Diarrhea, Bacterial Evaluation

Diarrhea, Bacterial Evaluation

 

Campylobacter species

Epidemiology

  • Incidence – Campylobacter jejuni is leading cause of bacterial gastroenteritis in the U.S.
  • Age – affects all age groups with peak incidence among children under 5 years of age
  • Occurrence
    • Campylobacter-caused diarrheal cases are sporadic, but most occur in the spring and fall
      • Associated with incorrect food handling practices, consumption of poorly cooked poultry, raw milk, contact with pets and travel
      • Outbreaks commonly associated with raw milk and contaminated water

Organism

  • Campylobacter spp are motile, gram-negative curved or spiral-shaped rods with fastidious growth requirements

Clinical Presentation

  • Campylobacter gastroenteritis ranges from asymptomatic infection to severe, inflammatory diarrhea
  • Onset of symptoms occurs 2-5 days after ingestion of contaminated food or water
  • Symptoms
    • Abdominal pain
    • Watery stools containing blood and mucous
    • Fever
    • Nausea or vomiting
  • Symptoms generally last 7-10 days
  • Complications include reactive arthritis (increased risk if individual is positive for HLA-B27 phenotype), Guillain-Barré syndrome and hemolytic syndrome
    • Complications in patients with AIDS or hypogammaglobulinemia include relapse and osteomyelitis (especially with HLA-B27 phenotype)

Diagnosis

  • Culture
  • Campylobacter antigen detection by EIA – for cases of reactive arthritis and Guillain-Barré syndrome following a history of diarrhea

Treatment

  • Antimicrobial-based in conjunction with supportive care

Salmonella species

Epidemiology

  • Incidence
    • 70% of U.S. cases are related to international travel
    • Remaining 30% of cases are from large, sporadic outbreaks
  • Transmission
    • Non-symptomatic individuals can transmit disease to others
    • Incubation period is 3-21 days
    • Remaining 30% of cases are from large, sporadic outbreaks

Organism

  • Salmonella are motile gram-negative bacilli belonging to the family Enterobacteriaceae
    • Subgroup 1 pathogenic for humans
    • Etiologic agent of typhoid fever

Clinical Presentation

  • Typhoid fever
    • Prodrome of chills, headache, sore throat, fever, anorexia, cough
    • Progresses with rash (rose spots), epistaxis, diarrhea, relative bradycardia
    • 90% have positive blood cultures in week 1, drops to 50% by week 3
    • Late complications found in untreated adults and include intestinal perforation and gastrointestinal hemorrhage
    • Rare complications include pancreatitis, hepatic and splenic abscesses, endocarditis, pericarditis, orchitis, meningitis, parotitis, osteomyelitis
    • Up to half of infected individuals develop chronic carrier state
      • Usually occurs in patients with gall bladder disease or gastric carcinomas
    • Fatality rate is 10%
  • Enteritis
    • Onset of symptoms 6-48 hours after exposure; typically with resolution after 1-2 days
      • Fever, headache
      • Intestinal symptoms – diarrhea (watery), abdominal pain
    • Associated foods include raw meat, poultry, eggs, milk, salad dressing, shrimp and peanut butter

Diagnosis

  • Stool culture
  • Blood culture

Treatment

  • Antimicrobial therapy in conjunction with supportive care

Escherichia species (Shiga toxin)

Epidemiology

  • Incidence – in the very young and elderly, renal failure (HUS), thrombocytopenia and encephalopathy may occur 
  • Age – most common in the very young and elderly
  • Transmission
    • Person-to-person contact is a source of outbreaks in daycare facilities and nursing homes
    • Outbreaks from consumption of undercooked meats and unwashed produce

Organism

  • E. coli is a gram-negative bacillus belonging to the family Enterobacteriaceae
  • Shiga toxin-producing strains (eg, E. coli 0157:H7) cause hemorrhagic colitis and hemolytic uremic syndrome (HUS)

Clinical Presentation

  • Watery diarrhea turning to bloody diarrhea
  • Abdominal pain
  • Symptoms usually resolve within 8 days

Diagnosis

  • Stool culture
  • Shiga toxin detection by EIA, if diagnosis involves HUS

Treatment

  • Supportive; antibiotics do not improve outcomes and may increase the risk of developing HUS
  • Treatment efficacy not well established since disease is usually self-limiting

Shigella species

Epidemiology

  • Incidence – prevalent worldwide distribution
    • Common in countries where sanitation is poor
    • Accounts for <10% of reported outbreaks of foodborne illness in the U.S.
  • Transmission – fecal-oral route

