Food Poisoning, Bacterial
BASICS
- Foodborne illness results from ingestion of contaminated food/water with pathogens or toxins.
- Symptoms mainly gastrointestinal; typically self-limited but can cause severe dehydration and critical illness.
EPIDEMIOLOGY
- Cause unclear in up to 80% cases; viral causes most common (Norovirus predominant).
- Campylobacter and nontyphoidal Salmonella are most common bacterial causes in the US.
- Annually ~1 in 6 Americans (~56 million) affected; ~128,000 hospitalizations and 3,000 deaths in the US.
- Worldwide, foodborne diarrhea causes ~2.2 million deaths per year.
ETIOLOGY AND PATHOPHYSIOLOGY
| Pathogen | Incubation | Symptoms | Common Food Sources |
|---|---|---|---|
| Staphylococcus aureus | 1-6 hours | Sudden severe nausea, vomiting, cramps, fever | Improperly refrigerated meats, potato/egg/mayo salads |
| Bacillus cereus | 10-16 hours | Severe nausea, vomiting, watery diarrhea | Soil, improperly cooked rice, fried rice, red meats |
| Clostridium perfringens | 8-16 hours | Watery diarrhea, nausea, cramps | Dry/precooked/undercooked meats, poultry, canned goods |
| Clostridium botulinum | 12-72 hours | Vomiting, diarrhea, slurred speech, paralysis | Improperly canned foods |
| Enterohemorrhagic E. coli (0157:H7) | 1-8 days | Bloody diarrhea, abdominal pain, vomiting | Undercooked ground beef, raw produce, unpasteurized milk |
| Enterotoxigenic E. coli | 1-3 days | Watery diarrhea, cramps, tenesmus, vomiting | Contaminated food/water |
| Salmonella (nontyphoidal) | 6-48 hours | Bloody/mucopurulent diarrhea, fever, cramps, vomiting | Eggs, poultry, unpasteurized milk, raw fruits/vegetables, peanut butter |
| Campylobacter jejuni | 2-5 days | Bloody diarrhea, cramps, vomiting, fever | Raw/undercooked poultry, unpasteurized milk |
| Shigella | 4-7 days | Abdominal cramps, fever, bloody diarrhea | Contaminated water, raw produce, infected food handlers |
| Vibrio parahaemolyticus | 4-96 hours | Nausea, vomiting, diarrhea, abdominal pain | Raw/undercooked seafood, especially shellfish |
| Vibrio vulnificus | 1-7 days | Vomiting, diarrhea, bacteremia, wound infections | Raw/undercooked oysters; severe risk in liver disease |
| Yersinia enterocolitica | 4-7 days | Abdominal pain, fever, diarrhea (possibly bloody), vomiting | Undercooked beef/pork, unpasteurized dairy, tofu, contaminated water |
| Listeria monocytogenes | 4-48 hours | Nausea, vomiting, fever, watery diarrhea; serious in pregnancy and immunocompromised | Unpasteurized milk, soft cheese, processed deli meats |
RISK FACTORS
- Travel to developing countries
- Food handlers, daycare/nursing home exposure
- Recent hospitalization or antibiotic use
- Immunocompromised states, pregnancy, extremes of age (<5 or >65)
- Use of antacids, H2 blockers, proton pump inhibitors
- Cross-contamination and improper food storage/preparation
GENERAL PREVENTION
- Hand washing, cleaning utensils and surfaces
- Thorough washing of fresh produce
- Avoid cross-contamination between raw meats and other foods
- Cook meats thoroughly
- Refrigerate leftovers promptly (<2-3 hours; <1 hour if >90°F ambient temp)
- Avoid local water, ice, and improperly prepared food when traveling
- Chemoprophylaxis for traveler’s diarrhea in high-risk groups
COMMONLY ASSOCIATED CONDITIONS
- Botulism: neurologic paralysis from C. botulinum toxin, often home-canned foods
- Neonatal meningitis from Listeria in immunocompromised hosts
- Hemolytic uremic syndrome (HUS) from STEC and Shigella
- Guillain-Barré syndrome post-Campylobacter infection
- Reactive arthritis post-Salmonella, Shigella, Yersinia, Campylobacter
- Postinfectious irritable bowel syndrome
DIAGNOSIS
History
