Chapter 11

It is desirable to remove microbes from an area for reasons of health and safety. However some microbes are easier to remove than others. Order these microbes from the highest resistance (hardest to remove =1) to the lowest resistance (easiest to remove =3)

1. bacterial endospores and prions 2. protozoan cysts, some viruses, and some bacterial species like Mycobacterium and Pseudomonas 3. most bacterial vegetative cells, most fungal spores, fungal yeast, mold, and protozoan trophozoites

The concentration of alcohol that is the most effective in hand sanitizer is _________.

70%

HEPA is?

A type of filter that removes microbes from air.

__________: a controversial phenolic used in many personal hygiene and household products

Triclosan

Besides physical control methods, there are chemical control methods. This method includes a wide variety of chemicals that are called germicides. All microbes including endospores are killed by ________-level germicides while only vegetative cells are killed by _________-level germicides.

high .... low

____________: due to its low toxicity, used as an antiseptic, but also useful as a disinfectant especially in contact lens cleaner

hydrogen peroxide

The second type of physical control method uses energy in the form of radiation which comes in two forms. Which are characteristics of ionizing radiation? (Hint: 4 items are to be checked)

includes gamma rays penetrates surfaces so can be used on packaged items can be used for sterilization (removal of all microbes including endospores) causes breaks in microbial DNA to cause death

The second type of radiation used as a physical control method is nonionizing radiation. Which are characteristics of nonionizing radiation? (Hint: 4 items are to be checked)

includes ultraviolet (UV) light does not penetrate surfaces causes thymine dimers in microbial DNA to cause death more useful as a disinfection technique

Depending on the method of control, certain factors can be altered to make it more effective. Which of the following could help make a control method more effective. (Hint: 4 items should be checked).

increase the exposure time increase the temperature increase the concentration of the agent remove inhibitory substances like dirt from a wound

____________: an antiseptic incorporated into hand scrubs or used topically on a patient's skin prior to surgery

iodine

Which are the benefits of using pasteurization on beverages like milk and juice? (Hint: 3 items are to be checked)

lowers the microbial load on the beverage increases shelf life so it usable for longer maintains the quality of taste of the beverage

_____________: a freeze-drying method that removes water quickly using a vacuum; used to preserve microbes

lyophilization

_____________: a heavy metal found in a tincture and was used as a skin antiseptic until it was found to be toxic

mercury

Bacteria from the genus Mycobacterium are more resistant than most other bacterial species due to the _______________ giving the cell a waxy exterior.

mycolic acid in the cell wall

____________: a gentle heating process used on beverages to disinfect the item, thereby lowering the microbial load

pasteurization

___________: more useful as a disinfectant; due to toxicity it is used as an antiseptic with a prescription (pHisoHex)

phenolics

The third physical control method is filtration. It is different because it uses a membrane with pores (tiny holes) to pass liquid or gases through. This technique is different because it

physically removes the microbes from the substance

_____________: a detergent used in disinfectants like Lysol, but also used in antiseptics for the skin and mouth

quaternary ammonium

Packaged food items that are exposed to irradiation like gamma rays to lower the microbial load carries the ___________ symbol on its packaging.

radura

______________: placing items at cold temperatures to slow microbial growth, making it a bacteriostatic control method

refrigeration

_______________: cleaning of inanimate objects to remove microbes and debris to reduce potential of infection

sanitization

_____________: a heavy metal used as an antiseptic in ointments or surgical bandages

silver

A bacteriostatic method of control

slows the growth of bacteria

__________: used daily for sanitization or degerming; commonly used for hand washing

soaps

_________________: removal or killing of all microbes including endospores on inanimate objects

sterilization

The first type of control agents are physical methods of control. These methods utilize these techniques (Hint: 3 items are to be checked)

temperature filtration radiation

______________: sterilant used in a special device for respiratory, dialysis or endoscopy equipment

glutaraldehyde

_____________: a toxic substance used to preserve biological specimens/tissue

formaldehyde

___________: used to disinfect surfaces like in lab or as an antiseptic in hand sanitizers; examples are ethanol or isopropyl

alochol

________________: an antimicrobial chemical that destroys vegetative cells on skin and tissues (humans)

antisepsis

____________: most effective method for sterilization; uses a moist heat method in the form of steam and pressure; takes only a short time to achieve sterilization

autoclave

A germicide is a broad term for any control agent that kills a microrganism. More specifically. A [a] kills bacteria. A [b] kills fungi. A [c] destroys bacterial endospores.

bactericide fungicide sporicidal

___________: one of the oldest form of disinfection by submerging items in water heated to over 100oC

boiling

____________: versatile low toxicity antiseptic used in many applications including the control of MRSA in hospitals

chlorhexidine

_____________: used as a disinfectant in drinking water, swimming pools, and bleach

chlorine

______________: gas used to sterilize whole rooms as in the senate buildings during the anthrax attacks

chlorine dioxide

A broad term that includes all control methods to destroy, remove, or reduce the number of microbes is ______________.

decontamination

________________: removes debris and reduces number of microbes on skin or tissue through gentle methods like hand scrubbing

degermation

____________: the removal of water from an item to dehydrate and kill microorganisms; typically done on food products (like raisins) to prolong shelf life

desiccation

_____________: destruction of vegetative cells and other low resistance microbes on inanimate objects

disinfection

______________: use of flames to achieve sterilization; examples are a Bunsen burner (like in lab) or incinerator

dry heat sterilization

___________: gas used in a special chamber to sterilize prepackaged medical supplies

ethylene oxide