Enterobacterales Key Tests Flashcards
What three groups of organisms is the VP test positive for?
Klebsiella, Enterobactor, and Serratia.
What organisms test negative for motility?
The two organisms that test NEG for motility + the one that sometimes tests NEG (depending on temp) are:
- Klebsiella
- Shigella
- Yersinia at 35C.*
Yersinia is motile at 25C but not at the higher temp.
What organisms does Phenyl-alanine (PA) test POS for?
The PMP group tests positive for Phenyl-alanine (PA).
- Proteus,
- Morganella, and
- Providencia.
What organisms are Hydrogen sulphide (H2S) positive?
H2S Pos are:
- Citrobacter (Lactose Pos)
- Salmonella (Lactose Neg)
- Proteus (Lactose Neg)
What organism is said to “swarm” on its plate (i.e. gets all over the plate with no distinct colonies)?
Proteus swarms.
Which organism is considered mostly mucoid? And what others could be considered too?
Mucoid:
Klebsiella (usually)
Enterobacter …. could be
E. coli …. could be
What organism has a red-orange pigment?
Serratia
Which organism is the only one to be DNAse positive (out of the Enterobacteriaceae)?
Serratia is the only DNAse POS.
What can Indole help differentiate between?
Indole can differentiate between Klebsiellas and Proteus:
Klebsiellas –> pneumonia is NEG, oxytoca is POS)
Proteus –> (mirabilis is NEG, vulgaris is POS)
What organism is the only one that is POS for the MUG test?
E.coli is the only POS for the MUG test.
What are the results for IMViC for E.coli, K. pneumonia, Enterobacter, and K.oxytoca?
E.coli –> ++–
K. pneumonia –> –++
Enterobacter –> –++
K. oxytoca –> +-++
What are common test results for ALL Enterobacteriaceae?
Oxidase NEG
Reduce Nitrates
Ferment Glucose
Also
O/F +/+ and butt of TSI is yellow.
What does it mean if TSI’s slant is alkaline (red)?
If the TSI test slant is red (alkaline) –> Non-Lactose Fermenter.
What organism typically gives a “peachy butt” in their TSI test?
Yersinia typically gives a “peachy butt” in its TSI test.
