Microbiology Test II
Sites to be treated: What can't be used on humans? Choose microbial control based on? Example? Immunocompromised means you have to?
1. Harsh chemicals & heat 2. Site of the procedure because it affects potential for infection; finger nail - must use topical cream, not oral medication because minimal blood supply 3. Steralize
An antimicrobial that inhibits cell wall synthesis will result in which of the following? A. Cells become more susceptible to osmotic pressure. B. Cells cannot attach to their hosts. C. Ribosomes lose their function. D. The sterols in the cell wall become nonfunctional. E. The replication of cells, including cancer cells, slows down.
A
Many antimicrobial drugs that affect the cytoplasmic memrane are used only externally because they can be toxic to humans
A
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 ?-lactamases.
A
Which of the following drugs inhibits nucleic acid synthesis specifically in prokaryotes? A. quinolones B. actinomycin C. rifampin D. tetracycline E. 5-fluorocytosin
A
Who discovered the first widely available antibiotic? A. Domagk B. Ehrlich C. Fleming D. Waksman E. Ehrlich and Waksman
A
The mechanism of action of erythromycin is A) inhibition of protein synthesis B) inhibition of cell wall synthesis C) inhibition of nucleic acid synthesis D) inhibition of metabolic pathway E) disruption of cytoplasmic membranes
A - Inhibition of protein synthesis
Which of the following is an example of sanitization
A public toilet is treated with disinfectants.
The mechanism of action of sulfonamides is A) inhibition of metabolic pathways. B) inhibition of cell wall synthesis. C) inhibition of nucleic acid synthesis. D) disruption of cytoplasmic membranes. E) inhibition of protein synthesis.
A- inhibition of metabolic pathways
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.
B
B-lactamase production is an example of which of the following types of resistance? 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
B
Beta-lactam antibiotics 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
B
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.
B
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
B
Which of the following is a measurement associated with the broth dilution test? A. the zone of inhibition B. lack of turbidity C. cell lysis D. lack of turbidity and zone of inhibition E. presence of turbidity and cell lysis
B
Which of the following pathways 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
B
Which of the following statements about the zone of inhibition is FALSE? A. It is measured as a diameter. B. The larger the zone, the more resistant the organism is. C. It is a clearing zone with no growth. D. It is a result of diffusion of the drug out of the paper disk. E. It is measured after incubation.
B
Reducing surface tension does what to solvent?
Becomes more effective at dissolving solute molecules
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 have a broader spectrum of action. D. They must be administered intravenously. E. They are not readily absorbed, so they persist longer.
C
Which of the following statements concerning development of antibiotic resistance is FALSE? A. It is often mediated by R-plasmids. B. Resistant cells are normally in the minority in a bacterial population. C. Resistant cells grow more efficiently and quickly than susceptible cells. D. New resistance genes can be gained through transformation, transduction, or conjugation. E. Resistance can occur through mutation of existing bacterial genes.
C
The antimicrobials called quinolones act by A) disrupting cytoplasmic membranes B) inhibiting cell wall synthesis C) inhibiting nucleic acid synthesis D) inhibiting a metabolic pathway E) inhibiting protein synthesis
C - inhibiting nucleic acid synthesis
Example of sanitization
Cutlery at restaurant - do not make them get sterilized only sanitized
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 hard to kill. C. these diseases exhibit cross resistance. D. these diseases are caused by viruses. E. these diseases can act synergistically with each other.
D
The Etest determines which of the following? A. susceptibility B. MBC C. MIC D. both susceptibility and MIC E. both MBC and MIC
D
The most limited group of antimicrobial agents is the ________ drugs. A. antibacterial B. antifungal C. anthelmintic D. antiviral E. antiprotozoan
D
Which of the following drugs specifically targets cell walls that contain arabinogalactan-mycolic acid? A. vancomycin B. penicillin C. methicillin D. isoniazid E. bacitracin
D
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
D
Ribavirin is an antiviral that interferes with A) protein synthesis B) cell wall synthesis C) cell membrane component synthesis D) Nucleic acid synthesis E) viral attachment
D - Nucleic acid synthesis
Trimethoprim is an example of antimicrobials that A) disrupt cytoplasmic membranes B) inhibit cell wall synthesis C) inhibit nucleic acid synthesis D) inhibit metabolic pathways E) inhibit protein synthesis
D - inhibit metabolic pathways
hot air is an effective sterilizing agent because it denatures proteins & fosters oxidation of metabolic & structural chemical, but requires a LOT OF heat...
Dry heat
A large percentage of antibiotics and semisynthetic drugs are produced by members of the genus A. Cephalosporium. B. Penicillium. C. Bacillus. D. Mycobacterium. E. Streptomyces.
E
Antimicrobial agents that interfere with nucleic acids also stop protein synthesis because A) the ribosome contains ribozymes. B) nucleic acids are involved in the production of proteins. C) proteins are involved in the production of nucleic acids. D) Both A and B are correct. E) A, B, and C are correct.
