Enteric Pathogen Panel

The Enteric Pathogen Panel includes:

• PCR for 22 targets: 13 bacteria (includes C. difficile), 4 parasites, and 5 viruses
• Reflexive susceptibility testing

PCR details (The Biofire FilmArray Gastrointestinal (GI) panel):

The Biofire FilmArray Gastrointestinal (GI) panel is an FDA-cleared multiplex PCR panel with a reported overall sensitivity of 98.5% and specificity of 99.3%. If the panel detects Salmonella, Shigella, Vibrio, and/or Campylobacter, reflexive culture will be performed for these organisms. Susceptibility testing will also be reflexively performed (Salmonella, Shigella, and Campylobacter at HMC / Salmonella, Shigella, Vibrio, and Campylobacter at UW-MT) if a bacterial isolate is recovered. For other bacterial pathogens, please contact the lab for additional information on susceptibility testing.

• The American College of Gastroenterology has published clinical guidelines - see weblink below. These guidelines recommend diagnostic testing in patients with dysentery, moderate-to- severe disease, or symptoms lasting >7 days, and in the setting of outbreaks involving food handlers, health-care workers, daycare attendees/employees and residents of institutions. This guidance should be followed when ordering the FilmArray GI panel.
• PCR testing is more sensitive than traditional culture and can identify low numbers of pathogens. Therefore, the results of PCR testing for stool pathogens should be interpreted in clinical context when making treatment decisions.
• PCR testing can identify nucleic acid from non-viable organisms. Therefore, the FilmArray GI panel should not be used as a test of cure and should not be re-ordered within 7 days.

The Biofire FilmArray GI panel detects the following organisms:

Bacteria

• Campylobacter - Detects C. jejuni, C. coli and C. upsaliensis. These bacteria cause acute abdominal pain, fever and diarrhea, which may be bloody. Generally self-limited but antibiotics may shorten the duration of illness.
• Clostridium difficile - Causes acute abdominal pain, fever and diarrhea, especially in patients who have recently received antibiotics. If C. difficile is specifically suspected, PCR for toxigenic C. difficile should be individually ordered instead of an enteric panel.
• Enteroaggregative Escherichia coli (EAEC) - Causes acute diarrhea in children and adults; may cause prolonged symptoms.
• Enteropathogenic Escherichia coli (EPEC) - Causes acute diarrhea in children and adults; may cause prolonged symptoms.
• Enterotoxigenic Escherichia coli (ETEC) - Assay detects heat- labile (LT) and heat-stable (ST) toxin-producing strains. Causes acute watery diarrhea in children and adults, including travelers. Antibiotics may shorten the duration of illness.
• Plesiomonas shigelloides - Causes acute watery or inflammatory diarrhea in children and adults. Antibiotics may shorten the duration of illness.
• Salmonella enterica - Causes acute abdominal pain, fever and diarrhea, which may be bloody. Generally self-limited, and antibiotics are not recommended in uncomplicated cases (to avoid prolongation of carriage).
• Shiga-like toxin-producing Escherichia coli (STEC) - Assay detects STEC generally, and also includes specific detection of E. coli O157:H7. Causes hemorrhagic colitis with little or no fever, and can also cause hemolytic-uremic syndrome (HUS). Antibiotics are contraindicated to avoid precipitating HUS.
• Shigella - This target also detects Enteroinvasive E. coli (EIEC). Causes vomiting, acute abdominal pain, fever and diarrhea, which may be watery, mucoid or bloody. May be self-limiting but antibiotics may shorten duration of illness.
• Vibrio - Detects V. cholerae, V. parahaemolyticus and V. vulnificus, including the specific detection of V. cholerae. V. cholerae causes secretory diarrhea which may become profuse. V. parahaemolyticus causes fever, abdominal pain and diarrhea. V. vulnificus may cause sepsis and necrotizing skin and soft tissue infections.
• Yersinia enterocolitica - Causes acute abdominal pain, fever and diarrhea; may also cause mesenteric adenitis simulating acute appendicitis.

Parasites

• Cryptosporidium - Causes prolonged nausea, abdominal cramping and diarrhea in normal and immunocompromised hosts. Antiparasitic treatment may shorten duration of symptoms but have limited effectiveness in individuals with HIV.
• Cyclospora cayetanensis - Causes prolonged nausea, abdominal cramping and diarrhea in normal and immunocompromised hosts. Antiparasitic treatment may shorten duration of illness.
• Entamoeba histolytica - Clinical manifestations of GI infection range from asymptomatic carriage to subacute diarrhea and severe dysentery. Antiparasitic treatment may shorten duration of illness.
• Giardia intestinalis - Also known as G. lamblia or G. duodenalis. Causes nausea, bloating, abdominal cramps and diarrhea, which may be acute or chronic. Antiparasitic treatment may shorten duration of illness.

Viruses

• Adenovirus F 40/41 - Causes acute and sometimes prolonged diarrhea, especially in children.
• Astrovirus - Causes diarrhea, vomiting, abdominal pain, and fever in children and adults.
• Norovirus GI/GII - Causes acute vomiting, diarrhea and constitutional symptoms in children and adults. Highly contagious and may be responsible for institutional or cruise ship outbreaks.
• Rotavirus A - Causes vomiting, diarrhea and fever, especially in children.
• Sapovirus - Detects genogroups I, II, IV and V. Causes acute vomiting, diarrhea and constitutional symptoms similar to Norovirus, especially in children.

For questions, please contact:

• Microbiology fellow on-call: page through the UWMC-Montlake paging operator (206-598-6190).
• HMC microbiology laboratory: 206-744-5858.
• UWMC-Montlake microbiology laboratory: 206-598-6147.