1. Enterobacteria. Biological characteristic and classification of genera
Enterobacteria. Biological characteristic and classification of genera. Characteristics of genus Escherichia, Shigella and Salmonella

2. Family Enterobacteriaceae Genus
Escherichia
Shigella
Edwardsiella
Salmonella
Citrobacter
Klebsiella
Enterobacter
Hafnia
Serratia
Proteus
Morganella
Providencia
Yersinia
Ervinia

3. Escherichia

4. Antigenic structure O antigen K antigen H-antigen
These antigens detected by agglutination reactions.

5. Biochemical reactions
They ferment most of the sugars
Glucose
Lactose
Mannitol
Maltose with production acid and gas.
Indol reaction is positive.
H2S is not formed.
Gelatin is not liquified.

6. Diarrhoea 1. Enteropathogenic E.coli (EPEC)
E.coli causing diarrheal diseases are of five groups.
1. Enteropathogenic E.coli (EPEC)
2. Enterotoxigenic E.coli (ETEC)
3.Enteroinvasive E.coli (EIEC)
4.Enterohaemorrhagic E.coli (EHEC)
5.Enteroaggregative E.coli (EAEC)

7. Laboratory diagnosis
Bacteriological method.

8. Shigella Classification Subgroup A (S.dysenteriae)
Subgroup B (S.flexneri)
Subgroup C (S.boydii)
Subgroup D (S.sonnei)

9. Morphology

10. Laboratory diagnosis
Bacteriological method.

11. Salmonella Classification
Causative agents of enteric fever S.typhi , S.paratyphi A, S.schottmuelleri
Causative agents of gastroenteritis
S.typhimurium, S.enteritidis, S.newport, S.dublin and etc.
3. Salmonella causing septicemia
S.cholerae-suis

12. Morphology of salmonellae

13. Antigenic structure Flagellae antigen – H Somatic antigen – O
Surface antigen – Vi, found in some species.

14. Classification Kauffmann-White scheme
Salmonellae are classified into groups based on distinctive O antigen factors.
Within each group, further identification and differentiation is by phase 1 and phase 2 H antigens.

15. Culture Lactose-including media SS-agar Nutrient agar Bile broth
Wilson and Blair bismuth sulphite medium (BSA)

16. Biochemical reactions
Salmonellae ferment:
Glucose
Mannitol
Maltose forming acid and gas except S.typhi which produces only acid and no gas.
Most salmonellae produce H2S.
They do not ferment lactose.
Indol is not produced.

17. Laboratory diagnosis Isolation of bacilli Demonstration of antibodies
Demonstration of circulating antigen

18. Vaccination TAB vaccine – Live oral typhoid vaccine
Purified Vi polysaccharide vaccine

19. Salmonella typhi