Chapter 9 Questions
What do you call agents that kill or permanently inactivate bacteria, fungi and viruses respectively
Bactericide, fungicide, or virucide.
What are chemical or physical agents that inhibit metabolism and growth of bacteria, fungi, and viruses respectively, but do not necessarily kill or inactivate them
Bacteriostatic, fungi static, or virustatic
What do halogens do to cells
Believed they damage enzymes via oxidation or by denaturing them
What is the brand name for iodine?
Betadine
This physical agent kills vegetative cells of bacteria and fungi, protozoan trophozoites, and most viruses within 10 minutes at sea level.
Boiling
What is a common disinfectant use in hot tubs?
Bromine
Betadine is an example of which of the following groups of antimicrobial agents? A) alcohols B) heavy metals C) halogens D) phenolics E) surfactants
C
Standard methods of sterilization are not effective in inactivating A) viruses. B) bacterial cells. C) prions. D) bacterial endospores. E) fungi.
C
The endospores of which of the following microbes are used to measure the effectiveness of autoclave sterilization? A) Clostridium botulinum B) Neisseria gonorrhoeae C) Bacillus stearothermophilus D) Pseudomonas aeruginosa E) Mycobacterium bovis
C
Which of the following is NOT a feature associated with filtration? A) nitrocellulose or plastic membrane filters B) sterilization of heat-sensitive materials C) varying thicknesses of membrane filters used D) use of HEPA filters to filter air E) ability of some filters to trap viruses and proteins
C
Which of the following is NOT an effective means of sterilization? A) ionizing radiation B) incineration C) lyophilization D) autoclaving E) dry heat
C
What does using dry heat as a physical agent do to microbial growth?
Dehydrates the cell & denatures proteins
What do alcohols do to cells?
Denature proteins & disrupt cell membranes
What do phenols do to cells
Denature proteins & disrupt cell membranes
What do gaseous agents do to cells?
Denature proteins and DNA
What do aldehydes do to cells
Denature proteins; inactivate nucleic acids
How does the phenol coefficient method evaluate the efficacy of disinfectants and antiseptics
Determines the ratio of the agent's ability to control microbes to that of phenol.
For our purposes, the electromagnetic spectrum emits 3 things which give an antimicrobial effect. What are they?
Gamma rays, UV light, strong visible light
What types of radiation are suitable for microbial control?
Gamma rays, x-rays, UV radiation
What isa disadvantage of using pasteurization
Heat-tolerant and heat-loving microbes survive
What are colorless, tasteless, harmless to humans, and antimicrobial? These are ideal for many medical and industrial applications.
Quats
What indicates that the agent is more effective than phenol?
Result greater than 1.0.
Gamma irradiation mode of action is _________________.
destroys dna
what is ultrahigh-temp sterilization
exposing milk and other liquids to superheated steam at 140 degrees c for 1-3 sec then rapid cooling
Name 6 physical methods of microbial control
exposure to extreme heat, cold, desiccation, filteration, osmotic pressure, and radiation
Elements such as iodine, chlorine, and bromine are examples of ________, which are the basis for many effective antimicrobial agents.
halogens
Incineration mode of action is _________________.
heat sterilization
what can survive during pasteurization?
heat tolerant (thermoduric) and heat-loving(thermophilic) microbes survive
What effectiveness rating do alcohols have?
Intermediate-level disinfectants
define the batch method of pasteurization used on milk
30 min at 63 degrees c which is the old method
What happens when using moist heat to control microbial growth?
Coagulation and denaturation of proteins
What suffix means to destroy or kill microbial growth?
-cide/cidal
What suffix means to inhibit or slow microbial growth?
-stasis/static
The containment level ________ is appropriate when handling highly contagious deadly microbes
4
List 2 points of action taken by antimicrobial agents
1) alteration of cell walls or cell membranes 2) Interference with protein and nucleic acid structures
what are autoclaving conditions?
121 degrees c at 15 psi for 15 minutes
define ultrahigh-temp pasteurization
134 degrees c for 1 sec, may affect taste.
Which is best for disinfecting purposes, pure alcohol or 70% alcohol? Why?
70% because it penetrates more deeply into the cells. Alcohol-water mixture allows for more diffusion.
define milk flash pasteurization
72 degrees c for 15 sec, milk runs through tubes, no pathogens
9) All of the following achieve sterilization EXCEPT: A) lyophilization. B) dry heat. C) autoclaving. D) incineration. E) ionizing radiation.
A
Seventy percent alcohol is effective against A) enveloped viruses. B) nonenveloped viruses. C) bacterial endospores. D) protozoan cysts. E) prions.
A
The process of incineration is used for A) sterilization B) disinfection C) sanitization D) both disinfection and sanitization E) degerming
A
Which of the following is an example of sanitization? A) A public toilet is treated with disinfectants. B) A surgeon washes her hands before surgery. C) Heat is used to kill potential pathogens in apple juice. D) An autoclave is used to prepare nutrient agar. E) A nurse prepares an injection site with an alcohol swab.
A
Which of the following is used to sterilize items that should not, or cannot, be exposed to heat or water? A) ethylene oxide B) formaldehyde C) hydrogen peroxide D) calcium hypochlorite E) triclosan
A
Which of the following procedures is currently the standard test used in the United States for evaluating the efficiency of antiseptics and disinfectants? A) use-dilution test B) microbial death rate C) in-use test D) thermal death point E) phenol coefficient
A
Which of the following types of radiation is nonionizing and has the shortest wavelength? A) ultraviolet light B) infrared radiation C) microwaves D) X rays E) gamma rays
A
What enhances antimicrobial effects of heat and some chemical disinfectants(bleach, sodium hypochlorite)?
