156 Questions
Which of the following is a method of microbial control that destroys bacteria?
Bactericide
Which of the following is a method of microbial control that inhibits/prevents the growth of fungi?
Fungistatic
Which of the following is a method of microbial control that destroys viruses?
Viricide
Which of the following is a method of microbial control that destroys spores?
Sporicide
Which type of disinfectant is useful as an antiseptic and disinfectant and is active against chlorophyllobtaining organisms, especially algae?
Copper
Which type of disinfectant is commonly used as a disinfectant and can kill Gram positive and negative bacteria, algae, protozoa, viruses, and biofilms within 30 minutes of application?
Halogens
Which type of disinfectant is active against vegetative cells, denatures proteins, and dissolves lipids?
Alcohols
Which type of disinfectant is considered a surfactant, primarily works as a degerming agent, and reduces the surface tension of surfaces?
Surfactants
Which method can be used to sterilize substances that are destroyed by heat, such as drugs, serum, vitamins, and sucrose?
Filtration
Which type of radiation consists of photons and/or moving particles that have sufficient energy to knock electrons out of the shells from either an atom or molecule, thus forming an ion?
Radiation gamma rays
Which type of radiation causes the formation of thymine dimers in DNA, leading to lethal mutations in exposed microbes?
Radiation UV rays
Which method can be used to collect microorganisms from air and water samples for water quality testing?
Filtration
Which method of moist heat sterilization requires a pressure of 28-30lb/in2 and a temperature of 132oC to 134oC for as little as 4 minutes?
Autoclaving
Which method of moist heat sterilization uses free flowing steam at 100oC for 30 minutes on each of three consecutive days?
Fractional sterilization/Tyndallization
Which method of moist heat sterilization is used to destroy pathogenic organisms in food, but does not achieve sterility?
Pasteurization
Which method of pasteurization involves heating at 63oC for 30 minutes?
Holding(batch) pasteurization method
Which of the following is NOT a type of filter mentioned in the text?
Carbon filter
Which of the following is NOT a characteristic of disinfectants?
Used to sterilize objects
Which of the following is a limitation of phenolic compounds as antiseptics?
All of the above
Which of the following is a characteristic of heavy metals as disinfectants?
Combine with proteins to inactivate them
Which of the following is NOT a method of microbial control for use on fomites?
Degerming
Which of the following is the LEAST resistant to microbial control?
Enveloped viruses
What is the process of killing or inhibiting the growth of pathogens without leading to sterilization called?
Disinfection
What is the application of chemicals for removal of potential pathogens from living tissue called?
Antisepsis
Which type of disinfectant is broken down by catalase in tissue and results in the production of superoxide radicals?
Hydrogen peroxide
Which category of effectiveness of chemical disinfectants has the ability to kill vegetative cells, fungi, viruses, and endospores?
High-level germicides
What makes a chemical agent a good disinfectant or antiseptic?
Ability to kill or slow the growth of microorganisms
Which factor should be considered when selecting a disinfectant or antiseptic?
All of the above
Which type of microorganism is more susceptible to disinfectants?
Gram-positive
What type of surface should be considered when selecting a disinfectant or antiseptic?
Both wound and bench
Which of the following methods of microbial control involves the complete destruction/removal of all living microbes, spores, and viruses on an object or in an area?
Sterilization
What is the process of killing or inhibiting the growth of pathogens without leading to sterilization called?
Disinfection
Which type of microbial control method significantly reduces microbial numbers by using mild chemicals and gentle scrubbing of a small area of skin or tissue to avoid the transmission of pathogenic microbes?
Degerming
Which type of microbial control method involves the application of chemicals for removal of potential pathogens from living tissue?
Antisepsis
Which method of microbial control uses salting to induce water to diffuse out of microorganisms via osmosis?
Desiccation
Which type of radiation has a wavelength between 100 and 400 nm and is most destructive to cells at 265 nm?