E
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. both Mycobacterium and Clostridium difficile E. Candida albicans, Mycobacterium, and Clostridium difficile
E
Probiotics A. involve microbial antagonism. B. are an alternative to the use of chemotherapy. C. involve the use of extracts from microorganisms. D. is a term for resistance to antibiotics. E. are an alternative to the use of chemotherapy involving microbial antagonism.
E
Sulfonamides A. are antimetabolic drugs. B. were the first widely used antimicrobial drugs. C. indirectly inhibit the synthesis of nucleic acids. D. are no longer widely used. E. were the first widely used antimetabolic antimicrobial and indirectly inhibit nucleic acid synthesis.
E
Which of the following antibiotics disrupts cytoplasmic membrane function? A. streptomycin B. erythromycin C. tetracycline D. penicillin E. amphotericin B
E
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
E
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
E
Which of the following works by inhibiting ergosterol synthesis? A. fluconazole B. turbinafine C. amphotericin B D. nystatin E. both fluconazole and turbinafine
E
Which scientist coined the term antibiotic? A. Fleming B. Domagk C. Kirby D. Ehrlich E. Waksman
E
Which of the following antifungals works by inhibiting ergosterol synthesis? A) fluconazole B) turbinafine C) amphotericin B D) nystatin E) both fluconazole and turbinafine
E - both fluconazole & turbinafine
Disruption of the normal microbiota can result in infections caused by which of the following microbes? A. Candida albicans B. Clostridium difficile C. Mycobacterium D. Candida albicans, Mycobacterium, and clostridium difficile E. Both mycobacterium and clostridium difficile
E - candida albicans, mycobacterium & clostridium difficile
Energy without mass traveling in waves at speed of light; released from atoms undergone internal changes
Electromagnetic radiation
Which of the following drugs inhibits nucleic acid synthesis specifically in most bacteria?
Fluoroquinolones
What is used to disinfect inanimate surfaces?
Germicide
Antibacterial drugs that alter cytoplasmic membranes
Gramicidin Nisin Polymyxin Pyrazinamide
Presumably denature proteins
Halogens
Denature proteins (4)
Heavy metals, aldehydes, gaseous agents, enzymes
Can kill bacterial endospores (one of the only things that can kill them)
High level germicides
♣ MRSA (disease) ♣ Development of resistance
How to create resistance to antimicrobial drugs
Process of disinfecting places and utensils used by public to reduce # of pathogenic microbes to meet accepted public health standards
Sanitizations
Which of the following statements is true of selective toxicity? A. Selective toxicity takes advantage of structural differences between host and pathogen B. Selective toxicity takes advantage of metabolic differences between host and pathogen C. To be effective an antimicrobial agent must be more toxic to the patient than the pathogen D. Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogens* E. Antimicrobial agents must target structural differences between host and pathogen and be more toxic to the patient than the pathogen.
Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogens
discovered that other mo's are the sources of useful antimicrobials, most notably species of soil dwelling bacteria in the genus Streptomyces; name? coined what term?
Selman Waksman - coined term antibiotics
The removal or destruction of ALL microbes including viruses & bacterial endospores in or on an object (NOT PRIONS)
Sterilization
electron beams
Sterilizing agent
ethylene oxide
Sterilizing agent
glutaraldehyde
Sterilizing agent
Decrease surface tension of water and disrupt cell membranes
Surfactants
Positively charged organic surfactants that are more soluble in water than soaps
Synthetic detergents
Organs that are commonly affected by drug toxicity include the kidneys & the liver. (T/F)
True
The dairy creamer used in restaurants is usually sterilized by
UHT sterilization
denaturation requires what? which is why aqueous preparations are more effective MO's than what?
Water, pure alcohol
Antiviral drugs that inhibit viral uncoating
amantadine rimantadine
antimicrobial agent that inhibits protein synthesis by changing shape of 30S ribosomal subunit
aminoglycosides
Waxy cell wall
Mycobacterium - tuberculosis
antimicrobial agent produced naturally by an organism
antibiotics
chemotherapeutic agent used to treat microbial infection
antimicrobial agents
Antimicrobials that block protein synthesis by binding to the mRNA are
antisense nucleic acids
RNA or single-stranded DNA with nucleotide sequence complementary to molecule of mRNA; control translation of polypeptide
antisense nucleic acids
antiviral drugs that inhibit protein synthesis
antisense nucleic acids (fomivirsen)
chemotherapy lead to discovery of
arsenic compounds against syphilis
antiprotozoan drugs that are antimetabolites
artemisinin atovaquone benzimidazole furazolidone heavy metals iodoquinol lumefrantrine lumefantrine nifurtimox nitazoxanide proguanil pyrimethamuine sulfonamides suramin trimethoprim
A------is an instrument that sterilizes by exposing materials to steam under pressure
autoclave
pressure, pipes to introduce steam, valves to remove air & control pressure, pressure/temperature gauges
autoclave
Which of the following would NOT be bacteriostatic? freezing below 0°C lyophilization autoclaving refrigeration of mesophiles desiccation
autoclaving
temp of 121 C for 15 min w/ 15 lbs pressure per square inch
autoclaving parameters to kill everything!
