Module 6 Summary

Question 1

Suffix -icidal

Answer 1

Suffix means death
Used with a word root to indicate the micro-organism being kiled
eg. bactericidal, fungicidal, viricidal

Question 2

Suffix -static

Answer 2

Suffix means that the microorganism is halted in its present state - it can no longer grow, but it is not killed.

Removal of the agent may allow growth to resume.

Used iwth root word to indicate microbe being affected.

Eg. bacteriostatic, fungistatic

Question 3

Germicide means

Answer 3

an agent that kills germs (a generic term for referring to all microorganisms)

Question 4

Fungicide means

Answer 4

An agent that kills fungi

Question 5

Bactericide means

Answer 5

An agent that kills bacteria

Question 6

Sporicide means

Answer 6

An agent that kills spores

Question 7

Viricide means

Answer 7

An agent that kills viruses

Question 8

sterilization

Answer 8

destroys ALL forms of microbial life; no degrees of sterilitiy - article is either sterile or not sterile

Question 9

disenfection

Answer 9

destroys pathogens; other microbes and spores may survive; several levels; usually chemical

Question 10

Terminal disinfection

Answer 10

disinfection procedure when patient leaves area - done before next patient arrives

Question 11

antisepsis

Answer 11

disenfection mild enough for living tissue

Question 12

sanitation

Answer 12

disinfection of eating utensils and dishes; mechnanical or chemical; agents used must not alter properties of food

Question 13

cleaning

Answer 13

removal of soil/body secretions; does not imply disinfection; often soap and H2O

Question 14

SUD

Answer 14

single use device - item used only once and then discarded (for ex - needles, catheters, syringes that have been in contact with body fluids)

Question 15

Incineration

Answer 15

-terminal decontamination for biological or disposable waste (used needles, lab cultures, bandages, blood samples)
-burn at very high temperature → reduce everything to ash
-now usually done off-site → health care facility must adhere to TDG (Transportation of Dangerous Goods) regulations

Question 16

Autoclave

Answer 16

-steam under pressure; “moist heat”
-optimum temperature: 121°C; pressure: 15 psi; time: 15 minutes, once temp. reached (longer if large load)
-re loading:
items on perforated tray
load loosely
dry goods on edge; lids ajar; jars, canisters, tubes → on sides
-testing for efficiency:
spore strips placed in autoclave (center and bottom)
place strips in culture medium after autoclaving → incubate → check for growth
growth means spores not killed; → autoclave not working properly
-items suitable for autoclaving:
surgical instruments
dressings (before use)
surgical gowns
anything that has to be sterile and can withstand the heat
not good for plastics (they melt) or rubber (gets sticky)
most items wrapped in protective packaging (cloth/paper) that steam can penetrate; indicator on package changes color during autoclaving so can distinguish sterile from nonsterile packages
if indicator has not changed color, don’t use materials in package
if packaging gets wet, items may no longer be sterile

Question 17

Ethylene Oxide (ETO)

Answer 17

gas sterilization; no heat
use for heat-sensitive items (especially plastics)
large capacity
slow (8 hours); expensive; toxic to human tissue

Question 18

Chemical Disinfection / Sterilization - Properties

Answer 18

desirable properties of “ideal” disinfectant:
broad spectrum
rapid action
resistance to inactivation by other material
nontoxic, odorless, nondestructive
residual action
user friendly
economical

Question 19

Spaulding classification of items requiring disinfection/sterilization:

Answer 19

critical: items going into sterile area of body; must be sterile
semi-critical: items going into or touching area of body that is not sterile; no pathogens, but don’t have to be sterile
non-critical: items not going into body, but may touch body surface (e.g. beds, countertops); OK to have microbes; don’t want any that can be inhaled and cause infection

Question 20

Resistance of microbes to disinfection:

