Lab 5 Enterobacteriaceae: Escherichia, Klebsiella, Enterobacter Flashcards
Enterobacteriaceae habitat
Gut: normal gut flora
Can get out into environment through feces
Enterobacteriaceae benefits
Most are saprophytes which can be beneficial for host:
Inhibits growth of unwanted pathogens
Produces vitamins
Help in digestion
Some contain enzymes which the host doesn’t have
Enterobacteriaceae morphology, resistance
Rod
Flagellated (except Shigella, Klebsiella)
Some have capsule and fimbria
Resistance: fair, moderate, average
Enterobacteriaceae culture
Simple
10-45
1 day to produce colony
Samples often contain a lot of bacteria and they can be hard to identify and separate from each other
Differentiation is mainly lactose fermentation
Selective enrichment: salmonella
Rambach agar: propylene glycol fermentation: salmonella
Chromocult coliform agar to diff btw coliform and e.coli
All contain lactose, indicator and inhibitory materials
Enterobacteriaceae low selectivity
Drigalski, MacConkey (bile salts inhibit swarming)
Methylene blue
Enterobacteriaceae medium selectivity
Phenol red: Escherichia and Salmonella
DC: Shigella
Enterobacteriaceae high selectivity
Bismuth sulfide agar: salmonella
Enterobacteriaceae biochemistry
Cat +
Oxi -
Ferm: acid + gas prod
Enterobacteriaceae antigens
O: cell wall
K: capsule
H: flagella (ø Shigella, Klebsiella)
F: fimbria (generally involved in pathogenicity)
Enterobacteriaceae grouping
Genus: biochem (Cat/Oxi, OF) Species: biochem and serological Serogroups: O antigens Serotypes: O, K, H, F antigens Biotypes: fermentation pattern
Enterobacteriaceae
Lactose positive
Escherichia
Klebsiella
Enterobacter
= EKE
Enterobacteriaceae
Lactose negative
Salmonella Shigella Yersinia Proteus Providencia Edwardsiella Serratia Citrobacter
Yersinia tok Serr Salen på hestene sine Shigella og Edward, Pro, Pro, Citro
Enterobacteriaceae indol positive
E. coli
Enterobacteriaceae urease positive
Klebsiella
Enterobacteriaceae methyl red positive
E. coli
