Bacitracin C) Ciprofloxacin D) Mupirocin E) Tetracycline

What is one disadvantage associated with the use of broad-spectrum antibiotics? A. They kill pathogens too quickly. B. They cause toxicity for the host. C. They cannot be used orally. D. They kill normal microbiota.

Which of the following drugs specifically targets cell walls that contain mycolic acid? A) vancomycin B) penicillin C) methicillin D) isoniazid E) bacitracin

Which of the following groups of drugs can become incorporated into the bones and teeth of a fetus? A) beta-lactams B) aminoglycosides C) quinolones D) tetracyclines E) sulfonamides

Which of the following is NOT associated with the work of Paul Ehrlich? A. arsenic compounds B. the concept of the "magic bullet" C. the concept of chemotherapy D. sulfanilamide

Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug? A. The efflux pumps would not stop penicillin from blocking metabolic pathways. B. There are fewer efflux pumps on the cell membrane. C. The cell membrane is the target of penicillin. D. Penicillin disrupts the cell wall, which is located outside of the cell membrane.

Layer in Mucous Membranes that is responsible for producing antimicrobial chemicals such as lysozyme and provides nutritional support

Deep Connective Tissue Layer

How does antibiotic resistance develop?

Destruction or inactivation of the drug; prevention of penetration; drug site is altered; rapid ejection;

cross resistance

Development of resistance to one drug in a particular class that results in resistance to the other drugs in that class

Both Eosinophils and Neutrophils are capable of ____________, or moving through blood vessels to infected tissue

Diapedsis

In order to determine which antibiotic might treat an infection most effectively, a plate is inoculated with a pathogen. A variety of paper disks, each containing a known amount of antibiotic, are placed on the surface of the plate. After incubation, the plates are examined for zones of inhibition. Which type of test is this?

Diffusion susceptibility test

What is DOT?

Directly Observed Therapy

What is DOT? Died of the Treatment Directly Observed Therapy Department of Transportation Done on Tuesday

Directly Observed Therapy

Many MRSA strains are sensitive to other antibiotics. Which of the following methods would be the best way to evaluate sensitivity to other antibiotics?

Disk Diffusion

Many antimicrobials have side effects. Which side effect can be circumvented, at least in part, by the use of probiotics?

Disruption of normal microbiota

Who discovered the first antibiotic widely available to the general public?

Dogmagk

Each phrase below is applicable to a particular mechanism of antimicrobial resistance. Match each phrase to its respective mechanism.

Drug Inactivation-Bacterial B, antimicrobial altered Efflux pumps- active transport, antimicrobial moved from inside to outside of cell turning on transport mechanisms Decreased permeability- bacterial porins, turning off transport Altered binding site- structural changes of drug target, mutation of drug target

Penicillin's target is transpeptidase, a protein involved in cell wall synthesis. For a Gram-positive bacterium, which of the following mechanisms would be most effective in resisting penicillin's effects?

Drug inactivation via β-lactamases and altered target binding site

Human normal microbiota begin to develop __________

During birth

A drug is structurally similar to PABA and inhibits folic acid synthesis. It is most likely a(n) A) nucleic acid analog. B) penicillin. C) tetracycline. D) azole. E) sulfonamide.

Disruption of the normal microbiota can result in infections caused by which of the following microbes? A) Mycobacterium B) Candida albicans C) Clostridium difficile D) Streptococcus E) both Candida albicans and Clostridium difficile

How might efflux pumps increase antibiotic resistance in bacteria? A. Resistant bacteria may have a greater number of efflux pumps on their cell surfaces. B. Some bacteria can decrease the specificity of their efflux pumps, increasing the number of different antibiotics the pumps can eliminate. C. Some bacteria can change the chemical structure of the antibiotic. D. Efflux pumps can never be modified to increase antibiotic resistance. E. Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.

The broth dilution test can provide information for determining A) the molecular target of an antibiotic. B) the MIC (minimum inhibitor concentration). C) the rate of diffusion of an antibiotic. D) the MBC (minimum bactericidal concentration), with an additional step. E) both the MIC and the MBC (with an additional step).

Which of the following antifungals works by binding to ergosterol in membranes? A) fluconazole B) turbinafine C) amphotericin B D) nystatin E) both amphotericin B and nystatin

Which of the following can result when antibiotic therapy disrupts the normal microbiota? A) anaphylactic shock B) black hairy tongue C) pseudomembranous colitis D) thrush E) both pseudomembranous colitis and thrush

Which of the following interferes with cell wall synthesis by blocking alanine bridge formation? A) beta-lactams B) cycloserine C) bacitracin D) vancomycin E) both cycloserine and vancomycin

Which of the following is a semi-synthetic drug that blocks the action of RNA polymerase and is often used to treat tuberculosis? A. Doxycycline B. any Fluoroquinolone C. Streptomycin D. Isoniazid E. Rifampin

Which of the following is an example of a modification of the target of an antibiotic which leads to bacterial resistance? A. Microbes switching to a dormant state B. Modification of an amino group of gentamicin C. Increased expression of efflux pumps D. Production of beta lactamase E. A point mutation in DNA gyrase

Which of the following statements is true of selective toxicity? A) Selective toxicity takes advantage of structural similarities between host and pathogen. B) To be effective, an antimicrobial agent must be more toxic to the patient than the pathogen. C) Selective toxicity takes advantage of differences in metabolic rates of the host and pathogen. D) Selective toxicity damages only pathogenic bacteria and not beneficial bacteria. E) Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen.

____-producing bacteria are gram neg rods resistant to all penicillins, cephalosporins and monobactams.

ESBL

Membrane transport proteins are required for which mode(s) of antibiotic resistance?

Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.

membrane transport proteins are required for which mode(s) of antibiotic resistance? Modification of a metabolic enzyme Beta-lactamases Modification of a porins Efflux pumps Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.

Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.

Toxins that affect the lining of the digestive tract are....

Enterotoxins

Which leukocyte would increase in a parasitic infection?

Eosinophil increase

Granulocyte that specifically phagocytize parasites

Eosinophils

Which of the following will most likely contribute to the spread of a genetic mutation among bacterial species?

Exposure to antibiotics selects for the members of a bacterial population which already have a resistant phenotype

A side effect known as "black hairy tongue" may result from antifungal therapy

If a subculture of an MIC test grows in an MBC test, the concentration of the drug was bactericidal.

Nucleic acid analog drugs act by inhibiting ribosome function.

Paul Ehrlich coined the term antibiotics for the "magic bullet" antimicrobials he pursued.

The outer membrane of Gram-negative bacteria enables many antimicrobial drugs to enter the cell more easily.

(T/F) Dendritic cells are only found in the epidermis and can both phagocytize pathogens and active adaptive immunity

False

(T/F) In commensalism, one member of the relationship harms the other

False

(T/F) Lipid A is an example of a exotoxin

False

T/F Paul Ehrlich coined the term antibiotics for the "magic bullet" antimicrobials he pursued

False

T/F because all cells engage in protein synthesis, there are a few antimicrobial drugs that selectively inhibit this process

False

T/F if a subculture of an MIC test grows in an MBC test, the concentration of the drug was bactericidal

False

T/F nucleic acid analog drugs act by inhibiting ribosome function

False

T/F the outer membrane of gram-negative bacteria enables many antimicrobial drugs to enter the cell more easily

False

T/F: The oral route of drug administration is best because it is the simplest route. Why?

False While the oral route of administration is undoubtedly the simplest route, it can also be the most problematic because of the lower concentrations of the drug achievable in the body. There may also be problems if patients do not take the drug as prescribed.

(T/F) Dendritic cells are only found in the epidermis and can both phagocytize pathogens and active adaptive immunity

False, also in mucous membrane...not only epidermis!

(T/F) Persister cells grow very quickly

False. Persister cells grow slowly and are metabolically inactive

(T/F) Chemokines stimulate the hypothalamus to increase body temperature

False. Pyrogens trigger hypothalamus increase the body's core temperature

(T/F) There are no positive effects from a fever

False. There are positive effects of a fever: inhibits growth of pathogens, enhances activities of phagocytes, tissue repair

T/F :Broad-spectrum antimicrobial drugs are more desirable than narrow-spectrum drugs. Why?

False: Overuse of broad-spectrum drugs can kill the normal microbiota or contribute to antibiotic resistance.