- Characterize diarrhea (onset, duration, frequency, presence of blood/mucus)
- Look for clustering of cases after common meal
- Symptoms: fever, abdominal pain, vomiting, dehydration
- Travel history, exposure risks, food sources
Physical Exam
- Assess dehydration (capillary refill, skin turgor, mucous membranes, orthostatic vitals)
- Abdominal exam for tenderness, peritoneal signs
- Rectal exam for blood
Differential Diagnosis
- Inflammatory bowel diseases, celiac disease
- Other infectious/inflammatory GI conditions
- Structural bowel disorders
- Mesenteric ischemia
Diagnostic Tests
- Stool culture: reserved for severe or prolonged illness, bloody diarrhea, fever
- CBC, electrolytes, renal function in severe cases
- Abdominal imaging if diagnosis unclear or complications suspected
- Ova and parasite testing for symptoms >2 weeks or travel history
- Endoscopy for persistent/severe cases or immunocompromised
TREATMENT
General
- Supportive care: oral rehydration therapy is mainstay
- Avoid antidiarrheals in suspected invasive infections
- Empiric antibiotics generally not recommended except for traveler’s diarrhea or severe disease
Medications
| Pathogen | Treatment |
|---|---|
| Bacillus cereus | Supportive only |
| Campylobacter jejuni | Mild: supportive; Severe: erythromycin or azithromycin; avoid fluoroquinolones |
| Clostridium botulinum | Supportive care; antitoxin early in illness |
| Clostridium perfringens | Supportive only |
| Enterohemorrhagic E. coli | Supportive; antibiotics contraindicated (risk of HUS) |
| Enterotoxigenic E. coli | Usually self-limited; antibiotics shorten duration (ciprofloxacin, azithromycin, TMP-SMX) |
| Salmonella (nontyphoidal) | Mild: none; Moderate/severe/immunocompromised: fluoroquinolones, azithromycin, ceftriaxone |
| Shigella | Azithromycin (preferred), ciprofloxacin |
| Staphylococcus aureus | Supportive only |
| Noncholera Vibrio | Mild: none; Severe: ceftriaxone + doxycycline |
| Vibrio cholerae | Single-dose doxycycline or azithromycin, ceftriaxone, or ciprofloxacin |
| Yersinia enterocolitica | Supportive; severe: TMP-SMX or ciprofloxacin |
Adjunctive Therapies
- Antiemetics (promethazine adults; ondansetron children)
- Loperamide for diarrhea only if no fever, bloody stools, or severe pain
- Bismuth subsalicylate for traveler's diarrhea
ADMISSION
- Inability to maintain oral hydration
- Severe dehydration or sepsis
ONGOING CARE
- Reportable infections per local public health guidelines (Salmonella, Shigella, STEC, Listeria, Vibrio)
- Diet: bland, low-fat as tolerated; avoid alcohol, caffeine, nicotine, spicy foods
- Breastfeeding infants encouraged to continue
PROGNOSIS
- Most cases self-limited
- Antibiotics reduce duration in moderate/severe traveler’s diarrhea
REFERENCES
- Sell J, Dolan B. Common gastrointestinal infections. Prim Care. 2018;45(3):519-532.
- Lee H, Yoon Y. Etiological agents implicated in foodborne illness worldwide. Food Sci Anim Resour. 2021;41(1):1-7.
- Wang B, Wang H, Lu X, et al. Recent advances in electrochemical biosensors for the detection of foodborne pathogens: current perspective and challenges. Foods. 2023;12(14):2795.
CODES
- ICD10: A05.9 Bacterial foodborne intoxication, unspecified
- ICD10: A02.0 Salmonella enteritis
- ICD10: A04.5 Campylobacter enteritis
CLINICAL PEARLS
- Suspect bacterial food poisoning if multiple patients develop fever and bloody/mucus diarrhea after same meal or travel to developing countries.
- Culture and antibiotics indicated if fever, blood/mucus in stool, prolonged symptoms, or signs of sepsis.
- Avoid antidiarrheals if signs of enteroinvasion (high fever, bloody diarrhea, severe pain).
- Empiric antibiotics for traveler’s diarrhea only in moderate to severe cases.