Chapter 9: Physical and Chemical control of Microbes

If an agent acts on the cell wall, it can

-Block cell wall synthesis -digest the cell wall

Iodine compounds are commonly used for

-antisepsis of skin -disinfection of medical equipment -treatment of skin wounds

Ethylene oxide typically kills microbes by

-blocking DNA replication -disrupting enzyme function

Which of the following substances should be removed from items before decontamination? -detergent -blood -sterile packaging -70% alcohol -saliva

-blood -saliva

Which of the following are examples of disinfection? -boiling eating utensils -cleansing a wound with a bleach solution -a 5% solution of bleach to clean a lab table -Immersing thermometers in an iodine solution -wiping skin with alcohol before an immunization

-boiling eating utensils -a 5% solution of bleach to clean a lab table -Immersing thermometers in an iodine solution

The root -______ is used to indicate killing.

-cide

Which of these items is considered noncritical for sterilization? -crutches -stethoscope -an artificial hip -a syringe needle -an endoscopy tube

-crutches -stethoscope

Which of the following are limitations to the use of radiation for sterilization? -danger to machine operators -damage to some materials -ill effects to consuming irradiated food -it is only bacteriostatic in most cases

-danger to machine operators -damage to some materials

Filtration has been used in which of the following? -disposal of biohazards -water purification -decontamination of milk products -sterilization of medical products -decontamination of air -sterilization of powders

-decontamination of milk products -water purification -sterilization of medical products -decontamination of air

Glutaraldehyde typically kills microbes by

-disrupting enzyme function -altering amino acids

Alcohols usually affect microbes by

-disrupting the cell wall -disrupting the cell surface tension

What are the modes of action for chlorhexidine?

-disrupts cell membranes -targets proteins

Which of the following are not usually destroyed or inactive with regular pasteurization methods? -viruses -vegetative fungi -endospores -vegetative bacteria -heat-resistant microbes

-endospores -heat-resistant microbes

The two microbial agents that are least resistant to physical and chemical control methods include: -enveloped viruses -prions -bacterial endospores -Mycobacterium -fungi

-enveloped viruses -fungi

Which of the following are compounds used as gaseous sterilants or disinfectants? -ethylene oxide -carbon monoxide -carbonic acid -chlorine dioxide

-ethylene oxide -chlorine dioxide

Dry heat occurs in the forms of

-hot air oven -an open flame

As the most extensively used chlorine compounds, hypochlorites are used for

-household cleaning -wound treatment and skin cleaning -good equipment sanitation -swimming pool treatments

Which factors can influence the actions of antimicrobial agents?

-microbial load -temperature of the environment -presence of interfering matter

Which are examples of using moist heat to sterilize or disinfect materials? -pasteruization -hot air oven -incineration -boiling -autoclaving

-pasteurization -boiling -autoclaving

The root -_____ is used to indicate the inhibition of microbial growth.

-stasis or -static

What factors must be considered in order to adequately sterilize using heat?

-temperature -length of exposure -presence of water

What are two examples of antisepsis?

-using iodine compounds on skin before a surgical incision -swabbing an open root canal with hydrogen peroxide

Which of the following statements regarding microbial sensitivity to heat are correct? -viruses are among the more heat-stable microbes -vegetative cells of endospore-formers are less susceptible to heat killing than vegetative cells of other species -nematodes are surprisingly resistant to heat killing -Pathogens are equally susceptible to heat killing as other microbes

-viruses are among the more heat-stable microbes -Pathogens are equally susceptible to heat killing as other microbes

What should be considered when initially choosing a method of microbial control?

1. Is it cost and labor-efficient? 2. Is sterilization needed? 3. Can it withstand physical or chemical treatments? 4. Is the item reusable or disposable? 5. Is it safe? 6. Will it penetrate effectively?

T/F: There are several degrees of sterility, based on the destruction of endospores.

False

What is desiccation?

The dehydration of microbes for preservation

What is incineration?

The use of dry heat to destroy all microbes

Why do younger, active cells die more quickly when exposed to microbicidal agents?

They are more metabolically active

______ are organic substances that contain a -CHO functional group on a terminal carbon.

aldehydes

In sterilization, _________ are destroyed or removed.

all microorganisms

A sterile object is free of

all viable microorganisms and viruses

Degermation and ___ can be accomplished with the same procedure.

antisepsis

____ are applied directly to the skin to destroy or inhibit vegetative pathogens.

antisepsis

______ is the physical removal of surface oils, debris, and soil from skin to reduce the microbial load.

antisepsis/ degermation

A chemical agent applied directly to exposed body surfaces (skin and mucous membranes), wounds, and surgical incisions to destroy or inhibit pathogens is a(n) ______.

antiseptic

_______ is referring to a procedure or process designed to prevent entry of infectious agents into sterile tissues.

asepsis

A(n) _____ is a sterilization chamber that allows the use of steam under pressure to sterilize materials

autoclave

Chlorohexidine is reliably

bactericidal

Which type of agent will kill bacteria?

bactericidal

Any process or agent that inhibits bacterial growth is referred to as _____.

bacteriostatic

Which method of pasteurization uses a lower temperature for a longer period of time? -flash method -batch method

batch method

_______ spectrum action is a desirable characteristic of a germicide

broad

_______ detergents are more effective then _____ detergents.

cationic; anionic

Ethylene oxide and ___ dioxide are commonly used as gaseous sterilants or disinfectants

chlorine

Gaseous and liquid ____ compounds are mostly used for large-scale water disinfection

chlorine

Iodine compounds are commonly used in the ___ setting. -household -clinical

clinical

____ involves the permanent termination of a particular organism's vital processes, and special qualifications are often needed to define and delineate the phenomenon in microbes.