Methicillin is an example of the beta-lactum class of drugs that A) disrupt cytoplasmic membranes. B) inhibit cell wall synthesis. C) inhibit nucleic acid synthesis. D) inhibit metabolic pathways. E) inhibit protein synthesis.
b - inhibit cell wall synthesis
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.
b - inhibition of cell wall synthesis
antimicrobial that blocks NAG & NAM secretion from cytoplasm, prompting cell lysis
bacitracin
Beta-lactam antibiotics have an effect on which of the following types of cells?
bacterial cells
which of the following is the most difficult to inactivate?
bacterial endospores
Put the following in order, from most resistant to antimicrobial agents to least resistant to antimicrobial agents
bacterial endospores, protozoan cysts, protozoa, nonenveloped viruses, enveloped viruses
anthelmintic drugs taht are antimetabolites
benzimidazole derivatives iodoquinol ivermectin metrifonate niclosamide praziquantal pyrantel pamoate diethylcarbamazine
bacterial enzyme that breaks the beta-lactam rings of penicillin & similar molecules, rendering them inactive
beta-lactamases
antimicrobial whose functional portion is composed of beta-lactam rings, which inhibit peptidoglycan formation by irreversibly binding to the enzymes that cross-link NAM subunits
beta-lactams
Electromagnetic radiation with wavelength greater than 1 nm does not have enough energy to force electrons out of orbit (contain enough energy to excite electrons & make new covalent bonds, affect 3D structure)
Nonionizing radiation (UV light, visible light, infrared radiation, radio waves)
drugs that inhibit nucleic acid synthesis
Nucleosides analogs - molecules with structures similar to the normal nucleotide building blocks of nucleic acids. The analogs enable them to be incorporated into the DNA or RNA of pathogens, where they distort the shapes of the nucleic acid and prevent more replication, transcription, or translation.
Concerning alcohol, which of the following statements is false? Dissolving another chemical in alcohol is a good way to make it more effective. One hundred percent alcohol is the most effective form. Alcohols are intermediate-level disinfectants. Isopropanol is a better disinfectant than ethanol. Alcohols have more than one cellular target.
One hundred percent alcohol is the most effective form (70 is)
Denature proteins by oxidation
Oxidizing agents
High level disinfectants and antiseptics that work by releasing oxygen radicals, particularly effective against anaerobic microorganisms
Oxidizing agents like hydrogen peroxide
*Good for eliminating odor and taste *Supplement chlorination of water (more effective than chlorine but unstable in water)
Ozone
2 types of radiation
Particulate & electromagnetic
High speed subatomic particles freed from their atoms
Particulate radiation
heating beer/wine destroy MO's that cause spoilage without ruining taste (NOT STERILIZATION)
Pasteurization
The use of chemicals that would selectively kill pathogens while having little or no effect on the patient
Paul Ehrlic - chemotherapy
Denature proteins & disrupt cell membranes
Phenol + phenolics, alcohols
Lysol is and example of which of the following groups of chemical antimicrobial agents?
Phenolics
chemically modified by addition of halogens or organic functional groups
Phenolics
Works well with organic materials and thus food for blood and body fluid decontamination.
Phenols-carboxylic acid
Alcohols are used for
both antisepsis & disinfection
Which of the following interferes with cell wall synthesis by blocking alanine bridge formation?
both cycloserine & vancomycin
Formalin (37% formaldehyde) is used for
both disinfection and sterilization
boiling water for 10 minutes is effective in ridding it of...
both growing bacteria & enveloped viruses
Acts against many different kinds of pathogens
broad spectrum drugs
antimicrobial that works against many types of pathogents
broad-spectrum drugs
test for determining the MIC in which a standardized amount of bacteria is added to serial dilutions of antimicrobial agents in tubes or wells containing both
broth dilution test
A chemical agent that dissolves lipids can damage
cells & enveloped viruses
Work to inhibit DNA, alter cell walls; use antiseptics and disinfectants
chemical methods to control MO's
Elderly, young children, organ recipients, CA, AIDS, autoimmune ds., corticosteroid
immunodeficient patients
Determines efficacy of a chemical
in-use test
formaldehydes and gluteraldehyde are antimicrobial through their actions in
inactivating proteins
iodine w/ alcohol
incture of iodine
drugs that BLANK - selectively toxic to certain fungal or bacterial cells which have cell walls, but not to animals because animals lack cell walls
inhibit cell wall synthesis (antimicrobial action)
All of the following are characteristics of iodophors except: they are halogens. they have long-lasting effects. they are used as an antiseptic. they are inorganic molecules. betadine is an example.
inorganic molecules
can be used with certain amino acids to inactivate enzymes and other cellular proteins
iodine
2 halogens
iodine & chlorine
Example of antisepsis
iodine and/or rubbing alcohol on arm before getting blood drawn
Gamma rays and X rays are examples of---------radiation
ionizing
blast the food with radiation, which alters the cell wall
ionizing radiation
Gamma irradiation is effective for sterilization because it
is penetrating and causes extensive molecular damage.
