MICRO Ch. 11

Alcohols A. denature proteins when in a 50-95% alcohol-water solution. B. disinfect items when soaking method is utilized. C. are skin degerming agents. D. at 50% or higher concentrations dissolve cell membrane lipids. E. All of the choices are correct.

All of the choices are correct

Endospores can be inactivated by A. dry heat at 170°C for 2 hours. B. incineration. C. glutaraldehyde for 3 or more hours. D. ethylene oxide for 3 or more hours. E. All of the choices are correct.

All of the choices are correct

Hydrogen peroxide is A. sporicidal. B. fungicidal. C. bactericidal. D. virucidal. E. All of the choices are correct.

All of the choices are correct

Which of the following is not a factor that affects germicidal activity? A. Material being treated B. Length of exposure C. Strength of the germicide D. Microorganism being treated E. All of the choices are factors.

All of the choices are factors

Which of the following factors will influence the action of microbial agents? A. The number of microorganisms B. The type of microorganisms present C. Temperature and pH D. Mode and dosage of the agent E. All of the choices will influence the action.

All of the choices will influence the action

The alcohol wipe used on a patient's skin before an injection is an example of ______. A. antisepsis B. disinfection C. sterilization D. decontamination E. sanitization

Antisepsis

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is ______. A. disinfection B. sterilization C. antisepsis D. sanitization

Antisepsis

Which of the following is not used as an antiseptic? A. Iodophor B. Aqueous glutaraldehyde C. 3% hydrogen peroxide D. Chlorhexidine E. Merthiolate

Aqueous glutaraldehyde

Which of the following microbial forms has the highest resistance to physical and chemical controls? A. Naked viruses B. Protozoan cysts C. Fungal spores D. Bacterial endospores E. Yeast

Bacterial Endospores

The use of filtration for sterilization A. leaves behind endospores. B. removes toxins. C. uses heat and filtration. D. relies on gravity. E. can remove viruses.

Can remove viruses

Which is correct regarding the rate of microbial death? A. Cells die at increasingly greater rates. B. Only older cells die in a culture. C. Cells in a culture die at a constant rate. D. Upon contact with the control agent, all cells die at one time. E. Cells become metabolically inactive but are never killed.

Cells in a culture die at a constant rate

Scrubbing or immersing the skin in chemicals to reduce the numbers of microbes on the skin is ______. A. disinfection B. sterilization C. sanitization D. degermation

Degermation

The use of a physical or chemical process to destroy vegetative pathogens on inanimate objects is ______. A. disinfection B. sterilization C. antisepsis D. sanitization E. degermation

Disinfection

Using a HEPA filter in a vacuum or furnace is an example of which microbial control method? A. Surfactant B. Gases C. Chemical agent D. Dry control

Dry control

True or False: A microorganism that is not motile and has stopped metabolizing is considered dead.

FALSE

True or False: All microbicidal agents are sterilants.

FALSE

True or False: Bacteriostatic agents kill bacterial cells.

FALSE

True or False: Continued widespread use of the phenolic compound triclosan is advantageous in that it is important to remove as many organisms as possible from our hands and there is little risk of resistant organisms evolving.

FALSE

True or False: Isopropyl alcohol wiped across a skin site can sterilize it.

FALSE

True or False: Most microbial contaminants of food are killed or inactivated at freezing temperatures.

FALSE

True or False: Surgeons preparing for an invasive surgical procedure will scrub their hands thoroughly, and then they use a strong alcohol-based hand sanitizer which renders their hands sterile.

FALSE

_____ is a control method that removes microorganisms rather than inhibiting or killing them. A. Disinfection B. Filtration C. Boiling D. Radiation E. Sterilization

Filtration

The chemical agent/s that produce/s highly reactive hydroxyl-free radicals and also decomposes to O2 gas is A. hydrogen peroxide B. chlorhexidine C. iodophors D. cationic detergents E. Cidex

Hydrogen peroxide

Cold temperatures are considered microbistatic, whereas excessive heat is considered microbicidal. This is due to the fact that A . in cold temperatures, the energy of activation is not sufficient to drive chemical reactions regardless of the presence of enzymes, whereas excessive heat denatures enzymes and/or incinerates the cell causing irreparable damage. B. cold temperatures denature enzymes causing irreparable damage to the cell, whereas heat limits the energy of activation available to drive chemical reactions. C. cold temperatures freeze and therefore kill the cell, whereas excess heat keeps the cell metabolically active but not dividing. D. cold temperatures halt binary fission and is therefore considered a sterilant, whereas heat does not kill spores so it is not an effective method of control.