death

The lowest temperature that achieves sterilization in a given quantity of broth culture upon a 10-minute exposure is referred to as the thermal _____ _____

death point

The shortest length of time required to kill all test microbes at a specified temperature is referred to as the thermal ______ ________.

death time

_____ is the general term used for the reduction of the microbial load in order to lower the possibility of infection or spoilage.

decontamination/ sanitation

The disruption of proteins from their native state is known as

denaturation

Boiling water can be an effective means of

disinfection

The goal of regular pasteurization methods is the _____ of the liquid.

disinfection

____ is the use of a physical process or chemical to destroy vegetative pathogens but not bacterial endospores, usually on inanimate surfaces.

disinfection

____ heat requires longer exposure time and higher temperatures that _____ heat.

dry; moist

_____ heat requires longer exposure times and higher temperatures than ____ heat.

dry; moist

High-level germicides can kill _____, whereas intermediate-level germicides can kill fungal spores and resistant pathogens but not endospores.

endospores

Viruses, prions, and ____ are relatively resistant to heat.

endospores

____ oxide is valuable for sterilization of heat-sensitive objects such as plastics, surgical and diagnostic appliances, and spices, but other related gases are available that are less toxic.

ethylene

The effects of a germicide is affected by the time of ____

exposure

T/F: The effectiveness of an antimicrobial agent is only governed by time.

false

A liquid can be suctioned through precise uniform pores for sterilization by _______.

filtration

Microbes can be effectively removed for air by ____.

filtration

____ are chemical agents that kill non-endospore forming pathogens.

germicides

The dosage of radiation is measured in

grays

____ is the most common physical agent used to control microbes.

heat

The dry oven is not suitable for items that may burn at ____ temperatures, or for liquids which will _____.

high; evaporate

In most cases, an agent with a _____ concentration will be more germicidal.

higher

Plasmolysis of bacteria in foods occurs when high concentrations of salt or sugar are added to the foods creating a ______ environment.

hypertonic

Virucides _____ viruses.

inactivate

A(n) _____ is a combination of iodine and an organic carrier (such as alcohol) that served as a moderate-level disinfectant and antiseptic.

iodophor

Fungicides _____ fungal spores, hyphae, and yeasts.

kill

A bactericide __ bacteria.

kills

Filtration is used to prepare ___ that cannot be heated, and to remove ____ contaminants that are a common source of infection and spoilage

liquids; airborne

Quats are rated as _____ disinfectants in the clinical setting.

low-level

What method preserves microorganisms (and other substances) by freezing and then drying them directly from the frozen state?

lyophilization

The cell __ is responsible for preventing the loss of important molecules and stopping the entry of damaging substances.

membrane

Regarding the use of the terms microbicidal and microbistatic, higher temperatures are usually ____, whereas lower temperatures are usually _____.

microbicidal; microbistatic

An agent's effect on cells is known as its _____ of action.

mode or mechanism

Agents that are highly selective in their targets are usually effective against a _____ range of microbes.

narrow

To prepare a common disinfectant like Lysol by performing a 1:200 dilution, you would mix

one part Lysol to 200 parts water

Items are classified as critical, semicritical, or noncritical based on

parts of the body contacted by the item.

The heat treatment of perishable liquids to destroy heat-sensitive vegetative cells and prevent infection and spoilage is called ______

pasteurization

Cold treatment and desiccation are reliably used for

preventing microbial growth

Iodine compounds typically kill microbes by denaturing ______.

proteins

The four general cellular targets of antimicrobial agents are the cell wall, the cell membrane, nucleic acid synthesis, and _____

proteins

_______ is electromagnetic waves or rays, such as those of light given off from an energy source.

radiation

The inability to __ is the practical definition of microbial death.

reproduce

The most practical way to identify if a microbe is dead is by determining if it can still ____ when it is exposed to a suitable environment.

reproduce

Prions are

resistant to heat and chemicals

The synthesis of proteins involves organielles known as ____ in a process called translation.

ribosomes

_________ is defined as growth of microorganisms in the blood or other tissues.

sepsis

The main effect of cold treatment is to ____ the activity of microbes

slow

Which of the following type of materials can be more reliably disinfected with a germicide? -smooth objects -porous objects

smooth objects

A ___ agent can also be a sterilant because it can destroy bacterial endospores and leave an object free of all life.

sporicide

A ____ is an agent that can destroy bacterial endospores.

sporicide

Chemical agents that can destroy all forms of life, including endospores are called _____.

sterilants

A process that completely removes or destroys all viable microorganisms, including viruses, from an objects or habitat is referred to as ____________.

sterilization

The goal of __ is to remove or destroy all viable microorganisms including viruses.

sterilization

What items would not be reliably treated by boiling water? -surgical instruments -drinking water -eating utensils

surgical instruments

An important side effect of adding antimicrobial chemical to soaps and detergents used in the home is

the development of resistance

What is filtration?

the straining of a fluid or air through a membrane to trap microorganisms

UV radiation is effective at disinfecting ____ solid substances.

the surfaces of

Death of microorganisms is hard to detect because:

they have no obvious vital signs

Antimicrobial solutions with alcohol or water-alcohol mixtures as the solvent are called

tinctures

T/F: The primary targets of microbial control are microorganisms that cause infection or spoilage.

true

______ radiation is most lethal from 240 nm to 280 nm.

ultraviolet

All of the following describe the typical microbial population targeted by antimicrobial drugs EXCEPT: -microbes with variable resistance -complex mixtures of types of microbes -uniform populations of like microbes -microbes with variable pathogenic capabilities

uniform populations of like microbes

Liquids can be sterilized by suctioning through a filter with uniform pores. Viruses can be eliminated from the liquid by

using a small pore size

Desiccation can preserve foods by reducing the availability of _____ to microbes for their metabolism.

water