Body temperature over 37 degrees Celcius

Fever

Rank the following events in order from GREATEST to LEAST contribution to the spread of antibiotic resistance in bacterial populations.

Horizontal, Vertical, New Mutations

Turbitity is

How cloudy or murky water is

Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?

Humans and other animal hosts lack peptidoglycan cell walls.

Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug? They are less expensive that other chemotherapeutic agents. Bacteria are especially sensitive to these compounds. Humans and other animal hosts lack peptidoglycan cell walls. The drugs also work against DNA gyrase.

Humans and other animal hosts lack peptidoglycan cell walls.

Why is a pure culture used?

If have a mixed culture, the results may be confusing and the test results will not be valid.

Stage of infectious disease with most severe signs and symptoms

Illness

Beta-lactamase production is an example of what type of resistance?

Inactivation of the drug

The mechanism of action of the antibiotic Vancomycin is....

Inhibition of cell wall synthesis.

What does Penicillin (a beta-lactam) do?

Inhibits & disrupts cell wall synthesis

The first and second lines of defense against microbial invasion are part of...

Innate Immunity

What is NOT a target of drugs that inhibit protein synthesis?

Interference with alanine-alanine bridges

Which way of administering antimicrobial agents is the best?

Intravenous

Why is polymyxin only used on the skin? It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead. It is sensitive to degradation by acid, making oral delivery unsuitable. It can disrupt the metabolic pathways found in humans. It has no effect on bacteria that live in the GI tract.

It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead.

Salt is a property of sweat that makes it lethal too pathogens. Why?

It dries out bacteria, causes bacteria to lose water

Which of the following statements about drug resistance is FALSE? It may be due to increased uptake of a drug. It is found only in gram-negative bacteria. It may be due to enzymes that degrade some antibiotics. It may be transferred from one bacterium to another during conjugation. It may be carried on a plasmid.

It is found only in gram-negative bacteria.

Why is penicillin regarded as the first true antibiotic?

It is produced naturally by the fungus Penicillium.

Why is methicillin-resistant Staphylococcus aureus (MRSA) methicillin resistant? It has an enzyme that destroys methicillin. It actively pumps the antibiotic out of the cell. It produces a modified version of the molecule that is targeted by the drug. The bacteria are able to prevent entry of the drug into the cell.

It produces a modified version of the molecule that is targeted by the drug.

What is a measurement associated with the broth diluting test?

Lack of tubidity

Virulence factors directly contributes to severe inflammation

Lipid A

Chronic Inflammation is...

Long lived, causes damage

Which leukocyte would increase in a viral infection?

Lymphocyte increase

Agrranulocyte, mostly involved in adaptive immunity

Lymphocytes

The abbreviation (MIC/MID/MBC) stands for the smallest amount of a drug that will inhibit the growth and reproduction of a pathogen.

MIC

The abbreviation _______ stands for the smallest amount of a drug that will inhibit the growth and reproduction of a pathogen

MIC

___ is the most common superbug worldwide

MRSA

____ is commonly a cause of surgical wound infections, urinary tract infections, blood stream infections and pneumonia.

MRSA

Mycoplasmas are bacteria that do not contain cell walls. These bacteria are naturally resistant to which of the following?

Methicillin

Mycoplasmas are bacteria that do not contain cell walls. These bacteria are naturally resistant to which of the following?

Methicillin Methicillin is a beta-lactam and targets growing peptidoglycan layers in the cell wall. Since mycoplasmas do not have a cell wall, they are naturally resistant to beta-lactams.

Staph aureus strains, especially those resistant to the drug _____, referred to as MRSA. Another even more dangerous resistance is coming: VRSA. ______ is the drug of last resort.

Methicillin; Vancomycin

Test that reveals the smallest amount of a drug that will inhibit growth and reproduction of the pathogen

Minimun Inhibitory Concentration Test ((MIC)

Which of the following point mutations is most likely to alter a protein product without destroying its function?

Missense

Why are some drugs that inhibit protein synthesis in bacteria also harmful to humans?

Mitochondria found in eukaryotic have 70S ribosomes.

Semisynthetic derivatives of beta-lactams

More stable in acidic environments More readily absorbed Less susceptible to deactivation More broad spectrum

Clostridium difficile is a common healthcare associated infection. It is a Gram-positive spore-forming anaerobe that is associated with antibiotic therapy. It is most commonly transferred between patients on the hands of health care workers. Based on this information, rank the following prevention and control strategies from most beneficial (1) to least beneficial (4).

Most likely- soap and water Use of Gloves Use of approved chemicals Least- hand hygiene with gels

What term best describes an organism that is resistant to three or more different antimicrobial agents?

Multi-Resistant Drug

What term best describes an organism that is resistant to three or more different antimicrobial agents?

Multiple-drug-resistant

How does mupirocin interfere with protein synthesis in Gram-positive bacteria such as Staphylococcus and Streptococcus?

Mupirocin prevents the amino acid isoleucine from being added to growing peptide chains by blocking its binding to tRNA

How does mupirocin interfere with protein synthesis in Gram-positive bacteria such as Staphylococcus and Streptococcus?

Mupirocin prevents the amino acid isoleucine from being added to growing peptide chains by blocking its binding to tRNA.

Why do antimicrobial agents active against mycobacteria have to be administered for months or years rather than the typical 10-30 days prescribed to treat other infections?

Mycobacteria reproduce very slowly.

Why do antimicrobial agents active against mycobacteria have to be administered for months or years rather than the typical 10-30 days prescribed to treat other infections?

Mycobacteria reproduce very slowly. Mycobacteria take 12-24 hours to reproduce, in part due to their complex cell walls. Therefore, drugs against these bacteria must be administered over long periods of time.

To enlarge or divide, bacteria must synthesize more peptidoglycan by adding more ____ & _____ molecules to existing polysaccharide chain

NAM & NAG

VRE is ___ usually spread by casual contact such as hugging or touching or through the air.

NOT

Do Humans in womb have microbiota?

No, uterus and amniotic sac act as a barrier

Normal microbiota that do not normally cause disease, that may become harmful if the opportunity arises

Opportunistic Pathogens

Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what?

PABA

Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what? PABA Sulfonamide Tetrahyrdrofolic acid Tetracycline

PABA

Which symbiotic relationship would be used to describe a tapeworm living in the intestines of a human host?

Parasitism

Which scientist proposed the idea of "chemotherapy", using chemical that would selectively kill pathogens with little/no harm to the patient

Paul Ehrlich

Who proposed the concept of chemotherapy, that compounds might selectively kill pathogens without harming people?

Paul Ehrlich

During the early part of the 20th century, ________ speculated that some "magic bullet" would find and destroy pathogens in the body without harming the person. This idea provided the basis for _____.

Paul Ehrlich; chemotherapy

Which antibiotic is overcome by beta-lactamases?

Penicillin

Which antibiotic is overcome by beta-lactamases? Tetracycline Sulfonamide Penicillin Tetracycline, Penicillin, and Sulfonamide are all affected by beta-lactamase.

Penicillin

Effect penicillin has on susceptible bacterial cells

Penicillin disrupts cell wall synthesis

What effect does penicillin have on susceptible bacterial cells?

Penicillin disrupts cell wall synthesis.

Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug? The efflux pumps would not stop penicillin from blocking metabolic pathways. There are fewer efflux pumps on the cell membrane. The cell membrane is the target of penicillin. Penicillin disrupts the cell wall, which is located outside of the cell membrane.

Penicillin disrupts the cell wall, which is located outside of the cell membrane

Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug?

Penicillin disrupts the cell wall, which is located outside of the cell membrane.

Beta-lactam antibiotics

Penicillins Cephalosporins

Cells in a population that resist the effect of antimicrobial drugs, despite being identical to susceptible cells

Persister Cells

When a lysosome fuses with a phagosome it forms a ______________

Phagolysosome

A CLASS of fungicides that bind to ergosterol

Polyenes

Which group of drugs includes Nystatin and Amphotericin B, and cause cell lysis by forming channels/pores in the cytoplasmic membranes of fungal cells?

Polyenes

Which method of drug resistance renders bacteria resistant to penicillin and similar drugs?

Producing beta-lactamase enzymes.

In examining a MRSA strain, researchers find that degraded penicillin is found in the culture medium. What is the most likely mechanism of resistance?

Production of a beta-lactamase

hat is the difference between prokaryotic and eukaryotic ribosomes?

