Table 1A.

Clinical and epidemiological characteristics of the main bacterial enteropathogens

Pathogen	Typical age at presentation	Type of diarrhea	Duration of symptoms	Clinical features	Transmission	Seasonality
Campylobacter spp	C jejuni: highest rate among young children and young adults. In rich countries, highest rate in early childhood. In poor countries, highest rate in children < 2 years old.C fetus: highest rates at the extremes of age	Acute diarrhea with or without blood or mucus in stool	>1 week in only 10%–20%	Malaise Abdominal pain Abdominal tenderness Fever Nausea Vomiting Headache Myalgia Arthralgia	Contact with farm animals (age 2–11 years). Drank raw milk. Drank untreated water from lake, river, stream. Eat chicken and other meat prepared in a restaurant. Consumption of undercooked poultry.	Incidence peaks during summer and early autumn
Clostridium difficile  Clostridium difficile-associated disease (CDAD)	1–4 years of age	Stools are almost never grossly bloody and range from soft and unformed to watery or mucoid in consistency, with a characteristic odor	The diarrhea ranges from a few days of intestinal fluid loss to life-threatening pseudomembranous colitis (PMC)	Abdominal pain Fever Leukocytosis	CDAD occurs most frequently in hospitals and nursing homes where the antimicrobial use is high and the environment is contaminated by C difficile spores. C. difficile has been hypothesized as a possible source for community-associated infections through food ready for consumption, such as raw meat and salad.	Winter months
Escherichia coli: Five pathotypes dominate the clinical spectrum: – Enterotoxigenic E. coli (ETEC) – Enteropathogenic E. coli (EPEC) – Enteroinvasive E. coli (EIEC) – Enteroaggregative E. coli (EAEC) (EAEC serotype OI04:H4 Shiga toxin-producing STEC) – Enterohemorrhagic E. coli (EHEC) (EHEC OI57 Shiga toxin-producing – STEC)	ETEC children < 5 years old. In infants, age 0–6 months, more dehydrating diarrhea in resource-constrained countries. EPEC most common in children < 1 year of age. EIEC can cause systemic infection. EAEC predominant in children < 2 years EAEC OI04:H4 infection: higher risk of hemolytic uremic syndrome (HUS) EHEC bloody diarrhea EHECOI57:H7 infection especially in children < 5 years, higher risk of HUS.	Watery (ETEC, EPEC, EAEC) or bloody diarrhea and dysentery (ETEC, STEC, EHEC)	Variable, depending on the pathotype and the age: from mild self-limiting (1–2 days) to severe bloody disease (4-20 days). Life-threatening complication, such as hemolytic uremic syndrome, often needs hospitalization	ETEC: the most common cause of traveler’s diarrhea. EPEC: severe and protracted diarrhea in neonates and infants. EIEC: bloody, mucoid diarrhea with fever, crampy abdominal pain EHEC: bloody diarrhea with low or no fever at all. EAEC: bloody, mucoid diarrhea, abdominal cramps, malaise EHEC serotype 0157:H7: 10% develop HUS, a triad of acute renal failure, hemolytic anemia and thrombocytopenia. Mortality for HUS is approximately 5%. Only EIEC and EHEC can cause systemic infection or complication.	Contaminated food and water. Person-to-person transmission can occur if infected people do not wash their hands after using the toilet or changing diapers. E. coli 0157:H7 is transmitted by ingestion of beef and other foods contaminated with cattle feces	ETEC infections in areas of endemic infection tend to be clustered in warm, wet months, when multiplication of ETEC in food and water is most efficient. EPEC, EAEC identified in the same proportions during winter and summer seasons. EHEC infections most sporadic cases reported in the summer in rich countries of the Northern Hemisphere
Salmonella spp	<20–24 months in resource-constrained nations (S. typhimurium is predominant, followed by S. typhi and S. paratyphi). Children < 5 years old in rich countries.	Usually loose, nonbloody, moderate volume. Large volume, bloody stools, or symptoms of dysentery do not rule out the diagnosis	Usually self-limited – Diarrhea (3–7 days) – Fever (72 hours)	Nausea, vomiting, abdominal cramping Fever usually 38°C–39°C Rare: pseudoappendicitis, illness that mimics inflammatory bowel disease	Most commonly transmitted through eggs and poultry. Also transmitted through undercooked ground meat, unpasteurized dairy products, seafood, and fresh produce.	Tropical climates: highest during rainy season. Temperate climates: highest during warmer months
Shigella spp	Worldwide 69% of all cases among children < 5 years old	Many patients have only self-limited watery diarrhea (watery diarrhea may progress to bloody diarrhea and dysentery). Bacillary dysentery with blood, mucus, and pus	Mild disease usually lasts from a few days to a week. Severe disease can progress to toxic dilatation and colonic perforation	Fever (in children, frequently 40°C–41°C. Abdominal cramps, tenesmus, dehydration from mild (common) to severe (rare) and vomiting.	From feces to mouth, from person-to-person contact, although intermediate vectors, such as food, water, flies, and fomites, can be involved. Also transmitted during participation in water sports in poorly chlorinated pools or contaminated lakes.	July–October
Vibrio cholerae	Affects adults and children equally when newly introduced. Predominantly a pediatric disease in endemic areas	Watery diarrheal disease, acutely dehydrating	4–5 days	Vomiting. Severe dehydration (thirst, muscle cramps, painful contractions, hypothermic skin with normal rectal temperature, tachycardia, hypotension, decreased dieresis) and electrolyte disorders (hypokalemia, and hypocalcemia). Complications: renal failure, pulmonary edema, profound hypoglycemia, and seizures in children.	Drinking of contaminated water or consumption of contaminated seafood, particularly undercooked shellfish	Endemic areas: more common in summer and fall months
Yersinia enterocolitica	Children < 5 years of age	Mucoid diarrhea, containing leukocytes, with or without blood	1–3 weeks	Fever, Abdominal cramps	Most commonly transmitted through undercooked pork meat. Also caused by infected water, milk and other foods stored at refrigerator temperatures	Winter months