Radiation UV rays
Which method of microbial control uses microwaves to vibrate mainly water molecules, causing friction and heat to defrost and cook foods?
Radiation Microwaves
Which method of microbial control uses high-efficiency particulate air (HEPA) filters to trap particles, microorganisms, and spores?
Filtration
Which method of moist heat sterilization is commonly used in hospitals and labs and can reach temperatures exceeding 100 °C?
Autoclaving
What is the temperature and pressure used in autoclaving for sterilization?
121°C at 15 pounds of pressure per inch²
Which method of moist heat sterilization relies on the germination of spores and is used for materials that cannot be sterilized by other methods?
Fractional sterilization
Which method of moist heat treatment is used to heat food to a specific temperature and then cool it immediately, targeting pathogenic organisms?
Pasteurization
Which of the following is a chemical used to kill or inhibit pathogenic microorganisms on a lifeless object such as a table top?
Disinfectant
Which of the following is a chemical used to reduce or kill pathogenic microorganisms on a living object, such as the surface of the human body?
Antiseptic
Which type of disinfectant is a combination of two phenol compounds and is prominent in modern disinfection and antisepsis?
Hexachlorophene
Which type of disinfectant is commonly used as an antiseptic and disinfectant and is active against chlorophyllobtaining organisms, especially algae?
Chlorhexidine
Which type of disinfectant is commonly used as an antiseptic and can kill Gram positive and negative bacteria, algae, protozoa, viruses, and biofilms within 30 minutes of application?
Halogens
Which method of microbial control is used to sterilize heat-sensitive items such as catheters, artificial heart valves, and optical equipment?
Gases
Which type of sterilizing agent replaces hydrogen atoms with alkyl groups and is used to sterilize delicate objects like optical equipment?
Alkylating agents
Which type of disinfectant is active against vegetative cells, denatures proteins, dissolves lipids, and is commonly used in hand sanitizers?
Alcohols
Which type of disinfectant is commonly used as a rinse in wounds, scrapes, and abrasions?
Hydrogen peroxide
What is the active ingredient in teeth whitening and used to treat acne?
Benzoyl peroxide
Which category of effectiveness of chemical disinfectants kills only vegetative cells and certain enveloped viruses, and is ineffective against endospores?
Low-level germicides
What makes a chemical agent a good disinfectant or antiseptic?
Ability to kill or slow the growth of microorganisms
Which factor should be considered when selecting a disinfectant or antiseptic?
Type of microorganism targeted
Which type of microorganism is more susceptible to disinfectants?
Gram positive
Which of the following is true about microbial death curve?
It is a logarithmic curve that can be observed using a semilog plot.
Which of the following is true about decimal reduction time (DRT) or D-value?
It is the time it takes for a specific protocol to produce a one order of magnitude decrease in the number of organisms.
Which of the following is true about heat as a method of microbial control?
Heat destroys cellular enzymes, which become irreversibly denatured.
Which of the following is true about moist heat as a method of microbial control?
Moist heat can be used at a lower temperature and shorter exposure time than dry heat.
Which of the following is a method of microbial control that destroys viruses?
Viricide
Which of the following is a method of microbial control that inhibits/prevents the growth of bacteria?
Bacteriostatic
Which of the following is a method of microbial control that inhibits/prevents the growth of fungi?
Fungistatic
Which of the following is a method of microbial control that destroys spores?
Sporicide
Which type of radiation is used to sterilize heat-sensitive pharmaceuticals and preserve and extend the shelf life of food?
Gamma rays
What is the most destructive wavelength of UV radiation to cells?
265nm
Which type of radiation is absorbed by water molecules and causes heat to defrost and cook foods in a microwave oven?
Microwaves
Which method of microbial control can be used to remove microorganisms from air and water samples?
Filtration
Which of the following is the LEAST resistant to microbial control?
Enveloped viruses
Which method of microbial control is used to sterilize heat-sensitive items such as catheters, artificial heart valves, and optical equipment?