Prokaryotic ribosomes consist of a 50S large and a 30S small subunit, while eukaryotic ribosomes consist of a 60S large and a 40S small subunit. Submit

What drug inhibits nucleic acid synthesis specifically in prokaryotes?

Quinolones

________________ inhibit the activity of enzyme DNA gyrase, stopping DNA replication

Quinolones

Bacteria may become resistant to antibiotics by acquiring resistance genes located on _________.

R plasmids

If a particular bacterial species is resistant to beta-lactam antibiotics, which of the following might you expect to find inside the bacterial cells?

R plasmids

Symptoms/Signs of Inflammation?

Redness, Swelling, Heat, Pain

What benefit would the presence of an R plasmid provide to a microbe that has this extra piece of DNA?

Resistance to particular antibiotics

How might efflux pumps increase antibiotic resistance in bacteria? Resistant bacteria may have a greater number of efflux pumps on their cell surfaces. Some bacteria can decrease the specificity of their efflux pumps, increasing the number of different antibiotics the pumps can eliminate. Some bacteria can change the chemical structure of the antibiotic. Efflux pumps can never be modified to increase antibiotic resistance. Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.

Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps

How might efflux pumps increase antibiotic resistance in bacteria?

Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.

An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition, this indicates that the microbe being tested is

Resistant to the drug

Period of Convalescence

Returns to normal functions

Which of the following mutations would not result in antibiotic resistance? Missense mutation Nonsense mutation Silent mutation Frameshift insertion Frameshift deletion

Silent mutation

Responsible for lowering the pH of skin

Sebum

Which of the following is responsible for lowering the pH of skin?

Sebum

What modern term best describes the property of an antimicrobial compound that lets it target bacteria while having little effect on humans?

Selective toxicity

What is true concerning selective toxicity?

Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen

Chemically altered antibiotics that are more effective, longer lasting, or easier to administer than naturally occurring ones

Semisynthetics

Acute Inflammation is ......

Short lived ,usually beneficial

Microbes known as transient microbiota are in the body for a long or short time?

Short time

Which of the following mutations would not result in antibiotic resistance?

Silent mutation

What microbes were used for this experiment?

Staph aureus and E. coli

Which of the following organisms would MOST likely be sensitive to natural penicillin? penicillinase-producing Neisseria gonorrhoeae Penicillium helminths Mycoplasma Streptococcus pyogenes

Streptococcus pyogenes

To date, most of our natural antibiotics have been found to be produced by members of what genus? Bacillus Penicillium Streptomyces Paenibacillus Cephalosporium

Streptomyces

What is a superinfection?

Superinfection is a disease caused by an organism that is often an opportunist or one that was present in low numbers. Superinfection is a sequel to removal of the normal flora by antibiotic treatment.

What is a superinfection? -Superinfection is a disease caused by an organism that is often an opportunist or one that was present in low numbers. Superinfection is a sequel to removal of the normal flora by antibiotic treatment. -A superinfection is caused by a multidrug resistant organism. -A superinfection is one that is caused by a viral organism. -A superinfection is one that is caused by a eukaryotic organism.

Some antimicrobial drugs can work in tandem with one another to produce an enhanced antimicrobial effect. What is this process called?

Synergism

__________ is a process by which one drug can enhance the effect of a second drug.

Synergism

Which type of antimicrobial drug is produced entirely in a lab?

Synthetic antimicrobials

Antimicrobials that are completely synthesized in a lab

Synthetics

A compound that slows the activity of efflux pumps, when administered with an antibiotic which requires high concentration to be effective, the combination is highly effective for treating bacterial infections. This is an example of synergy.

Antisense nucleic acids are designed to have no side effects against humans.

Medications administered intravenously can provide much higher effective concentrations than other delivery methods

R-plasmids are extrachromosomal DNAs that contain genes for antimicrobial resistance.

Some bacterial cells are resistant to a variety of antimicrobials because they actively pump the drugs out of the cell.

Drug that binds to ribosome and BLOCKS the tRNA from being able to dock and deliver a new amino acid.....making the synthesis of the protein prevented

Tetracycline

Which statement regarding tests for microbial susceptibility to chemotherapeutic agents is FALSE? The Kirby-Bauer test is useful because it can differentiate bacteriostatic effects from bactericidal effects. A broth dilution test is often used to determine MIC and MBC of an antimicrobial drug. During the Kirby-Bauer test, a Petri plate with agar medium is uniformly inoculated with a standardized amount of a test organism. During a disk-diffusion test, a clear zone around the test disk indicates that growth was inhibited.

The Kirby-Bauer test is useful because it can differentiate bacteriostatic effects from bactericidal effects.

How does the antibiotic get from the disk into the agar?

The antibiotic diffuses out of the disk and into the agar. This diffusion can be affected by temperature and depth of agar in the plate.

A patient develops a severe intestinal infection as a result of antibiotic therapy treating a respiratory infection. Which of the following is the best explanation for why this occurred?

The antibiotic has disrupted the normal microbiota of the intestine.

When performing Diffusion Susceptibility Test (Kirby-Bauer Test), a larger zone of inhibition means.....

The antimicrobial agent was more effective

What is meant when a bacterium is said to become "resistant" to an antibiotic?

The bacterium is neither killed nor inhibited by the antibiotic.

What is meant when a bacterium is said to become "resistant" to an antibiotic? The antibiotic kills or inhibits the bacterium. The antibiotic is metabolized by the bacterium, providing more energy for growth of the cell. The bacterium is neither killed nor inhibited by the antibiotic. The antibiotic mutates in a way that benefits the bacterium.

The bacterium is neither killed nor inhibited by the antibiotic.

Why do the beta-lactam drugs affect bacteria but NOT human cells? -Beta-lactam antibiotics attack bacterial DNA and do not affect human DNA. -The beta-lactam antibiotics act on bacterial cell walls; human cells do not have cell walls. -Beta-lactam antibiotics are destroyed by human enzymes that limit the drug's action. -The mechanism of action for beta-lactam drugs inhibits protein synthesis, and bacteria that do not require proteins are automatically resistant.

The beta-lactam antibiotics act on bacterial cell walls; human cells do not have cell walls

Typically, beta-lactam drugs affect the peptidoglycan layer on bacteria. Why would beta-lactam drugs typically be considered more active against Gram-positive bacteria and less so against Gram-negative bacteria? -The cell walls of Gram-positive bacteria have a thick peptidoglycan component. -The Gram-positive bacteria are more susceptible to all antibiotics. -Gram-positive bacteria have an inner and outer cell membrane that makes them less susceptible to beta-lactam drugs. -Beta-lactam drugs attack the capsule, and many Gram-positive bacteria have a capsule.

The cell walls of Gram-positive bacteria have a thick peptidoglycan component.

In clinical applications of the Kirby-Bauer test, diluted cultures (for the McFarland standard comparison) must be used within 30 minutes. Why is this important?

The cells divide as time passes. What was equivalent to a .5 McFarland standard may be considered more dense after 30 min.

What pathway is specifically inhibited by sulfonamides?

The conversion of PABA to dihydrofolic acid

If the patient were to get a subsequent urinary tract infection, what should the doctor prescribe knowing that she is susceptible to thrush?

The doctor should prescribe an antibiotic specific for the bacterial species causing the urinary infection.

After incubation, does the antibiotic extend into the agar beyond the zone of inhibition? How does your answer relate to the concept of MIC?

The edge of the zone of inhibition is not the limit of antibiotic diffusion. Diffusion occurs beyond the zone, but the concentration of the antibiotic is too low to be lethal. The edge of the zone represents the minimum inhibitory concentration (MIC) of the antibiotic.

Virulence is.....

The likelihood or ability a microbe will infect a host and cause disease. Virulence DOES NOT equal severity of the disease!!

The microbial growth curve has four phases: lag, log, stationary, and death. If a chemical could prevent microbial cell division, in which phase of growth would it be most effective?

The log phase

The most common antibacterial agents act by _____________

The most common antibacterial agents act by inhibiting cell wall synthesis by preventing the cross linking of NAM subunits pithing the peptidoglycan

The Mueller-Hinton II plates are supposed to be used within a specific time after their prep and should be free of visible moisture. What negative effect (s) might moisture have on the test?

The older the plates, the drier they become. This could affect the ability of the antibiotic to diffuse through the agar. Moisture might help spread the antibiotic further than diffusion alone.

