Gram Negative Bacilli - Enterobacteriaceae Flashcards
Indicator for TSI(pH)
Phenol red
H2s indicator is Sodium thiosulfate and ferric ammonium sulfate
Fermentable sugar for CIN, indicator used is
Mannitol
Neutral red
Fish eye appearance on emb
Enterobacter
Negative color for NLF in HEA
Green or colorless with or without black
Positive is yellow with or without black
Selenite broth can be used for
Salmonella and shigella
On SSA, what reaction is indicative of the presence of salmonella and shigella
Colorless with black center
If h2s (+) = salmonella If neg = shigella
Inhibitors in MAC
Crystal Violet and bile salts
Tetrathionate broth is used for ID of
Salmonella
Positive reaction for onpg, what organisms are positive
Yellow
Serratia, citrobacter, s.sonnei, s.Arizonae, y.enterocolitica,hafnium alvei
What test is useful to detect an organism that produces a red pigment (_____)
Gelatin hydrolysis = liquefaction
Serratia
Prodigiosin
Incubation settings in the test used to detect serratia
Gelatin hydrolysis test
14 days at 35-37C
Special indication when testing for gelatin hydrolysis to avoid false (+) results
Remove nutrient gelatin media from incubator daily and ref for 30min . If truly positive, it should liquefy even when put to ref
What substance is detected\produced in the VP test that indicates the organism is positive for that
Acetoin or acetylmethyl carbinol
Reagent used in coblentz method. This is for what test
40% Koh plus creatine
VP
What Broths may be used when testing for MR
Mrvp broth and Clark lubbs
Sim and tryptophan broth maybe used in what imvic test
Indole
What can differentiate k. Oxytoca and k.pneumoniae
K oxytoca is indole (+)
Indicator for urease test, what is the positive and negative result color
Phenol red
(+) pink
(-) yellow
What organisms are slow urease producers
KEYSC Klebsiella Enterobacter Yersinia Serratia Citrobacter
What organisms are rapid urease producers
Ppm + helicobacter
Positive result if tryptophan agar is used in deaminase test
Brown
If phenylalanine = green
Negative for both is yellow
Reagent used in deaminase test
Ferric chloride (10%)
What tests are useful to differentiate salmonella and shigella
- Motility (shigella non motile)
- Malonate utilization
- H2s production
- Decarboxylase
Which among salmonella and shigella is H2s positive
SPACED
Salmonella, proteus, arizonae , citrobacter, Edwardsiella,