Sterilization
Which type of disinfectant is commonly used as an antiseptic and can kill Gram positive and negative bacteria, algae, protozoa, viruses, and biofilms within 30 minutes of application?
Hydrogen peroxide
Which method of moist heat sterilization requires a pressure of 28-30lb/in2 and a temperature of 132oC to 134oC for as little as 4 minutes?
Tyndallization
Which of the following is NOT a type of chemical control mentioned in the text?
Heat
Which of the following is a limitation of phenolic compounds as disinfectants?
They are ineffective against Gram-positive bacteria
Which type of disinfectant is commonly used as an antiseptic and disinfectant, and is active against chlorophyllobtaining organisms, especially algae?
Hexachlorophene
Which type of microbial control method involves the application of chemicals for removal of potential pathogens from living tissue?
Chemical control
Which type of disinfectant is commonly used as an antiseptic and disinfectant and is active against chlorophyllobtaining organisms, especially algae?
Copper
What is the process of killing or inhibiting the growth of pathogens without leading to sterilization called?
Antisepsis
Which type of radiation consists of photons and/or moving particles that have sufficient energy to knock electrons out of the shells from either an atom or molecule, thus forming an ion?
Ionizing radiation
Which method of microbial control uses high-efficiency particulate air (HEPA) filters to trap particles, microorganisms, and spores?
Filtration
Which method of moist heat treatment is used to heat food to a specific temperature and then cool it immediately, targeting pathogenic organisms?
Pasteurization
What is the temperature and pressure used in the autoclaving process for sterilization?
121°C at 15 pounds of pressure per inch2
Which method of moist heat treatment relies on having the proper conditions for spore germination?
Fractional sterilization
What is the temperature and exposure time required for effective sterilization in the prevacuum autoclave method?
132°C for 28-30lb/in2 for 4 minutes
Which type of germicide has the ability to kill vegetative cells, fungi, viruses, and endospores, leading to sterilization with extended use?
High-level germicides
Which type of germicide is less effective against endospores and certain viruses?
Intermediate-level germicides
Which type of germicide kills only vegetative cells and certain enveloped viruses, and is ineffective against endospores?
Low-level germicides
What is one of the factors to consider when selecting a disinfectant or antiseptic?
Temperature
Which type of microorganism is more susceptible to disinfectants?
Gram-positive
Which type of disinfectant is broken down by catalase in tissue and results in the production of superoxide radicals?
Hydrogen peroxide
Which method is commonly used to determine the minimal bactericidal concentration (MBC)?
Tube dilution method
What are some current strategies for antimicrobial discovery?
High-throughput screening and combinatorial chemistry
What is the purpose of developing drugs that inhibit resistance mechanisms?
To prevent the development of antibiotic resistance
What is the goal of developing drugs that target virulence factors?
To reduce the severity of infections
What is the purpose of using combinatorial chemistry in antimicrobial drug development?
To develop novel drugs
What is the purpose of searching for antibiotics from sources other than soil?
To discover novel antibiotics
What is the purpose of identifying new antibacterial targets?
To develop drugs that target specific bacteria
What is the purpose of developing drugs that hold infections in check?
To prevent the development of antibiotic resistance
What is the purpose of using high-throughput screening in antimicrobial drug discovery?
To quickly screen a large number of compounds for antimicrobial activity
What is the purpose of using combinatorial chemistry in antimicrobial drug development?
To develop novel drugs
Which scientist initiated the purposeful and systematic search for a chemical 'magic bullet' that specifically targets infectious microbes?
Paul Ehrlich
Who discovered the natural antibiotic penicillin in 1928?
Alexander Fleming
Who discovered the first synthetic antimicrobial, sulfanilamide?
Gerhard Domagk
What is the preferred type of antimicrobial drug to avoid superinfection and the development of antimicrobial resistance?
Narrow-spectrum antimicrobial
When is broad-spectrum antimicrobial use warranted?
All of the above
What are important considerations when selecting an antimicrobial to treat an infection?
