Physical and Chemical Control of Microbes

Which of the following are some of the desirable qualities in a germicide?

-Broad-spectrum action -Selective toxicity -Penetrating ability -Rapid action -Solubility in a solvent

Phenolics typically kill microbes by

-Denaturing metabolic enzymes -Disrupting the cell membrane -Disrupting the cell wall

Alcohols are commonly used for:

-Disinfection of medical equipment -Degermination of skin

Which items can be sanitized by boiling with boiling water prior to safe, acceptable use?

-Drinking water -Utensils -Bedding and clothing

Iodine compounds are commonly used for:

-Emergency disinfection of drinking water -Antisepsis of skin -Treatment of skin wounds -Disinfection of medical equipment

Which of the following compounds are commonly used as gaseous sterilants or disinfectants?

-Ethylene oxide -Propylene oxide -Chlorine dioxide

Which of the following are examples of chemical agents used to control microbes?

-Heavy metals -Phenolics -Aldehydes -Halogens -Oxidizers -Alcohols

What are the effects of adding pressure to water in an autoclave?

-Increases boiling point of water -Increases temperature of steam

Which of the following statements are correct regarding OPA?

-OPA is an aldehyde -OPA is non-irritating to eyes and nasal passages

The four general cellular targets of antimicrobial agents are

-Protein function -The cell membrane -The cell wall -Nucleic acid synthesis

Alcohols are effective against

-Resistant bacteria -Enveloped viruses

Which are goals of pasteurization?

-Retention of liquid qualities -Reduction of microbial load

Which of the following statements about soaps are correct?

-Soaps help to mechanically remove surface debris -Some bacteria can grow on soap as a nutrient source. -Soaps are only weakly microbicidal.

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

-Swimming pool treatments -Wound treatment and skin cleasing -Household cleaning -Food equipment sanitation

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

-Temperature -Length of exposure -Presence of water

Which root indicates the ability to kill microorganisms?

-cide

A critical concern for the food packaging industry is the elimination of endospores of

Clostridium botulinum

Classification of medical device

Critical- syringe needle Semicritical- dental mirror Noncritical- blood pressure cuff

chlorine dioxide typically kills microbes by:

Disrupting protein function

The dosage of radiation is measured in _________________.

Grays

Which four of the following are examples of physical agents or mechanical means used to control microbes?

Heat, cold, radiation and filtration

Which two types of macromolecules make up the majority of the cell membrane in organisms?

Lipids and Proteins

Disinfection destroys

Only vegetative bacterial cells

________________ is a technique in which heat is applied to liquids to kill potential agents of infection and spoilage.

Pasteurization

Which levels of protein structure are disrupted in denaturation?

Secondary and Tertiary

Which of the following heavy metals are still in used in germicidal preparations?

Silver and Mercury

Dyes are important for:

Staining techniques, selective and differential media, chemotherapeutic drugs

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

They are more metabolically active

_____________ are chemical agents applied directly to body surfaces to inhibit vegetative pathogens.

antiseptics

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

bacteriostatic

A _____________ agent will inhibit the growth of bacteria, whereas a ____________ agent will kill bacteria.

bacteriostatic; bactericidal

If an agent disrupts the cell wall, the cell is likely to experience:

death by lysis

The disruption of proteins from their native state is known as ____________.

denaturation

UV radiation is usually used for ___________.

disinfection

__________ heat requires longer exposure times and higher temperatures than _________ heat.

dry; moist

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

ethylene

True or False: Only a few microorganisms are killed by Iodine even if proper concentrations and exposure times are used.

false

True or False: There are several degrees of sterility, based on the destruction of endospores.

false

True or false: Biological matter such as serum, blood, or urine increases the effectiveness of a germicide.

false

True or false: Ionizing radiation is not an effective method of controlling microbes in food products.

false

True or false: The effectiveness of an antimicrobial agent is only governed by the time of exposure to the agent.

false

True or false: The shortest length of time required to kill all test microbes at a specified temperature is referred to as the thermal death point.

false

True or false: Thymine, uracil, and cytosine are called purines which are a type of nitrogenous bases found in either DNA or RNA.

false (they are pyrimidines)

True of false: Sepsis is a term referring to a condition free of pathogenic microorganisms or a procedure or process designed to prevent entry of infectious agents.

false (this is asepsis)

_______________ is an aqueous solution of formaldehyde gas that is used as a potent chemical fixative and microbicide.

formalin

The two aldehydes used most often in microbial control are __________ and ____________.

glutaraldehyde and formaldehyde

Ionizing radiation is a good technique for sterilizing material that are sensitive to ______________ or _____________.

heat or chemicals

The property of having antimicrobial effects in exceedingly small amounts belongs to which class of chemicals?

heavy metals

___________ _____________ typically kills microbes by producing toxic free radicals.

hydrogen peroxide

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

hypertonic

Which of the following is the practical definition of microbial death?

inability to reproduce

A virucide _________ viruses.

inactivates

_____________ is a dry heat that is commonly used in student laboratories to sterilize inoculating loops and wires.

incineration

____________ are complexes of iodine and alcohol

iodophors

Ethyl and ____________ alcohols are effective in microbial control.

isopropyl

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 common source of infection and spoilage.

liquids; airborne

Cationic detergents disrupt the cell _____________ leading to a loss of selective permeability.

membrane

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

microbial death

Phenolics are

microbicidal

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

microbistatic

the normal 3-dimesional state of a protein is called its _____________ state.

native

__________ radiation is a method of microbial control that causes the formation of abnormal bonds within the DNA of microbes, increasing the rate of mutation.

nonionizing

The two broad categories that describe methods for controlling microbes are

physical and chemical

A ____________ _____________ is the union of 2 adjacent pyrimidines on the same DNA strand, brought about by exposure to ultraviolet light.

pyrimidine dimer

______ is a decontamination technique that mechanically removes microorganisms and debris from inanimate objects such as utensils to reduce contamination to safe levels.

sanitization

_________ 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

_________ objects are more reliably disinfected with a germicide.

smooth

__________ is an alkaline compound made by combining the fatty acids in oils with sodium or potassium salts.

soap

Household bleach is known by its chemical name

sodium hypochlorite

A ____________ is an agent that can destroy bacteria endospores.

sporicide

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

sterilization

Disinfectants are normally used on inanimate objects because

the high concentration needed are harmful to living tissues

One of the most widely used phenolics used today is ________.

triclosan

True or False: 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.

true

True or False: The primary targets of microbial control are microorganisms that cause infection or spoilage.

true

True or false: Acids or alkalis are limited in their application by their corrosive and hazardous nature.

true

True or false: An agent's effect on cells is known as its mode of action.

true

True or false: An autoclave is a sterilization chamber that allows the use of steam under pressure to sterilize materials.

true

True or false: Antimicrobial solutions with alcohols or water-alcohol mixtures as the solvent are called tinctures

true

True or false: Quats are rated for only low-level disinfection in the clinical setting.

true

True or false: Radiation is energy emitted from atomic activities and dispersed at high velocity through matter or space.

true

True or false: The necessity of sterilization or disinfection should be considered when initially choosing a method of microbial control.

true

Which of the following is/are types of nonionizing radiation?

ultraviolet rays