Gram Stain - Gram Negative features: - Peptidoglycan - Outer membrane Staining characteristic

- Thin peptidoglycan cell wall - Outer membrane present Lose crystal violet/Iodine during decoloarization -- Visualized w/ Red Safranin counterstain

Bacteriology-Methods Flashcards by Filip Garrett

What bacteria grow best at 25-30C? (2)

Yersinia entercolitica

- Psuedomas spp.

How well did you know this?

Not at all

Perfectly

Gram Stain Morphology:

-Pyogenic streptoccoci

Gram Positive Cocci

-Pairs/Short chains

How well did you know this?

Not at all

Perfectly

Indole Test use/function.

Identification of E. coli (indole Positive)

*not unique to E. coli

How well did you know this?

Not at all

Perfectly

What biochemical test is used to identify Group B pyogenic strep and Listeria monocytogenes?

CAMP Test

*Both produce CAMP factor

How well did you know this?

Not at all

Perfectly

Gram Stain - Gram Negative features:

Peptidoglycan*
Outer membrane

*Staining characteristic

Thin peptidoglycan cell wall*
Outer membrane present

*Lose crystal violet/Iodine during decoloarization – Visualized w/ Red Safranin counterstain

How well did you know this?

Not at all

Perfectly

Hippurate Hydrolysis Test is used for the presumptive identification of which organisms? (5)

Campylobacter jejuni
LIsteria monocytogenes
Strep agalactiae
Gardnerella vaginalis
Legionella pneumophila

*All are POSITIVE

How well did you know this?

Not at all

Perfectly

Oxidase Positive Organisms (7)

Neisseria spp.
Moraxella
Pseudomonas
Legionella
Campylobacter*
Vibrio*
Helicobacter*

*Curved Gram Negative RODS

How well did you know this?

Not at all

Perfectly

Gram Stain Morphology:

-Campylobacter

Gram Negative Rods

Thin, Curved
S-shaped, Seagull/Corkscrew

How well did you know this?

Not at all

Perfectly

Oxidase Negative Organism.

Enterobacteriaceae

How well did you know this?

Not at all

Perfectly

What selective media is used for recovery of Neisseria spp. from nonsterile sites?

Thayer-Martin medium

How well did you know this?

Not at all

Perfectly

Which organisms don’t grow on Sheep blood agar? (3)

N. gonorrhea
H. influenzae
Legionella

How well did you know this?

Not at all

Perfectly

Gram Stain Morphology:

-Staphylococci

Gram Positive Cocci

-Grapelike clusters

How well did you know this?

Not at all

Perfectly

Novobiocin Susceptibility testUse/Function.

S. saprophyticus (Novobiacin Resistent) Vs. other coagulase Negative staphylococci
-S. epidermidis (Novobiacin Susceptible)

How well did you know this?

Not at all

Perfectly

What selective media is used for recovery of Yersinia spp.?

Cefsulodin-Irgasan-Novobiocin agar

CIN

How well did you know this?

Not at all

Perfectly

Growth in Lysozyme containing broth medium is indicative of what bacteria?

Nocardia

How well did you know this?

Not at all

Perfectly

Oxidase Test use/function.

Initial classification of Gram Negatives

What medium is used to recover Legionella spp.?

Buffered Charcoal Yeast Extract agar

BCYE

Coagulase Test Use/Function.

S. aureus (Coagulase Positive) Vs. other Staphylococci (Coagulase Negative)

*should always be confirmed using the tube test

Gram Stain Morphology:

-Vibrio spp.

Gram Negative Rods

Curved, Comma-shaped
Short rods

Gram Stain Morphology:

-Yersinia pestis

Gram Negative Rods

-Bipolar staining (“Closed Safety-Pin”)

Gram Stain Morphology:

-Nonpyogenic streptococci

Gram Positive Cocci

-Long chains

Gram Stain - Gram Positive features:

Peptidoglycan
Outer membrane

*Staining characteristic

THICK peptidoglycan cell wall*
NO outer membrane

*Retains purple crystal violet/Iodine stain during the decolarization step (alcohol)

Catalase Test Use/Function.

Gram Positive Cocci

Staphylococci - Catalase Positive
Streptococci/Enterococci - Catalase Negative

Why don’t Mycobacteria stain well with Gram Stain?

Mycolic Acids in Peptidoglycan Cell wall

-Hydrophobic-Repels Crystal violet/Iodine

PYR tests use/function.

Identifies Group A pyogenic streptococci and Enterococcus spp. (Positive Test - Red color change)

Which body sites normally harbor indigenous Anaerobic flora (and should not be cultured for anearobes)? (5)

- Stool - Skin - Oropharynx - Vagina - Urethra

What selective media inhibits growth of Gram Positive bacteria and many Enterics? -What does grow?

Selenite Broth | -Samonella

Gram Stain Morphology: | -Neisseria spp.

Gram Negative Diplocci | -Coffee Bean shaped

Listeria monocytogenes - Temperature characteristics.

37C - Optimal growth 25C - Shows motility 4C - Able to multiply

Optochin Susceptibility test (P disk) Use/Function.

S. pneumoniae (Optocin Susceptible*) vs other alpha-hemolytic Streptococci -Viridans strep (Optocin Resistent) *Shows Clearing

Besides Staphylococci, what other bacteria are Catalase Positive? (3)

- Campylobacter spp. - Listeria spp. - Bacillus spp.

Gram Stain Morphology: | -S. pneumoniae

Gram Positive Diplocci | -Lancet shaped

Acid-Fast Stain principle.

Uses Heat and/or Phenol to allow a Fuchsin dye to penetrate the Hydrophobic barrier -Stains Mycolic Acids in cell wall

Gram Stain Morphology: | -Enterococcus

Gram Positive Diplocci

Bile Esculin Test Use/Function.

Identifies Enterococci and Group D strep (S. bovis)

What selective media is used for recovery of Vibrio spp.?

Thiosulfate-Citrate-Bile Salts-Sucrose agar | TCBS

Rapid Urease Test use/function.

Proteus spp. and H. pylori identification -Urease Positive (Red/Pink coloration)

Gram Stain Morphology: | -Legionella

Gram invisible in primary smear

Campylobacter spp. grows best at what temperature?

42C