Which of the following statements is TRUE of disinfectants? -They are effective in destroying endospores. -They are only effective for short periods of time (seconds to minutes). -They are used on inanimate surfaces. -They are used on living tissue. -They are used for sterilization.

They are used on inanimate surfaces.

What is a primary advantage of semisynthetic drugs?

They have a broader spectrum of action

Why is chemotherapy against Mycobacterium species so problematic?

They have very complex cell walls and reproduce very slowly.

A class of antiviral drugs known as attachment antagonists help deter viral infections. What mechanism do they use?

They prevent attachment.

How do the antiviral drugs amantadine and rimantadine work?

They prevent viral uncoating by increasing the pH in phagolysosomes.

All aspects of the Kirby-Bauer test are standardized to assure reliability of comparison with the published standards. What might the consequence be of pouring the plates 2mm deep instead of 4mm?

This would affect the distance the antibiotic diffuses from the disk. The thicker the agar, the more downward diffusion there is and the less antibiotic available to diffuse outward. Thus, the zone would be smaller.

Why are pure cultures used for antimicrobial susceptibility testing?

To specifically determine which microbe is susceptible to which antimicrobial.

External infections can be treated by __________ administration, in which a drug is applied directly to the site of infection.

Topical

Blood plasma contains Transferrin which is...

Transferrin induces cells to take in Iron

Which of the following will most likely contribute to the spread of a genetic mutation among bacterial species?

Transformation

A class of drugs that prevent the release of newly formed viruses in an infected cell is known as

Transition State Analogs

(T/F) Amphotericin B is a polyene that binds to ergosterol and disrupts it by forming a pore in cytoplasmic membrane. results in vital chemical leaking out

True

(T/F) Beta-Lactams have an effect on BACTERIAL CELLS

True

(T/F) Lysozyme in tears destroys bacteria

True

(T/F) One of the issues with using Broad Spectrum Drugs is that it may allow for secondary or superinfection to develop

True

(T/F) Prokaryotic ribosomes are smaller than eukaryotic

True

(T/F) Selective Toxicity takes advantage of structural and/or metabolic differences between host and pathogen

True

A bacteria has invaded the respiratory tract. it DOES NOT INTERFERE with normal body function, but it is multiplying. This is an infection. (T/F)

True

Lipid A can be released when gram negative bacteria divide, die, or are consumed by a a phagocyte (T/F)

True

T/F R-plasmids are extrachromosomal DNAs that contain eyes for antimicrobial resistance

True

T/F antisense nucleic acids are designed to have no side effects against humans

True

T/F medications administered intravenously can provide much higher effective concentrations than other delivery methods

True

T/F organs that are commonly affected by drug toxicity include the kidneys and the liver

True

T/F some bacterial cells are resistance to a variety of antimicrobials because they actively pump the drugs out of the cell

True

T/F: Selective toxicity means that a drug is more toxic to a pathogen than to the host.

True

True or False: Some bacterial cells are resistant to a variety of antimicrobials because they actively pump the drugs out of the cell.

True

(T/F) Infective people can remain asymptomatic for years

True (HIV, Syphillis, TB)

Most common portal of entry for a pathogen

Upper respiratory tract

Enterococcus species resistant to vancomycin is known as ____.

VRE

___ is the leading cause of healthcare associated bacteremia, as well as surgical wound infections and urinary tract infections.

VRE

Prodromal period

Vague, general symptoms

Increase in the diameter of a blood vessel

Vasodilation

What is responsible for heat and redness associated with inflammation?

Vasodilation

Why is it difficult to find good chemotherapeutic agents against viruses?

Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.

Why is it difficult to find good chemotherapeutic agents against viruses? There is no effective way to deliver the drug to the virus. Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected. Viruses are not cells, and therefore not sensitive to such compounds. Viruses infect both bacteria and human cells.

Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.

Why are viruses more susceptible to nucleotide analogs than their host cells?

Viruses replicate their nucleic acid more rapidly than do host cells do.

Why are viruses more susceptible to nucleotide analogs than their host cells?

Viruses replicate their nucleic acid more rapidly than host cells do.

Why is it more difficult to treat viral infections than it is to treat bacterial infections? Viruses have cell walls. Viruses use the host cell's processes to carry out their own reproduction. Viruses are smaller than human cells. Viruses are very similar to human cells.

Viruses use the host cell's processes to carry out their own reproduction.

Signs are

Visible evidence of the disease that can be observed or measured in a laboratory test (Rash, Vomiting, Fever)

Which scientist coined the term antibiotic? Fleming Ehrlich Waksman Kirby Domagk

Waksman

While not the first person to discover antibiotics (Domagk/Fleming/Waksman) discovered the sources of many useful antibiotics

Waksman

A disease is

When pathogen MULTIPLIES and INTERFERES WITH NORMAL BODY FUNCTIONS after infection

What is Exocytosis?

When the vesicle carrying the digested pathogen fuses with the plasma membrane, RELEASING ITS CONTENTS

Which of the following is NOT an important consideration when preparing to use a chemical to disinfect a diaper changing table in a public restroom

Whether or not hand sanitizer is available at the changing table

E. coli and S. aureus were chosen to represent Gram (-) and Gram (+) bacteria respectively. For a given antibiotic, is there a difference in susceptibility between the - and + bacteria? If so, what differences do you see?

Yes. Antibiotics that affect the pg of the cell wall are more effective against gram + cells because of their greater abundance of pg.

Could an organism that is susceptible to an antimicrobial agent in lab testing fail to respond to it when that drug is used to treat the patient?

Yes. The human body is a complex environment. Many factors can affect the effectiveness of the antimicrobial: pH, organics, failure to reach target.

Antimicrobial drugs are selectively toxic. This means _____. a. the drugs are more toxic to the pathogens than to the patient b. the drugs will affect only a particular type of pathogen c. the drugs are reactive within a specific part of the patient's anatomy (for example, the inner ear) d. the drugs will not have toxic effects on a patient

If a particular bacterial species is resistant to beta-lactam antibiotics, which of the following might you expect to find inside the bacterial cells? a. R plasmids b. resistance pumps c. ergosterol d. porins

Quinolones and fluoroquinolones act against what bacterial target? a. DNA gyrase b. Metabolic pathways unique to bacteria c. Cell membranes d. Bacterial ribosomes e. Cell walls

The process of acquiring antibiotic resistance by means of bacteriophage activity is called a. transduction. b. R-plasmid acquisition. c. point mutation. d. transformation.

Which category of antimicrobial drug works by changing the shape of a ribosome? a. aminoglycosides b. tetracyclines c. chloramphenicol d. oxazolidinones

Which of the following is NOT a beta-lactam antibiotic? a. vancomycin b. penicillin G c. cephalothin d. methicillin

Which of the following is NOT associated with microbial mechanisms of resistance? a. Denaturation of proteins b. porins .c MfpA protein d. beta-lactamases

Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug? a. Humans and other animal hosts lack peptidoglycan cell walls. b. Bacteria are especially sensitive to these compounds. c. They are less expensive that other chemotherapeutic agents. d. The drugs also work against DNA gyrase.

__________ cells would be expected to be the most susceptible to the action of polyene drugs such as amphotericin B, while __________ cells would be the least susceptible. a. Fungal; bacterial b. Bacterial; fungal c. Bacterial; human d. Fungal; human

Which of the following is NOT a beta-lactam antibiotic? a) vancomycin b) cephalothin c) penicillin G d) methicillin

a) vancomycin Methicillin, penicillin G, and cephalothin are all examples of beta-lactam antibiotics. Vancomycin inhibits cell wall formation in bacteria, but it has a different chemical structure.

Rank the following point mutations in order of least damaging to most damaging if they occur in the middle of the coding sequence of a polypeptide. a. silent b. nonsense c. missense d. frameshift

a, c, d, b

Disruption of the normal microbiota can result in infections caused by which of the following microbes? Select one: a. Candida albicans, Mycobacterium, and Clostridium difficile b. Clostridium difficile c. Candida albicans d. both Mycobacterium and Clostridium difficile e. Mycobacterium

a. Candida albicans, Mycobacterium, and Clostridium difficile

Beta-lactam antibiotics have an effect on which of the following types of cells? Select one: a. bacterial cells b. both animal and fungal cells c. fungal cells d. animal cells e. virus-infected cells

a. bacterial cells

Which of the following can result when antibiotic therapy disrupts the normal microbiota? Select one: a. both pseudomembranous colitis and thrush b. black hairy tongue c. thrush d. anaphylactic shock e. pseudomembranous colitis

a. both pseudomembranous colitis and thrush

A new antibacterial medication prevents the assembly of ribosomes on mRNA. The new medication would be Select one: a. either an antisense RNA or a type of oxazolidinone. b. a type of macrolide. c. an antisense RNA. d. either an antisense RNA or a type of macrolide. e. a type of oxazolidinone.

a. either an antisense RNA or a type of oxazolidinone.

