Chapter 9 - Controlling Microbial Growth in the Environment
a.
Are antimicrobials ever used outside of the human body? a. Yes. They are used in soaps, lotions, and some foods, to name a few applications. b. Yes. Antibiotics are aerosolized and released into the air supply of hospitals. c. No. They are only taken orally. d. No. They are only used topically.
germicide
- another name for microbicide - any chemical agent that kills pathogenic microorganisms
nonenveloped viruses
- have greater tolerance of harsh conditions - harder to eliminate
d.
What is the main difference between chemical agents and antibiotics? a. Antibiotics are more expensive. b. Chemical agents are made synthetically and antibiotics are not. c. Chemical agents cannot be used on humans. d. Antibiotics are used to treat disease, while chemical agents are used for environmental control of microbes.
c.
Which of the following statements best describes the use of antimicrobials? a. Antimicrobials will always be effective at killing pathogens. b. Antimicrobials continue to be used sparingly to prevent increased resistance. c. Overuse of antimicrobials is selecting for resistant, highly pathogenic bacteria. d. Antimicrobials should be used more often than they are used now.
a.
Which statement most accurately describes the microbial death rate after exposure to a microbicidal agent? a. Microbicidal agents do not kill all cells simultaneously. b. As soon as a population of cells is exposed to a microbicidal agent, they all die at the same time. c. Microbicidal agents do not kill microorganisms, but rather temporarily inhibit their growth. d. The microbial death rate is not constant.
a.
Why is 70% to 90% alcohol more effective at denaturing proteins than 100% alcohol? a. because water is required to denature proteins b. because 100% alcohol is too flammable c. because phenol is used to dilute the alcohol and is more effective d. 100% alcohol is the most effective.
d.
a company that manufactures an antimicrobial cleaner for kitchen counters claim that its product is effective when used in a 50% water solution. by what means might scientists best verify this statement? a. disk-diffusion test b. phenol coefficient c. filter paper test d. in-use test
microbial death rate
a measurement of the efficacy of an antimicrobial agent
c.
a sample of E. coli has been subjected to heat for a specified time, and 90% of the cells have been destroyed. which of the following terms best describes this event? a. thermal death point b. thermal death time c. decimal reduction time d. none of the above
catalase
an enzyme released from damaged human cells
oxidizing agents
antimicrobial agent that releases oxygen radicals
antimicrobials
any compound used to treat infectious diseases
a.
biosafety level 3 includes _______. a. double sets of entry doors b. pressurized suits c. showers in entryways d. all of the above
surfactants
chemical that acts to reduce the surface tension of solvents
antiseptic
chemical used to inhibit or kill microorganisms on skin or tissue
d.
common methods of using moist heat to control microbial growth include all but which of the following? a. pasteurization b. autoclaving c. boiling d. incineration
bisphenolics
composed of two covalently linked phenolics
aldehydes
compound containing terminal -CHO groups
phenolics
compounds derived from phenol molecules that have been chemically modified by the addition of halogens or organic functional groups
autoclave
consists of a pressure chamber, pipes to introduce an evacuate steam, valves to remove air and control pressure, and pressure and temperature gauges to monitor the procedure
cytoplasmic membrane
contains cytoplasm and controls passage of chemicals into and out of cell
aseptic
describes an environment or procedure that is free of contamination by pathogens
quaternary ammonium compounds
detergent antimicrobial that is harmless to humans
nonionizing radiation
electromagnetic radiation with a wavelength greater than 1 nm
antimicrobial enzymes
enzyme that acts against microbes
ionizing radiation
form of radiation with wavelengths short than 1 nm that are energetic enough to create ions by ejecting electrons from atoms
high-level germicides
germicide classification: kill all pathogens, including endospores
intermediate-level germicides
germicide classification: kill fungal spores, protozoan cysts, viruses, and pathogenic bacteria
d.
how does the alteration of the cytoplasmic membrane of a microbe by an antimicrobial agent lead to cell death? a. the compromised membrane allows viruses to infect the cell and the cell dies b. the cell fills with water until it bursts c. the cell is not able to conjugate d. cellular contents will leak out of the cell, leading to cell death
b.
how is an autoclave able to achieve temperatures higher than that of boiling water? a. by decreasing the volume of liquid b. by increasing the pressure c. by increasing the time of exposure d. autoclaves cannot reach temperatures higher than boiling water
a.
