Shigellosis (bacillary dysentery)

Pathogens: Shigella dysenteriae, Shigella flexneri, Shigella sonnei

• Gram-negative rods

• Produce Shiga toxin (enterotoxin) and endotoxin

• Invade M cells via pinocytosis and travel from cell to cell via actin filaments (no hematogenous spread)

Transmission

• Fecal-oral (especially a concern in areas with poor sanitation)

• Oral-anal sexual contact

• Foodborne (unpasteurized milk products and raw unwashed vegetables)

• Contaminated water

Incubation period: 0–2 days

Infectivity: highly contagious; very low infective dose required (≥ 10 bacteria)

Prevention: no vaccine available

Duration: 2–7 days

High fever

Tenesmus, abdominal cramps

Profuse inflammatory, mucoid-bloody diarrhea

Supportive therapy for gastroenteritis: e.g., bland diet, oral rehydration therapy

Antibiotic therapy

• Preferred regimens

  • Ciprofloxacin

  • OR azithromycin

  • OR ceftriaxone

• Alternative: trimethoprim/sulfamethoxazole

HUS

Intestinal complications (e.g., toxic megacolon, colonic perforation, intestinal obstruction, proctitis, rectal prolapse)

Febrile seizures

Reactive arthritis