In cold temperatures, the energy of activation is not sufficient to drive chemical reactions regardless of the presence of enzymes, whereas excessive heat denatures enzymes and/or incinerates the cell causing irreparable damage

Which of the following is not true of glutaraldehyde? A. It cross-links proteins on cell surfaces. B. It is classified as a carcinogen. C. It inactivates endospores in 3 hours. D. It inactivates viruses. E. It does not damage plastics.

It is classified as a carcinogen

Which of the following does not affect microbial nucleic acids? A. Moist heat B. Ultraviolet light C. X rays D. Ethylene dioxide E. Formaldehyde

Moist heat

Which antimicrobial method does not sterilize? A. Ionizing radiation B. Ethylene oxide gas C. Autoclave D. Pasteurization

Pasteurization

Which of the following acids is not used to destroy or inhibit microbial cells in food? A. Benzoic acid B. Acetic acid C. Lactic acid D. Phosphoric acid E. Propionic acid

Phosphoric acid

Which of the following methods of microbial control is mismatched? A. Pickling eggs - osmotic pressure B. Exposure of surgical equipment to ultraviolet light - radiation C. Heating a liquid to 71.6oC for 15 seconds - pasteurization D. Autoclaving nutrient agar before pouring into Petri plates - sterilization

Pickling eggs - osmotic pressure

Your aim is to sterilize prosthetic devices like heart valves and artificial joint structures before being used in the patient. Considering where they will be placed and the probable composition of the devices, what would be the best chemical to use? A. Crystal violet dye B. Iodine C. Quaternary ammonium compounds D. Bleach

Quaternary ammonium compounds

Which of the following types of control agents would be used to achieve sterility? A. Virucide B. Bactericide C. Germicide D. Sporicide E. Fungicide

Sporicide

The process that destroys or removes all microorganisms and microbial forms, including bacterial endospores, on inanimate objects is ______. A. disinfection B. sterilization C. antisepsis D. sanitization E. degermation

Sterilization

The removal of all life forms from inanimate objects is termed ______. A. antisepsis B. disinfection C. sterilization D. decontamination E. degerming

Sterilization

True or False: Alcohols are more effective at inactivating enveloped viruses than naked viruses.

TRUE

True or False: Aniline dyes like crystal violet have antimicrobial activity particularly against gram-positive bacteria and some fungi.

TRUE

True or False: Chlorine and ethylene oxide are sterilizing gases.

TRUE

True or False: Hydrogen peroxide is used in the process of sterilizing instruments such as endoscopes.

TRUE

True or False: Ozone is a very effective disinfectant.

TRUE

True or False: Prions require more extensive methods of sterilization than are needed for bacterial endospores.

TRUE

True or False: The presence of organic matter such as saliva and pus can interfere with the actions of disinfectants.

TRUE

True or False: When a control agent targets the metabolic processes of microbial cells, active younger cells typically die more rapidly than older cells.

TRUE

Which of the following is an advantage to using phenolics as antimicrobial agents? A. The presence of organic matter does not limit its antimicrobial qualities. B. They are not susceptible to resistance by organisms. C. They have low toxicity. D. They are effective sterilants against all microbial forms.

The presence of organic matter does not limit its antimicrobial qualities

Your friend Joe recently visited the doctor for steroid injections into his knee to reduce swelling due to a previous knee injury. Within a couple of days, he had an infection caused by Pseudomonas, a very pathogenic and drug resistant bacterium. Luckily, Joe went to the doctor immediately and received antibiotics. The doctor tells him that the same problem has occurred to many other people across the United States. Predict the most likely cause of this situation. A. The steroid was contaminated at the production plant, so all batches of that drug made at that plant were contaminated with the bacterium. B. The bacterium is normally on the skin of people, so can easily access the patient's blood during the needle stick. C. The staff giving the steroid injections did not use proper aseptic technique. D. The needles were re-used and already contaminated before being used on the patients.

The staff giving the steroid injections did not use proper aseptic technique

All of the following pertain to hypochlorites except A. they cause denaturation of enzymes. B. they release hypochlorous acid in solution. C. they are found in common household bleach. D. they are used to disinfect dairy, restaurant, and medical equipment. E. they are found in iodophors.

They are found in iodophors

Which of the following is not true of chloramines? A. They contain chlorine. B. They are used to treat wounds and skin surfaces. C. They are safer than free chlorine. D. They can sanitize and disinfect. E. They form trihalomethanes with organic compounds.

They form trihalomethanes with organic compounds

You have inherited some old glass baby milk bottles from your grandmother, and you would like to use them instead of plastic bottles. The bottles are placed into a large metal container and placed in the oven at 325oF for about 2 hours. What factor would you change if you wanted the sterilization to occur much quicker? A. Place the bottles outside in the sunlight and then place in the oven B. Use a pressure cooker to sterilize the bottles with steam C. Pour an antimicrobial chemical into the bottles before placing into the oven D. Increase the temperature of the oven by 5 degrees

Use a pressure cooker to sterilize the bottles with steam

Which of the following is a disadvantage of dry heat methods such as using a Bunsen burner to incinerate microbes from an inoculating loop and the use of a hot air oven? A. Bunsen burners and hot air ovens only reach a maximum of 100oC so they are not effective against endospores. B. Neither of these methods actually sterilize/ they only kill vegetative cells. C. Bunsen burners take too long to sterilize and hot air ovens are hazardous for the operators. D. Use of an open flame can be dangerous and hot air ovens take much longer to sterilize than autoclaves.

