Summary
Bacterial gastroenteritis is caused by a variety of organisms, including Campylobacter, Salmonella, Shigella, Yersinia, Vibrio cholerae, Staphylococcus aureus, diarrheagenic Escherichia coli, Clostridium difficile, Clostridium perfringens, and noncholera Vibrio species. Infection may be foodborne, fecal-oral, or involve direct or indirect animal transmission. Clinical features can be mild, manifesting as abdominal pain and diarrhea, or severe, including vomiting and watery or inflammatory diarrhea, fever, and hypotension. Stool analysis may reveal leukocytes or blood in certain cases. Stool cultures may be considered in severe gastroenteritis. Bacterial gastroenteritis is usually self-limiting and only requires supportive therapy. However, antibiotics are indicated when supportive therapy does not suffice or in immunosuppressed patients. Adequate food and water hygiene is crucial for preventing disease.
Overview
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Clinical features
- Mild–moderate: abdominal pain, diarrhea
- Severe: tachycardia, hypotension; , fever, bloody or profuse watery diarrhea, and metabolic acidosis
Overview of bacterial gastroenteritis | |||
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Pathogen | Pathophysiology | Associations | Stool findings |
Secretory diarrhea | |||
Bacillus cereus |
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ETEC |
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Clostridium perfringens |
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Staphylococcus aureus |
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Vibrio cholerae |
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Invasive diarrhea | |||
Yersinia |
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Salmonella typhi or paratyphi |
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Inflammatory diarrhea | |||
Campylobacter |
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EHEC | |||
Clostridium difficile |
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Shigella | |||
Noncholera Vibrio species |
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Salmonella (non-typhoidal) |
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Diagnosis: stool analysis
- Leukocytes, occult blood, and/or lactoferrin (best initial tests)
- Stool culture (confirmatory test): indicated in suspected invasive bacterial enteritis, severe illness, or fever (> 38.5 degrees), required hospitalization, or stool tests positive for leukocytes/occult blood/lactoferrin
- Clostridium difficile toxin: if patient has a recent history of antibiotic use
- Stool microscopy in certain cases (e.g., ova and parasites)
- Differential diagnosis: See “Differential diagnosis”in food-related diseases.
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Treatment
- Usually self-limiting: supportive therapy (see diarrhea)
- Antibiotic therapy is not routinely indicated in bacterial gastroenteritis.
- Indications for antibiotic therapy
- Complicated diarrhea with high-grade fever and severe symptoms
- High-risk population group (e.g., infants, patients with comorbidities such as sickle cell disease)
- Confirmed C. difficile infection
- Contraindicated for EHEC!
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Complications
- Dehydration (most common; especially severe in shigellosis, cholera)
- Malnutrition
- Permanent carrier status
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Prevention
- Food and water hygiene
- Report diseases according to the CDC guidelines: salmonellosis, shigellosis, yersiniosis, cholera, shiga toxin-producing Escherichia coli (EHEC) colitis, non-cholera Vibrio species infections, vancomycin-resistant Staphylococcus aureus food poisoning
- Cholera vaccination
- See also the overview of diarrhea and food poisoning.
References:[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]
Campylobacter enteritis (campylobacteriosis)
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Pathogen
- Campylobacter jejuni, Campylobacter coli
- Curved, gram-negative, oxidase-positive rods with polar flagella
- Most common pathogen responsible for foodborne gastroenteritis in the US
- Highly contagious
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Transmission
- Fecal-oral
- Foodborne (undercooked meat; , and unpasteurized milk; ) and contaminated water
- Direct contact with infected animals (cats and dogs)/animal products
- Incubation period: 2–4 days
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Clinical features
- Duration: up to a week
- High fever, aches, dizziness
- Inflammatory (bloody) diarrhea (50% of cases)
- Severe abdominal pain may present as pseudoappendicitis or colitis
- Treatment: : (in severe cases) macrolides (e.g., erythromycin or azithromycin)
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Complications (more common and severe in HIV-positive patients)
- Guillain-Barré syndrome
- Reactive arthritis
- Acute abdomen: cholecystitis, pancreatitis
- Bacteremia
References:[5][16][17][18][19]
Salmonellosis (Salmonella gastroenteritis)
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Pathogen: Salmonella enterica serotype Enteritidis, Salmonella enterica serotype Typhimurium
- Gram-negative bacteria, obligate pathogen
- Produces hydrogen sulfide
- Does not ferment lactose
- 2nd most common pathogen responsible for bacterial foodborne gastroenteritis
- Transmission: : foodborne (poultry, raw eggs, and milk)
- Incubation period: 0–3 days
- Clinical features
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Treatment (antibiotic therapy in severe cases)
- Fluoroquinolones (e.g., ciprofloxacin)
- Alternative: TMP-SMX or cephalosporins (e.g., ceftriaxone), depending on the antimicrobial susceptibility test
- Antibiotic treatment prolongs fecal excretion of the pathogen; only indicated for systemic manifestations; or diarrhea > 9/day
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Complications: (especially in immunocompromised patients, e.g., HIV)
- Bacteremia
- Reactive arthritis
- Systemic disease: osteomyelitis, meningitis, myocarditis
