Introduction to Microbiology Techniques

Question 1

What is a defined media?

Answer 1

Media where all ingredients AND their amounts are known.

Question 2

What is another name for a Primary media, what does it do and what are examples?

Answer 2

Non selective media, supports large number of organisms. Sheep Blood agar, Trypticase soy

Question 3

What is selective media and what is an example?

Answer 3

Inhibits some organisms, CNA

Question 4

What is differential media and what is an example?

Answer 4

Indicators of biochemical reactions, MAC

Question 5

What are some examples of combination medias?

Answer 5

MAC, XLD, HEK

Question 6

What are enrichment medias? Examples?

Answer 6

Allows for more growth than primary media, Chocolate. Often incubated in CO2 for fastidious organisms.

Question 7

What are maintenance medias? What can be grown on them?

Answer 7

Allows for extended growth time (limits sugars or adds extra buffer) Salmonella and E. Coli.

Question 8

What do Dyes inhibit?

Answer 8

Gram pos

Question 9

What are some selective agents and what do they inhibit?

Answer 9

Heavy Metals (ex: Bismuth sulfite for Salmonella*)
Antimicrobials
Sodium desoxycholate (bile salts) inhibits GP
Phenylethyl alcohol= inhibits GN
Azide= Inhibits GN
NaCl = Only allows Staphylococcus

Question 10

What type of media is SBA?

Answer 10

Primary

Question 11

What type of media is Trypticase Soy?

Answer 11

Primary

Question 12

What type of media is CNA?

Answer 12

Selective

Question 13

What type of media is MAC? Selective for? Colors?

Answer 13

Selective and differential; selective for Gram (-), dark pink = pos= uses lactose Clear = (bright pink)= neg= does not use lactose

Question 14

What are specimens from normally sterile areas place on?

Answer 14

Enrichment (chocolate)

Question 15

What things are taken into account when selecting a media?

Answer 15

Type of specimen
What condition is suspected
Results of preliminary exam of specimen

Question 16

What type of Media is XLD? selective for? Colors?

Answer 16

Selective Isolation and Selective differential media; Selects Gram (-) via bile salts; CHO (+)= Yellow, CHO (-) = Clear/red H2S = Black

Question 17

What type of media is HEK?

Answer 17

Hektoen; Selective Isolation and Selective differential media Selects Gram (-) via bile saltsCHO (+)= orange, CHO (-) = Clear/gree H2S = Black

Question 18

What type of media is EMB?

Answer 18

Selective Isolation and Selective differential media Selects Gram (-) Ecoli = metallic green

Question 19

What type of media is bismuth sulfide?

Answer 19

Heavy metals; Selective FOR Gram (-)

Question 20

What type of media is thoglycollate?

Answer 20

liquid; anaerobes grow lower

Question 21

What media type is Brain Heart infusion?

Answer 21

Primary

Question 22

What media type is Martian lewis or Thayer Martian? What grows on it?

Answer 22

Selective enrichment agar for fastidious, inhibits usually flora for Neisseria gonorrhoea

Question 23

What are the three levels of hemolysis?

Answer 23

Alpha = Partial and Green
Beta = Complete
Gamma = no hemolysis

Question 24

What is the most commonly used disinfectant used on non metallic surfaces?

Answer 24

10% Bleach

Question 25

What is the standard temperature, PSI, and time for autoclave?

Answer 25

121 Degrees C, 15PSI, 15-20min

Question 26

What is Obligate anaerobe

Answer 26

Requires O2

Question 27

What is it called when an organism requires little O2?

Answer 27

Microareophilie

Question 28

What is a facultative anaerobe?

Answer 28

Grows best with O2 but can grow without O2

Question 29

What is Ambient Air and its Element amounts?

Answer 29

Room air, non-CO2, O2=21% CO2= .03%

Question 30

What are CO2 incubator element amounts? What kind of incubator is it?

Answer 30

O2= 15% CO2= 5-10%; aerobic

Question 31

What are Microareophilic incubator elements?

Answer 31

O2= 5% CO2= 10%

Question 32

What are anaerobic incubator elements?

Answer 32

O2=0% CO2= 5-10% (rest is N)

Question 33

What goes in ambient air incubation?

Answer 33

Biochemicals, differential media, Antimicrobial susceptibility

Question 34

What goes in CO2 incubation?

Answer 34

Primary plates and fastidious organisms

Question 35

What is a direct smear?

Answer 35

Specimen is plated directly on slide and then gram stained provides initial clue to cause of infection

Question 36

What are two stains that require fluorescent microscope readings?

Answer 36

Acid fast, Acridine orange, and Calcofluor white

Question 37

What is the most important characters for making the diagnosis of "gangrene" based on a direct smear?

Answer 37

Necrotic Background and absence of intact cells

Question 38

What method is MALDI-TOF?

Answer 38

Rapid method