Chapter 11 Microbiology

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

All of the choices will influence the action

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

C. quaternary ammonium compounds

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

D. pasteurization

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 quaternary ammonium compound carbolic acid triclosan formalin chlorhexidine

chlorhexidine

Which of the following is not a heavy metal? Tincture of iodine Merthiolate Silver nitrate solution Zinc Mercurochrome

tincture of iodine

_____ radiation excites atoms to a higher energy state within molecules such as DNA, which leads to the formation of pyrimidine dimers. Ultraviolet Ionizing Infrared Gamma Particle

ultraviolet

The minimum sterilizing conditions in a steam autoclave are 121°C at 15 psi for 15 minutes. 63°C for 30 minutes. 100°C for 30 minutes. 160°C for 2 hours. 71.6°C for 15 seconds.

121°C at 15 psi for 15 minutes.

Pasteurization A. kills all vegetative forms. B. reduces the number of vegetative forms. C. reduces the number of endospores. D. increases food nutrient value. E. is used to sterilize food products.

B. reduces the number of vegetative forms

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

B. use a pressure cooker to sterilize the bottles with steam

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.

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.

Which of the following represents microbial control by osmotic pressure? Pickling cucumbers and other vegetables for long-term storage Placing fruit slices on a drying rack Canning tomatoes after a summer growing season to use throughout the winter The crew of the Mayflower using salted meats throughout their voyage to the New World

The crew of the Mayflower using salted meats throughout their voyage to the New World

Which of the following is an advantage to using phenolics as antimicrobial agents? The presence of organic matter does not limit its antimicrobial qualities. They are not susceptible to resistance by organisms. They have low toxicity. 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. The steroid was contaminated at the production plant, so all batches of that drug made at that plant were contaminated with the bacterium. The bacterium is normally on the skin of people, so can easily access the patient's blood during the needle stick. The staff giving the steroid injections did not use proper aseptic technique. 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.

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? Bunsen burners and hot air ovens only reach a maximum of 100oC so they are not effective against endospores. Neither of these methods actually sterilize; they only kill vegetative cells. Bunsen burners take too long to sterilize and hot air ovens are hazardous for the operators. 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.

Agents that can denature microbial proteins include all of the following except ______. moist heat alcohol acids metallic ions X rays

X rays

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

all of the choices are correct

Antimicrobial agents can target the cell wall by blocking its synthesis. digesting it. denaturing proteins. All of the choices are correct.

all of the choices are correct

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

all of the choices are correct

Hydrogen peroxide is sporicidal. fungicidal. bactericidal. virucidal. All of the choices are correct.

all of the choices are correct

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

all of the choices are factors.

Which of the following items are typically irradiated in order to kill microbes? Cured meats Human tissues such as heart valves and skin Operating room air Surgical gloves All of the choices are correct.

all of these choices are correct

Which of the following germicides is/are also sporicidal? Betadine Chlorine Phenolics Chlorhexidine All of these except phenolics.

all of these except phenolics

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

antisepsis

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

antisepsis

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

antisepsis

Which of the following is not used as an antiseptic? Iodophor Aqueous glutaraldehyde 3% hydrogen peroxide Chlorhexidine Merthiolate

aqueous glutaraldehyde

_____ is a halogen used in gaseous and liquid form for large scale disinfection of drinking water and sewage. Iodine Chlorine Bromine Fluorine Betadine

chlorine

Each of the following is a target of antimicrobial agents except ______. cell walls cell membranes ribosomes cellular proteins cytoplasm

cytoplasm

Surfactants work by coating the organism preventing interaction with its environment. blocking transport into the organism. blocking transport out from the organism. disrupting membrane integrity.

disrupting membrane integrity

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

dry control

The sterilizing gas used in chemiclaves is ______. chlorine dioxide iodophor glutaraldehyde ethylene oxide formaldehyde

ethylene oxide

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

filtration

Electrons are ejected from atoms in cells when organisms are exposed to ______. desiccation ultraviolet light ethyl alcohol hydrogen peroxide gamma rays and X rays

gamma rays and x rays

Which of the following forms of radiation are in order from the most penetrating to the least penetrating? Gamma, cathode, X rays Gamma, X rays, cathode Cathode, gamma, X ray X ray, gamma, cathode Cathode, X ray, gamma

gamma, x rays, cathode

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

hydrogen peroxide

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

hydrogen peroxide

Cold temperatures are considered microbistatic, whereas excessive heat is considered microbicidal. This is due to the fact that 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. cold temperatures denature enzymes causing irreparable damage to the cell, whereas heat limits the energy of activation available to drive chemical reactions. cold temperatures freeze and therefore kill the cell, whereas excess heat keeps the cell metabolically active but not dividing. 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.

