Gastro Intestinal Panel (Detectable Organism) information

*Campylobacter species: Detects but does not differentiate C jejuni, C coli, and C upsaliensis. Other species will not be detected.
Helicobacter pullorum may cross react.

*Salmonella species: Detects but does not differentiate S enterica and S bongori. Cross-reactivity may occur with some strains of Escherichia coli, which have the cryptic ETT2 type-III secretion system.

*Vibrio species: Detects but does not differentiate Vibrio parahaemolyticus and Vibrio vulnificus. The assay may also react with less common Vibrio species such as, Vibrio alginolyticus, Vibrio fluvialis, and Vibrio mimicus. The assay is not expected to detect rare species of Vibrio such as:  Vibrio cincinnatiensis, Vibrio furnissii and Vibrio metschnikovii. Grimontia hollisae may cross react.

Vibrio cholerae:   V cholerae is specifically reported when detected.  V cholerae strains that do not carry the toxR gene or which carry highly divergent toxR genes may not be detected.  Rare non-cholerae strains of Vibrio that have acquired the toxR gene may cross-react (eg, Vibrio harveyi, Vibrio mimicus, Vibrio alginolyticus, Vibrio vulnificus).

*Yersinia species: Detects Y enterocolitica but does not differentiate known serotypes or biotypes. Y kristensenii, Y frederiksenii, and Y intermedia cross-react at high levels with Y enterocolitica; detection is reported to genus level only.

Diarrheagenic Escherichia coli: Detects genetic determinants associated with classic diarrheagenic E coli/Shigella pathotypes. Transfer of these genes between organisms has been documented; therefore, detected results for multiple diarrheagenic  E coli/Shigella may be due to the presence of multiple pathotypes or a single strain containing the genes characteristic of multiple pathotypes.

Enteroaggregative Escherichia coli (EAEC): Detects but does not differentiate 2 gene targets typically associated with enteroaggregative E coli; the aggR regulatory gene and the putative outer membrane protein, aatA, both located on the partially-conserved pAA plasmid. pAA is not present in all strains phenotypically identified as EAEC, and not all pAA plasmids carry aggR and aatA genes; therefore, the assay will not detect all members of this diverse pathotype, but is likely to detect most pathogenic strains. EAEC causes epidemic and sporadic diarrhea among children and adults in developing and developed countries. It has been associated with traveler’s diarrhea, as well as persistent diarrhea in infants. EAEC produces enterotoxins and cytotoxins.

Enterotoxigenic Escherichia coli (ETEC): Detects but does not differentiate heat-labile (LT) enterotoxin (ltA) and 2 heat-stable (ST) enterotoxin variants (st1a and st1b). Cross-reactivity may occur with strains of Hafnia alvei, Citrobacter koseri, Citrobacter sedlakii, and Cedecea davisae. LT-II and the STB/ST2 toxins are not detected.ETEC causes gastroenteritis in humans and is best known as the causative agent of travelers’ diarrhea. It is also an important cause of diarrhea in infants, in less-developed countries.

Enteropathogenic Escherichia coli (EPEC): Detects eae gene but does not differentiate typical and atypical EPEC.The LEE pathogenicity island, which includes the eae gene, is also found in some Shiga toxin-producing E coli (STEC; O157 and non-O157 strains). Therefore, the results of the eae assay (positive or negative) are only reported when STEC is not detected.When STEC is detected, EPEC will not be reported, regardless of the EPEC assay result. Consequently, the assay cannot distinguish between STEC containing eae and a coinfection of EPEC and STEC. Rare instances of other organisms carrying eae have been documented. Others assays target bfp to detect EPEC and, if positive, reflex to eae detection to characterize isolates as typical or atypical EPEC. The bfp gene is not used to detect EPEC in this assay. For the reasons described above, EPEC may be missed or overcalled. The disease usually associated with EPEC is infantile diarrhea.

