Ch 9: Physical and Chemical Control of Microbes

The methods of microbial control used outside of the body are designed to result in these possible outcomes EXCEPT:

All choices are outcomes of microbial control.

Bacterial endospores have traditionally been considered the __ microbial entities.

most resistant

The goal of any sterilization process is the __ of bacterial endospores.

destruction

Any process that kills endospores will …

… invariably kill all less resistant microbial forms.

Which type of agent:

__ - chemical that destroys bacteria except for those at the endospore stage.

Bactericide

Which type of agent:

__ - chemical that can kill fungal spores.

Fungicide

Which type of agent:

__ - chemical known to inactivate viruses, especially on living tissue.

Virucide

Which type of agent:

__ - an agent capable of destroying bacterial endospores.

Sporicide

Which type of agent:

__ - chemical agents that kill microorganisms.

Germicide/microbicide

Which type of agent:

__ - growth of microorganisms in the blood and other tissues.

Sepsis

Which type of agent:

__ - any practice that prevents the entry of infectious agents into sterile tissues and thus prevents infection.

Asepsis

Which type of agent:

__ - chemical agents applied directly to exposed body surfaces (skin and mucous membranes), wounds, and surgical incisions to prevent vegetative pathogens.

Antiseptics

Stasis and static mean …

“to stand still.”

Which type of agent:

__ - chemical agents that prevent the growth of bacteria on tissues or on objects in the environment.

Bacteriostatic

Which type of agent:

__ - chemicals that inhibit fungal growth.

Fungistatic

Antiseptics and drugs often have __ effects because microbicidal compounds can be __ to human cells.

microbistatic, toxic

Which type of medical device:

• Expect to come into contact with sterile tissues

• Must be sterilized before use!

Critical medical devices

Which type of medical device:

• Come into contact with mucosal membranes

• Must receive high-level disinfection

Semicritical devices

Which type of medical device:

• Do not touch the patient or only touch intact skin

• Require only low-level disinfection

Noncritical devices

What is Microbial Death?

The permanent termination of an organism’s vital processes, and permanent loss of reproductive capability.

Eventually, a point is reached within the Death Rate at which survival of any cells is highly unlikely; this point is equivalent to __.

sterilization.

All are factors affecting death rate of Microbes EXCEPT:

All choices are factors.

Most disinfectants are __ active at __ concentrations.

more, higher

The followings are cellular targets of physical and chemical agents EXCEPT:

All choices are cellular targets.

The use of iodine compounds to prepare the skin for surgery is known as __.

antisepsis

Which type of heat:

• Hot or boiling water/steam between 60°C and 135°C

• Operates at lower temperatures and shorter exposure times

• Biggest microbicidal effect is the coagulation and denaturation of proteins

Moist heat

Which type of heat:

• Hot air or open flame which ranges from 160°C to thousands

• At very high temperatures, oxidizes cells, burning them to ashes

• Dehydrates the cell, removing water necessary for metabolic reactions, may also denature proteins

Dry heat

The destruction of spores usually requires temperatures above __.

boiling.

__ operates like a pressure cooker, as pressure increase, the temp to boil water goes up. It’s mostly this increase in temp that makes it so effective at sterilizing.

Autoclave

Most microbes are not adversely affected by …

… gradual cooling, long-term refrigeration, or deep-freezing.

Which radiation method:

• Devices that emit ionizing rays include gamma-ray machines containing radioactive cobalt, X-ray machines similar to those used in medical diagnosis, and cathode-ray machines.

• Ionizing radiation is a highly effective for sterilizing materials the are sensitive to heat or chemicals.

Ionizing Radiation: Gamma Rays and X-Rays

Which radiation method:

• Ranges in wavelength from approximately 100 to 400 nm.

• It is most lethal from 240 to 280 nm (with a peak at 260 nm).

• Not as penetrating as ionizing radiation because it passes readily through air, slightly through liquids and only poorly through solids.

Nonionizing Radiation: Ultraviolet Rays

__ is an effective method to remove microbes from air and liquids.

Filtration

Pore sizes can be controlled to __ by trapping viruses or large proteins.

permit true sterilization

Which chemical agents in microbial control:

__ - chemicals dissolved in pure water as the solvent.

Aqueous solutions

Which chemical agents in microbial control:

__ - chemicals dissolved in pure alcohol or water-alcohol mixtures.

Tinctures

Which level of germicide:

__ - kill endospores and can be used as sterilants.

High-level germicides

Which level of germicide:

__ - kill fungal, but not bacterial, spores, resistant pathogens, and viruses.

Intermediate-level germicides

Which level of germicide:

__ - eliminate only vegetative bacteria, vegetative fungal cells, and some viruses.

Low-level germicides

Chemical Strength or Concentration:

__ - a small volume of the liquid chemical is diluted in a larger volume of solvent to achieve a certain ratio.

Dilutions

Chemical Strength or Concentration:

__ - used for solutions such chlorine that are effective in very diluted concentrations.

Parts per million

Chemical Strength or Concentration:

__ - solute is added to water by weight or volume.

Percentage solutions

An RN is preparing to access a patient’s IV catheter for infusion of a medication. What is the most appropriate agent for cleaning the plastic cap of the IV catheter prior to connecting the medication tubing?

Alcohol

Following a surgical procedure, which of the following methods of microbial control would be used for sterilization of metal surgical instruments intended for reuse?

autoclaving

Which germicidal agents:

__ - usually used more as disinfectant.

Chlorine (bleach)

Which germicidal agents:

__ - used to prepare skin and surgical scrubs.

Iodine (betadine)

Which germicidal agents:

__ - used to sterilize resp equip, scopes, dental equip ect.

Glutaraldehyde

Which germicidal agents:

__ - used to sterilize delicate instruments, syringes, plastics.

Ethylene Oxide (disinfect/sterilize)

Bactericidal/Bacteriostatic:

__ - toxic used to clean drains cesspools, but antimicrobial soaps and some toothpastes had Triclosan.

Phenols

Bactericidal/Bacteriostatic:

__ - target most bacteria, viruses, fungi. Hibiclens used in surgical scrubs.

Chlorhexidine

Bactericidal/Bacteriostatic:

__ - target most bacteria, viruses, fungi. Routinely used to prep skin.

Alcohols

Bactericidal/Bacteriostatic:

__ - target some but not all bacteria, viruses, fungi. Used to clean restaurant utensils, dairy equipment, restrooms.

Detergents

Bactericidal/Bacteriostatic:

__ - target some bacteria. Used in ointments (mercury, silver), some soaps.

Heavy metal compounds