Bacterial DNA replication requires the enzyme gyrase, but eukaryotic replication does not. Ciprofloxacin ("Cipro") inhibits gyrase activity. This is an example of Select one: a. selective toxicity. b. antimicrobial resistance. c. synergism. d. an antimetabolite. e. use of an analog.

a. selective toxicity.

A compound is structurally similar to PABA and inhibits folic acid synthesis. It is most likely a(n) Select one: a. sulfonamide. b. nucleic acid analog. c. penicillin. d. azole. e. tetracycline.

a. sulfonamide.

The first synthetic antimicrobial widely available for treatment of infections Select one: a. was an antimetabolite. b. interfered with bacterial cell wall synthesis. c. was a nucleotide analog. d. was an attachment antagonist. e. disrupted cytoplasmic membranes.

a. was an antimetabolite.

spontaneous mutation in critical chromosomal genes

acquisition of new genes or sets of genes via transfer from another species. Originates from R plasmids encoded with drug resistance, transposons

Which category of antimicrobial drug works by changing the shape of a ribosome?

aminoglycosides

antimicrobials that cause change in the 30S ribosome shape so mRNA is misread

aminoglycosides

Which antimicrobial drugs affect the structure of the ribosome itself?

aminoglycosides, antisense nucleic acids, and oxazolidinones

What is the general term used to describe drugs that are chemically similar enough to a metabolite (such as PABA or a nucleotide) that they can substitute for that metabolite in a chemical reaction, possibly disrupting the chemical reaction sufficiently to halt the process?

analog

Nucleotide or nucleoside (analogs/antisense/acids) are antimicrobial agents that mimic the chemical structure of DNA building blocks.

analogs

Nucleotide or nucleoside _______________ are antimicrobial agents that mimic the chemical structure of DNA building blocks

analogs

Sulfonamides are structural ________ of para-aminobenzoic acid (PABA).

analogs

Competition between beneficial microbes and potential pathogens is called microbial (synergy/antagonism).

antagonism

Competition between beneficial microbes and potential pathogens is called microbial ______________

antagonism

Drugs that slow bacterial growth would be (competitive/synergistic/antagonistic) to penicillin.

antagonistic

Drugs that slow down bacterial growth would be _______________ to penicillin

antagonistic

The mechanism of inhibition of the growth of colonies on solid medium is called ____.

antibiosis

A term for an antimicrobial compound produced by living organisms that inhibits another microorganism.

antibiotic

A(n) _____ is defined as an antimicrobial substance that is produced naturally by an organism

antibiotic

Bacillus licheniformis secretes a compound that inhibits the growth of other gram-positive bacteria. This is an example of a(n) ____________

antibiotic

Some medications for influenza are ________________ antagonists that block the ability of the virus to enter cells

attachment

R-plasmids are most likely acquired via a. translation. b. bacterial conjugation. c. transduction. d. transformation.

The tRNA molecule holding a growing polypeptide chain is at the _____. a. E site b. P site c. A site d. 50S site

b d c a

Which of the following does not spread drug resistance throughout a population of bacteria? a) Transformation b) Efflux pumps c) Transduction d) Conjugation

b) Efflux pumps Efflux pumps can remove a drug from a cell, but do not spread resistance from one cell to another.

If a particular bacterial species is resistant to beta-lactam antibiotics, which of the following might you expect to find inside the bacterial cells? a) porins b) R plasmids c) ergosterol d) resistance pumps

b) R plasmids Beta-lactamases are the enzymes responsible for many types of resistance against beta-lactam drugs. The genes for these enzymes are often carried on R plasmids within bacterial cells.

Rank the following events in order from GREATEST to LEAST contribution to the spread of antibiotic resistance in bacterial populations. a. new mutations b. horizontal transfer c. vertical transfer

b, c, a

b, d, c, a

The E-test determines which of the following? Select one: a. susceptibility b. both susceptibility and MIC (minimum inhibitory concentration) c. both MBC (minimum bactericidal concentration) and MIC (minimum inhibitory concentration) d. MBC (minimum bactericidal concentration) e. MIC (minimum inhibitory concentration)

b. both susceptibility and MIC (minimum inhibitory concentration)

The CDC issued alerts about a bacterial strain known as NDM1 (New Delhi metalo-lactamase 1). What type of antibiotic resistance is indicated by the name? Select one: a. removal of the drug via a pump b. inactivation of the drug c. overproduction of an enzyme in a key metabolic pathway d. alteration of the target of the drug e. change in the permeability of the drug

b. inactivation of the drug

The therapeutic range of an antimicrobial is the Select one: a. range of microorganisms the antimicrobial effects. b. range of concentrations at which the antimicrobial is both effective and non-toxic. c. ratio of the concentration of antimicrobial in the blood to the oral dose. d. length of time the medication persists in the body after a single dose. e. ratio of the dose a patient can tolerate to the effective dose.

b. range of concentrations at which the antimicrobial is both effective and non-toxic.

Medications which should NOT be prescribed for a pregnant woman include Select one: a. tetracyclines. b. sulfonamides and tetracyclines. c. aminoglycosides. d. penicillins. e. sulfonamides.

b. sulfonamides and tetracyclines.

Which of the following pathways is specifically inhibited by trimethoprim? Select one: a. the conversion of tetrahydrofolic acid to PABA b. the conversion of dihydrofolic acid to tetrahydrofolic acid c. the conversion of dihydrofolic acid to PABA d. the conversion of PABA to tetrahydrofolic acid e. the conversion of PABA to dihydrofolic acid

b. the conversion of dihydrofolic acid to tetrahydrofolic acid

The β-lactams are narrow spectrum antibacterials because Select one: a. they block a synthetic step unique to the Gram-positive bacteria. b. the outer membrane prevents their entry into cells. c. they are analogs for a compound metabolized only by Gram-negative bacteria. d. the thick peptidoglycan walls prevent their entry into cells. e. they are analogs for a unique cell membrane lipid.

b. the outer membrane prevents their entry into cells.

Which group of microorganisms is a source of common antibiotics?

bacteria and fungi

R-plasmids are most likely acquired via

bacterial conjugation.

R-plasmids are most likely acquired via transduction. transformation. bacterial conjugation. translation.

bacterial conjugation.

Which of the following is the most difficult to inactivate? nonenveloped viruses bacterial endospores fungus spores protozoal cysts enveloped viruses

bacterial endospores

A new bacterial molecule is discovered. This molecule binds to an antibiotic and facilitates the binding of a phosphate group, thus inactivating the antibiotic. Which category best describes the mechanism of antibiotic resistance conferred by this molecule? bacterial enzymes altered porins conjugation rapid efflux of the antibiotic

bacterial enzymes

The zone may be produced as a result of killing the bacteria, in which case it is said to be ______.

bactericidal

Some bacteria use antibacterial polypeptides called ______ to inhibit the growth of other bacterial strains.

bacteriocins

A (bacteriostatic/bacteriocidal/minimum) concentration of a drug is one at which microbes survive but are not able to grow and reproduce.

bacteriostatic

A ________________ concentration of a drug is one at which microbes survive but are not able to grow and reproduce

bacteriostatic

In other cases, the drug may only stop bacterial growth without killing them, in which case it is said to be _______.

bacteriostatic

Why is the drug actinomycin used only in research applications or in the treatment of cancer?

because it is active against both prokaryotic and eukaryotic cells

Antisense nucleic acids

bind to mRNA, blocking ribosomal subunits

What is meant when a bacterium is said to become "resistant" to an antibiotic? a. The antibiotic kills or inhibits the bacterium. b. The antibiotic is metabolized by the bacterium, providing more energy for growth of the cell. c. The bacterium is neither killed nor inhibited by the antibiotic. d. The antibiotic mutates in a way that benefits the bacterium.

