Identification, Disinfection

Question 1

Answer 1

-streaking culture technique

Question 2

Answer 2

-serial dilutions culture technique

Question 3

MacConkey Agar

Answer 3

-selective and differential media
-differentiates lactose utilizers
-red = lactose utilizers
-white = don’t utilize lactose
-selects against gram positive bacteria

Question 4

how to tell if spores present

Answer 4

-refractile to gram stain – colorless hole in cell

Question 5

motility test - wet mounts

Answer 5

-direct microscopic observations
-left negative
-right positive

Question 6

motility test - motility culture media

Answer 6

-soft agar stab
-left nonmotile
-right motile

Question 7

H, O, K antigens

Answer 7

-H antigens - flagella –> protein
-O antigens - LPS –> polysaccharides
-K antigens - capsule –> polysaccharides or protein

Question 8

what serological test is used for initial screenings of colonies than may be Salmonella

Answer 8

-slide agglutination

Question 9

what serological tests do you not need to isolate pathogen for and can use patient’s serum

Answer 9

-ELISA
-latex agglutination
-Western blotting

Question 10

what is triple iron media used for

Answer 10

-differentiate enteric bacteria based on ability to ferment sugars, produce H2S, produce gas

Question 11

Triple iron media

Answer 11

-non fermenter
-alkaline slant, alkaline deep

Question 12

Triple iron media

Answer 12

-non lactose fermenter
-alkaline slant, acid deep
-acids produced can result in orange to yellow color

Question 13

Triple iron media

Answer 13

-lactose and sucrose fermenters
-acid slant, acid deep

Question 14

Triple iron media

Answer 14

• non lactose fermenters, H2S producer
  -alkaline slant, H2S deep

Question 15

what is protein degradation

Answer 15

-following hydrolysis of peptide bonds, amino acids are catabolized

Question 16

deamination

Answer 16

deaminase

Question 17

desulfurylation

Answer 17

sulfurylase

Question 18

decarboxylation

Answer 18

decarboxylase

Question 19

combined tests for biochemcial characteristics

Answer 19

-enterotube
-API20E system

Question 20

what is a prerequisite prior to testing

Answer 20

isolation of homogenous culture

Question 21

define decontamination

Answer 21

-cleaning to eliminate risk of infection
-reduction in pathogenic organisms

Question 22

define disinfection

Answer 22

-elimination of most pathogenic organisms, including spores

Question 23

define sterilization

Answer 23

-elimination of all living organisms

Question 24

moist heat

Answer 24

-denaturing of proteins
-autoclave

Question 25

dry heat

Answer 25

-limited to inanimate heat resistant objects

Question 26

incineration

Answer 26

-fast, but expensive -elimination of pathogen contaminated materials (bandages, carcasses, tissues)

Question 27

ultraviolet radiation

Answer 27

-thymine dimer distorts DNA -endonuclease cuts out region with thymine dimer -repair synthesis by DNA polymerase -DNA ligase seals new strand to old strand

Question 28

ionizing radiation (ozone)

Answer 28

-x rays, gamma rays -produce oxygen radical and OH radical from water -disruption of covalent bonds -sterilization of inanimate heat sensitive materials

Question 29

liquid filtration

Answer 29

-average pore size 0.2 um -bacteria average 0.5 um -sterilize liquids that are heat sensitive

Question 30

air filtration

Answer 30

-high efficiency particulate air filter -99.999% of 0.12 um particles

Question 31

alkylating chemical agents

Answer 31

-gaseous and liquids -reactive with carboxyl, hydroxyl, sulfhydryl groups of proteins -sterilize things sensitive to heat

Question 32

sonication

Answer 32

-vibrating probe -bubbles bombard cells and lyse them

Question 33

define MEC

Answer 33

-minimum effective concentration of a germicide required to achieve advertised microbial activity

Question 34

what is the gradient of microbial activity on bacteria of disinfectants

Answer 34

gram+ < gram- < acid fast < spore formers

Question 35

alocohols

Answer 35

denature proteins and solubilize lipids

Question 36

alkalines

Answer 36

-destroys cell wall and cell membranes -used on inanimate objects

Question 37

heavy metals

Answer 37

-poison enzyme activities by interacting with sulfhydryl groups of cysteine residues

Question 38

oxidizing agents

Answer 38

-halogens -- iodine, chlorine -inactivate enzymes by converting functional SH groups to oxidized SS forms

Question 39

surface active agents

Answer 39

-induce reaction of surface or interfacial tension -wetting agents, detergents -anionic -- soaps, fatty acids with negative charge cationic -- quaternary ammonium compounds

Question 40

phenolic compounds

Answer 40

-membrane disruption and protein denaturation -phenol no longer used due to toxicity -lysol

Question 41

aldehydes

Answer 41

-glutaraldehyde -ortho-phthalaldehyde -formaldehyde

Question 42

what do gross metabolic poisons do

Answer 42

alter permeability, irreversibly denature macromolecules

Question 43

most commonly used disinfectant

Answer 43

bleach