All of the above
What is the key difference between prokaryotic and eukaryotic cell structure that allows antibacterial compounds to exhibit selective toxicity?
Presence of a nucleus
What is the term used to describe antimicrobial drugs that inhibit the growth of bacteria without killing them?
Bacteriostatic
What is the term used to describe antimicrobial drugs that kill bacteria?
Bactericidal
What is the term used to describe antimicrobial drugs that are effective against a wide range of bacteria, including both Gram-positive and Gram-negative bacteria?
Broad-spectrum
Which type of antimicrobial drug specifically targets the lipopolysaccharide component of gram-negative bacteria?
Polymyxins
Which type of antimicrobial drug interferes with bacterial RNA transcription?
Rifamycins
Which type of antimicrobial drug interferes with bacterial DNA replication?
Fluoroquinolones
Which type of antimicrobial drug acts as a competitive inhibitor for bacterial metabolic enzymes?
Sulfonamides
Which type of antimicrobial drug interferes with mycolic acid synthesis in mycobacteria?
Isoniazid
Which type of antimicrobial drug interferes with ergosterol synthesis in fungi?
Azoles
Which type of antimicrobial drug disrupts helminthic and protozoan microtubule formation?
Benzimidazoles
Which type of antimicrobial drug inhibits viral uncoating?
Fusion inhibitors
Which type of antimicrobial drug is commonly used to treat HIV and can include reverse transcriptase inhibitors and protease inhibitors?
Antiretrovirals
Which of the following is a common mode of antimicrobial drug resistance?
All of the above
Which type of disinfectant is commonly used in swimming pools, fish tanks, and municipal water supplies?
Copper
Which type of disinfectant is useful as an antiseptic and disinfectant and is active against chlorophyllobtaining organisms, especially algae?
Copper
Which type of disinfectant denatures proteins, dissolves lipids, and is commonly used in hand sanitizers?
Alcohols
Which type of sterilizing agent is used for the sterilization of heat-sensitive items and is highly explosive?
Gases
Which of the following is the most effective method of microbial control for complete destruction/removal of all living microbes, spores, and viruses on an object or in an area?
Sterilization
Which method of microbial control significantly reduces microbial numbers by using mild chemicals and gentle scrubbing of a small area of skin or tissue to avoid the transmission of pathogenic microbes?
Degerming
Which type of control method inhibits/prevents the growth of fungi?
Antisepsis
Which of the following is a process of killing or inhibiting the growth of pathogens without leading to sterilization?
Disinfection
Which of the following is true about microbial control methods?
Microbial control methods are most effective during the logarithmic growth phase of microorganisms.
What is the purpose of using dry heat as a microbial control method?
Dry heat kills bacteria by oxidizing cellular components.
What is the purpose of using moist heat as a microbial control method?
Moist heat is more effective in penetrating materials than dry heat.
Which factor affects the effectiveness of a microbial control protocol?
All of the above
Which type of filter is used to trap organisms in the pores of the filter pad as fluid passes through it?
Membrane filter
Which of the following is a chemical used to kill or inhibit pathogenic microorganisms on a lifeless object such as a table top?
Disinfectant
Which type of disinfectant is a combination of two phenol compounds and is prominent in modern disinfection and antisepsis?
Bisphenols
Which type of disinfectant is commonly used as an antiseptic and can kill Gram positive and negative bacteria, algae, protozoa, viruses, and biofilms within 30 minutes of application?
Chlorhexidine
Which method of moist heat sterilization is used for materials that cannot be sterilized by other methods?
Fractional sterilization/Tyndallization
Which method of microbial control is used to remove microorganisms from air and water samples?
Filtration
What is the temperature and pressure used in autoclaving for sterilization?
121°C at 15 pounds of pressure per inch2
Which type of radiation has a wavelength between 100 and 400 nm and is most destructive to cells at 265 nm?
UV rays
Which type of pasteurization method targets enteric bacteria like Salmonella and E. coli in fruit juices?