When a patient is treated with antibiotics, __________. a. mutations occur in all of the bacterial cells b. sensitive bacterial cells multiply uncontrollably c. the drug will kill or inhibit the growth of all of the sensitive bacterial cells d. the drug will kill or inhibit the growth of all of the resistant bacterial cells e. mutations will occur in the sensitive bacterial cells, but not in the resistant bacterial cells

Which category of antimicrobial drug essentially acts to stall a ribosome as it reads mRNA? a. chloramphenicol b. tetracyclines c. macrolides d. antisense nucleic acids

Which of the following is NOT a direct mode of action of antimicrobial drugs? a. inhibition of nucleic acid synthesis b. inhibition of cell wall synthesis c. inhibition of flagella formation d. inhibition of protein synthesis

Which of the following mutations would not result in antibiotic resistance? a. Missense mutation b. Nonsense mutation c. Silent mutation d. Frameshift insertion e. Frameshift deletion

Why is polymyxin only used on the skin? a. It is sensitive to degradation by acid, making oral delivery unsuitable. b. It has no effect on bacteria that live in the GI tract. c. It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead. d. It can disrupt the metabolic pathways found in humans.

In which of the following categories of antimicrobial drugs are the fewest drugs available? a) antiprotozoan b) antibacterial c) antiviral d) antifungal

c) antiviral

Which of the following is NOT a direct mode of action of antimicrobial drugs? a) inhibition of protein synthesis b) inhibition of cell wall synthesis c) inhibition of flagella formation d) inhibition of nucleic acid synthesis

c) inhibition of flagella formation Antimicrobial drugs can inhibit protein or nucleic acid synthesis and can also inhibit the formation of the cell wall. Inhibition of flagella formation might be an indirect result of the action of some antimicrobial drugs, but it is not a direct target.

Which of the following is NOT a possible side effect of antimicrobial therapy? a) toxicity b) allergies c) resistance d) disruption of normal microbiota

c) resistance

Which of the following is NOT associated with the work of Paul Ehrlich? a) the concept of chemotherapy b)the concept of the "magic bullet" c) sulfanilamide d) arsenic compounds

c) sulfanilamide Sulfanilamide was the discovery of Gerhard Domagk.

How does resistance to drugs spread in bacterial populations? Select one: a. The formation of biofilms protects bacteria from the effects of drugs. b. Horizontal gene transfer between bacteria spreads R (resistance) plasmids. c. Both horizontal gene transfer and the growth of biofilms spread drug resistance. d. Exposure to drugs alters gene expression in bacteria. e. Exposure to drugs causes mutations in bacterial genes.

c. Both horizontal gene transfer and the growth of biofilms spread drug resistance.

An antimicrobial that inhibits cell wall synthesis will result in which of the following? Select one: a. Cells cannot attach to their hosts. b. Ribosomes lose their function. c. Cells become more susceptible to osmotic pressure. d. The replication of cells, including cancer cells, slows down. e. The sterols in the cell wall become nonfunctional.

c. Cells become more susceptible to osmotic pressure.

Broad-spectrum synthetic antimicrobials were discovered by Select one: a. Selman Waksman. b. Paul Ehrlich. c. Gerhard Domagk. d. Joseph Lister. e. Alexander Fleming.

c. Gerhard Domagk.

The antimicrobial polymyxin is primarily effective for treating superficial infections with Select one: a. any bacteria. b. Staphylococcus bacteria. c. Gram-negative bacteria. d. fungi. e. viruses.

c. Gram-negative bacteria.

Which of the following is a primary advantage of semisynthetic drugs? Select one: a. They must be administered intravenously. b. They are less stable and consequently have fewer side effects. c. They have a broader spectrum of action. d. They are not readily absorbed, so they persist longer. e. They work faster.

c. They have a broader spectrum of action.

Which of the following interferes with cell wall synthesis by blocking alanine bridge formation? Select one: a. bacitracin b. vancomycin c. both cycloserine and vancomycin d. cycloserine e. beta-lactams

c. both cycloserine and vancomycin

Infection of the ________ would be the hardest to treat with antimicrobial drugs. Select one: a. liver b. kidneys c. brain d. heart e. colon

c. brain

Antiviral medications can best be described as Select one: a. broad spectrum antimicrobials. b. synthetic antimicrobials. c. extremely narrow spectrum synthetic antimicrobials. d. extremely narrow spectrum antimicrobials. e. antibiotics produced by bacteria.

c. extremely narrow spectrum synthetic antimicrobials.

In the compound lamivudine an -SH group replaces an -OH group found in cytosine. When used as a medication it will Select one: a. disrupt lipid membrane structure. b. interfere with protein synthesis. c. interfere with nucleic acid synthesis. d. interfere with cell wall synthesis. e. disrupt membrane structure.

c. interfere with nucleic acid synthesis.

A medication which specifically targets cell walls that contain arabinogalactan-mycolic acid is Select one: a. penicillin. b. methicillin. c. isoniazid. d. vancomycin. e. bacitracin.

c. isoniazid.

Most drugs that inhibit the synthesis of the cell wall act by Select one: a. preventing the formation of alanine-alanine bridges. b. preventing the formation of β-lactamases. c. preventing the cross-linkage of NAM subunits. d. disrupting the formation of the mycolic acid layer of the cell wall. e. blocking the secretion of cell wall molecules from the cytoplasm.

c. preventing the cross-linkage of NAM subunits.

A sulfonamide and trimethoprim may be administered in combination to Select one: a. inhibit multiple metabolic pathways. b. reduce relative toxicity. c. reduce development of antibiotic resistance. d. treat infections with microbes that require folic acid. e. provide broad-spectrum action.

c. reduce development of antibiotic resistance.

Bacitracin blocks the transport of NAG and NAM across the cytoplasmic membrane to the cell wall. Like other antimicrobials that block cell wall synthesis, this would result in weak cell walls and __________.

cell lysis due to the effect of osmotic pressure

An antimicrobial drug that blocks the transport of NAG and NAM from the cytoplasm is targeting which of the following cellular processes?

cell wall synthesis

Targets for antibiotics: 1. inhibition of ___ ____ synthesis. interferes with amino acid cross linking of PG. 2. Inhibition of ____ synthesis. 3.inhibition of enzymatic activity 4. injury to plasma membrane 5. inhibition of nucleic acid synthesis.

cell wall; protein

Which of the following is a beta-lactam antibiotic?

cephalothin

Any drug that acts against a disease is called a ________ agent

chemotherapeutic

Any drug that acts against a disease is called a(n) _______________ agent

chemotherapeutic

antimicrobial that blocks peptide bond formation

chloramphenicol

During world war ii, this park was not available, so chemists went to work and synthesized _____ and ____.

chloroquine; primaquine;

The bark of the ____ tree was used in South America to cure malaria.

cinchona

Why do antimicrobial agents active against mycobacteria have to be administered for months or years rather than the typical 10-30 days prescribed to treat other infections? a. Mycobacteria do not have cell walls. b. The only available agents are relatively ineffective drugs. c. They are too toxic to be used on a more rapid administration schedule. d. Mycobacteria reproduce very slowly.

Why is it difficult to find good chemotherapeutic agents against viruses? a. Viruses are not cells, and therefore not sensitive to such compounds. b. Viruses infect both bacteria and human cells. c. There is no effective way to deliver the drug to the virus. d. Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.

Why is penicillin regarded as the first true antibiotic? a. It is effective against a wide variety of bacteria. b. The sulfonamides were not effective in treating any bacterial infections. c. Ehrlich's arsenic-based compounds were produced after the discovery and mass production of penicillin. d. It is produced naturally by the fungus Penicillium.

Who discovered the first antibiotic widely available to the general public? Select one: a. Ehrlich b. Waksman c. Fleming d. Domagk e. Ehrlich and Waksman

d. Domagk

Which of the following antibiotics disrupts cytoplasmic membrane function? Select one: a. erythromycin b. streptomycin c. tetracycline d. amphotericin B e. penicillin

d. amphotericin B

Bacillus licheniformis secretes a compound that inhibits the growth of other Gram-positive bacteria. This is an example of a(n) Select one: a. analog. b. toxin. c. porin. d. antibiotic. e. chemotherapeutic.

d. antibiotic.

A medication that inhibits synthesis of ergosterol would be effective in treating Select one: a. bacterial infections. b. viral disease. c. protozoal infections. d. fungal infections. e. Mycobacterial disease.

d. fungal infections.