in practical terms in everyday use, which of the following statements provides the definition of sterilization? a. sterilization eliminates organisms and their spores or endospores b. sterilization eliminates harmful microorganisms and viruses c. sterilization eliminates prions d. sterilization eliminates hyperthermophiles
desiccation
inhibition of microbial growth by drying
alcohols
intermediate-level disinfectant that denatures proteins and disrupts cell membranes
use-dilution test
method of evaluating the effectiveness of a disinfectant or antiseptic against specific microbes in which the most effective agent is the one that entirely prevents microbial growth at the highest dilution
phenol coefficient
method of evaluating the effectiveness of a disinfectant or antiseptic that compares the agent's efficacy to that of phenol
decontamination
microbes are controlled by _______ procedures that destroy or remove contaminants.
a.
overuse of antimicrobial soap can lead to which of the following? a. increased microbial resistance b. decreased microbial resistance c. problems with human health d. allergies
disinfectants
physical or chemical agent used to inhibit or destroy microorganisms on inanimate objects
detergents
positively changed organic surfactant
lyophilization
removal of water from a frozen culture or other substance by means a vacuum pressure
b.
select the appropriate method of microbial control for surgical instruments a. disinfection b. sterilization c. pasteurization d. degerming
-cide -cidal
suffixes indicating destruction of a type of microbe
-stasis -static
suffixes indicating inhibition bu not complete destruction of a type of microbe
a.
surfactants function as microbial agents because they do what to microbes? a. lower the surface tension of solvents b. inhibit peptide bond formation c. prevent mRNA synthesis d. prevent synthesis of peptidoglycan
a.
the endospores of which organism are used as a biological indicator of sterilization? a. Bacillus stearothermophilus b. Salmonella enterica c. Mycobacterium tuberculosis d. Staphylococcus aureus
halogens
the four very reactive, nonmetallic chemical elements: iodine, chlorine, bromine, and fluorine.
antisepsis
the inhibition or killing of microorganisms on skin or tissue by the use of a chemical antiseptic
heavy-metal ions
the ions of high-molecular-weight metals that are used as an antimicrobial agents because they denature proteins
thermal death point
the lowest temperature that kills all cells in a broth in 10 minutes
d.
the microbial death rate is used to measure _______. a. the efficiency of a detergent b. the efficiency of an antiseptic c. the efficiency of sanitization techniques d. all of the above
filtration
the passage of fluid through a sieve designed to trap particles and separate them from the fluid
microbial death
the permanent loss of reproductive ability under ideal environmental conditions
c.
the preservation of beef jerky from microbial growth relies on which method of microbial control? a. filtration b. lyophilization c. desiccation d. radiation
osmotic pressure
the pressure exerted across a selectively permeable membrane by the solutes in a solution on one side of the membrane
sanitization
the process of disinfecting places and utensils used by the public to reduce the number of pathogenic microbes to meet accepted public health standards
radiation
the release of high-speed subatomic particles or waves of electromagnetic energy from atoms
degerming
the removal of microbes from a surface by scrubbing
sterilization
the removal or destruction of all microbes, including viruses and bacterial endospores, in or on an object
Kelsey-Sykes capacity test
the standard alternative assessment by the European Union to determine the capacity of a given chemical to inhibit bacterial growth
thermal death time
the time it takes to completely sterilize a particular volume of liquid at a set temperature
decimal reduction time
the time required to destroy 90% of the microbes in a sample
pasteurization
the use of heat to kill pathogens and reduce the number of spoilage microorganisms in food and beverages
disinfection
the use of physical or chemical agents to inhibit or destroy microorganisms on inanimate objects
membrane filters
thin circles of nitrocellulose or plastic containing specific pore sizes, some small enough to trap viruses
disinfection
used ONLY on inanimate objects because it is toxic to living tissues
aldehydes
used as a high-level disinfectant because it cross-links organic functional groups in proteins and nucleic acids
1. inexpensive 2. fast-acting 3. stable during storage 4. capable of controlling microbial growth
what 4 things should agents be?
