Diarrhea, Bacterial Evaluation

Clinical Background

Algorithm(s)

PDF algorithm(s) available at www.arupconsult.com.

Diarrhea, Acute Testing Algorithm

Campylobacter, Salmonella, Escherichia, Shigella, Yersinia, Vibrio and Aeromonas species are the most common causes of bacterial diarrhea.

Campylobacter species

Epidemiology

Incidence - Campylobacter jejuni is leading cause of bacterial gastroenteritis worldwide
Age - affects all age groups with peak incidence among children under 5 years
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 most 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
- Reactive arthritis (increased risk if individual is positive for HLA-B27 phenotype)
- Guillain-Barré syndrome
- Hemolytic syndrome
- Complications in patients with AIDS or hypogammaglobulinemia include relapse and osteomyelitis (especially with HLA-B27 phenotype)
- Local complications - hemorrhage, megacolon
- Bacteremic complications - cellulitis, meningitis

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
- Contact with animals or undercooked food are usual routes of acquisition
- Associated foods include raw meat and vegetables, poultry, eggs, milk, salad dressing, shrimp and peanut butter
- Non-symptomatic individuals can transmit disease to others
- Incubation period is 3-21 days

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

Treatment

Antimicrobial therapy in conjunction with supportive care
Mild symptomatic disease does not require antibiotic therapy

Escherichia species (Shiga toxin)

Epidemiology

Incidence - in the very young and elderly, renal failure associated with hemolytic uremic syndrome (HUS), thrombocytopenia and encephalopathy may occur
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)
Also referred to as Shiga Toxin-Producing Escherichia Coli (STEC) or verotoxin-producing E. coli

Clinical Presentation

Watery diarrhea turning to bloody diarrhea
Abdominal pain
Symptoms usually resolve within 8 days
HUS - fever, renal dysfunction and hemolytic anemia, thrombocytopenia
- Most frequent in children <15 years and adults >65 years

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; no nonhuman hosts
- Higher risk groups - day care personnel and clients, nursing home clients and male homosexuals

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)

Treatment

Antimicrobial-based in conjunction with supportive care for moderate to severe infections

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 (eg, beef, pork) 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
- Joint fluid is sterile
- Chronic joint disease or ankylosing spondylitis occurs rarely
- In two-thirds of cases, acute arthritis persists for 1-4 months
- Reiter syndrome (arthritis, uveitis and urethritis) occurs in 5% of cases
- Less common nonsuppurative sequelae of Y. enterocolitica infections include reactive uveitis, iritis, conjunctivitis, glomerulonephritis, urethritis, HUS

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

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. veronii

Clinical Presentation

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

Treatment

Antimicrobial

See Also

Celiac Disease

Clostridium difficile

Diarrhea, Parasitic Evaluation

Diarrhea, Viral Evaluation

Inflammatory Bowel Disease - IBD

Malabsorption

Neuropathic Disease

Refer to Diarrhea, Bacterial Evaluation at http://www.arupconsult.com for list of references

Tests

Tests generally appear in the order most useful for common clinical situations

Test name: CBC with Platelet Count & Automated Differential

ARUP #: 0040003

Methodology: Automated Cell Count with Flow Cell Differential

Use:

Nonspecific, but suggests bacterial etiology if leukocytosis is present

Test name: Stool Culture, Routine (Includes E. coli Shiga-like Toxin by EIA 0060047)

ARUP #: 0060134

Methodology: Standard reference procedures for Salmonella, Shigella, Shiga-like toxin producing E. coli, and Campylobacter culture and identification.

Use:

First-line test for suspected bacterial diarrhea

Test includes procedures for identification of Salmonella, Shigella, Campylobacter and Shiga-like toxin-producing E. coli

Limitations:

Follow-up:

Test name: Campylobacter Antigen by EIA

ARUP #: 0058002

Methodology: Enzyme Immunoassay

Use:

Use in cases of reactive arthritis and Guillain-Barré syndrome following a history of diarrhea

Limitations: Assay cannot differentiate between C. jejuni and C. coli

Assay will cross-react with C. upsaliensis

Data on detection of other Campylobacter spp is not available

Test name: Stool Culture, Campylobacter

ARUP #: 0060135

Methodology: Standard reference procedures for Campylobacter culture and identification

Use:

Diagnose Campylobacter-associated gastroenteritis diarrhea in patients with appropriate exposure history or risk factors

Test name: Stool Culture, Yersinia

ARUP #: 0060137

Methodology: Standard reference procedures for Yersinia culture and identification

Use:

Diagnose Yersinia-associated gastroenteritis diarrhea in patients with appropriate exposure history or risk factors

Limitations:

Follow-up:

Test name: Stool Culture, Vibrio

ARUP #: 0060136

Methodology: Standard reference procedures for Vibrio culture and identification

Use:

Diagnose Vibrio-associated gastroenteritis diarrhea in patients with appropriate exposure history or risk factors

Test name: Giardia Antigen by EIA

ARUP #: 0060048

Methodology: Enzyme Immunoassay

Use:

Useful if appropriate history

Test name: Ova & Parasite Exam, Fecal (Immunocompromised or Travel History)

ARUP #: 2002272

Methodology: Concentration Technique/Trichrome Stain/Microscopic Evaluation

Use:

Useful if appropriate history

Additional Tests Available

Test name: Campylobacter jejuni Antibody, IgG

ARUP #: 0098841

Methodology: Indirect Fluorescent Antibody

Comments:

Test name: Lactoferrin, Fecal by ELISA

ARUP #: 0061164

Methodology: Enzyme-Linked Immunosorbent Assay

Comments:

Test name: Salmonella typhi Antibodies

ARUP #: 2001586

Methodology: ImmunoDOT

Comments:

Test name: E. coli Shiga-like Toxin by EIA

ARUP #: 0060047

Methodology: Enzyme Immunoassay

Comments:

Test name: Yersinia Species Antibodies, IgA, IgG, & IgM by Western Blot

ARUP #: 0051241

Methodology: Western Blot

Comments:

Test name: Yersinia Species Antibody, IgG by Western Blot

ARUP #: 0051229

Methodology: Western Blot

Comments:

Test name: Yersinia Species Antibody, IgM by Western Blot

ARUP #: 0051172

Methodology: Western Blot

Comments:

Test name: Yersinia Species Antibody, IgA by Western Blot

ARUP #: 0051228

Methodology: Western Blot

Comments:

Test name: Yersinia Species Antibodies, IgA & IgG by Western Blot

ARUP #: 0051230

Methodology: Western Blot

Comments:

Medical Reviewers

Fisher, Mark A., PhD. Medical Director, Bacteriology and Antimicrobials at ARUP Laboratories; Assistant Professor of Pathology, University of Utah

Litwin, Christine, MD. Medical Director, Immunology at ARUP; Professor of Pathology (Clinical), University of Utah

Petti, Cathy A., MD. Medical Director, Infectious Diseases at ARUP; Associate Professor of Pathology and Medicine, University of Utah

Comprehensive Review: May 2009
Last Update: May 2009