Etiologic Agent OF Shigellosis
•Members of the family Enterobacteriaceae
– tribe Escherichieae.
•These are closely related to Escherichia coli
•The two genera cannot be distinguished by DNA hybridization methods.
•Shigellae are now thought to be differentiated pathogenic E. coli
•Shigellae are small, gram-negative, non motile bacilli
•cocobacillary forms occur in young cultures
•Four Species of shigellae