Food Poisoning

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Introduction

Food poisoning is a  spectrum of disorders arising from:

  • Infections acquired by eating contaminated food
  • Clinical problems that result from eating food contaminated with toxins
  • Clinical sequelae from inherently poisonous animals, plants or mushrooms

Clinical forms:

  1. Staphylococcal food poisoning:
    • Food is contaminated by S. aureus when prepared unhygienically by individuals who are carriers
    • Subsequent growth of S. aureus in the food and enterotoxin production occurs if the food is not cooked at temperatures sufficient to kill the bacteria, or is not refrigerated
  2. Food-borne botulism
  3. Non-typhoidal Salmonellosis
  4. Shigellosis
  5. E. coli food poisoning
  6. Campylobacter food poisoning
  7. Listeria monocytogenes food poisoning
  8. Yersinia enterocolitica food poisoning
  9. Norwalk virus food poisoning
  10. Hepatitis A virus food poisoning
  11. Giardiasis
  12. Helminthic parasitic food poisoning

Clinical features

Staphylococcal food poisoning:

  • Nausea
  • Diarrhoea 2 – 6 hours after eating food contaminated by enterotoxin

Food-borne botulism:

  • Incubation period is 18 36 hours, but depending on toxin dose, can extend from a few hours to several days
  • Symmetric descending paralysis
  • Diplopia
  • Dysarthria/dysphagia
  • Nausea, vomiting and abdominal pain may precede or follow the onset of paralysis

Non-typhoidal Salmonellosis:

  • Nausea
  • Diarrhoea
  • Vomiting
  • Abdominal cramps
  • Fever
  • Headache
  • Myalgia

Shigellosis:

  • Fever
  • Self-limiting watery diarrhoea
  • Bloody diarrhoea
  • Dysentry
    • Frequent passage, 10 – 30 times/day of small volume stools containing blood, mucus and pus
  • Abdominal cramps
  • Tenesmus

Campylobacter food poisoning:

  • A prodrome with fever, headache, myalgia and/or malaise
  • 12-48 hours later: Diarrhoea and abdominal pain

E. coli food poisoning:

  • Watery diarrhoea accompanied by cramps

L. monocytogenes food poisoning:

  • Common source of outbreaks of acute gastritis
  • Not a major cause of sporadic diarrhoea

Norwalk virus food poisoning:

  • Abrupt onset of nausea and abdominal cramps followed by vomiting and/or diarrhoea

Hepatitis A virus food poisoning:

  • May cause large outbreaks of diarrhoea and vomiting from contaminated food, water, milk and shellfish
    • Intrafamily and intra-institutional spread is common

Diagnosis

  • Essentially clinical laboratory confirmation of the specific microbe(s) involved

Differential diagnoses

  • Other causes of acute onset diarrhoea, nausea, abdominal cramps and vomiting with or without systemic manifestations

Complications

  • Fluid and electrolyte derangements
  • Others (By no means limited to the stated organisms)

Shigellosis:

  • Dehydration
  • Rectal prolapse
  • Protein-losing enteropathy
  • Malnutrition
  • Haemolytic-uraemic syndrome
  • Toxic megacolon
  • Perforation

Campylobacter food poisoning:

  • Bacteraemia
  • Cholecystitis
  • Pancreatitis
  • Cystitis
  • Meningitis
  • Endocarditis
  • Arthritis
  • Peritonitis
  • Cellulitis
  • Septic abortion

Treatment objectives

  • Restore fluid and electrolyte balance
  • Neutralize toxin
  • Eradicate microbe

Non-drug measures

  • Gastric lavage in food-borne botulism

Drug treatment

  • Appropriate fluid and electrolyte
    replacement
  • Trivalent (types A, B, and E) equine anti-toxin should be administered as soon as possible after specimens are obtained for laboratory analysis for food-borne botulism
  • Emetics in food-borne botulism
  • Administer appropriate medicines

Shigellosis

  • Oral Rehydration Therapy

Plus:

Amoxicillin

  • Adult: 50-100 mg/kg/day orally
    every 8 hours; up to 2 g/day
  • Child up to 10 years: 125 mg every 8 hours, doubled in severe infections

Or:

Trimethoprim/sulfamethoxazole (cotrimoxazole)

  • Adult: 960 mg orally every 12 hours for 5 days
  • Child:
    • weeks to 5 months: 120 mg orally;
    • 6 months -5 years: 240 mg;
    • 6-12 years: 480 mg given every 12 hours for 5 days

Or:

Ceftriaxone:

  • Adult: 1 g intravenously slowly
  • Child: 50 mg/kg/day intravenously for 5 days

Campylobacter food poisoning

  • Fluid and electrolyte replacement

Plus:

Erythromycin

  • Adult: 250 mg orally every 6 hours for 5 – 7 days
  • Child: 30-50 mg/kg orally every 6 hours for 5 -7 days

E. coli food poisoning

Ciprofloxacin

  • Adult: 500-750 mg orally every 12 hours

Or:

  • 200 – 400 mg 12 hourly by intravenous infection over 30-60 minutes
  • Child and adolescent: not recommended

L. monocyogenes food poisoning

  • Amoxicillin Plus Gentamicin
  • Treat specific complications as appropriate e.g.
    • Antibiotic-unresponsive toxic
      megacolon: colectomy
    • Haemolytic-uraemic syndrome: dialysis
    • Malnutrition from protein-losing enteropathy: nutritional support; optimal nutritional management

Prevention

  • Appropriate environmental and personal hygiene
    • Hand washing with soap and water
    • Decontamination of water supplies
    • Use of sanitary latrines or toilets
  • Identify and treat chronic carriers among food handlers
  • Hygienic preparation and storage of food
  • Ensure that food is cooked at temperatures sufficient to kill bacteria
  • Refrigerate food whenever possible
  • Encourage measures to reduce the burden of malnutrition (with its attendant predisposition to severe infections)
  • Encourage exclusive breastfeeding
  • Administer a pentavalent vaccine (A, B, C, D, and E) for persons at high of botulism
  • Report new cases to public health authorities

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