Most broad-spectrum antibiotics act by Select one: a. inhibiting nucleic acid synthesis. b. inhibiting metabolic pathways. c. disrupting the cytoplasmic membrane. d. inhibiting protein synthesis. e. inhibiting the synthesis of the cell wall.

d. inhibiting protein synthesis.

The mechanism of action of the antibiotic vancomycin is Select one: a. inhibition of protein synthesis. b. inhibition of nucleic acid synthesis. c. disruption of cytoplasmic membranes. d. inhibition of cell wall synthesis. e. inhibition of a metabolic pathway.

d. inhibition of cell wall synthesis.

Ribavirin is an antiviral that interferes with Select one: a. cell membrane component synthesis. b. viral attachment. c. cell wall synthesis. d. nucleic acid synthesis. e. protein synthesis.

d. nucleic acid synthesis.

Several antiviral medications used to treat HIV interfere with Select one: a. folic acid synthesis. b. cell wall synthesis. c. protein synthesis. d. nucleic acid synthesis. e. assembly of membranes.

d. nucleic acid synthesis.

Alterations in the structure of which of the following are an important aspect of Gram-negative bacterial resistance to antimicrobial drugs? Select one: a. cytoplasmic membrane b. plasmids c. mitochondria d. porins e. ribosomes

d. porins

Which of the following is NOT associated with microbial mechanisms of resistance?

denaturation of proteins

The zone of inhibition is the measurement of the _____ of ____ ____ of the zone circle in millimeters.

diameter; no growth;

The depth is important because of its effect upon _____.

diffusion

Factors to consider when interpreting antibiotic sensitivity of a pathogen: -The rate of _____ of antibiotic through the agar medium-controlled by using MH plates of the correct depth. -Degree of _____ of the bacteria to the antibiotic drug- each strain is different; must do the test to know for sure. -Number of organisms on the plate- controlled by using the _____ __. -Rate of ____ of the organism- controlled by putting plates in incubator at body temp. -_____ of the antibiotic- controlled by using disks with standard concentrations only.

diffusion; susceptibility; mcfarland std; growth; concentration;

VRE can be transmitted by: - ___ contact with stool, urine or blood containing VRE. - _____ by contaminated hands of healthcare providers or contact with contaminated environmental surfaces such as bedrails, wheelchairs, thermometers, doorknobs, bed linens and patient gowns.

direct; indirectly

Many antimicrobials have side effects. Which side effect can be circumvented, at least in part, by the use of probiotics?

disruption of normal microbiota

The antimicrobial polymyxin _______________________

disrupts cytoplasmic membranes

What is the therapeutic index? -the range of drug dosage levels that are effective without being excessively toxic -drug dose the patient can tolerate divided by the effective dose -the dosage that kills 50% of the patients -the effective dose/ the dose the patient can tolerate

drug dose the patient can tolerate divided by the effective dose

analogs

drugs with similar structures

Bacterial cells may acquire drug resistance by which of the following mechanisms? a) Resistant cells may alter the target of the drug. b) Resistant cells may alter the drug itself. c) efflux pumps e) All of the listed answers are correct.

e) All of the listed answers are correct.

This figure represents a Petri plate. The gray area is where bacteria A is growing. The black area is where bacteria B is growing. The white area is a zone where neither organism is growing. What is the best interpretation of what is observed on the plate? Select one: a. No conclusion can be made from this information. b. Bacteria A produces a compound that inhibits the growth of bacteria B. c. Bacteria A grows faster than bacteria B. d. Bacterial colony B has depleted the nutrients in the area around the colony. e. Bacteria B is producing an antibiotic that inhibits the growth of bacteria A.

e. Bacteria B is producing an antibiotic that inhibits the growth of bacteria A.

Pentamidine is an example of an antimicrobial that Select one: a. inhibits metabolic pathways. b. inhibits cell wall synthesis. c. binds to ribosomes. d. disrupts cytoplasmic membranes. e. binds to DNA.

e. binds to DNA.

Drug-resistant populations of microbes arise when Select one: a. exposure to drugs causes mutations that produce resistance. b. the patient becomes immune to the drug. c. synergy between medications occurs. d. resistant cells become numerous in a population due to their greater vigor. e. exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells.

e. exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells.

The mechanism of action of erythromycin is Select one: a. inhibition of nucleic acid synthesis. b. inhibition of cell wall synthesis. c. disruption of cytoplasmic membranes. d. inhibition of a metabolic pathway. e. inhibition of protein synthesis.

e. inhibition of protein synthesis.

Which of the following is measured in the broth dilution test? Select one: a. presence of turbidity and cell lysis b. cell lysis c. lack of turbidity and zone of inhibition d. the zone of inhibition e. lack of turbidity

e. lack of turbidity

Antimicrobial sugar analogs are effective for Select one: a. preventing bacterial protein synthesis. b. preventing nucleic acid synthesis. c. preventing cell membrane synthesis. d. blocking a metabolic pathway. e. preventing virus attachment.

e. preventing virus attachment.

Inhibiters of DNA synthesis specifically effective on prokaryotes are Select one: a. 5-fluorocytosine. b. rifampin. c. tetracycline. d. actinomycin. e. quinolones.

e. quinolones.

A compound is extracted from a microbial culture and is modified in the laboratory for use as an oral medication. This product would be a(n) Select one: a. analog. b. probiotic. c. synthetic antimicrobial. d. antibiotic. e. semisynthetic antimicrobial.

e. semisynthetic antimicrobial.

The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, a β-lactamase inhibitor, is known as Select one: a. selective toxicity. b. cross resistance. c. antimetabolism. d. chemotherapy. e. synergism.

e. synergism.

Antiviral medications frequently block unique (proteins/enzymes/molecules) to prevent production of new virus.

enzymes

Antiviral medications frequently block unique ____________ to prevent production of new virus

enzymes

Which of the following antimicrobial drugs would likely be useful to treat a staphylococcal infection?

erythromycin

Which of the following would be selective against the tubercle bacillus? streptomycin - inhibits protein synthesis bacitracin - inhibits peptidoglycan synthesis vancomycin - inhibits peptidoglycan synthesis ethambutol - inhibits mycolic acid synthesis streptogramin - inhibits protein synthesis

ethambutol - inhibits mycolic acid synthesis

Which of the following would be used to sterilize a mattress? heavy metals formaldehyde radiation ethylene oxide autoclaving

ethylene oxide

__________ cells would be expected to be the most susceptible to the action of polyene drugs such as amphotericin B, while __________ cells would be the least susceptible.

fungal; bacterial Fungal cells are the most susceptible to the activity of polyene drugs due to the presence of ergosterol in their cytoplasmic membranes. Bacterial cells are the least susceptible because they usually have no sterols in their membranes.

Which of the following is used for microbial control in fresh fruits and vegetables? ultraviolet light microwaves X rays gamma rays electron beams

gamma rays

Considering the cell structure of mycoplasmas and other bacteria that stain either Gram negative, Gram positive, or with acid-fast stains, which group should you expect relies most on the presence of peptidoglycan for strength?

gram positive

gram- positive bacteria

If penicillin G is chosen as the best treatment for a given infection, what microorganisms are most likely the cause? viruses fungi gram-positive bacteria gram-negative bacteria

gram-positive bacteria

____ ____ is the single most important procedure in preventing the spread of MRSA and VRE.

hand hygiene

highest concentration to the lowest concentration: intravenous, intramuscular, oral, topical

interferons

human based glycoprotein produced primarily by fibroblasts and leukocytes

A patient is infected with a bacterium that produces the enzyme beta-lactamase; this enzyme

inactivates penicillins, carbapenems, and cephalosporins.

