1 / 20

ENTEROBACTERIACEAE

ENTEROBACTERIACEAE. General characters: Predominant aerobic bacterial flora of large intestine. Composed of non sporing, nonacid fast, gram negative bacilli. May or may not be capsulated. Motile by peritrichate flagella or non motile.

taariq
Télécharger la présentation

ENTEROBACTERIACEAE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ENTEROBACTERIACEAE

  2. General characters: • Predominant aerobic bacterial flora of large intestine. • Composed of non sporing, nonacid fast, gram negative bacilli. • May or may not be capsulated. • Motile by peritrichate flagella or non motile. • Grow readily in ordinary media. • Ferments glucose, producing acid and gas or acid only. • Reduces nitrates to nitrites. • Form catalase but not oxidase.

  3. CLASSIFICATION: • TRIBE 1: Escherchiae Genus : 1.Escherchia 2.Edwardsiella 3.Citrobacter 4.Salmonella 5.Shigella

  4. TRIBE 2: Klebsiellae Genus : 1.Klebsiella 2.Enterobacter 3.Hafnia 4.Serratia

  5. TRIBE 3: Proteae Genus : 1.Proteus 2.Morganella 3.Providencia • TRIBE 4: Erwinieae Genus : Erwinia

  6. ESCHERICHIA COLI • Parasite living only in human or animal intestine • Voided in faeces and remain viable for some days only • Detection of E.coli in drinking water – recent pollution with or human or animal faeces

  7. MORPHOLOGY: • Gram negative, straight rods • size 1-3x0.4-0.7 microns • Arrangement-singles/pairs • Motility-Peritrichious flagella some are non motile • Some strains are Capsulated and Fimbriated • Non sporing

  8. CULTURAL CHARACTERISTICS: • Aerobe and facultative anaerobe • Temp.range 10-40c optimum :37c • Good growth occurs on ordinary media • Growth inhibited on selective media-DCA/SS agar • In broth turbid growth occurs

  9. COLONY MORHOLOGY: • 2 Types of colonies are observed • 1.Smooth colonies: Large,thick,greyish white, moist,smooth or partially translucent discs. • 2.Rough colonies: colonies are irregular,dull surface and are often auto agglutinable.

  10. ON BLOOD AGAR: Hemolytic colonies seen. • ON MAC CONKEY AGAR: Bright pink colonies seen due to lactose fermentation.

  11. BIOCHEMICAL REACTIONS: • Catalase : positive • Oxidase : negative • Indole : positive • Methylred: positive • VP : negative • Citrate : negative

  12. SUGAR FERMENTATION TESTS: • Glucose : positive • Lactose : positive • Mannitol: positive • Maltose : positive

  13. Gelatin liquefaction : negative • H2s production test : negative • Urease test : negative • Growth does not occur in KCN media

  14. ANTIGENIC STRUCTURE: • Serotyping done based on 3 antigens 1.SOMATIC antigen “O” 2.CAPSULAR antigen”K” 3.FLAGELLAR antigen”H”

  15. “K” ANTIGEN: • Acid polysaccharide antigen located in envelope • Encloses “O” Ag • Contributes virulence by inhibiting phagocytosis Thermolabile ‘L’ Ag • “K” Ag ‘A’ Ag Thermostabile ‘B’ Ag

More Related