Gram Θ rod. Non-lactose fermenter, oxidase Θ.

Reservoir: Human colon onlyTransmission: fecal-oral spread. Low infectious dose (vs. Salmonella - high).

Pathogenesis:- Invasion of M cells, create very shallow ulcers.- Shiga toxin: inhibit protein synthesis by clipping 60S ribosomal subunit.

Disease:- Fever (generally >101.0˚F)- Lower abdominal cramps, tenesmus- Diarrhea: first watery, then bloody- Invasive but rarely causes septicemia

Treatment: Mild – supportive; Severe – Quinolones