Acidic conditions
Alcohol dries fast. Why is this an advantage? Why is it a disadvantage?
Advantage because it dries quickly. Disadvantage because it dries before it kills all the bacteria.
A chemical agent that kills pathogenic microbes in general is a(n) A) sanitizer B) germicide C) disinfectant D) fungicide E) antiseptic
B
Name 2 ways that antimicrobial agents kill microbes
Alteration of the cells walls or cytoplasmic membranes, and interfering with their metabolism and reproduction by damaging proteins and nucleic acids.
Antimicrobial substances applied to living tissue to reduce microbes.
Antisepsis
What is a solution called in which the solvent is water?
Aqueous
An instrument that will come into contact with only the skin of a patient should be disinfected with a(n) A) high-level germicide. B) low-level germicide. C) intermediate-level germicide. D) degerming agent only. E) germistatic agent only.
B
Disinfecting agents naturally produced by microorganisms are A) aldehydes. B) antimicrobials. C) halogens. D) quats. E) triclosans
B
The process of filtration is a(n) A) disinfectant method B) sterilizing method C) sanitization method D) antiseptic procedure E) ineffective method for removing microbes
B
Which of the following describes flash pasteurization? A) heating at 63°C for 30 minutes B) heating at 72°C for 15 seconds C) heating at 72°C for 15 minutes D) heating at 134°C for one second E) passing liquid through steam at 140°C
B
Put the following in order, from most resistant to antimicrobial agents to least resistant to antimicrobial agents: Protozoa, bacterial endospores, enveloped viruses, nonenveloped viruses, protozoan cysts
Bacterial endospores, protozoan cysts, protozoa, nonenveloped viruses, enveloped viruses
What are disadvantages of using gaseous agents?
Can be hazardous to people, often highly explosive, extremely poisonous and are potentially carcinogenic.
List some important factors to keep in mind when choosing an item to autoclave.
Cannot melt, can get wet, can withstand pressure, steam must be able to penetrate
What are High-level germicides used to sterilize
Catheters, implants, parts of heart-lung machines.
What happens when the cytoplasmic membrane is damaged
Cellular contents leak out.
What is germicide
Chemical agent that destroys pathogenic microbes in general .
What is used to treat drinking water, bleach and is in wound dressings?
Chlorine
Hydrogen peroxide is a(n) A) sterilizing agent B) disinfecting agent C) antiseptic D) disinfecting and sterilizing agent E) ineffective method of disinfecting
D
The dairy creamer used in restaurants is usually sterilized by A) filtration. B) ionizing radiation. C) lyophilization. D) UHT sterilization. E) autoclaving.
D
What is the relationship of disinfectants and antiseptics? A) Disinfectants are usually more concentrated than antiseptics. B) Antiseptics are used on living tissue, while disinfectants are used on inanimate objects. C) Disinfectants can sterilize, whereas antiseptics cannot. D) Both A and B are correct. E) Both A and C are correct.
D
Which of the following can be used to disinfect air? A) HEPA filters B) ethylene oxide C) ultraviolet light D) both HEPA filters and ultraviolet light E) both ethylene oxide and ultraviolet light
D
Which of the following statements is true of disinfectants? A) Disinfectants are effective in destroying endospores. B) Disinfectants are used on living tissue. C) Disinfectants are used for sterilization. D) Disinfectants are used on inanimate surfaces. E) Disinfectants are only effective for short periods of time (seconds to minutes).
D
Which of the following would NOT be bacteriostatic? A) desiccation B) freezing below 0°C C) lyophilization D) autoclaving E) refrigeration of mesophiles
D
Removing unwanted bacteria
Decontamination
Physical or chemical agents used to destroy microbes. Does not guarantee sterilization. Used for non-living surfaces.
Disinfection
Kirby Bauer using a Mueller-Hinton medium is an example of this type of test:
Disk diffusion test
What test is used to determine if an organism is S, R, or I to a selection of antimicrobial agents?
Disk diffusion test
Which reaches a higher temperature - dry or moist heat?
Dry
This physical agent is used to control microbial growth of materials that cannot be sterilized with or are damaged by moist heat.
Dry heat
Alcohols are used for A) disinfection. B) sterilization C) antisepsis D) both sterilization and disinfection E) both antisepsis and disinfection
E
Antimicrobial agents that damage nucleic acids also affect A) the cell wall. B) the cell membrane. C) the viral envelope. D) endospores. E) protein synthesis.
E
Aseptic means A) sterile. B) free of all microbes. C) clean. D) sanitized. E) free of pathogens.
E
Boiling water for 10 minutes is effective in ridding it of A) actively growing bacteria. B) enveloped viruses. C) bacterial endospores. D) protozoan cysts. E) both growing bacteria and enveloped viruses.
E
Disinfectants that damage membranes include A) alcohol B) phenolics C) iodine D) hydrogen peroxide E) both alcohol and phenolics
E
The spores of which of the following microbes are the most resistant to every known sterilization technique? A) Mycobacterium bovis B) Clostridium botulinum C) Neisseria gonorrhoeae D) Pseudomonas aeruginosa E) Bacillus stearothermophilus
E
Which of the following is a target of pasteurization? A) Bacillus stearothermophilus B) Clostridium botulinum C) Neisseria gonorrhoeae D) Chlamydia trachomatis E) Brucella melitensis
E
Which of the following is used for microbial control in fresh fruits and vegetables? A) X rays B) ultraviolet light C) electron beams D) microwaves E) gamma rays
E
Which of the following statements concerning microbial death is FALSE? A) It can be used to evaluate the efficacy of antimicrobial agents. B) It is constant over time of exposure to an antimicrobial agent. C) It is the permanent loss of a microbe's reproductive ability. D) It is the permanent loss of a microbe's ability to reproduce and can be used to evaluate antimicrobial agents. E) It is not an effective means of evaluating the efficacy of antimicrobial agents.