antimicrobial drug that disrupts formation of aribogalactan-mycolic acid by mycobacteria
isoniazid (INH) or ethambutol
♣ It is the SMALLEST amount of the drug that will INHIBIT the growth and reproduction of the pathogen- can be determined via the BORTH DILUTION TEST • A standard amount of bacterial is added to serial dilutions of antimicrobial agents in tubes
minimum inhibitory control
lack of sensitivity to three or more antimicrobials by so-called superbugs
multiple-drug-resistant pathogens
antimicrobial that works against only a few types of antibiotics
narrow-spectrum drugs
anthelmintic drugs that inhibit nucleic acid synthesis
niridazole oltipraz oxamniquine
blast food with UVA light, alters the DNA
non-ionizing radiation
chemical with structure similar to natural nucleoside
nucleoside analogs
compound structurally similar to normal nucleotide that can be incorporated into DNA; may result in mismatched base pairing
nucleotide analogs
Once scientist identify an effective microbial agent they quantitatively express
Potency as the MIC using ug/mL
The term "sterlization" applies to the removal of the following except: bacterial endospores. prions. fungi. viruses. bacterial cells.
Prions
The tetracyclines interfere with
Protein synthesis
extrachromosomal piece of DNA containing genes for resistance to antimicrobial drugs
R plasmids
Clinical indications in prescribing antimicrobial drugs
Readily available, inexpensive, chemical stable, easy to administer, nontoxic and no allergenic, selectively toxic against a wide range of pathogens
The colder the temp, the higher ability to prevent...
the growth/ reproduction of mo's but at these temperatures we do not kill any mo's just halt their growth
Why do heavy metals work?
their action of oligodynamic action. - when heavy metals combine with sulfhydryl (-SH groups of organic compounds) proteins are denatured
estimate safety of an antimicrobial drug by calculating this
therapeutic index (TI)
range of concentrations of the drug that are effective without being excessively toxic
therapeutic range (window)
The lowest temperature that kills all cells in a broth in 10 minutes is known as the
thermal death point
amount of time it takes to completely sterilize an amount of liquid at a given temperature (time remains constant, we alter temperature to see which minimal temperature can completely get rid of certain MO)
thermal death time
all of the following are characteristics of aldehydes except: some can sterilize after long periods of time they are used only to preserve dead tissues. they are used in aqueous solutions. they denature proteins. they are usually hazardous to humans.
they are used only to preserve dead tissues
All of the following are characteristics of quaternary ammonium compounds EXCEPT: Zephiran is an example of a quat. they are a type of detergent. they function by cross-linking proteins. they are used by Pseudomonas aeruginosa as a nutrient. they are harmless to humans except at high concentrations.
they function by cross-linking proteins.
All of the following are characteristics of quaternary ammonium compounds except
they function by cross-linking proteins.
Which of the following is a primary advantage of semisynthetic drugs?
they have a broader spectrum of action
why are aldehydes antimicrobial?
they interfere with cross linking of organic functional groups. They do not work on DNA or the cell wall directly
they enhance the effectiveness of other antimicrobial agents
tinctures (alcohols)
when you get too much a drug it becomes a poison to you
toxicity
-----is an phenolic antimicrobial compound that has been incorporated into consumer items such as garbage bags and diapers
triclosan
Which of the following types of radiation is nonionizing and has the shortest wavelength?
ultraviolet light
Both cultures of bacteria, dry them at 37C - standard test bacteria = P. aeruginosa, Salmonella entercia, S. aureus.
use-dilution test
Method for measuring the efficacy of disinfectants against specific microbes
use-dilution test
which of the following procedures is currently the standard test for evaluating the efficiency of antiseptics and disinfectants
use-dilution test
Antimicrobial drug that disrupts formation of Gram-positive bacterial cell walls by interfering with alanine-alanine crossbridges link- ing N-acetylglucosamine subunits.
vancomycin
All of the following are associated with filtration except: a. sterilization of heat-sensitive materials b. varying thicknesses of membrane filters used c. use HEPA filters to filter air d. nitrocellulose or plastic membrane filters e. ability of some filters to trap viruses & proteins
varying thicknesses of membrane filters used
drugs that block a pathogen's recognition of or attachment to it's host
virus; arildone is a synthetic antiviral that prevents removal of poliovirus capsids (coating) thereby interrupting viral replication cycle
Desiccation, a time-honored method of preserving food is effective because the
water content is too low to support metabolic function
1) through new mutations of chromosomal genes 2) acquiring resistance genes on extrachromosomal pieces of DNA called R PLASMIDS (R factors) via the process of horizontal gene transfer - transformation, transduction, or conjugation
ways to acquire resistance
Actions of antimicrobial agents
work to either kill or inhibit bacteria
Ultraviolet light penetrates materials----(better/worse than) gamma rays.
worse then
use in antidandruff shampoo
zinc (pyrithione)
used in some mouthwash
zinc chloride
in a diffusion susceptibility test, clear area surrounding drug-soaked disk where microbe doesn't grow
zone of inhibition
Silver is used as 1% silver nitrate solution to prevent...