- Special variant of salmonella infections: enteric fever (see typhoid fever)
References:[5][16][20][21][22][23][24][25]
Shigellosis (bacillary dysentery)
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Pathogens: Shigella dysenteriae, Shigella flexneri, Shigella sonnei [26]
- 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)
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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 or more bacteria)
- Clinical features
- Treatment: in severe cases, antibiotic therapy with fluoroquinolones or 3rd generation cephalosporins [27]
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Complications
- HUS
- Intestinal complications (e.g., toxic megacolon, colonic perforation, intestinal obstruction, proctitis, rectal prolapse) [27]
- Febrile seizures
- Reactive arthritis
- Prevention: no vaccine available
[26][27][28][29]
Cholera
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Pathogen: Vibrio cholerae
- Rare in developed countries
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Gram-negative, oxidase positive, curved bacterium with a single polar flagellum → produces cholera toxin
- Cholera toxin stimulates adenylate cyclase via activation of Gs → increased cyclic AMP → increased ion secretion (mainly chloride)
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Transmission
- Fecal-oral
- Undercooked seafood or contaminated water (e.g., non-segregated drinking water and sewage systems)
- Incubation period: 0–2 days
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Infectivity
- Acid-labile (grows well in an alkaline medium); → High infective dose required (over 108 pathogens)
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Clinical features
- Low-grade fever; , vomiting
- Profuse 'rice-water' stools
- Diagnosis: dipstick (rapid test; initial test); and stool culture (confirmatory)
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Treatment
- Urgent fluid replacement
- Antibiotic therapy in severe cases: doxycycline; alternatively, erythromycin in children
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Complications
- Severe dehydration
- Pneumonia may occur in children.
References:[5][15][30][31][32]
Yersiniosis
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Pathogen: Yersinia enterocolitica, Yersinia pseudotuberculosis
- Gram-negative, rod-shaped, pleomorphic bacterium; obligate pathogen
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Transmission
- Foodborne (e.g., raw/undercooked pork, unpasteurized milk products)
- Contaminated water
- Direct/indirect contact with infected animal (e.g., dogs, pigs, rodents, and their feces)
- Incubation period: 4–6 days
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Clinical features
- Duration: 1–46 days
- Low-grade fever, vomiting
- Inflammatory diarrhea (may be bloody in severe cases)
- Pseudoappendicitis → mesenteric lymphadenitis, particularly in the ileum, with typical signs of appendicitis
- Diagnosis: direct pathogen detection in culture or cold enrichment
- Treatment: in severe cases, antibiotic therapy with fluoroquinolones or 3rd generation cephalosporins (depends on susceptibility to the drug)
- Complications: particularly in patients with HLA-B27
References:[33][34][35][36][37][38][39]
Clostridium perfringens enterocolitis
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Pathogen: Clostridium perfringens
- Gram-positive, anaerobic, spore-forming rod-shaped bacterium → produce exotoxins
- Also causes gas gangrene
- Transmission: foodborne (undercooked or poorly refrigerated meat, legumes)
- Incubation period: 6–24 hours
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Clinical features
- Duration: < 24 hours
- Severe abdominal cramping
- Watery diarrhea
- Diagnosis: toxin detection in stool cultures
- Treatment: supportive therapy only
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Complications: clostridial necrotizing enteritis
- Requires antibiotic therapy: penicillin, metronidazole
- Surgery may be required for complicated and/or refractory disease (e.g., perforation)
References:[1][5][30][40][41]
Noncholera Vibrio infection
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Pathogen
- Vibrio parahaemolyticus; : non-lactose fermenter, gram-negative bacilli
- Vibrio vulnificus: lactose fermenter, gram-negative bacilli
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Transmission
- Foodborne (raw or undercooked shellfish)
- Wounds infected by contaminated sea water
- Incubation period: 12–52 hours
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Clinical features
- Inflammatory diarrhea
- Low-grade fever, vomiting, abdominal pain
- Cellulitis, bullous skin lesions
- Treatment: : in severe infection or wound infection, doxycycline or fluoroquinolone (e.g., ciprofloxacin)
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Complications
- Complications of noncholera Vibrio infection are common in patients with high levels of free iron (e.g., liver disease, hemochromatosis) or immunocompromise.
- Septic shock and necrotizing fasciitis associated with Vibrio vulnificus infection (rare)
References:[42][43][44]
Acute management checklist
- Identify and treat sepsis.
- Oral rehydration or intravenous fluid therapy
- Oral or parenteral antiemetics (e.g., Ondansetron or promethazine
- Electrolyte repletion
- Consider stool analysis (e.g., fecal leukocytes, stool NAAT, RT-PCR) and stool culture.
- Avoid antimotility drugs. [45]
- Consider indications for empiric antibiotic therapy in patients with suspected bacterial gastroenteritis: [46][47]
- Immunocompromised patients
- Sepsis
- Bloody or watery diarrhea in patients with: suspected Shigella infection , febrile patients with recent international travel, or infants < 3 months of age with a suspected bacterial infection
- If indicated, start empiric antibiotic therapy for community-acquired bacterial gastroenteritis [46]
Trimethoprim/sulfamethoxazole is not recommended as an empiric treatment for infectious gastroenteritis because of the high prevalence of resistant organisms.