E
Which of the following was used in the past to prevent the transmission of gonorrhea from an infected mother to her newborn? A) hydrogen peroxide B) beta-propiolactone C) thimerosal D) hexachlorophene E) silver nitrate
E
What is the most susceptible microbe in terms of controlling microbial growth?
Enveloped viruses
Define aseptic
Environment or procedure free of pathogens
Name 3 examples of specific gaseous agents
Ethylene oxide, propylene oxide, betapropiolactone
UV light has the most effect on protein structure.
F
True or false: Fungi are less able than bacteria to survive hypertonic environments.
False
What happens to nucleic acids when chemicals, radiation or heat alters them
Fatal mutations can be produced, protein synthesis can be halted
What method is used to control microbial growth if the substance is difficult to heat?
Filtration
What halogen can inhibit oral bacteria's ability to create acids?
Fluoride
List examples of non-metals which are classified as halogens?
Fluorine, iodine, chlorine, bromine
What aldehyde is used for embalming & disinfection of rooms and instruments?
Formalin
__________ kills by ice crystal disruption of cells and molecules.
Freezing
What is one thing used to filter air?
HEPA filters
Where are phenols commonly used?
Health care settings, labs, homes (Examples: Lysol, triclosan which is found in garbage bags/diapers)
What physical agent is used to control microbial growth because it is economical & easily controlled?
Heat
How are the effectiveness of germicides classified
High, intermediate, or low.
What level of effectiveness are aldehydes?
High-level
What level of effectiveness are gaseous agents?
High-level
Effectiveness of chemical agents are classified as high, intermediate or low. Describe each.
High-level: Kills all pathogens, including endospores Intermediate-level: Kill fungal spores, protozoan, cysts, viruses and pathogenic bacteria Low-level: Kill vegetative bacteria, fungi, protozoa, and some viruses
What is the active ingredient of Chlorox bleach?
Hypochlorite ion (OCl-)
Which test is being described here: Swabs taken from objects before & after use of disinfectant/antiseptic. Swabs are inoculated & incubated then monitored for growth. This aids in determining proper strength/application procedure for each situation.
In-Use test
What are prions?
Infectious proteins that cannot be eliminated by standard sterilizing techniques. (example: Mad cow)
What effectiveness rating do halogens have?
Intermediate-level antimicrobial chemicals
What effectiveness rating does Phenol & Phenolics have?
Intermediate-to low-level disinfectants
What is an iodine-containing organic compound?
Iodophore
This type of radiation consists of a loss of electrons and causes mutations.
Ionizing
Which type of radiation is used to sterilize medical products?
Ionizing
This type of radiation is for cold sterilization, is highly effective for sterilizing materials that are sensitive to heat or chemicals. Give 3 examples.
Ionizing - gamma rays, x-rays, cathode rays
Why is it important to swab the skin with 70% ethanol prior to injection?
It allows for diffusion into the cells
What is an advantage of using Kirby Bauer/Mueller-Hinton medium for the disk diffusion test? Give examples.
It is highly standardized (certain thickness to allow for appropriate diffusion/broth is diluted to match a turbidity standard, zone of inhibition measured in mm)
What scientist is phenol coefficient connected to?
Lister
What level of effectiveness are heavy metals?
Low-level bacteriostatic & fungistatic agents
What effectiveness rating do Quats have?
Low-level disinfectant
This is a combination of freezing and drying. It is used for long term preservation of microbial cultures & prevents freezer burn.
Lyophilization
The abbreviation ________ stands for the smallest amount of a drug that will inhibit the growth and reproduction of a pathogen.
MIC
What happens in the Use-dilution test
Metal cylinders are exposed to bacteria, then put into dilution of disinfectant for 10 min., then removed washed and put into medium for 48 hours, then most effective agent entirely prevents microbial growth at highest dilution.
With this type of radiation, specific damage occurs on the pyrimidine bases (T &C)
Non-ionizing
What can be used as an intermittent form of sterilization when pressurized steam is not available?
Non-pressurized steam
The most resistant microbes contain what in their cell wall?
Mycolic Acid
Mycobacterium tuberculosis contains what in its cell wall & what does this do?
Mycolic acid, enhances resistance
Name three factors that effect the efficacy of antimicrobial methods
Nature of the site to be treated, degree of susceptibility of microbes involved, and environmental conditions that pertain
Is disinfecting considered a form of sterilization?
No
Is filtration sterilization?
No
Is pasteurization disinfection?
No
Is pasteurization sterilization?
No
Is "commercial sterilization" really sterilization? Why? What does this allow?
No, not necessarily free of all microorganisms, but those that survive the sterilization process are unlikely to grow during storage and cause spoilage. Allows for longer shelf period w/o refrigeration.
Which have a greater tolerance to harsh conditions, Enveloped or non-enveloped viruses
Non-enveloped viruses
What are Intermediate-level germicides used to disinfect
Non-invasive instruments used in contact with mucous membranes.
What type of radiation are UV rays?
Non-ionizing
What are Low-level germicides used to disinfect
Objects that come in contact with skin. ex. electrodes and furniture.
High concentrations of salt or sugar in foods to inhibit growth. Water in cell is drawn out by osmosis; cell desiccates.