opthalmia neonatorum (when the mom has chlamydia and gives vaginal birth it can cause the baby to become blind)
what is "simplest" but the concentrations in the body are less that then other routes of admin
oral
the use of high levels of salt or sugar in the preservation of foods relies on the concept of
osmotic pressure
antibacterial drug that inhibits initiation of polypeptide synthesis in gram-positive bacteria
oxazolidinones
what kills by oxidizing the enzyme (pick up free radicals)
ozidizing agents
highly reactive, forms when O2 is passed through an electrical field
ozone
sulfonamides are analogs of (chemically similar to)
para-aminobenzoic acid (PABA)
the process of heating milk or fruit juice to levels that kill any pathogenic microbes present is known as
pasteurization
use of HEAT to kill/eliminate bacteria that cause SPOILAGE to foods (wine, juice, milk)
pasteurization
*very good liquid disinfectant, highly sporocidial, leaves no toxic byproducts behind *Is for sterilizing food processing and medical equipment and is approved for washing fruit and veggies
peracetic acid
Which of the following is a sterilizing agent?
peracetic acid ONLY
Natural antiseptics such as pine or clove oil are examples of antimicrobial compound called
phenolics
group of antimicrobial drugs such as amphotericin B that disrupt cytoplasmic membrane of targeted cells by becoming incorporated into membrane & damaging its integrity
polyenes
must heat to 428 to denature it (alter structure & cannot function/reproduce) *proteins need DNA/RNA to function/reproduce
prion (denatured / abnormal protein)
*Help to preserve the normal microbiome during the use of drugs- especially antibiotics.
probiotics (disruption of normal microbiota)
antiviral drugs that inhibit viral proteins
protease inhibiotrs (-avir)
Antimicrobial agents that interfere with nucleic acids also affect
protein synthesis
drugs that inhibit BLANK by targeting the differences between prokaryotes and eukaryotes ribosomes
protein synthesis (translation)
what acts similar to bacterial endospore; heat stable & harder to kill
protozoa can lay a cyst
Boiling water rapidly kills all of the following EXCEPT: protozoan trophozoites. fungal cells. most viruses. bacterial cells. protozoan cysts
protozoan cysts
High level disinfectants and antiseptics that work by?
releasing oxygen radicals, which are particularly effective against anaerobic mo's
Topical, local, oral, intramuscular, intravenous
routes of administration
Which of the following is an example of degerming? cleaning a public toilet using heat to make milk safe to drink scrubbing your hands preparing your lab benchtop for work canning fruits or vegetables
scrubbing your hands
an effective antimicrobial agent must be more toxic to a pathogen than to the pathogen's host.
selective toxicity
principle by which an effective antimicrobial agent must be more toxic to a pathogen than to pathogen's host
selective toxicity
antimicrobial that has been chemically altered
semisynthetics
Which of the following was used in the past to prevent the transmission of gonorrhea from an infected mother to her newborn?
silver nitrate
antimicrobial agent that inhibits protein synthesis by blocking tRNA docking site
tetracyclines
Over 90% of Staphylococcus aureus isolates are penicillin- resistant why?
They produce beta lactamase
smallest amount of drug that will inhibit a pathogen
minimum inhibitory concentration (MIC)
* Aqueous ethanol (60-90% pure alcohol); isopropanol (62-65%)= disinfectants *70% is considered the best ethanol concentration
Tincture forms
UV light
disinfectant
alcohols
disinfectant
hydrogen peroxide
disinfectant
quats
disinfectant
What is the relationship of disinfectants and antiseptics
disinfectants are usually more concentrated than antiseptics, and antiseptics are used on living tissue, while disinfectant are used on inanimate objects
Quaternary ammonium compounds ("Quats") are used for...
disinfection
use for items in contact with skin or mucous membranes
disinfection
Amphotericin B is an antifungal drug that
disrupts cytoplasmic membranes
The antimicrobial polymyxin
disrupts cytoplasmic membranes
♣ Beta- lactams (penicillin's/ cephalosporin's/ carbapenems) ♣ Bacitracin blocks the transport of NAG and NAM across the cytoplasmic membrane ♣ Isoniazid disrupt the formation of mycolic acid
drugs that inhibit cell wall synthesis
antifungal drug that inhibits cell wall synthesis
echinocandins
transmembrane pump that removes antimicrobial drugs from a cell or from the periplasm
efflux pumps
antiprotozoan drugs that inhibit DNA synthesis
eflorinthine nitroimidazoles pentamidine quinolones
Sterilization procedures generally focus on the inactivation or elimination of bacterial
endospores
Which of the following is the least resistant to antimicrobial agents? protozoan cysts bacterial endospores enveloped viruses protozoa Gram-positive bacteria
enveloped viruses
Either speed up chemical reactions or can act to denature proteins/ DNA - speeding up rctn nothing is altered
enzyme
A "zone of inhibition" is associated with which of the following tests used to determine efficacy of antibiotics
etest & diffusion suscepitibility test
Kill enveloped viruses but not naked viruses, 70%- must make surfaces really WET in order to achieve optimum killing
ethyl & isopropyl alcohols
Work via their ability to denature proteins and dissolve lipids
ethyl & isopropyl alcohols
what is NOT good for wound disinfection because proteins coagulate and form a protective coat around bacteria
ethyl & isopropyl alcohols
Penetrates most materials and kills all mo's (and destroys endospores) by cross linking proteins and nucleic acids
ethylene oxide
Which of the following antimicrobial agents is the most toxic to humans? 70% alcohol chloramines ethylene oxide quats iodophors
ethylene oxide
Which of the following is used to sterilize items that should not, or cannot, be exposed to heat or water
ethylene oxide
which of the following would be used to sterilize a mattress?
