Disinfection

Question 1

sterilization

Answer 1

killing all organisms

Question 2

germicide

Answer 2

agent for killing

Question 3

disinfection

Answer 3

using a germicide on inanimate objects. does not imply killing all organisms

Question 4

antisepsis

Answer 4

application of agents of surface of body to limit pathogens

Question 5

septic

Answer 5

presence of pathogenic bacteria in living tissue

Question 6

aseptic

Answer 6

tissue w/o pathogenic bacteria

Question 7

sanitize

Answer 7

lowering bacterial content on fomites w/o using a germicide. use of heat is implied

Question 8

perservative

Answer 8

inhibits growth of organisms. nontoxic and used in food and vaccines

Question 9

phenol coefficient

Answer 9

killing capacity of an agent compared to phenol

greater than 1 means more effective than phenol
less than 1 means less effective than phenol

Question 10

describe the descending order of resistance of various biological agents to germicidal chemicals

Answer 10

bacterial spores- mycobacteria- non lipid/small viruses- fungi- vegetative bacteria- lipid/medium sized viruses

Question 11

first order kinetics killing curves for organisms

Answer 11

shows that the number of microbes killed is directly proportionate to the dose

Question 12

change in killing kinetics w/ temp

Answer 12

increasing the temp decreases the time needed to kill

Question 13

chlorohexidine

Answer 13

chlorinated phenol used as a surgical scrub

Question 14

ethylene oxide

Answer 14

alkylating agent that destroys amino acids and hydroxyl groups. used to sterilize things that are heat sensitive

STERILAZTION

Question 15

ethanol

Answer 15

disorganizes protein and lipids via hydrolysis reactions. 60-70% is optimal b/c water is necessary for the hydrolysis rxn

not as effective as iodine containing compounds

ANTISEPTIC

common uses: skin, antiseptics, germicides

Question 16

isopropoanol

Answer 16

same uses as ethanol, but w/o legal restriction

Question 17

iodine

Answer 17

tincure is a mix of iodine and KI in water

most effective antiseptic on skin

binds reactive tyrosine residues and forms inactive disulfide bridges on sulfur

ANTISEPTIC

Question 18

chlorine

Answer 18

advantage- rapidly dissolves w/o scent

used in water supplies and food

ANTISEPTIC

Question 19

detergents

Answer 19

destroy membranes and dissolve lipids

quaternary ammonium ions (or other cations) drawn toward negative charges on bacterial sufrace

ANTISEPTIC

Question 20

hydrogen peroxide

Answer 20

particularly useful against anaerobes. action is inhibited by catalase

kills via ROS

ANTISEPTIC

Question 21

soaps

Answer 21

surfactants containing hydrophobic/hydrophilic portions

mostly anionic detergents

physically remove bacteria rather than killing them

ANTISEPTIC

Question 22

antibacterial soaps

Answer 22

active ingredient is triclosan

has a specific target that inhibits bacterial fatty acid synthesis

ANTISEPTIC

Question 23

heavy metals

Answer 23

mercury and silver most common

mercury compounds bind SH groups

perservative used in vaccines

Question 24

aldehydes

Answer 24

formaldehyde in vaccines- alkylation

glutaraldehyde - sterilizes syringes and blood

alternative preservative to heavy metals

Question 25

heat

Answer 25

3 ways- moist heat, dry heat, pasteruization wet heat- complete sterilzation caused by steam under pressure- autoclave. pressure allows you increase temp while keeping fluid state. unsuitable for heat sensitive materials. spores are resistant to boiling dry heat- good for materials damaged by water. much higher temp over longer duration. 180 C for 2 hours pasteurization- classically- 62 C for 30 minutes (milk in america) HTST- used in europe 71-72 for just 15-17 seconds.

Question 26

sterilizing prions

Answer 26

autoclave w/ NaOH, 121 C, for 30 minutes

Question 27

tests for effective pasteurization

Answer 27

loss of alkaline phosphatase activity negative culture for coxiella burnetti

Question 28

filtration

Answer 28

used for heat sensitive liquids. allows retention of high quality, no effects of heat treatment. can be used quickly for smal samples drawbacks- expensive, clogged filters, most viruses pass through all common filters

Question 29

nonionizing radiation

Answer 29

nonionizing radiation- (UV light) used in operating rooms or bio hoods causes thymidine dimers that interfere w/ DNA replication causes peroxide formation advantages- cheap and contained disadvantages- non-penetrating, damages human tissue

Question 30

ionizing radiation

Answer 30

xray, gamma rays, high enery, not widely used, except some food disadvantage- containment

Question 31

drying

Answer 31

lowers water level below requirement for bacterial growth can be done by salt and sugar- osmotic agents that dry

Question 32

dyes

Answer 32

MOA unknown used as an antifungal for athletes foot infections