Osmotic pressure
What is a reactive form of oxygen produced by subjecting molecular oxygen to an electrical discharge? What is an example?
Ozone; drinking water
What deals with preventing spoilage and potential pathogens in milk, ice cream, yogurt, and fruit juices?
Pasteurization
What is a much less extreme use of moist heat than autoclaving?
Pasteurization
This is an effective sporocide used to sterilize equipment.
Peracetic acid
What 3 things kill by oxidation of microbial enzymes?
Peroxide, ozone, and peracetic acid
This is a test used to measure bactericidal activity.
Phenol Coefficient
Name 3 methods used to evaluate disinfectants and antiseptics
Phenol coefficient, Use-dilution test, and In-use Test.
Are detergents positively or negatively charged?
Positive
The term "sterilization" applies to the removal of all of the following EXCEPT: Bacterial cells, prions, viruses, bacterial endospores
Prions
What is the most resistant microbe in terms of controlling microbial growth?
Prions
What will sterilization not kill
Prions in or on an object
What is sanitization
Process of disinfecting public areas, or utensils used in public place to reduce the number of pathogens to meet public health standards.
What species can grow in solutions of quats?
Pseudomonas
What type of microbes can multiply in refrigerated foods?
Psychrophillic
Extrachromosomal pieces of DNA called ________ promote horizontal transfer of genes among bacteria and contribute to the spread of antimicrobial resistance.
R plasmids
Energy emitted from atomic activities and dispersed at high velocity through matter or space.
Radiation
How do you degerm
Scrubbing and removing microbes from a surface.
What one thing is important in the efficacy of autoclaving?
Steam must be able to penetrate
List 4 ways that moist heat is employed to control microbes:
Steam under pressure, nonpressurized steam, pasteurization, boiling water
What is complete removal of microbes called?
Sterilization
List 4 methods of microbial control used outside the body.
Sterilization, disinfection, antisepsis, decontamination
Soaps and detergents are what sort of de-germing agents?
Surfactants
What is sterilization
The destruction of all microbes, including bacteria, viruses and endospores.
What does thermal death point mean?
The lowest temperature required to kill a microbe.
What is the length of time it takes for heat to kill a microbe called?
Thermal death time
What is an advantage of using the phenol coefficient test?
This test can be determined in the presence or in the absence of organic matter such as blood and feces.
What is it called when antimicrobial chemicals are dissolved in alcohol to produce a liquid solution?
Tincture
True or False: Greater than 1 indicates that an agent is more effective than phenol.
True
True or false: Alcohol can cause tissue damage.
True
True or false: Refrigeration halts growth of most pathogens.
True
True or false: Water boils at lower temperatures at higher elevation.
True
When non-pressurized steam is used for sterilization, what process is needed to kill the endospores that still exist? This cycle would need to be repeated 3 days in a row.
Tyndallization
What type of sterilization is used in commercial sterilization?
Ultrahigh-temperature pasteurization
This is a tool for new product development, new disinfectant registrations, and EPA's compliance testing.
Use Dilution Test
What test is being demonstrated here: Metal cylinders are dipped into broth cultures of bacteria, removed, rinsed, & placed into medium for 48 hrs. Most effective agent entirely prevents growth at lowest dilution of the disinfectant.
Use Dilution Test
Antisepsis
Use of chemical agents to destroy microorganisms on skin or mucous membranes of body.
Define Disinfection
Use of physical or chemical agents to destroy microorganisms, especially pathogens, on non living objects
What is pasteurization
Using heat to kill pathogens and most spoilage organism in food and beverages with out altering quality of food
What is responsible for attachment of virus to target cell
Viral Envelope
What happens when there is damage to the viral envelope
Viral replication is interrupted.
Which works better warm or cool disinfectants
Warm b/c chemicals react faster at higher temps.
Are these phenols effective in the presence of organic matter
Yes
Does autoclaving provide sterilization?
Yes
Has Phenol Coefficient been replaced by newer methods
Yes
Is ionizing radiation sterilization?
Yes
Is strong visible light disinfecting?
Yes
Is non-ionizing radiation sterilization?
Yes for surfaces, No for depths
Is non-ionizing radiation disinfecting?
Yes, does not penetrate
What are 2 brand names of quats
Zephiran and Cepacol
) Beta-lactam antibiotics have an effect on which of the following types of cells? A) bacterial cells B) fungal cells C) virus-infected cells D) animal cells E) both animal and fungal cells
a
A chemical agent that kills pathogenic microbes in general is a(n) A) germicide. B) disinfectant. C) fungicide. D) antiseptic. E) sanitizer
a
Alterations in the structure of which of the following are an important aspect of Gram-negative bacterial resistance to antimicrobial drugs? A) porins B) cytoplasmic membrane C) mitochondria D) plasmids E) ribosomes
a
Another term for the Kirby-Bauer test is the A) diffusion susceptibility test. B) broth dilution test. C) minimum bactericidal concentration test. D) E test. E) minimum inhibitory concentration test
a
Antimicrobials that block protein synthesis by binding to the mRNA are A) antisense nucleic acids. B) nucleic acid analogs. C) beta-lactams. D) aminoglycosides. E) macrolides.
a
Disinfecting agents naturally produced by microorganisms are A) antimicrobials. B) triclosans. C) quats. D) halogens. E) aldehydes.