ethylene oxide
Peroxides, ozone, Peracetic acid
examples of oxidizing agents
Can do disinfection and sterilization - commonly used with pharmaceutical drugs because they cannot be heated because that would denature the active chemicals
filtration
Determines the amount of drug required to kill the microbe rather than just the amount to inhibit it
minimum bacterial concentration test
Antimicrobial sugar analogs are effective for A. preventing bacterial protein synthesis. B. preventing cell membrane synthesis. C. preventing virus attachment. D. preventing nucleic acid synthesis. E. blocking a metabolic pathway.
C
The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, A. cross resistance. B. antimetabolism. C. synergism. D. selective toxicity. E. chemotherapy.
C
Which of the following is NOT a criterion by which all antimicrobial agents can be evaluated? A. their spectrum of action B. their efficacy C. their activity against cell walls D. their route of administration E. their safety
C
boiling water
Disinfectant
chlorine dioxide
Disinfectant
Use of physical or chemical agents to destroy or inhibit MO's (pathogens)? Examples?
Disinfection UV, heat, alcohol, bleach
Refer to agents that destroy or permanently inactivate a particular type of microbe
-cidal / -cide
Suffix to indicate a chemical or physical agent inhibits microbial growth, but doesn't necessarily kill
-static (stasis)
Alteration of cell walls & membranes (via osmosis)
1. Cell wall disrupted by physical of chemical agents; no longer prevents cell from bursting as water moves into cell by osmosis 2. Alter integrity of cell well, cell more susceptible to destruction
Agents used for control of microbes should be
1. Inexpensive 2. Fast acting 3. Stable during storage
All chemical methods to control MO's
1. Phenols 2. Alcohols 3. Halogens 4. Oxidizing agents 5. Surfactants 6. Heavy metals 7. Aldehydes 8. Gaseous agents 9. Enzymes
4 levels capable of handling different levels of pathogens
1. can handle MO's not known to cause ds. in health humans (E. Coli) 2. moderate dangerous = influenza virus MRSA 3. manipulations done within safety cabinets, filters, and air must undergo HEPA, double set doors, lower air pressure in lab that allows air to move into not out of room 4. Most secure = "oh shit" = Zika; lab in separate building, entry/exit controlled airlocks; all air/water filtered; space suits (BSL-4 suits)
3 things impacting efficacy of antimicrobial methods
1. site to be treated 2. relative susceptibility of MO 3. Environmental conditions (temperature / pH)
1. kinda high heat, long time 2. little higher heat, shorter time 3. highest heat, really short time "flash"
3 methods of pasteurization
Bactericides, fungicidal, virucidal against enveloped viruses, not effective against fungal or bacterial spores
Alcohols
Considered to be some of the MOST EFFECTIVE chemical disinfectants
Aldehydes
Antibacterial drugs that inhibit protein synthesis
Aminoglycosides (Neomycin, -mycin) Chloramphenicol Lincosamides Macrolides Mupirocin Oxazolidinones (linezolid) Streptogramin (-pristin) Tetracyclines (-cycline)
Which of the following antibiotics disrupts cytoplasmic membrane function in fungi?
Amphotericin B
Act against cell walls + cell membranes, protein synthesis, & DNA transcription/replication
Antimicrobials
Chemical used on skin or other LIVING tissue; reduction of number of pathogens in living tissue
Antiseptisis
Attachment Antagonists
Arildone Neuraminidase inhibitors
Environment free of contamination by pathogens
Aseptic
Drugs that disrupt unique components of a cytoplasmic membrane
Azoles and alanine's
Alterations in the structure of which of the following are an important aspect of Gram-negative bacterial resistance to antimicrobial drugs? A. plasmids B. porins C. mitochondria D. cytoplasmic membrane E. ribosomes
B porins
The spores of which of the following microbes are the most resistant to every known sterilization technique
Bacillus stearothermophilus
Antibacterial drugs that inhibit cell wall synthesis
Bacitracin Beta-lactams (penicillin, imipenem, ampicillin, etc.) Cycloserine Ethambutol Isoniazid Vancomycin
When environment is not good for bacteria to growth they form a hard layer around themselves so that it can persevere the RNA allowing bacterium to re-open, reproduce, and continue growing in more favorable conditions; what is this situation talking about?
Bacterial endospore
Bacillus & clostridium are resilient species; examples of?
Bacterial endospore (heat STABLE)
Why is mycobacterium not susceptible to normal antibiotics?
Because it doesn't have classic cell wall (waxy)
OTC acne medicine
Benzoyl peroxide
kills vegetative cells of bacteria & fungia, trophozoites of ptrotozoa, and most viruses within 10 min at sea level
Boiling (type of moist heat)
Which of the following can be used to disinfect air? ultraviolet light ethylene oxide HEPA filters Both A and C are correct. Both A and B are correct.
