Salmonella sp. | Contaminated food or water (eggs, poultry, milk). Animals or pets (turtles, chicks, lizards). Group gatherings. | 8–72 hours | Very common. Fever, abdominal pain, headache, myalgia, diarrhea with little vomiting. Risk of sepsis in the young, elderly, or the compromised (sickle cell disease, diabetes, HIV, intravenous drug abusers, the asplenic). Rare fecal RBCs; common WBCs. | Treat infection in those with severe illness or sepsis, the immunocompromised, or the hospitalized. Ciprofloxacin, 500 mg orally (400 mg intravenously) twice daily for 3–7 days. Alternative: azithromycin or ceftriaxone. |
Shigella sp. | Fecal-oral, person-to-person transmission, or contaminated food. Daycare and institutions. Poor sanitation. Highly contagious. | 1–3 days | Very common. Children aged 1–5 years, institutionalized patients. Fever, headache, abdominal pain, myalgia, diarrhea with little vomiting. Febrile seizures and a toxic appearance may prompt lumbar puncture. Diarrhea may begin during the procedure. Fecal RBCs common; sheets of WBCs. | Treat infection in those with severe dysentery, sepsis, or institutional outbreaks. Ciprofloxacin, 500 mg orally (400 mg intravenously) twice daily for 3–5 days. Alternative: TMP-SMZ or azithromycin. |
Campylobacter sp. | Unchlorinated water, contaminated food (unprocessed milk, poultry). Animals or pets. Natural water supplies in the national parks. | 1–7 days | Very common. Backpacker's diarrhea, summer months, children and young adults. Fever, headache, abdominal pain, myalgias for several days followed by diarrhea with little vomiting. May mimic appendicitis. Fecal RBCs and WBCs common. | Treat infection in those who are compromised or appear toxic. Ciprofloxacin, 500 mg orally twice daily for 5 days. Alternative: azithromycin. |
Yersinia enterocolitica | Contaminated food or water (pork, milk). Fecal-oral, person-to-person transmission. Wild and domestic animals. | 1–5 days | Children and young adults. Anorexia, low-grade fever, right lower quadrant abdominal pain, and vomiting may precede diarrhea and mimic appendicitis. Bacteremia is rare. Fecal RBCs and WBCs common. | Treat infection in severely ill patients. Usually self-limiting. Ciprofloxacin, 500 mg orally twice daily for 3–5 days. Alternative: TMP-SMZ. |
Vibrio parahaemolyticus | Contaminated food or water. Raw or undercooked shellfish. | 8–72 hours | Most common during the summer months and in adults; common in Japan; diarrhea, abdominal cramps, low-grade fever, headache, and nausea with minimal vomiting; bacteremia is rare; fecal RBCs and WBCs common | None proven; usually self-limiting; in vitro sensitivity to fluoroquinolones or doxycycline |
Enterohemorrhagic E. coli 0157:H7 | Contaminated food or water; raw undercooked meats, hamburger; fecal–oral, person-to-person transmission; institutions, daycare | 3–8 days | Children and the elderly; fever, abdominal pain, vomiting, grossly bloody diarrhea; may mimic gastrointestinal bleed or mesenteric ischemia; hemolytic uremic syndrome (common cause of renal failure in children) occurs in 5%, 5–20 days postinfection; fecal RBCs and WBCs common | Supportive care; antibiotics are not recommended; may increase the risk of complications (hemolytic uremic syndrome) |
Aeromonas hydrophilia | Contaminated water. | 1–5 days | More common in the elderly or the compromised; more severe in children; cause of 10–15% of cases of pediatric diarrhea; diarrhea, vomiting, and abdominal cramps with or without fever; chronic infection may mimic inflammatory bowel disease; fecal RBCs and WBCs common | Ciprofloxacin, 500 mg orally twice daily for 3–7 days; alternative: TMP-SMZ or tetracycline |
Strongyloides stercoralis | Soils with fecal contamination. Warm climates, poor sanitation, institutions. | Weeks to months | Fever, abdominal pain, vomiting, diarrhea, and sepsis in the immunocompromised; the compromisedmay develop cutaneous, pulmonary, or central nervous system symptoms. | Thiabendazole, 25 mg/kg orally twice daily for 3–5 days. |
Clostridium difficile (antibiotic associated) | Recent antibiotic use. Clindamycin, penicillins, and cephalosporins are most commonly implicated. | 1–12weeks | More common in adults; more severe in children; fever, abdominal pain, diarrhea, rarely vomiting; may cause significant illness especially in the elderly, the compromised, or the very young; fecal RBCs and WBCs common | Discontinue associated antibiotics; metronidazole, 500 mg orally three times daily for 10–14 days, or vancomycin, 125 mg orally four times daily for 10–14 days. |
Entamoeba histolytica (amebic dysentery) | Contaminated food or water. Poor sanitation, institutions. Travel to developing countries. | 1–12weeks | Patients with acute amebic dysentery present with abrupt onset of fever, abdominal pain, tenesmus, and bloody diarrhea; vomiting is rare; chronic dysentery causes malaise, weight loss, bloating, and blood-streaked diarrhea; may develop an hepatic abscess; fecal RBCs and WBCs common | Metronidazole, 750 mg orally three times daily for 10 days followed by iodoquinol, 650 mg orally three times daily for 20 days. |