The ratio of a medication's dose that can be tolerated to its effective dose is the therapeutic ____________ of the medication

index

Azoles...

inhibit ergosterol synthesis, disrupt the plasma membrane

Oxazolidinones

inhibit initiation of translation

The antimicrobials called quinolones act by __________________

inhibiting DNA replication

The antimicrobials called quinolones act by disrupting cytoplasmic membranes. inhibiting protein synthesis. inhibiting cell wall synthesis. inhibiting a metabolic pathway. inhibiting nucleic acid synthesis.

inhibiting nucleic acid synthesis

Most broad-spectrum antibiotics acts by __________________

inhibiting protein synthesis

The mechanism of action of the antibiotic vancomycin is _______________

inhibition of cell wall synthesis

Which of the following is NOT a direct mode of action of antimicrobial drugs?

inhibition of flagella formation

Which of the following is NOT a type of side effect exhibited by antimicrobial drugs?

inhibition of host cellular enzymes

The mechanism of action of erythromycin is ______________

inhibition of protein synthesis

Methicillin is an example of the beta-lactam class of drugs that ______________

inhibits cell wall synthesis

Pentamidine is an example of an antimicrobial that _________________

inhibits metabolic pathways

In the compound lamivudine an -SH group replaces an -OH group found in cytosine. When used as a medication it will ____________

interfere with nucleic acid synthesis

What is the mode of action for the drug quinolone?

it inhibits DNA gyrase

Which of the following is NOT a desirable characteristic of an ideal antimicrobial agent? it is inexpensive. it only arrests growth of vegetative cells. it is stable during storage. it is harmless to humans. it acts quickly.

it only arrests growth of vegetative cells.

Penicillin was considered a "miracle drug" for all of the following reasons EXCEPT it was the first antibiotic. it kills bacteria. it has selective toxicity. it does not affect eukaryotic cells. it inhibits gram-positive cell wall synthesis.

it was the first antibiotic.

Also called the disk diffusion test, is a valuable standard tool for measuring the effectiveness of antimicrobics against pathogenic microorganisms.

kirby bauer

which category of antimicrobial drugs works by blocking proper mRNA movements and stopping synthesis (stops translocation)

lincosamides

antimicrobials that bind to the 50S subunit thereby blocking mRNA movement through the ribosome and stopping synthesis

lincosamides and macrolides

Which category of antimicrobial drug essentially acts to stall a ribosome as it reads mRNA?

macrolides

Most drugs that inhibit the synthesis of the cell wall act by ________________

preventing the cross-linkage of NAM subunits

Antimicrobial sugar analogs are effective for ___________________

preventing virus attachment

Chloramphenicol blocks the action of the large (50S) subunit. This essentially _____.

prevents the formation of peptide bonds

Microorganisms used for health benefits are also known as _________.

probiotics

More than half of our antibiotics are synthesized in laboratories. produced by fungi. produced by Fleming. produced by bacteria. produced by eukaryotic organisms.

produced by bacteria.

Which method of drug resistance renders bacteria resistant to penicillin and similar drugs?

producing beta- lactamase enzymes Beta-lactamase (penicillinase) enzymes break the beta-lactam ring of penicillin and penicillin-like molecules.

The majority of broad spectrum antibacterial medications inhibit (DNA/protein/RNA) synthesis.

protein

The tetracyclines interfere with _______________

protein synthesis

Peruvian Indians called it "quina quina"; from this the name _____ evolved

quinine

If a particular bacterial species is resistant to beta-lactam antibiotics, which of the following might you expect to find inside the bacterial cells?

r plasmids

The therapeutic range of an antimicrobial is the __________________

range of concentrations at which the antimicrobial is both effective and non-toxic

Discoloration and damage to tooth enamel caused by

tetracycline

Which of the following groups of drugs can become incorporated into the bones and teeth of a fetus? tetracyclines beta-lactams aminoglycosides sulfonamides quinolones

tetracyclines

antimicrobials that block tRNA docking by sitting in the A site

tetracyclines

The antimicrobial drugs with the broadest spectrum of activity are macrolides. aminoglycosides. chloramphenicol. tetracyclines. penicillin G.

tetracyclines.

What is microbial antagonism?

the ability of the normal flora to outcompete and outgrow pathogens

What is microbial antagonism? -the overgrowth of opportunistic organisms when the normal flora are removed by antiseptic soaps -microbes that cause food to smell bad and test bad -the ability of the normal flora to outcompete and outgrow pathogens -microbes that cause disease in humans

the ability of the normal flora to outcompete and outgrow pathogens

By what mechanism do bacteria develop resistance to tetracycline?

the bacteria prevent entry of tetracycline into the cells.

Beta-lactamases protect which of the following from damage by antimicrobial drugs?

the cell wall

What is the therapeutic index?

the drug dose the patient can tolerate divided by the effective dose

When a patient is treated with antibiotics, __________.

the drug will kill or inhibit the growth of all of the sensitive bacterial cells

When a patient is treated with antibiotics, __________. mutations occur in all of the bacterial cells sensitive bacterial cells multiply uncontrollably the drug will kill or inhibit the growth of all of the sensitive bacterial cells the drug will kill or inhibit the growth of all of the resistant bacterial cells mutations will occur in the sensitive bacterial cells, but not in the resistant bacterial cells

the drug will kill or inhibit the growth of all of the sensitive bacterial cells

Antimicrobial drugs are selectively toxic. This means _____.

the drugs are more toxic to the pathogens than to the patient

therapeutic index

the ratio of the dose of the drug that is toxic to humans as compared to its minimum effective does (high index is desirable)

Is is inappropriate to prescribe antibacterial agents to treat colds or flu because __________________

these diseases are caused by viruses

It is inappropriate to prescribe antibacterial agents to treat colds or flu because -these diseases exhibit cross resistance. -these diseases can act synergistically with each other. -the microbes involved can develop resistance rapidly. -these diseases are transmitted by endospores, which are hard to kill. -these diseases are caused by viruses.

these diseases are caused by viruses

A class of antiviral drugs known as attachment antagonists help deter viral infections. What mechanism do they use

they prevent attachment

A young Hispanic mother brought her frail infant to a southern Texas emergency room. While she waited, her baby began to have seizures. The staff stabilized the child, while the mother explained that the child had been ill for many days. Feverish at times, the infant had lost weight because she was too short of breath to nurse. Other family members were ill with bad coughs. The girl was diagnosed with a form of tuberculosis (TB) that affected her brain. She was hospitalized and isolated. Health department officials discovered that two individuals had exposed the baby to TB: an uncle and her father, whom the mother had visited in a Mexican jail. Inmates from the jail carried a strain of TB that was resistant to several standard anti-tuberculosis drugs. It would take many weeks to determine which of the two strains was affecting the baby. Doctors had to make a tough decision: Should they immediately begin treating the infant for the multi-drugresistant strain (MDR-TB), which involves using five to seven different drugs with multiple and painful side effects for many months, or treat her for the more normal form of TB using a more typical and less stressful drug regimen for an equal length of time? Who was the most likely source of infection for this child? mother grandmother uncle father

uncle

The action of some antivirals prevent (attachment/synthesis/uncoating), an event shortly after entry of the virus into the cell.

uncoating

Which of the following is NOT a beta-lactam antibiotic?

vancomycin

Commonly acquired MRSA is more ____ than MRSA found in hospitals, combining resistance with virulence.

virulent

The first synthetic antimicrobial widely available for treatment of infections __________________

was an attachment antagonist

Who is an increased risk of contracting VRE?

weakened immune systems; previously taken vancomycin; long term antibiotics, indwelling devices.

Sulfonamides -are antimetabolic drugs. -were the first widely used antimicrobial drugs. -indirectly inhibit the synthesis of nucleic acids. -are no longer widely used. -were the first widely used antimetabolic antimicrobial and indirectly inhibit nucleic acid synthesis.

were the first widely used antimetabolic antimicrobial and indirectly inhibit nucleic acid synthesis

Drug resistance occurs against antibiotics and not against synthetic chemotherapeutic agents. when antibiotics are taken after the symptoms disappear. when antibiotics are used indiscriminately. because bacteria are normal microbiota. All of the answers are correct.

when antibiotics are used indiscriminately.

Which of the following classifications would best describe Candida albicans?

yeast

Which of the following classifications would best describe Candida albicans? RNA virus bacteria protozoan yeast

yeast

In a diffusion susceptibility test, the clear area found around some antimicrobial drug disks is called the _______.

zone of inhibition

In the test, antimicrobic impregnated paper disks are placed on a plate that has been inoculated to form a bacterial lawn. The plates are incubated to allow growth of the bacteria and time for the agent to diffuse into the agar. As the drug moves through the agar, it establishes a concentration gradient. If the organism is susceptible to it, a clear ___ __ ______ will appear around the disk where growth has been inhibited.

zone of inhibition

Interpreting Kirby-Bauer Results: -____ of ____ is compared to a standardized chart. After incubation plates are examined for clear rings (no growth) around the antimicrobial disks.

Microbiology #3

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