Bacteria of the Mouth and G.I. Tract

What medium is used to isolate skin Staphylococcus?

Mannitol Salt Agar (MSA)

What is observed on Mannitol Salt Agar?

Large opaque colonies and mannitol fermentation

What test is performed after observing colonies on MSA?

Gram stain

What enzyme test is performed after Gram staining MSA colonies?

Catalase test

What type of bacteria are subcultured onto another MSA plate?

Catalase-positive, Gram-positive cocci

What is done after subculturing on MSA?

Streak for isolation

What fermentation tube is inoculated after subculturing?

Glucose fermentation tube

Which test is performed during the next lab?

Coagulase test

What does blood agar evaluate in the throat bacteria exercise?

Type of hemolysis

What sample is observed on blood agar?

Soil slurry

All enterics are Gram-positive or Gram-negative?

Gram-negative

All enterics are oxidase-positive or oxidase-negative?

Oxidase-negative

What shape are all enterics?

Bacilli (rods)

What metabolic characteristic do all enterics share?

Produce acid from glucose fermentation

Which two media are primarily used to identify enterics?

MacConkey agar and TSI

Which lactose fermenter produces H2S?

Citrobacter

Citrobacter is positive for what sulfur compound?

H2S

Which lactose fermenter is indole positive?

Escherichia

Which organism is identified by a positive indole test?

Escherichia

Which lactose fermenter is indole-negative and motile?

Enterobacter

Which lactose fermenter is indole-negative and nonmotile?

Klebsiella

Enterobacter is motile or nonmotile?

Motile

Klebsiella is motile or nonmotile?

Nonmotile

Which non-lactose fermenter produces H2S and has urease?

Proteus

Which organism is urease positive?

Proteus

Proteus produces H2S?

Yes

Which organism produces H2S, lacks urease, and ferments mannitol?

Salmonella

Salmonella ferments what sugar alcohol?

Mannitol

Which organism produces H2S but does not ferment mannitol?

Edwardsiella

Edwardsiella produces H2S?

Yes

Which organism forms pigment at 25°C?

Serratia

At what temperature is Serratia pigmented?

25°C

Which organism does not produce H2S and has no pigment?

Shigella

Which organism has ornithine decarboxylase?

Morganella

Which organism lacks ornithine decarboxylase?

Providencia

Morganella is positive for what enzyme?

Ornithine decarboxylase

Providencia is positive or negative for ornithine decarboxylase?

Negative

Which bacteria are listed as coliforms?

Citrobacter, Escherichia, Enterobacter, Klebsiella

Which bacteria are listed as non-coliforms?

Serratia, Shigella, Salmonella, Edwardsiella, Morganella, Providencia

What ingredients are listed in MacConkey agar?

Bile salts, crystal violet, lactose, casein, gelatin

MacConkey agar is selective, differential, or both?

Both selective and differential

MacConkey agar differentiates what two groups?

Coliforms and non-coliforms

What ingredients are listed in EMB agar?

Eosin, methylene blue, lactose, sucrose, peptone

EMB agar is selective, differential, or both?

Both selective and differential

What does EMB stand for?

Eosin Methylene Blue

What colony appearance is highlighted on EMB agar?

Black-centered colonies with a metallic green sheen

What type of medium is Tomato Juice Agar?

Enriched and selective

What selective agent is found in SF Broth?

Sodium azide

What four media are inoculated with the fecal specimen?

EMB agar, MacConkey agar, Tomato Juice agar, SF Broth

How are the fecal plates inoculated?

Swab a small area then streak for isolation

Where is the swab placed after streaking the plates?

SF Broth

Tomato Juice Agar is incubated where?

In an anaerobic jar

Which bacteria are listed as normal microbiota of the mouth?

Lactobacillus, Streptococcus sanguis, Streptococcus mutans, Streptococcus salivarius

What is the Snyder Test used for?

Dental caries susceptibility

What ingredients are listed for the Snyder Test?

Casein, dextrose, bromcresol green

Sucrose is broken into what two sugars?

Glucose and fructose

Sucrose fermentation can produce what polysaccharide?

Dextran

Sucrose fermentation can also produce what polysaccharide?

Levan

Gram-positive cocci in tetrads are most likely what genus?

Micrococcus

Gram-positive cocci in clusters are most likely what genus?

Staphylococcus

Which Micrococcus species is yellow?

Micrococcus luteus

Which Micrococcus species is red?

Micrococcus roseus

Which Staphylococcus species is coagulase positive?

Staphylococcus aureus

Which Staphylococcus species ferments trehalose?

Staphylococcus saprophyticus

Which Staphylococcus species does not ferment trehalose?

Staphylococcus epidermidis

Which organism is identified using the coagulase test?

Staphylococcus aureus

Which medium tests mannitol fermentation?

Mannitol Salt Agar

Which medium differentiates coliforms from non-coliforms?

MacConkey agar

Which medium is selective and differential using eosin and methylene blue?

EMB agar

Which medium contains sodium azide?

SF Broth

Which medium is enriched and selective for GI bacteria?

Tomato Juice Agar

Which test measures dental caries susceptibility?

Snyder Test