Microbiology Chapter 9

What are some environmental factors to consider when choosing an antimicrobial agent?

temperature, pH, presence of organic matter

________ germicides are used to disinfect items that contact only the skin of patients.

low-level

Antiseptics are disinfectant chemicals applied to utensils. medical devices. skin. food.

skin

T/F: Chemicals and physical methods of microbial control target the same cellular structures and functions, like cell walls/membranes, proteins

True

Why is moist heat more efficient than dry heat?

Water is a better conductor than air

What kind of microbes survive boiling?

endospores, some viruses, and protozoan cysts

How can antimicrobial agents act against its target?

-By disrupting the cell's integrity by altering their cell wall or membrane -Interrupting cellular metabolism or reproduction by interfering with the structures of proteins and nucleic acids

Biosafety level 3 includes: a. double entry doors b.. pressurized suits c. showers in entryways d. all of the above

A

In practical terms, which describes the term "sterilization" the best? a. Eliminates organisms and their spores or endospores b. eliminates harmful microorganisms and viruses c. eliminates prions d. eliminates hyperthermophiles

A

The endospores of which organism are used as a biological indicator for sterilization? A. bacillus stearothermophilus B. salmonella enterica C. Mycobacterium tuberculosis D. staph aureus

A

which of the following destroys microorganisms on laboratory surfaces? a. antiseptics b. disinfectants c. degermers d. pasteurization

B

In which biosafety level would you study E. coli?

BSL-1

In which biosafety level would you study hepatitis?

BSL-2

________ facilities require that all manipulations be performed in a safety cabinet with HEPA filtration.

BSL-3

How does the alteration of a microbe's cytoplasmic membrane by an antimicrobial agent lead to cell death? The compromised membrane allows viruses to infect the cell, and the cell dies. The cell fills with water until it bursts. The cell is not able to conjugate. Cellular contents will leak out of the cell, leading to cell death.

Cellular contents will leak out of the cell, leading to cell death.

What strategy do medical personnel use when selecting a method of microbial control? Choose the most expensive method, because it has to be the best. Always use bleach. Choose the cheapest method. Choose the method that will kill the most resistant microbes present.

Choose the method that will kill the most resistant microbes present.

What is the first thing you should do to control microbial growth on a surgical instrument that is covered with blood? Soak the instrument in disinfectant. Immediately immerse the instrument in bleach. Clean the blood off the instrument, then proceed to sterilize it. Throw the instrument away because it has blood on it.

Clean the blood off the instrument, then proceed to sterilize it.

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

D

Which of the following best describes the disinfecting of cafeteria plates? a. pasteurization b. antisepsis c. sterilization d. sanitation

D

Which of the following describes a surgical procedure that is free of microbial contaminants? A. disinfected B. sanitized C. degermed D. aseptic

D

Which of the following functions the most like an autoclave? A. boiling pan B. incinerator C. microwave D. pressure cooker

D

Which of the following is true concerning the selection of an ideal antimicrobial agent? a. stable in storage b. fast-acting c. does not exist d. all of the above

D

T/F: The use of chemical or physical agents to inhibit or destroy microbes on skin is called disinfection

False. When used on skin or tissue, the process is called antisepsis

What is an endospore-test ampule?

Indicates the sterility after autoclaving by breaking the ampule to expose it to medium that changes color in the presence of spores

Which statement MOST accurately describes the microbial death rate after cells are exposed to a microbicidal agent? Microbicidal agents kill a constant percentage of cells over time. As soon as a population of cells is exposed to a microbicidal agent, they all die at the same time. Microbicidal agents do not kill microorganisms, but rather temporarily inhibit their growth. The microbial death rate is not constant.

Microbicidal agents kill a constant percentage of cells over time.

What must be considered when choosing an antimicrobial agent?