Answer 20

vegetative bacteria - least resistant (easiest to destroy)
lipid viruses (except hepatitis B)
fungi
nonlipid viruses
tubercle bacilli (difficult to destroy)
bacterial spores - most resistant (most difficult to destroy)

Question 21

Levels of disinfectants:

Answer 21

low level: kill vegetative bacteria and lipid viruses; other stuff may survive
intermediate level: kill everything except maybe nonlipid viruses and bacterial spores
high level: kill everything if sufficient time; essentially sterilants; when disinfectant washed off, item losses its true sterility (high level disinfectants not classified with sterilization procedures)

Question 22

Groups of Chemical Disinfectants

Answer 22

detergents and soaps, alcohols, chlorine-containing, iodine, phenolic, glutaraldehyde, peroxygens

Question 23

Low level disinfectants - Detergents & Soaps

Answer 23

surface active agents (aka surfactants, wetting agents) reduce surface tension so liquid can spread out instead of bead up therefore liquid gets into nooks and crannies

detergent vs soap: detergent is better wetting agent
soaps and detergents can be “regular” or antibacterial
if “regular”:
don’t kill microbes
do facilitate removal of microbes under force of running water, following mechanical scrubbing

quats (quaternary ammonium compounds):
act as detergents
some antimicrobial action: attach to microbial cell membrane causing lysis
low level
uses: cleaning; skin antisepsis
e.g: Zephiran
advantages:
economical
no bad odor; nonirritating
good wetting agent
kills gram + bacteria

disadvantages:
narrow microbial spectrum
inactivated by soaps,
detergents, fibers, hard H20, organic material
gram - rods may grow in it (Pseudomonas)

Question 24

Intermediate level disinfectants - Alcohols (Ethanol and Isopropyl Alcohol)

Answer 24

intermediate level
optimum concentration = 70% (dilute with H20)
act by coagulating microbial protein”

main uses:
skin antisepsis (pre-venipuncture or pre-injection)
disinfect thermometers and tops of vials of injectable solutions

advantages of alcohols:
economical
nonirritating
kills vegetative bacteria, tubercle bacilli and lipid viruses

disadvantages:
if large number of microbes, not as effective
inactivated by organic material (probably ineffective against HBV in blood or other body fluid)
does not kill spores and nonlipid viruses

Question 25

Intermediate level disinfectants - Chlorine-Containing Agents (Bleach)

Answer 25

active ingredient = hypochlorous acid → kills microbes by oxidation
intermediate level
concentration expressed as: ppm available chlorine, % hypochlorite, or dilution of household bleach
Health Canada strong bleach vs weak bleach:
use of strong bleach: to disinfect where contamination with biological material, including blood (will kill HBV, HCV, HIV); need strong bleach if organic material present
use of weak bleach: for routine disinfection where no obvious contamination with biological material
shelf-life of diluted bleach: 24 hours (MAKE FRESH DAILY)
advantages:
economical; may be diluted; readily available
rapidly kills vegetative bacteria
with longer time, also kills tubercle bacilli and viruses
disadvantages:
no good for metal, plastic, rubber
must be diluted fresh daily
odor; irritating to skin/eyes
inactivated by organic material (need for strong vs weak bleach)
very high concentration needed to kill spores

Question 26

Health Canada strong bleach vs weak bleach:

Answer 26

Strong:
dilution - 1 in 10 (1 mL of bleach in 9 ML water)
ppm availble chlorine - 5000
% hypochlorite - 0.5%

Weak:
dilution - 1 in 100
(1mL bleach in 99 ML water)
“ppm availble chlorine - 500
% hypochlorite - 0.05%

Question 27

Intermediate level disinfectants - Iodine (Iodophores)