a
Infection of the ________ would be the hardest to treat with antimicrobial drugs. A) brain B) liver C) kidneys D) heart E) colon
a
Most broad-spectrum antibiotics act by A) inhibiting protein synthesis. B) disrupting the cytoplasmic membrane. C) inhibiting nucleic acid synthesis. D) inhibiting metabolic pathways. E) inhibiting the synthesis of the cell wall
a
Sulfonamides A) were the first widely used antimetabolic antimicrobial and indirectly inhibit nucleic acid synthesis. B) are antimetabolic drugs. C) were the first widely used antimicrobial drugs. D) are no longer widely used. E) indirectly inhibit the synthesis of nucleic acids.
a
Which of the following antibiotics disrupts cytoplasmic membrane function? A) amphotericin B B) erythromycin C) tetracycline D) penicillin E) streptomycin
a
Which of the following antimicrobial agents is the most toxic to humans? A) ethylene oxide B) iodophors C) chloramines D) quats E) 70% alcohol
a
Which of the following describes flash pasteurization? A) heating at 72°C for 15 seconds B) heating at 63°C for 30 minutes C) heating at 72°C for 15 minutes D) passing liquid through steam at 140°C E) heating at 134°C for one second
a
Which of the following is NOT a feature associated with filtration? A) varying thicknesses of membrane filters used B) nitrocellulose or plastic membrane filters C) ability of some filters to trap viruses and proteins D) sterilization of heat-sensitive materials E) use of HEPA filters to filter air
a
Which of the following is a measurement associated with the broth dilution test? A) lack of turbidity B) the zone of inhibition C) presence of turbidity and cell lysis D) lack of turbidity and zone of inhibition E) cell lysis
a
Which of the following is a primary advantage of semisynthetic drugs? A) They have a broader spectrum of action. B) They must be administered intravenously. C) They work faster. D) They are not readily absorbed, so they persist longer. E) They are less stable and consequently have fewer side effects
a
β-lactamase production is an example of which of the following types of resistance? A) inactivation of the drug B) removal of the drug via a pump C) change in the permeability of the drug D) alteration of the target of the drug E) overproduction of an enzyme in a key metabolic pathway
a
Disinfectants known as ________ have the chemical group CHO, which reacts with and damages both proteins and nucleic acids.
aldehydes
What do High-level germicides kill
all pathogens, including Endospores
Drugs that slow down bacterial growth would be ________ to penicillin.
antagonist
Antiviral medications frequently block unique ________ to prevent production of new virus
attachment antagonists
A(n) ________ is an instrument that sterilizes by exposing materials to steam under pressure
autoclave
An antimicrobial that inhibits cell wall synthesis will result in which of the following? A) The replication of cells, including cancer cells, slows down. B) Cells become more susceptible to osmotic pressure. C) Ribosomes lose their function. D) The sterols in the cell wall become nonfunctional. E) Cells cannot attach to their hosts.
b
Antimicrobial agents that damage nucleic acids also affect A) the cell wall. B) protein synthesis. C) endospores. D) the cell membrane. E) the viral envelope.
b
Disruption of the normal microbiota can result in infections caused by which of the following microbes? A) Clostridium difficile B) Candida albicans C) Mycobacterium D) Candida albicans, Mycobacterium, and Clostridium difficile E) both Mycobacterium and Clostridium difficile
b
Lysol is an example of which of the following groups of chemical antimicrobial agents? A) halogens B) phenolics C) aldehydes D) surfactants E) alcohols
b
Most drugs that inhibit the synthesis of the cell wall act by A) preventing the formation of β-lactamases. B) preventing the cross-linkage of NAM subunits. C) disrupting the formation of the mycolic acid layer of the cell wall. D) preventing the formation of alanine-alanine bridges. E) blocking the secretion of cell wall molecules from the cytoplasm
b
The endospores of which of the following microbes are used to measure the effectiveness of autoclave sterilization? A) Neisseria gonorrhoeae B) Bacillus stearothermophilus C) Mycobacterium bovis D) Pseudomonas aeruginosa E) Clostridium botulinum
b
The most limited group of antimicrobial agents is the ________ drugs. A) anthelmintic B) antiviral C) antiprotozoan D) antibacterial E) antifungal
b
Which of the following is NOT a target of drugs that inhibit protein synthesis? A) the tRNA docking site B) interference with alanine-alanine bridges C) the shape of the 30S ribosomal subunit D) movement of the ribosome from one codon to the next E) the enzymatic site of the 50S ribosomal subunit
b
Which of the following statements is true of disinfectants? A) Disinfectants are used for sterilization. B) Disinfectants are used on inanimate surfaces. C) Disinfectants are only effective for short periods of time (seconds to minutes). D) Disinfectants are used on living tissue. E) Disinfectants are effective in destroying endospores.
b
Which of the following statements is true of selective toxicity? A) Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen. B) Selective toxicity takes advantage of metabolic differences between host and pathogen. C) Selective toxicity takes advantage of structural differences between host and pathogen. D) Antimicrobial agents must target structural differences between host and pathogen and be more toxic to the patient than the pathogen. E) To be effective, an antimicrobial agent must be more toxic to the patient than the pathogen
b
Which of the following types of radiation is nonionizing and has the shortest wavelength? A) X rays B) ultraviolet light C) gamma rays D) infrared radiation E) microwaves
b
Which of the following was used in the past to prevent the transmission of gonorrhea from an infected mother to her newborn? A) hexachlorophene B) silver nitrate C) beta-propiolactone D) hydrogen peroxide E) thimerosal
b
Which of the following would be used to sterilize a mattress? A) formaldehyde B) ethylene oxide C) heavy metals D) autoclaving E) radiation
b
A(n) ________ concentration of a drug is one at which microbes survive but are not able to grow and reproduce.