Nature of the site to be treated, environmental conditions, degree of susceptibility of the microbes

_______ refers to a public place like a restaurant, and ______ refers to a private place like a kitchen

Sanitization, disinfection

what is UV light?

a disinfectant

aseptic

an environment or procedure that is free of contamination by pathogens

Autoclaving

applies pressure to boiling water, prevents the escape of heat in steam

What term would be used to describe a restaurant?

aseptic

What term would you use to describe an area being prepped for surgery?

aseptic

The mechanisms of cell death by moist heat include which of the following? denaturing of proteins creation of thymine dimers disruption of cytoplasmic membranes both a and c

both a and c

Which of the following is NOT a consideration for disinfectant use? age of disinfectant concentration of disinfectant brand of disinfectant exposure time

brand of disinfectant

How is an autoclave able to achieve temperatures higher than that of boiling water? by decreasing the volume of liquid by increasing the pressure by increasing the time of exposure Autoclaves cannot reach temperatures higher than boiling water.

by increasing the pressure

How are germicides classified?

by their proficiency for inactivating or destroying microbes that can't be sterilized by heat

What technique is utilized when a nurse uses an alcohol wipe before an injection?

degerming

What term would categorize the process of washing your hands?

degerming

Why are diluted alcohol solutions more effective than pure alcohol?

denaturing proteins requires water

We can use a scrubbing motion to _____ an area

disinfect

what is alcohol?

disinfectant

Steam is a method for ______

disinfection

What term is used to categorize bleach?

disinfection

What would you use heat for?

disinfection

T/F: all innocuous organisms are eliminated during sterilization

false

T/F: cells with least resistance require longer exposure before they die

false

T/F: intermediate-level germicides kill endospores

false

T/F: disinfection is effective against endospores and viruses

false. disinfection is not effective against endospores and some viruses

Which of the following procedures should be used to sterilize a protein solution? boiling autoclaving filtration nonionizing radiation

filtration

Which of the following is one of the older and more common means of microbial control? heat filtration radiation cold

heat

Common methods of using moist heat to control microbial growth include all of the following EXCEPT which one? pasteurization autoclaving boiling incineration

incineration

What are the characteristics of ideal antimicrobial agents?

inexpensive, fast acting, stable during storage, and harmless to humans, animals, and objects

A _______ level germicide is used to disinfect instruments that come in contact with mucous membranes, but are noninvasive, like respiratory equipment

intermediate

Alcohols are _________ disinfectants

intermediate

Which one is more effective: isopropanol (rubbing alcohol) or ethanol?

isopropanol

High-level germicides

kill all pathogens including endospores. Used to sterilize invasive instruments

Intermediate-level germicides

kill fungal spores, protozoan cysts, viruses and pathogenic bacteria

low-level germicides

kill vegetative bacteria, fungi, protozoa, and some viruses

What happens when a cell membrane is damaged?

loss of selective permeability allows cell contents to leak out

a _____ level germicide is used to disinfect items that come into contact with skin, like furniture or electrodes

low

Surfactants function as microbicidal agents because they do what to microbes? lower the surface tension of solvents inhibit peptide bond formation prevent mRNA synthesis prevent synthesis of peptidoglycan

lower the surface tension of solvents

what happens when a cell wall is damaged?

microbe is no longer protected from osmotic pressure and is lysed easily

biosafety level 3

microbes include anthrax, mycobacterium tuberculosis. high-efficiency particulate air filters, double doors, and ventilation regulations

biosafety level 4

microbes include ebola and smallpox. labs are isolated and strictly controlled, space suits

Biosafety level 1

microbes that are non-pathogenic to humans. Handwashing, disinfecting, etc

biosafety level 2

moderately hazardous microbes. limited access, safety cabinets

Which of the following microorganisms are MOST resistant to antimicrobial agents? bacteria fungi mycobacteria viruses

mycobacteria

What does the effectiveness of a chemical antimicrobial depend on?

number and kind of microbes present, kinds of materials being treated, length of exposure, strength and mode of action of the agent

The removal of ALL microbes in or on an object is known as pasteurization. sterilization. disinfection. sanitizing

sterilization

Which method of microbial control destroys all harmful microbes, including endospores and viruses?

sterilization

Objects that penetrate the skin must be _______, whereas something that would just touch the surface of the skin can be _____.

sterilized, disinfected

sterilization

the destruction of all harmful microbes on objects, including viruses and endospores

microbial death

the permanent loss of reproductive ability under ideal environmental conditions

sanitization

the process of disinfecting places and utensils used by the public to reduce exposure to pathogens

degerming

the removing of microbes from a surface by mechanical means

disinfection

the use of chemical or physical agents to inhibit or destroy microbes, especially pathogens, on inanimate objects