High-Temperature Short-Time (HTST)/Flash pasteurization
Which method of microbial control uses high-efficiency particulate air (HEPA) filters to trap particles, microorganisms, and spores?
Filtration
What is the temperature range for a freezer?
-18°C
Which type of radiation is used in microwave ovens to cook food by vibrating water molecules and causing friction and heat?
Microwaves
Which compound is commonly used as a rinse in wounds, scrapes, and abrasions?
Hydrogen peroxide
Which category of effectiveness of chemical disinfectants has the ability to kill only vegetative cells and certain enveloped viruses, and is ineffective against endospores?
Low-level germicides
What is one of the factors to consider when selecting a disinfectant or antiseptic?
Temperature
Which type of germicide is able to kill or slow the growth of microorganisms and is nontoxic to animals or humans?
High-level germicides
Which type of microorganism is more susceptible to disinfectants and antiseptics?
Gram positive
What is the purpose of developing drugs that inhibit resistance mechanisms?
To counteract antibiotic resistance
Which category of chemical disinfectants has the ability to kill vegetative cells, fungi, viruses, and endospores, leading to sterilization with extended use?
High-level germicides
What is the key characteristic of a chemical agent that makes it a good disinfectant or antiseptic?
Able to kill or slow the growth of microorganisms
Which type of microorganism is more susceptible to disinfectants and antiseptics?
Gram positive
Which type of disinfectant is broken down by catalase in tissue and results in the production of superoxide radicals?
Hydrogen peroxide
What is the key factor to consider when selecting a disinfectant or antiseptic?
Type of microorganism targeted
Which type of microorganism is resistant to many disinfectants?
M. tuberculosis
Study Notes
Microbial Control Methods
- Sterilization: complete destruction/removal of all living microbes, spores, and viruses on an object or in an area
- Disinfection: killing or inhibiting growth of pathogens without leading to sterilization
- Antisepsis: application of chemicals for removal of potential pathogens from living tissue
Types of Disinfectants
- Phenolic compounds: active against chlorophyll-containing organisms, especially algae
- Quaternary ammonium compounds: active against Gram-positive and negative bacteria, algae, protozoa, viruses, and biofilms
- Hypochlorites: active against vegetative cells, denatures proteins, and dissolves lipids
- Surfactants: reduces surface tension of surfaces, acts as a degerming agent
Microbial Control Methods
- Autoclaving: uses high-pressure steam to sterilize equipment and supplies
- Moist heat sterilization: uses free flowing steam at 100°C for 30 minutes on each of three consecutive days
- Radiation: uses photons and/or moving particles to knock electrons out of atoms or molecules, forming ions
- UV radiation: has a wavelength between 100 and 400 nm, most destructive to cells at 265 nm
- Microwaves: uses friction and heat to cook foods and defrost
- HEPA filters: traps particles, microorganisms, and spores
- Lyophilization: uses salting to induce water to diffuse out of microorganisms via osmosis
- Pasteurization: heats food to a specific temperature and then cools it immediately, targeting pathogenic organisms
Factors to Consider
- Type of microorganism: some are more susceptible to disinfectants than others
- Surface type: different disinfectants are effective on different surfaces
- Concentration and exposure time: effective disinfection requires proper concentration and exposure time
Radiation
- Ionizing radiation: has sufficient energy to knock electrons out of atoms or molecules, forming ions
- Non-ionizing radiation: has insufficient energy to knock electrons out of atoms or molecules
Microbial Death Curve
- Measures the rate of microbial death in response to disinfectants or radiation
- D-value (decimal reduction time): time required to reduce the microbial population by 90%
Limitations of Disinfectants
- Phenolic compounds: can be broken down by catalase in tissue, producing superoxide radicals
- Heavy metals: can be toxic to humans and animals
Test your knowledge on different types of disinfectants and antiseptics! Learn about the toxicity levels and effectiveness of mercury, merbromin, thimerosal, silver, and copper. Explore their uses as antiseptics and disinfectants.
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