bacteriostatic
There are 3 different types of pasteurization. Name each type listed. 1) 30 minutes at 63 degrees C 2) 72 degrees C for 15 seconds 3) 134 degrees for 1 second
batch method, flash pasteurization, ultrahigh-temperature pasteurization
name 4 methods of microbial control using moist heat.
boiling, autoclaving, pasteurization, and ultrahigh-temp sterilization
A(n) ________ drug is effective against a wide variety of pathogens
broad spectrum
A scientist develops a new medication that is a protein compound and that must be administered by injection. Which of the following would be the most effective and safest means of preparing a sterile solution of the new medication? A) dilution with alcohol B) ultraviolet irradiation C) filtration D) autoclaving E) lyophilization
c
Aseptic means A) free of all microbes. B) clean. C) free of all pathogens. D) sanitized. E) sterile.
c
Betadine is an example of which of the following groups of antimicrobial agents? A) alcohols B) phenolics C) halogens D) heavy metals E) surfactants
c
Boiling water for 10 minutes is effective in ridding it of A) protozoan cysts. B) actively growing bacteria. C) both growing bacteria and enveloped viruses. D) enveloped viruses. E) bacterial endospores.
c
Seventy percent alcohol is effective against A) nonenveloped viruses. B) prions. C) enveloped viruses. D) bacterial endospores. E) protozoan cysts.
c
The dairy creamer used in restaurants is usually sterilized by A) lyophilization. B) ionizing radiation. C) UHT sterilization. D) autoclaving. E) filtration.
c
Which of the following is a sterilizing agent? A) ozone B) ozone and hydrogen peroxide C) peracetic acid D) dish soap E) hydrogen peroxide
c
Which of the following is a target of pasteurization? A) Chlamydia trachomatis B) Clostridium botulinum C) Brucella melitensis D) Bacillus stearothermophilus E) Neisseria gonorrhoeae
c
Which of the following is used for microbial control in fresh fruits and vegetables? A) microwaves B) X rays C) gamma rays D) ultraviolet light E) electron beams
c
Which of the following pathways is specifically inhibited by sulfonamides? A) the conversion of PABA to tetrahydrofolic acid B) the conversion of tetrahydrofolic acid to PABA C) the conversion of PABA to dihydrofolic acid D) the conversion of dihydrofolic acid to tetrahydrofolic acid E) the conversion of dihydrofolic acid to PABA
c
Which of the following statements about quaternary ammonium compounds is FALSE? A) They are harmless to humans except at high concentrations. B) Zephiran is an example of a quat. C) They function by cross-linking proteins. D) They are a type of detergent. E) They are not effective against Pseudomonas aeruginosa.
c
Which of the following statements about the zone of inhibition is FALSE? A) It is a result of diffusion of the drug out of the paper disk. B) It is measured as a diameter. C) The larger the zone, the more resistant the organism is. D) It is a clearing zone with no growth. E) It is measured after incubation.
c
Which of the following statements concerning development of antibiotic resistance is FALSE? A) New resistance genes can be gained through transformation, transduction, or conjugation. B) It is often mediated by R-plasmids. C) Resistant cells grow more efficiently and quickly than susceptible cells. D) Resistance can occur through mutation of existing bacterial genes. E) Resistant cells are normally in the minority in a bacterial population.
c
Praziquantel alters the cytoplasmic membrane permeability of ________.
calcium ions
What happens when the cell wall is disrupted
cannot prevent cell from bursting due to osmotic effects
Polymyxin mode of action is _________________.
cell membrane of gram neg
Sterilization procedures generally focus on inactivating or eliminating bacterial ________.
cell wall
Any drug that acts against a disease is called a(n) ________ agent
chemotherapeutic agents
What should you do before sterilizing or disinfecting objects
clean them because body materials can reduce effectiveness.
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 resistance
A large percentage of antibiotics and semisynthetic drugs are produced by members of the genus A) Penicillium. B) Bacillus. C) Cephalosporium. D) Streptomyces. E) Mycobacterium.
d
Antimicrobial sugar analogs are effective for A) preventing bacterial protein synthesis. B) blocking a metabolic pathway. C) preventing cell membrane synthesis. D) preventing virus attachment. E) preventing nucleic acid synthesis.
d
It is inappropriate to prescribe antibacterial agents to treat colds or flu because A) these diseases are transmitted by endospores, which are hard to kill. B) the microbes involved can develop resistance rapidly. C) these diseases exhibit cross resistance. D) these diseases are caused by viruses. E) these diseases can act synergistically with each other.
d
Probiotics A) involve microbial antagonism. B) is a term for resistance to antibiotics. C) are an alternative to the use of chemotherapy. D) are an alternative to the use of chemotherapy involving microbial antagonism. E) involve the use of extracts from microorganisms.
d
The Etest determines which of the following? A) MBC B) MIC C) susceptibility D) both susceptibility and MIC E) both MBC and MIC
d
Which of the following can be used to disinfect air? A) ethylene oxide B) HEPA filters C) ultraviolet light D) both HEPA filters and ultraviolet light E) both ethylene oxide and ultraviolet light
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) sulfonamides D) tetracyclines E) quinolones
d
Which of the following is NOT a criterion by which all antimicrobial agents can be evaluated? A) their route of administration B) their efficacy C) their spectrum of action D) their activity against cell walls E) their safety
d
Which of the following is an example of sanitization? A) Heat is used to kill potential pathogens in apple juice. B) An autoclave is used to prepare nutrient agar. C) A surgeon washes her hands before surgery. D) A public toilet is treated with disinfectants. E) A nurse prepares an injection site with an alcohol swab
d
Which of the following is the most appropriate pairing of microbe and biosafety level? A) anthrax, BSL-1 B) E. coli, BSL-3 C) Ebola, BSL-2 D) methicillin-resistant Staphylococcus aureus (MRSA), BSL-2 E) tuberculosis, BSL-1
d
Which of the following is used to sterilize items that should not, or cannot, be exposed to heat or water? A) formaldehyde B) calcium hypochlorite C) triclosan D) ethylene oxide E) hydrogen peroxide
d
Which of the following statements concerning microbial death is FALSE? A) It can be used to evaluate the efficacy of antimicrobial agents. B) It is constant over time of exposure to an antimicrobial agent. C) It is the permanent loss of a microbe's ability to reproduce and can be used to evaluate antimicrobial agents. D) It is not an effective means of evaluating the efficacy of antimicrobial agents. E) It is the permanent loss of a microbe's reproductive ability.
