Chapter 9 Enterobacteriaceae Enterobacteriaceae Include Escherichia Shigella Salmonella

Chapter 9 Enterobacteriaceae

Enterobacteriaceae

Include – -- Escherichia – -- Shigella – -- Salmonella – -- proteus – -- Klebsiella spp. – -- Morgan spp. – -- Citrobacter – -- Enterobacter spp. – -- Sarre bacteria etc. Pathogenic bacteria The normal intestinal flora Conditional pathogenic bacteria Hospital infection

Common characteristics • 1．Form and structure : similar • 2．Culture characteristics: nutritional requirements is not high. • 3．Biochemical reactions : lively • 4．Antigenic structure: complex

• 5．Resistance: not strong. • 6. variation: Easy • 7. The main pathogenic substances : endotoxin, part of intestinal Bacillus produce exotoxin

Escherichia

Biological characters • Morphology and staining: G-, Bacillus • Culture characteristics EMB——Purple black S-S——Peach red • Biochemical reaction. IMVi. C（++--） • Antigen structure O H K Antigen O：K：H （ O 1 ---O 173）（H 1 ---H 56）（K 1 ---K 100）

Pathogenic substances 1. adhesine 2. Exotoxin Shiga toxin（ Stx）、 Heat stable enterotoxin（ ST）、 Heat labile enterotoxin（LT）； 3. Endotoxin and type III secretion systems

Disease • Extra intestinal infection – Urinary tract infection • Gastroenteritis

E. coli(Causing gastroenteritis) • • • enterotoxigenic E. coli enteroinvasive E. coli enteropathogenic E. coli enterohemorrhagic E. coli enteroaggregative E. coli ETEC EIEC EPEC EHEC EAgg. EC

Microbiological examination method • • • Specimen Isolation and culture Besides intestinal infection When Urinary tract infection The number of bacteria≥ 100000, Judge for the infection intestinal infection Identification of bacteria

The principle of prevention and treatment • Vaccination • Antibiotics

二 Salmonella

Biological characters • Morphology and staining – G– 0. 6 -1. 0µm╳ 2 -4µm With flagella and pili Culture characteristics Biochemical reaction – Facultative anaerobic – Nutritional requirements is not high – Don't break down lactose

Salmonella typhimurium

Antigen structure Component Antibody O-Antigen LPS Ig. M H-Antigen Protein Vi. Antigen：Surface antigen Ig. G classification Causing human salmonellosis mostly belong to the A-F group two kinds of： Specific phase Non specific phase

Resistance • Poor • It can survive 2 -3 W in water •

Pathogenic substances • Invasion • Endotoxin • Enterotoxin

Disease 1. enteric fever, typhoid fever 2. Gastroenteritis 3. Septicemia

Immunity • strong Immunity • Cellular immunity

Microbiological examination method Specimen SSCultur Disaccharide fermentation Serological identification Biochemical reaction Slide agglutina tion test

Rapid diagnosis technique • Latex agglutination test、ELISA

Widal reaction • Auxiliary diagnosis of typhoid fever

The principle of prevention and treatment • Vaccination • Combined vaccine • Ty 2 la Live vaccine

三 Shigella

Biological characters • Morphology and staining ： G-No flagella, no capsule， with Pili • Culture characteristics ： Nutritional requirements are not high， • Biochemical reaction • Don't break down lactose

Antigen structure and classification l Ø Ø O-antigen and K-antigen classification Strain Group. Shigella dysentery A Shigella bacteria – Martin Shigella – Shigella sonnei type subtype 1－12 8 a、8 b、8 c B 1－6、 1 a、1 b、2 a 、2 b 、 3 a x y变型 3 b、3 c、4 a、4 b C 1－18 D 1

• Variability: the resistance variation and so on • Resistance: weak; • Sensitive to acids and Disinfectant

Pathogenic substances Invasion Endotoxin Exotoxin

• Disease • 1．Acute bacterial dysentery: • 2 chronic bacillary dysentery: • 3 toxic bacillary dysentery

Immunity • Unstable：SIg. A

The principle of prevention and treatment Vaccination multiple drug resistance 。 Immune defense committed to live vaccine：streptomycin dependent strain, Sd。

Vibrio cholerae

It wasn’t until 1883 that the cholera bacteria was discovered by Robert Koch 1843～ 1910

Biological characters • Morphology and staining –G– Arc – A single flagellum, active movement

Culture characteristics – Culture medium： p. H 8. 8~9. 0 Alkaline peptone water • Biochemical reaction：Understanding •

Antigen structure classification • O 、H Antigen • More than 200 serum group，O 1、O 139 Causes cholera. • O 1 serum group Divided into 2 biological group：Classical biological type， El Tor type