Diagnosis of E. coli and Campylobacter infections

Different pathogens, similar symptoms

Because most foodborne pathogen infections present with the same symptoms—diarrhea, abdominal cramps, nausea—diagnosis is dependent on laboratory tests to determine which pathogen is responsible for the infection.

Learn more about E. coli and Campylobacter

CDC recommendations for detecting STEC infection

Because STEC infection is potentially deadly, the CDC recommends taking these diagnostic steps¹⁷:

• All stool samples from patients with acute community-acquired diarrhea and patients with possible HUS should be tested simultaneously for STEC O157 and Shiga toxin
• Detection of STEC or Shiga toxin should be reported immediately to treating physicians and state or local public health agencies

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The CDC recommendations for managing and treating foodborne illness¹⁸

In general, the CDC advises physicians and other healthcare professionals to:

• Recognize the potential for a foodborne etiology in a patient’s illness
• Realize that many but not all cases of foodborne illness have gastrointestinal tract symptoms
• Obtain stool samples in appropriate settings
  • Recognize that testing for some specific pathogens, e.g., E. coli O157:H7, Vibrio spp., must be requested
• Report suspect cases to appropriate public health officials
• Talk with patients about ways to prevent food-related diseases
• Appreciate that any patient with foodborne illness may represent the sentinel case of a more widespread outbreak

Important clues to determining the etiology of a foodborne include¹⁸:

• Incubation period
• Duration of the resultant illness
• Predominant clinical symptoms
• Population involved in the outbreak

Additional clues may be derived by asking:

• Has the patient consumed raw or poorly cooked foods (e.g., raw or undercooked eggs, meats, shellfish, fish), unpasteurized milk or juices, home-canned goods, fresh produce, or soft cheeses made from unpasteurized milk
• Do any of the patient’s family members or close friends have similar symptoms
• Does the patient live on or visit a farm, have pet contact, attend or work in day care
• Has the patient traveled abroad, to coastal areas, or gone camping to mountains or other areas where untreated water is consumed, or attended group picnics or similar outings

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E. coli differential diagnosis

Many bacterial infections present similar symptoms. The following pathogens must be ruled out in diagnosing E. coli¹⁹:

• Enterobacter species, including Salmonella
• Enterococcus species
• Klebsiella species
• Proteus mirabilis, vulgaris, penneri
• Providencia species
• Pseudomonas aeruginosa
• Serriata marcescens
• Shigella species
• Streptococcus Group B

Campylobacter differential diagnosis

The differential diagnosis of Campylobacter should include²⁰:

• Other bacterial species, including EHEC and enteroinvasive E. coli (EIEC), Shigella, Salmonella, Yersinia, Vibrio parahaemolyticus, and Aeromonas
• Inflammatory bowel disease
• Intussusception (in infants)
• Acute abdomen
• Acute appendicitis

Testing for Shiga toxin producing E. coli (STEC) and Campylobacter infection