idase negative
? Facultative anaerobic
? Motile except Shigella and Klebsiella
? Non-capsulated except Klebsiella
? Non-fastidious
? Grow on bile containing media (MacConkey agar)
Enterobacteriaceae
? Some Enterobacteriaceae are true pathogens
? Salmonella spp.
? Shigella spp.
? Yersinia spp.
? Certain strains of E. coli (ETEC, EPEC, EIEC, EHEC)
? Most members of the Enterobacteriaceae are opportunistic or cause secondary infections of wounds, the urinary and respiratory tracts, and the circulatory system e.g. E. coli.
? Enterobacteriaceae divided into TWO main groups according to action on LACTOSE
? Lactose Fermenters (LF)
? E. coli, Citrobacter, Klbesiella, Enterobacter
? Lactose Non-Fermenters (LNF)
? Salmonella, Shigella, Proteus, Yersinia
Identification of Enterobacteriaceae
? Gram stain
? All Enterobacteriaceae are Gram-negative rods
? Arranged in single
Virulence Factors Associated with Enterobacteriaceae
? Common Virulence Factors
? Endotoxin
? Capsule
? Antigenic phase variation
? Sequestration of growth factors
? Resistance to serum killing
? Antimicrobial resistance
? Factors Associated with Specific Pathogens
? Exotoxin production
? Expression of adhesion factors