A person returns to Delhi from Bangladesh after 2 days and has diarrhoea. Stool examination shows RBC&;s in the stool. The likely organism is

Shigellae cause bacillary dysentery. Infection occurs by ingestion.The minimum infective dose is low-as few as 10-100 bacilli are capable of initiating the disease. Sho incubation period. Clinical features - Frequent passage of loose, scanty faeces containing blood and mucus along with abdominal cramps and tenesmus. Ref: Ananthanarayan and Paniker&;s Textbook of Microbiology, 9th edition; pg no: 286, 287