Organism

  • Shigella are gram-negative, nonmotile bacilli belonging to the family Enterobacteriaceae
    • Agent of bacillary dysentery
    • 4 species – S. dysenteriae, S. flexneri, S. boydii, S. sonnei
  • Some strains produce enterotoxin and shiga toxin

Clinical Presentation

  • Diarrhea, frequently bloody and may contain mucous or pus
  • Fever
  • Abdominal pain, cramps
  • Dysentery (10-30 stools/day)
  • Onset of symptoms 12-50 hours after exposure
  • Complications include reactive arthritis (increased risk of development if individual is positive for HLA-B27 allele) and HUS (usually S. dysenteriae type 1)
  • Associated with Reiter syndrome (arthritis, uveitis, urethritis)

Diagnosis

  • Stool culture

Treatment

  • Antimicrobial-based in conjunction with supportive care

Yersinia species

Epidemiology

  • Age – most often in young children
  • Transmission – through soil, water, animals, food

Organism

  • Yersinia spp are gram-negative coccobacillary organisms
  • 3 species most commonly isolated from humans – Y. pseudotuberculosis, Y. pestis, Y. enterocolitica
    • Y. pseudotuberculosis and Y. pestis are uncommon causes of gastrointestinal disease
    • Y. enterocolitica can be found in meats (beef, pork, etc.) oysters, fish and unpasteurized milk

Clinical Presentation

  • Onset of symptoms 24-48 hours after ingestion of contaminated food or drink
  • Infection manifests in gastrointestinal tract causing symptoms of diarrhea (loose, watery, or bloody stools), abdominal pain and fever
    • Infections with Y. enterocolitica and Y. pseudotuberculosis can be asymptomatic, mild, or severe, with infection resolving within a few weeks, with or without use of antibiotics
    • Yersinia infections are known for mimicking appendicitis
  • Complications include reactive arthritis which can manifest 1 to 4 weeks post-infection (increased risk of development if individual is positive for HLA-B27 allele)
    • Occurs in about 2-3% of cases
    • The most commonly affected joints are knees and ankles, but other joints such as toes, fingers and wrists can be involved
    • In most cases, 2-4 joints become involved sequentially and asymmetrically over a period of a few days to 2 weeks
    • In two-thirds of cases, acute arthritis persists for 1-4 months
    • Joint fluid is sterile
    • Chronic joint disease or ankylosing spondylitis occurs rarely
    • Reiter syndrome (arthritis, uveitis and urethritis) occurs in 5%
    • Less common nonsuppurative sequelae of Y. enterocolitica infections include reactive uveitis, iritis, conjunctivitis, glomerulonephritis, urethritis, HUS

Diagnosis

  • Stool culture
  • Antibody testing – may require serial testing which is not readily available

Treatment

  • Antimicrobial-based in conjunction with supportive care

Vibrio species

Epidemiology

  • Incidence
    • Several pandemics of V. cholerae infection have occurred, but no major outbreaks have been recently reported in the U.S.
    • Sporadic cases occur frequently, particularly in the summer months along coastal waters
  • Transmission
    • Through ingestion of contaminated seafood or through open wounds in marine waters

Organism

  • Vibrio are motile gram-negative bacilli
  • Species which may cause gastroenteritis with decreasing frequency include V. parahaemolyticus, V. cholerae, V. vulnificus
  • Some strains produce enterotoxin and shiga toxin
  • V. parahaemolyticus is the leading cause of bacterial diarrhea associated with foods such as seafood, crab, shrimp, lobster
  • V. vulnificus is the leading cause of death in the U.S. related to seafood consumption 
    • Fatalities are typically due to septicemia and are more common in patients with hepatic disease

Clinical Presentation

  • Healthy individuals typically have onset of symptoms within 16 hours of ingestion of contaminated seafood
  • Watery diarrhea, abdominal pain, cramps, vomiting
  • Immunocompromised individuals and patients with cirrhosis may present with “primary septicemia”
    • Associated with >50% mortality
  • No associated long-term complications

Diagnosis

  • Stool culture

Treatment

  • Antimicrobial and supportive

Aeromonas species

Epidemiology

  • Incidence
    • Causes sporadic cases of gastroenteritis
    • No associated known outbreaks
    • Most commonly affects children and immunocompromised adults
  • Transmission –  through ingestion of raw or undercooked seafood and meat

Organism

  • Motile gram-negative bacilli
  • Found in fresh and brackish waters
  • Species associated with enteritis are A. hydrophilia, A. caviae, A.sobria

Clinical Presentation

  • Diarrhea varies from watery to mucous with blood, abdominal pain, fever
  • Immunocompromised individuals may develop septicemia

Diagnosis

  • Stool culture

Treatment

  • Antimicrobial

See Also