In lab, inoculating loops are sterilized using ______. chemicals incineration filtration moist heat gas sterilization

incineration

All of the following act as surfactants except ______. detergents quaternary ammonia iodine soaps alcohols

iodine

All of the following are alkylating control agents except ______. iodophor propylene oxide formaldehyde ethylene oxide glutaraldehyde

iodophor

Dry heat is less efficient than moist heat. cannot sterilize. includes tyndallization. is used in devices called autoclaves. will sterilize at 121°C for 15 minutes.

is less efficient than moist heat

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

it is classified as a carcinogen

Which of the following is not a primary target of milk pasteurization? Salmonella Campylobacter jejuni Lactobacillus Listeria monocytogenes Brucella

lactobacillus

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

lyophilization

Which is mismatched? Iodophor - iodine Sodium hypochlorite - chlorine Merthiolate - silver Benzalkonium chloride - quaternary ammonium compound Formalin - formaldehyde

merthiolate- silver

Which of the following does not affect microbial nucleic acids? Moist heat Ultraviolet light X rays Ethylene dioxide Formaldehyde

moist heat

_____ heat is more rapidly effective and efficient compared to _____ heat. High; dry High; moist Dry; moist Moist; dry Moist; high

moist; dry

Which of the following acids is not used to destroy or inhibit microbial cells in food? Benzoic acid Acetic acid Lactic acid Phosphoric acid Propionic acid

phosphoric acid

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

pickling eggs - osmotic pressure

Which of the following represents the use of osmotic pressure as a microbial control method? Exposing dental equipment to UV light Bleaching a kitchen counter Salting of meat Rinsing of a cut with Betadine

salting of meat

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

sanitization

_____ solution was introduced in the late 19th century for preventing gonococcal infections in a newborn's eyes after exposure to the mother's infected birth canal. Merthiolate Silver nitrate Triclosan Zinc oxide Betadine

silver nitrate

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

sporicidal

Which of the following types of control agents would be used to achieve sterility? Virucide Bactericide Germicide Sporicide Fungicide

sporicide

Sterilization is achieved by flash pasteurization. hot water. boiling water. steam autoclave. All of the choices are correct.

steam autoclave

The process that destroys or removes all microorganisms and microbial forms, including bacterial endospores, on inanimate objects is ______. disinfectioN sterilization antisepsis sanitization degermation

sterilization

The removal of all life forms from inanimate objects is termed ______. antisepsis disinfection sterilization decontamination degerming

sterilization

You have some old plastic Petri dishes that you would like to use for pouring bacteriological agar plates. The only method of physical sterilization is ultraviolet radiation sterilization with your UV light (you cannot use the autoclave because it will disfigure and melt the plastic). After sterilizing the plates, pouring the sterilized agar medium, and then leaving the plates out at room temperature for a day or two to let them solidify and dry, you find contaminating bacterial colonies growing on the agar. Predict what has happened in this situation. The room temperature enhanced the growth of normal biota of the agar. Air got into the poured agar plates, contaminating them. The lids of the Petri dishes were inadvertently left on while being sterilized. The agar had bacteria in it, even after sterilization in the autoclave.

the lids of the petri dishes were inadvertently left on while being sterilized

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

thermal death point

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

thermal death time (TDT)

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

they are found in iodophors.

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

they are inversely proportional to each other

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

they form trihalomethanes

Intermittent sterilization, which uses 3 days of lower temperature steam for short periods of time, is also called ______. pasteurization incubation tyndallization disinfection desiccation

tyndallization

A method for sterilizing milk, called _____ treatment, uses 134°C for 1 to 2 seconds. pasteurization batch pasteurization flash pasteurization ultra high temperature tyndallization

ultra high temperature

Which control method would not be a suitable choice for killing Mycobacterium in a capped culture tube? Ultraviolet (germicidal) light Gamma rays 121°C at 15 psi for 15 minutes 160°C for 2 hours All of the choices are correct.

ultraviolet (germicidal) light

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

vegetative bacteria and fungi

Which of the following is true regarding the use of osmotic pressure as an antimicrobial agent? Salts and sugars external to a microbe create a hypotonic environment, which causes lysis of the cell. Salt is an effective solute to create an osmotic pressure gradient outside of a cell; however, the use of sugar, such as in jams and jellies, works via a different mechanism. Exposing a microbe to a hypertonic environment draws water out of the cell, causing plasmolysis. Exposing organisms to the air on a benchtop so they completely dry out is an example of using osmotic pressure as a means of microbial control.

Exposing a microbe to a hypertonic environment draws water out of the cell, causing plasmolysis.

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

air

What instrument is most effective for pressure-temperature sterilization? Water-bath Autoclave Incubator Oven Bunsen burner

autoclave

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

bacterial endospores

Placing organisms at 4oC is ______. bactericidal bacteriostatic decontamination sterilization germicidal

bacteriostatic

Iodophors include ______. betadine chlorhexidine alcohols chloramines tincture of iodine

betadine

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

can remove viruses

Which is correct regarding the rate of microbial death? Cells die at increasingly greater rates. Only older cells die in a culture. Cells in a culture die at a constant rate. Upon contact with the control agent, all cells die at one time. 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 ______. disinfection sterilization sanitization degermation

degermination

Some microbial control agents are able to _____ cell proteins by breaking bonds that maintain the native state, the three-dimensional configuration of the proteins. mutate bind dissolve denature

denature

Removal of moisture by dehydration is called ______. flash freeze pasteurization desiccation lyophilization sterilization

desiccation

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

disinfection

Heavy metals work by binding to DNA. mutating DNA. rupturing the cell membrane. inactivating proteins. dissolving the cell wall.

inactivating proteins

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

no reproduction

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

pasteurization

All of the following are phenols or phenolics except ______. hexachlorophene Zephiran cresols triclosan Lysol

zephiran