d
Which scientist coined the term antibiotic? A) Kirby B) Fleming C) Ehrlich D) Waksman E) Domagk
d
Who discovered the first widely available antibiotic? A) Waksman B) Ehrlich C) Ehrlich and Waksman D) Domagk E) Fleming
d
Methicillin mode of action is _________________.
deactivates enzyme that cross links the NAM subunits of peptidogycan
Quats mode of action is _________________.
decrease surface tension, disrupt cell membrane
what are the effects of high temps
denaturation of proteins, interference with integrity of cytoplasmic membrane and cell walls, and disruption of structure and function of nucleic acids
Chlorine dioxide mode of action is _________________.
denature protein
Glutaraldehyde mode of action is _________________.
denature proteins
Ethylene oxide mode of action is _________________.
denature proteins, penetrate paper and plastic wraps and diffuse into every crack
Alcohols mode of action is _________________.
denatures protein and disrupts cell membrane
Boiling water mode of action is _________________.
denatures proteins and destroys membranes
what does dry heat do?
denatures proteins and oxidizes metabolic and structural chemicals
Vancomycin mode of action is _________________.
directly interferes with formation of alanine-alanine bridges between NAM
Amphotericin B mode of action is _________________.
disruption of cytoplasmic membrane
which requires higher temps for longer times, moist or dry heat?
dry heat, need 171 degrees c for 1 hour or 160 degrees c for 2 hours
An instrument that will come into contact with only the skin of a patient should be disinfected with a(n) A) degerming agent only. B) intermediate-level germicide. C) germistatic agent only. D) high-level germicide. E) low-level germicide.
e
Disinfectants that damage membranes include A) hydrogen peroxide. B) alcohol. C) iodine. D) phenolics. E) both alcohol and phenolics.
e
Standard methods of sterilization are not effective in inactivating A) viruses. B) fungi. C) bacterial endospores. D) bacterial cells. E) prions.
e
The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, a β-lactamase inhibitor, is known as A) chemotherapy. B) cross resistance. C) selective toxicity. D) antimetabolism. E) synergism.
e
Which of the following can result when antibiotic therapy disrupts the normal microbiota? A) thrush B) black hairy tongue C) anaphylactic shock D) pseudomembranous colitis E) both pseudomembranous colitis and thrush
e
Which of the following drugs inhibits nucleic acid synthesis specifically in prokaryotes? A) 5-fluorocytosine B) tetracycline C) actinomycin D) rifampin E) quinolones
e
Which of the following drugs specifically targets cell walls that contain arabinogalactan-mycolic acid? A) bacitracin B) vancomycin C) methicillin D) penicillin E) isoniazid
e
Which of the following interferes with cell wall synthesis by blocking alanine bridge formation? A) beta-lactams B) bacitracin C) vancomycin D) cycloserine E) both cycloserine and vancomycin
e
Which of the following is NOT a desirable characteristic of an ideal antimicrobial agent? A) It is harmless to humans. B) It acts quickly. C) It is stable during storage. D) It is inexpensive. E) It only arrests growth of vegetative cells.
e
Which of the following is NOT an effective means of sterilization? A) ionizing radiation B) dry heat C) autoclaving D) incineration E) lyophilization
e
Which of the following procedures is currently the standard test used in the United States for evaluating the efficiency of antiseptics and disinfectants? A) phenol coefficient B) in-use test C) microbial death rate D) thermal death point E) use-dilution test
e
Which of the following statements about aldehydes is FALSE? A) Some aldehydes can sterilize after long periods of exposure. B) They are used in aqueous solutions. C) They denature proteins. D) They are usually hazardous to humans. E) They are used only to preserve dead tissues.
e
Which of the following works by inhibiting ergosterol synthesis? A) fluconazole B) amphotericin B C) turbinafine D) nystatin E) both fluconazole and turbinafine
e
Which of the following would NOT be bacteriostatic? A) desiccation B) lyophilization C) refrigeration of mesophiles D) freezing below 0°C E) autoclaving
e
what can survive boiling?
endospores, protozoan cysts, and some viruses
Antimicrobial agents usually work best at high temperatures and pH levels
f
Because all cells engage in protein synthesis, there are few antimicrobial drugs that selectively inhibit this process.
f
Beta-lactam drugs act by inhibiting formation of the cytoplasmic membrane
f
Hydrogen peroxide is an effective antiseptic
f
If a subculture of an MIC test grows in an MBC test, the concentration of the drug was bactericidal
f
No chemical or antimicrobial agents inactivate prions
f
The decimal reduction time is the time required to kill all the microbes in a given sample
f
The outer membrane of Gram-negative bacteria enables many antimicrobial drugs to enter the cell more easily
f
phenol coefficient is one of the most widely used measurements of an antimicrobial agent's effectiveness.
f
What do Intermediate-level germicides kill
fungal spores, protozoan cysts, viruses and pathogenic bacteria.
which can survive hypertonic environments better, fungi or bacteria?
fungi
how is osmotic pressure used in microbial growth control?
high concentrations of salt or sugar in foods to inhibit growth, cells in hypertonic solutions of salt or sugar lose water and cell desiccates
why is slow freezing more effective?
ice crystals that puncture cell membranes have more time to form
What are the four things that agents should be
inexpensive, fast-acting, stable during storage , be harmless to humans, animals, and objects but still controlling all microbial growth.
