ENTEROBACTERIACEAE
ENTEROBACTERIACEAE
Morphology Identification Gram-negative non-spore forming rods. When motile, by peritrichous flagella. o Primarily normal flora of gastrointestinal tract. E. coli>klebsiella>proteus>Enterobacter o Free living, also transient colonizers of skin o Facultative anaerobes: mixed acid fermentation o All ferment glucose; all reduce nitrates to nitrites; all oxidase negative o Lactose fermentation: normal flora positive and pathogens negative o Primary isolation media include eosin-methylene-blue (EMB) and mac Conkey agar. o Differential selective media for specific organisms including dyes and bile salts( Salmonella-Shigella(ss)medium, bismuth sulfite media.)
Morphology & Identification ⚫ Gram-negative non-spore forming rods. When motile, by peritrichous flagella. ⚫ Primarily normal flora of gastrointestinal tract. E. coli>Klebsiella>Proteus>Enterobacter ⚫ Free living, also transient colonizers of skin. ⚫ Facultative anaerobes: mixed acid fermentation ⚫ All ferment glucose; all reduce nitrates to nitrites; all oxidase negative. ⚫ Lactose fermentation: normal flora positive and pathogens negative. ⚫ Primary isolation media include eosin-methylene-blue (EMB) and MacConkey agar. ⚫ Differential selective media for specific organisms including dyes and bile salts. (Salmonella-Shigella (SS) medium, bismuth sulfite media.)
Classification '29 genera, over 100 species. Escherichia Proteus shigella Providencia edwardsiella Morganella salmonella Yersinia Citrobacter Erwinia Klebsiella Pectinobacterium Enterobacter Hafnia serratia
Classification ~29 genera, over 100 species. – Escherichia – Shigella – Edwardsiella – Salmonella – Citrobacter – Klebsiella – Enterobacter – Hafnia – Serratia – Proteus – Providencia – Morganella – Yersinia – Erwinia – Pectinobacterium
Antigenic Structure Most are motile by peritrichous flagella --H antigens Capsule-K antigen( Vi for Salmonella). Cell envelope(wall) LPS(endotoxin)-O antigen. various outer membrane proteins. Pili-various antigen types, some encoded by plasmids
Antigenic Structure – Most are motile by peritrichous flagella --H antigens. – Capsule – K antigen ( Vi for Salmonella). – Cell envelope (wall) – LPS (endotoxin) – O antigen. – various outer membrane proteins. – Pili - various antigen types, some encoded by plasmids
鞭毛抗原(H Flagella (H antigen) Capsule(K or Vi antigen Lipopolysaccharide(LPS)or o polysaccharide saccharide core K或Ⅵ抗原 lipid A Outer membrane Periplasmic space 菌体抗原(O) Li n
鞭毛抗原（H） 菌体抗原(O) K或Vi抗原