1. particulate radiation 2. electromagnetic radiation
what are the 2 types of radiation?
d.
what category of antiseptic is particularly effective against anaerobic pathogens present in deep tissue wounds? a. halogens b. heavy metals c. phenolics d. oxidizing agents
b.
what category of chemical agents is placed in the eyes of newborns to prevent blindness caused by Neisseria gonorrhoeae? a. phenols b. heavy metals c. alcohols d. surfactants
b.
what is defined as the removal of ALL microbes in or on an object? a. pasteurization b. sterilization c. disinfection d. sanitizing
a.
what is one of the older and more common means of microbial control? a. heat b. filtration c. radiation d. cold
c.
what is the first thing you should do to control microbial growth on a surgical instrument that is covered with blood? a. soak the instrument is disinfectant b. immediately immerse the instrument in bleach c. clean the blood off the instrument, then proceed to sterilize it d. throw away the instrument because it has blood on it
bacterial endospores
what is the most resistant microbes to antimicrobial agents?
enveloped viruses
what is the most susceptible microbes to antimicrobial agents?
0.45
what is the pore size of the largest bacteria?
d.
what is the strategy of medical personnel when selecting a method of microbial control? a. choose the most expensive method because it must be the best b. always use bleach c. choose the cheapest method d. choose the method that will kill the most resistant microbes present
c.
what term applies to the use of heat to eliminate pathogens and reduce the number of spoilage-causing microbes from foods and beverages? a. disinfection b. degerming c. pasteurization d. sterilization
d.
which antimicrobial chemical has been used to sterilize spacecraft? a. phenol b. alcohol c. heavy metal d. ethylene oxide
a.
which class of surfactant is most soluble in water? a. quaternary ammonium compounds b. alcohols c. soaps d. peracetic acids
b.
which method for evaluating disinfectants can be used to determine the effectiveness of a disinfectant against biofilms found on objects in a health setting? a. phenol coefficient b. in-use test c. Kelsey-Sykes capacity test d. use-dilution test
d.
which of the following adjectives best describes a surgical procedure that is free of microbial contaminants? a. disinfected b. sanitized c. degermed d. aseptic
b.
which of the following chemicals is active against bacterial endospores? a. copper ions b. ethylene oxide c. ethanol d. triclosan
a.
which of the following disinfectants acts against cell membranes? a. phenol b. peracetic acid c. silver nitrate d. glutaraldehyde
d.
which of the following disinfectants contains alcohol? a. an iodophor b. a quat c. formalin d. a tincture of bromine
c.
which of the following factors does not affect the action of a chemical agent used to control microbial growth? a. freshness of the chemical b. temperature c. the agent's storage container d. concentration of the chemical
a.
which of the following is not a qualify of an ideal agent used for controlling microbial growth? a. unsafe for humans b. inexpensive c. fast-acting d. stable
d.
which of the following items functions most like an autoclave? a. a boiling pan b. an incinerator c. a microwave oven d. a pressure cooker
c.
which of the following microorganisms is most resistant to antimicrobial agents? a. bacteria b. fungi c. prions d. viruses
c.
which of the following procedures should be used to sterilize a protein solution? a. boiling b. autoclaving c. filtration d. nonionizing radiation
b.
which of the following statements is TRUE regarding Escherichia coli? a. antibiotics always kill E. coli b. new, resistant strains of E. coli have been isolated c. E. coli is unable to become resistant to antibiotics d. E. coli is the only bacterium capable of developing antibiotic resistance
d.
which of the following statements is true concerning the selection of an antimicrobial agent? a. an ideal antimicrobial agent is stable during storage b. an ideal antimicrobial agent is fast acting c. ideal microbial agents do not exist d. all of the above
c.
which of the following substances is least toxic to humans? a. carbolic acid b. glutaraldehyde c. hydrogen peroxide d. formalin
b.
which of the following substances or processes kills microorganisms on laboratory surfaces? a. antiseptics b. disinfectants c. degermers d. pasteurization
d.
which of the following substances would most effectively inhibit anaerobes? a. phenol b. silver c. ethanol d. hydrogen peroxide
d.
which of the following terms best describes the disinfecting of cafeteria plates? a. pasteurization b. antisepsis c. sterilization d. sanitization
a.
which of the following types of radiation is more widely used as an antimicrobial technique? a. electron beams b. visible light waves c. radio waves d. microwaves
a.
with a particular sterilization process, it takes 25 minutes to kill all organisms in a sample containing 100,000 microbes. how long does it take to eliminate 90% of the organisms using this process? a. 5 minutes b. 25 minutes c. 10 minutes d. 10^5 minutes
b.
work with moderately hazardous organisms such as methicillin-resistant Stephylococcus aureus should be performed in what kind of laboratory? a. BSL-1 b. BSL-2 c. BSL-3 d. BSL-4