Both A and C are correct
Which of the following is a true statement concerning microbial death? A) It is the permanent loss of a microbe's reproductive ability. B) It speeds up over time of exposure to an antimicrobial agent. C) It can be used to evaluate the efficacy of antimicrobial agents. D) Both A and C are correct. E) A, B, and C are correct.
Both A and C are correct
Alcohols are effective against all of the following except
Both C and D are correct
Infection of the BLANK would be the hardest to treat w/ anti-MO drugs.
Brain
Which of the following is a target of pasteurization?
Brucella melitensis
An antimicrobial that inhibits cell wall synthesis will result in which of the following?
Cells become more susceptible to osmotic pressure
Central endospore vs. terminal endospore?
Central = bacillus Terminal = clostridium
o Good oxidizing agent o Disinfectant in the gas form - used to disinfect drinking water and swimming pools
Chlorine
has germicidal actions based on the formation of hypochlorus acid (HOIC) when it is added to water - excellent disinfectant, sporocidial but easily inactivated by organic material
Chlorine (halogen)
Antibacterial Drugs that inhibit Nucleic Acid Synthesis
Clofazimine Fluoroquinolones Nitroimidazoles Rifamycin
Antibacterial drugs that are antimetabolites
Dapsone Sulfonamides Trimethoprim
Use scrubbing to remove microbes from a surface
Degerming
Damage to proteins & nucleic acids
Denature proteins - pathogen no longer can reproduce
inoculates petri dishes with a standard amount of pathogen, puts small disks of paper with certain amounts of drugs and determines which one is the best
Diffusion susceptibility test
test for determining MIC; plastic strip containing a gradient of the antimicrobial agent being tested is placed on a plate inoculated with the pathogen of interest
Etest
• Place plastic strips containing a gradient of the antimicrobial agent being tested on a plate inoculated with organism • Used in labs (petri dishes) to determine the minimum inhibitory concentration and weather or not a specific strain of a bacteria/ fungus is susceptible to the action of a specific antimicrobial
Etest test
gas commonly used for sterilization
Ethylene oxide
When do you have to use most secure level of pathogens?
Exotic microbes that cause severe or fatal ds. in humans (Ebola, small pox)
Drug-resistant populations of microbes arise when
Exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells*
Because all cells engage in protein synthesis, there are few antimicrobial drugs that selectively inhibit this process
False
Beta-lactam drugs act by inhibiting formation of the cytoplasmic membrane (T/F)
False
If a subculture of an MIC test grows in an MBC test, the concentration of the drug was bactericidal.
False
Paul Erlich coined the term antibiotics for the "magic bullet" antimicrobials he pursued (T/F).
False
The outer membrane of Gram (-) bacteria enables many antimicrobial drugs to enter the cell more easily.
False
o Swabs are taken from actual objects (operating room equipment), both before and after the application of a disinfectant. The swabs are then inoculated into appropriate growth media after that, after incubation, are examined for microbial growth o It allows for a more accurate determination of proper strength and applications o "the phenyl alanine coefficient, this is more realistic—the prior 2 test are used for initial screening"
In-use test
Will not kill bacterial endospores
Intermediate level germicide
is an iodine-containing organic compound found in such antiseptics as Betadine
Iodopher
Wavelengths shorter than 1 nm - when they strike molecules they have sufficient energy to eject electrons from atoms, creating ions
Ionizing radiation (electron beams, gamma rays, some X rays)
All of the following are characterisics of an ideal antimicrobial agent except:
It denatures proteins
What makes BSL-4 Suit during most secure level of handling pathogens so special?
It ensures that any possible pathogens are forced out, where as a regular suit does not ensure that if pathogen enters suit that is forcefully pushed out of suit
The STANDARD alternative assessment approved by the EU to determine the capacity of a given chemical to inhibit bacterial growth bottom
Kelsey Sykes capacity test
Kill vegetative bacteria (living/reproducing), fungi, protozoa
Low level germicide
Permanent loss of reproduction, calculated by BLANK rate
Microbial death
What is the best method for microbial control; commonly used to disinfect, sanitize, sterilize, and pasteurize; kills cells by denaturing proteins and destroying cytoplasmic membranes!
Moist heat
*A ratio comparing the dose of the drug that a patient can tolerate to the drugs effective dose *The higher THIS, the safer the drug!!
Therapeutic Index
Range of concentration of the drug that are effective without being excessively toxic = the IDEAL concentration of a drug
Therapeutic range aka therapeutic window
lowest temp that kills all cells in broth culture
Thermal death point
All of the following statements concerning radiation as a method of microbial control are true EXCEPT: UV light effectively kills cells but does not penetrate surfaces well. X rays are the most practical form of ionizing radiation for microbial control. microwaves are valuable in microbial control only when they are used to heat food. gamma rays penetrate substances well but require hours to kill microbes. electron beams have a lot of energy but do not penetrate substances very well.