Use of an open flame can be dangerous and hot air ovens take much longer to sterilize than autoclaves

All of the following are phenols or phenolics except ______. A. hexachlorophene B. Zephiran C. cresols D. triclosan E. Lysol

Zephiran

HEPA filters are used to remove microbes from A. air. B. liquids. C. human tissues. D. medical instruments. E. All of the choices are correct.

air

The method of removing vegetative life forms from living surfaces is termed ______. A. antisepsis B. disinfection C. sterilization D. decontamination

antisepsis

Placing organisms at 4oC is ______. A. bactericidal B. bacteriostatic C. decontamination D. sterilization E. germicidal

bacteriostatic

The compound that is an organic base containing chlorine and two phenolic rings, and is used increasingly for wound degerming, neonatal washes, hand scrubbing, and prepping surgical skin sites is ______. A. a quaternary ammonium compound B. carbolic acid C. triclosan D. formalin E. chlorhexidine

chlorhexidine

Removal of moisture by dehydration is called ______. A. flash freeze B. pasteurization C. desiccation D. lyophilization E. sterilization

desiccation

The sterilizing gas used in chemiclaves is ______. A. chlorine dioxide B. iodophor C. glutaraldehyde D. ethylene oxide E. formaldehyde

ethylene oxide

Physical agents for controlling microbial growth include all of the following except ______. A. ultraviolet radiation B. boiling water C. pasteurization D. hydrogen peroxide

hydrogen peroxide

In lab, inoculating loops are sterilized using ______. A. chemicals B. incineration C. filtration D. moist heat E. gas sterilization

incineration

All of the following are alkylating control agents except ______. A. iodophor B. propylene oxide C. formaldehyde D. ethylene oxide E. glutaraldehyde

iodophor

Vials of microorganisms that undergo the freeze-drying process, called _____, will remain preserved and viable for years. A. desiccation B. flash freeze C. lyophilization D. pasteurization E. sterilization

lyophilization

Microbial death occurs when there is A. no movement. B. no reproduction. C. a change in appearance. D. a decrease in size. E. All of the choices occur.

no reproduction

Disinfection of beverages such as apple juice, milk, and wine is optimally achieved by ______. A. filtration B. chlorination C. pasteurization D. boiling water E. moist heat autoclave

pasteurization

The method of removing vegetative microbial life forms and debris to reduce contamination to safe levels is termed ______. A. antisepsis B. disinfection C. sterilization D. decontamination E. sanitization

sanitization

Ethylene oxide is A. only effective with high heat. B. a halogen. C. the active agent in household bleach. D. used as an antiseptic against anaerobes. E. sporicidal

sporicidal

Sterilization is achieved by A. flash pasteurization. B. hot water. C. boiling water. D. steam autoclave. E. All of the choices are correct.

steam autoclave

The lowest temperature needed to kill or inactivate all microbes in 10 minutes is the A. thermal death point (TDP). B. thermal death time (TDT). C. sporicidal time. D. death phase point.

thermal death point (TDP)

The shortest time required to kill or inactivate all the microbes in a sample at a specified temperature is called the A. thermal death point (TDP). B. thermal death time (TDT). C. sporicidal time. D. death phase point.

thermal death time (TDT)

The difference between thermal death time and thermal death point in microbicidal activity is that A. thermal death time is the greatest amount of time required to kill an organism at a specific temperature, . whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes. B. thermal death time is the shortest amount of time required to kill an organism at a specific temperature, whereas thermal death temperature is the lowest temperature required to kill an organism in 30 minutes. C. thermal death time is the shortest amount of time required to kill an organism at a 100oC, whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes. D. thermal death time is the shortest amount of time required to kill an organism at a specific temperature, whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes.

thermal death time is the shortest amount of time required to kill an organism at a specific temperature, whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes

When considering time and temperature as factors in microbicidal activity A. they are directly proportional to each other. B. they are inversely proportional to each other. C. they must be of equal value e.g. 30 minutes at 30oC. D. time is not a factor, only temperature.

they are inversely proportional to each other

The easiest microbial forms to kill or inhibit are ______. A. naked viruses B. vegetative bacteria and fungi C. endospores D. protozoan cysts E. mycobacteria and staphylococci

vegetative bacteria and fungi