*Shiga toxin-producing Escherichia coli (STEC): Detects but does not differentiate Shiga toxin 1 (stx1) and Shiga toxin 2 (stx2) sequences. Shiga toxin-positive results indicate the likely presence of Shiga toxin-producing Escherichia coli. Rare instances of detection of Shiga-like toxin genes in other genera and species have been reported. Infections from EHEC may range from asymptomatic-to-mild diarrhea to severe complications. The acute symptoms are called hemorrhagic colitis (HC), characterized by severe abdominal cramps and bloody diarrhea, which may progress to such life-threatening complications as HUS or thrombotic thrombocytopenia purpura (TTP) – conditions that are most often associated with O157:H7, but that also can occur with other EHEC serotypes.

Escherichia coli O157: The Escherichia coli O157 assay is not reported as detected unless a Shiga-like toxin gene is also detected.The assay cannot distinguish between infections with a single toxigenic STEC O157 or rare coinfections of STEC (non-O157) with an stx1/stx2-negative E coli O157.

*Shigella/Enteroinvasive E. coli (EIEC): Detects but does not differentiate Shigella species from enteroinvasive E coli. EIEC is closely related to Shigella and is thought to cause watery diarrhea through invasion of the epithelial cells of the colon. It does not produce enterotoxins. Symptoms include abdominal cramps, malaise, tenesmus, and occasionally fever. The illness caused by EIEC is a mild form of bacillary dysentery, similar to that caused by Shigella spp.

*Cryptosporidium species: Detects but does not differentiate approximately 23 different Cryptosporidium species, including the most common species (eg, C hominis and C parvum), as well as less common species (eg, C meleagridis, C felis, C canis, C cuniculus, C muris, and C suis), but is not expected to detect the very rare species C bovis, C ryanae, and C xiaoi.

Cyclospora cayetanensis: Cyclospora are single-celled protozoan parasites and are classified as obligate intracellular coccidian parasites. Species of Cyclospora develop in the gastrointestinal tract of vertebrates throughout their entire live cycle. Immature (unsporulated) oocysts are then shed in feces. Though there are many species of Cyclospora, only Cyclospora cayetanensis has been observed to cause illness in humans.

Entamoeba histolytica: Detects E histolytica. E dispar present in high levels may cross-react.

*Giardia: Detects G lamblia (also known as G intestinalis, G duodenalis). A very low frequency of cross-reactivity with the commensal microorganisms Bifidobacterium and Ruminococcus species was observed in the clinical evaluation.

Adenovirus F40/41: Detects but does not differentiate F40 and F41. Does not detect respiratory adenovirus species such as B, C, and E. Enteric adenovirus causes 5-10%  of gastroenteritis in young children and are the second most common cause of gastroenteritis in this age group. By 4 years of age, 85% of all children have developed immunity.

Astrovirus: Detects but does not differentiate 8 subtypes (HAstV1-8). Astrovirus causes sporadic gastroenteritis in children

*Norovirus GI/GII: Detects but does not differentiate GI and GII. Does not detect genogroup GIV, nonhuman genogroups,or closely related Caliciviruses. Norovirus is self-limiting, but can be debilitating from a high rate of vomiting.

*Rotavirus: Detects all strains of rotavirus A. In silico sequence analysis indicates that these assays will not cross-react with rotavirus B and C, which are less common in human disease, or rotavirus D, E, and F, which have not been found in humans.Recent oral rotavirus A vaccines may result in patients passing the virus in stool and be detectable in stool PCR testing. Contamination of specimens with vaccine can cause false-positive rotavirus PCR results. Specimens should not be collected or processed in areas that are exposed to rotavirus A vaccine material.

*Sapovirus: Detects but does not differentiate genogroups I, II, IV, V. Genogroup III will not be detected. Sapovirus cause a sporadic gastroenteritis similar to norovirus in populations ranging from children to the elderly. These infections are more frequent in children <5 years than adults.

Information listed above concerning intestinal pathogens taken from: https://www.fda.gov/food/foodborne-pathogens/bad-bug-book-second-edition