X rays are the most practical form of ionizing radiation for microbial control.
antiviral drugs that inhibit nucleic acid synthesis
acyclovir adenosine arabinoside nucleotide analogs Ribavirin
The contents of a bottle labeled "tincture of iodine" is...
alcohol solution of iodine
who discovered penicillin mole causes a zone where bacteria can't grow around it
alexander flemming 1928
class of antifungal drugs that disrupt cytoplasmic membranes
allylamines and azoles
antimicrobial drug that blocks enzymatic site of 50S subunit, inhibiting polypeptide synthesis
chloramphenicol
gas used for water treatment to prevent or reduce the formation of carcinogens during chlorination - also used to fumigate enclosed building areas contaminated with anthrax endospores
chlorine dioxide
The perfect agent?
control growth + reproduction of every type of microbe while being harmless to humans / objects (DOES NOT EXIST)
used to control green algae growth in ponds, and sometimes used to prevent mildew
copper sulfate
phenomenon in which resistance to one antimicrobial drug confers resistance to similar drugs
cross resistance
semisynthetic antibiotic used to treat infections with gram-positive bacteria
cycloserine
time it takes to destroy 90% microbes
decimal reaction time
------is the process of drying foods such as fruits in order to preserve them from microbial growth
desiccation
drying that inhibits microbial growth because metabolism requires liquid & water
desiccation
Another term for the Kirby Bauer test is the
diffusion susceptibility test
Aseptic means
free of all pathogens
Which of the following is bacteriostatic?
freezing below 0 C
Which of the following is used for microbial control in fresh fruits and vegetables?
gamma rays
A chemical agent that kills pathogenic microbes in general is a
germicide
Betadine is an example of which of the following?
halogens
Betadine is an example of which of the following? phenolics halogens alcohols surfactants heavy metals
halogens
Elements such as iodine, chlorine, and bromine are examples of -------which are the basis for many eddective antimicrobial agents.
halogens
lung machines, sutures, pillows, artificial heart valves, catheters, electronics cannot use heat or water
heart - gaseous agents
which of the following is an example of pasteurization?
heat is used to kill potential pathogens in apple juice
Which of the following describes the batch method of pasteurization?
heating at 63°C for 30 minutes
Which of the following describes flash pasteurization?
heating at 72 C for 15 seconds
Silver, mercury, copper, zinc= germicides
heavy metals
An instrument that will be used in an invasive medical procedure should be disinfected with a(n) low-level germicide. high-level germicide. intermediate-level germicide. Both A and C are correct. A, B, and C are correct.
high-level germicide
not a good antiseptic because is rapidly detoxified by catalase released by injured cells in a wound, but does make good disinfectant on non-living surfaces (important)
hydrogen peroxide (H2O2)
salt and sugar can alter the cellular membrane and therefore change the pressure- example of?
i.e. osmotic pressure
extension of MIC test in which samples are taken from clear MIC tubes are transferred to plates containing a drug-free growth medium and monitored for bacterial replication
minimum bactericidal concentration (MBC) test
Why is disinfection not sterilization?
it only get's rid of MO's that are considered to be pathogens
the amount of time needed to sterilize materials using moist heat is ------(greater/less than) the time needed to sterilize using dry heat.
less than
antimicrobial drug that bind to 50S subunit of bacterial ribosomes, preventing ribosomal movement
lincosamides
Antiprozoan drugs that inhibit protein synthesis
lincosamides (clindamycin) paramomycin
father of ASEPTIC TECHNIQUE
louis pasteur
An instrument that will come into contact with only the skin of a patient should be disinfected with a
low-level germicide
All of the following achieve sterilization except
lyophilization
the process of freeze-drying microbes to preserve them.
lyophilization
combines freezing and drying to preserve microbes and other cells for many years (i.e. liquid nitrogen)
lypilization
antimicrobial agent that inhibits protein synthesis by inhibiting ribosomal 50S subunits
macrolides
What does waxy cell wall of mycobacterium do?
makes it so organism can only be killed via strong disinfectants & heat
Drugs that inhibit multiple things is example of:
mechanisms of antimicrobial action
All of the following are components of an autoclave except: valves. temperature gauges. a pressure chamber. pressure gauges. membrane filters.
membrane filters
bacteriostatic - linked to toxicity and autism
mercury
you notice a sign in a public restroom that states "sanitized for your safety" this means...
methods of disinfection that meet minimum standards of microbial removal have been used
# of different kinds of pathogens a drug acts against
spectrum of action
incineration
sterlizing agent
antimicrobial drug that bind the 50S ribosomal subunit and prevent ribosome movement along messenger RNA
streptogramins
antimetabolic drug that is structural analog of para-aminobenzoic acid (PABA)
sulfonamides
drugs that inhibit general metabolic pathways not use by humans
sulfonamides
All of the following have denaturing proteins included in their mechanism of action except: surfactants. oxidizing agents. gaseous agents. heavy metals. aldehydes.
surfactants
Soap & detergents - decrease surface tension among molecules of liquid
surfactants
interplay between drugs that results in efficacy that exceeds efficacy of either drug alone
synergism
antimicrobial that has been completely synthesized in a laboratory
synthetics