Sulfonamides mode of action is _________________.
inhibit folic acid synthesis
Erythromycin mode of action is _______________.
inhibit protein synthesis
Ribavirin mode of action is _________________.
inhibits nucleic acid
Trimethoprim mode of action is _______________.
inhibits protein systhesis
lyophilization
instant freezing in liquid nitrogen, then exposure to vacuum for water removal
A(n) ________ is an iodine-containing organic compound found in such antiseptics as Betadine
iodophor
what are electron beams
ionizing radiation effective at killing but do not penetrate well
what are gamma rays
ionizing radiation that penetrate well but require hours to kill microbes
why is moist heat used to disinfect, sanitize, and sterilize
kills by denaturing protein and destroying cytoplasmic membranes and is a better conductor of heat than dry heat.
Ultraviolet light penetrates materials ________ (more effectively/less effectively) than gamma rays
less
The amount of time needed to sterilize materials using moist heat is ________ (greater than/less than) the time needed to sterilize using dry heat.
less than
why is lyophilization used
long term preservation of microbial cultures
define nonionizing radiation
longer wavelength
thermal death point
lowest temp that kills all cells in broth in 10 minutes
_______________________ is the process of freeze-drying microbes to preserve them
lyophilization
what are gamma rays used to sterilize
meats, spices and fresh fruits and veggies
Competition between beneficial microbes and potential pathogens is called ________.
microbial antagonism
Are thermoduric and thermophilic microbes pathogenic?
no
are x rays used ionizing radiation
no b/c too much time to be practical
Has Use-dilution test been replaced?
no but new standards are being developed.
Do ultrahigh-temp sterilized liquids have to be kept cold?
no can be stored at room temp
Quinolones mode of action is _______________.
nucleic acid synthesis
Antimicrobial agents that mimic the chemical structure of DNA building blocks are called ______________.
nucleotide analogs
The use of high levels of salt or sugar in the preservation of foods relies on the phenomenon of ________.
osmotic pressure
Hydrogen peroxide mode of action is _________________.
oxidation
Filtration mode of action is _________________.
passage of liquid of through sieve to trap particles
process of heating milk or fruit juice to levels that kill any pathogenic microbes present is known as ________.
pasteurization
Natural antiseptics such as pine or clove oil are examples of antimicrobial compounds called ________.
phenolics
what is autoclaving?
pressure applied to boiling water preventing steam from escaping.
Tetracyclines mode of action is _______________.
prevent tRNA from binding to ribosomes
Heavy metal and oxidizing agent disinfectants damage ________, interfering with microbial metabolism
protein
what type of microbes can multiply in refrigerated foods?
psychrophilic microbes
________ drugs are semisynthetic drugs developed to combat resistance against an existing drug
second generation
________ means that a given antimicrobial agent is more toxic to a pathogen than to the host being treated
selective toxicity
define radiation ionizing
shorter wavelength
When using radiation in microbial control which is better short or long wavelength?
shorter wavelength has more energy and greater penetration
which is more effective slow or quick freezing?
slow freezing
what are electron beams used to sterilize
spices, meats, plastic ware and medical and dental supplies
________ are serious secondary infections that result from the killing of the normal microbiota
superinfections
What happens in the In-Use test
swabs are taken from objects before and after application of disinfectant or antiseptic, swabs are inoculated into growth media and incubated, media monitored for microbial growth, then accurate determination of proper strength and application procedure for each specific situation.
An environment may contain some microbes and still be considered sterile
t
Antisense nucleic acids are designed to have no side effects against humans.
t
Brain and spinal cord infections are difficult to treat because most antimicrobial drugs cannot diffuse out of the blood into these organs.
t
By themselves, soaps have only degerming activity, not antimicrobial activity
t
Many antimicrobial drugs that affect the cytoplasmic membrane are used only externally because they can be toxic to humans.
t
Organs that are commonly affected by drug toxicity include the kidneys and the liver.
t
Paul Erhlich coined the term antibiotics for the "magic bullet" antimicrobials he pursued
t
Slow freezing is more damaging to microbial cells than quick freezing.
t
Some bacterial cells are resistant to a variety of antimicrobials because they actively pump the drugs out of the cell
t
Some viruses are inactivated by the same chemical or physical agents that damage cytoplasmic membranes.
t
The lowest temperature that kills all cells in a broth in 10 minutes is known as the ________.
thermal death point
thermal death time
time to sterilize volume of liquid at set temperature
External infections can be treated by ________ administration, in which a drug is applied directly to the site of infection.
topical
) ________ is a phenolic antimicrobial compound that has been incorporated into consumer items such as garbage bags and diapers.
triclosan
what is incineration?
ultimate means of sterilization
why is dry heat used?
used for materials that cannot be sterilized with or are damaged by moist heat
What do low-level germicides kill
vegetative bacteria, fungi, protozoa, and some viruses.
What does boiling kill?
vegetative cells of bacteria and fungi, protozoan trophozoites, and most viruses within 10 min at sea level.
does ultrahigh-temp sterilization kill all living microbes
yes