Answer 27

intermediate level
iodophor = iodine + carrier; carrier slowly releases iodine; less irritating, less allergenic, and doesn’t stain or sting as badly as tincture of iodine ( iodine+alcohol)
uses:
pre-surgical skin antisepsis (providone iodophors such as Betadine, Prepodyne)
cleaning compounds (Wescodyne; carrier = detergent)
advantages:
economical and may be diluted
kills many microbes
good for cleaning when coupled with detergent
some residual action
disadvantages:
must be diluted fresh daily; not with hard water
staining
allergies
inactivated by organic material
may not be effective against HBV

Question 28

Intermediate level disinfectants - Phenolic Compounds

Answer 28

intermediate level
complex compounds: phenol + other disinfectant/detergent
hexachlorophene:
use: hand washing; skin cleaner
do not use to bathe newborns (toxic)
Hibitane and Bactoshield (chlorhexidine gluconate):
very effective for hand washing → renders hands bacteria-free for a while
keep away from eyes
advantages of complex phenolics:
economical
no bad odor; non-irritating
effective against many microbes
disadvantages:
do not kill spores
toxicity to some body tissues

Question 29

High level disinfectants - Glutaraldehyde

Answer 29

high level
disinfection time: 10 min.
sterilization time: 10 hours
cannot be used to sterilize critical items because too toxic to tissue; must rinse item well with H20 → sterility lost
several products available; differ in:
shelf life after activation
pH
length of time to kill microbes
uses:
disinfection of rubber and plastics (respiratory therapy equipment, bronchoscopes, endoscopes)
disinfection of metal equipment (cannot use bleach)
sterilization of equipment that cannot withstand heat
advantages:
broad spectrum
does not destroy rubber/plastic/metal
not inactivated by organic material
disadvantages:
expensive
limited shelf-life after activation
toxic
irritating fumes

Question 30

High level disinfectants - Peroxygens

Answer 30

combination of Hydrogen peroxide and peracetic acid

advantages
disinfect or sterilize
Good for heat sensitive, complex items such as endoscopes
Can be used as a wipe for surface disinfection
disadvantages
Cost of equipment if using for sterilization

Question 31

Mechanical Disinfection

Answer 31

Pasteurization
Filtration
Microfiber cloths

Question 32

Pasteurization

Answer 32

75-77°C; 30 min.
intermediate level disinfection; kills everything but spores
use: reusable tubing from respiratory equipment
economical

Question 33

Filtration

Answer 33

use filters with small pores to remove microbes from liquids and air; microbes larger than pore size do not pass through (including larger viruses)
uses:
Membrane filters – remove microorganisms from fluids - IV solutions; drugs; vaccines
respiratory therapy equipment -to keep patient bugs out of other parts of the equipment/ surrounding air
HEPA filters: for air filtration - isolation rooms, drying cabinets; lab safety cabinets

Question 34

Microfiber cloths

Answer 34

used for environmental cleaning of surfaces

Question 35

Miscellaneous methods of Microbial Control

Answer 35

UV (ultra violet) radiation
Ionizing radiation
Moist Heat (boiling)

Question 36

UV (ultra violet) radiation

Answer 36

good at inactivating viruses
good for destroying some bacteria
reduces number of airborne microorganisms
surfaces
no good for spores
must be a direct exposure
water treatment
avoid eye and skin exposure

Question 37

Ionizing radiation

Answer 37

Includes irradiation, microwave and strong visible light
Used to destroy microorganisms in blood products for transfusion, food

Question 38

Moist Heat (boiling)

Answer 38

Destroys most microorganisms within 10 minutes
Not effective against spores – need prolonged time such as 6 – 8 hours to destroy botulism spores

Question 39

Aseptic Technique - reason for using

Answer 39

to prevent sepsis (infection) in patient; keep sterile materials sterile, so do not introduce microorganisms in to patient

Question 40

Aseptic Technique -Applications

Answer 40

removing sterile solution from a vial for patient injection
removing sterile swab from package, collecting specimen from patient for culture, and returning swab to package for transit to lab (want the specimen to represent the patient’s microbes, not your microbes or microbes from the environment)
removing sterile dressings from package for patient use