GASTROINTESTINAL PATHOGEN PANEL

Bacteria

Campylobacter (C. coli and C. jejuni)

Campylobacter spp. are gram-negative, S-shaped or spiral-shaped bacteria that are non-spore forming and often motile, they are often found in healthy food animals such as poultry, cattle, sheep, and pigs. Transmission occurs through the food borne route, often from eating undercooked poultry, but can occur through consumption of raw milk and feces-contaminated water and produce. Onset of illness usually occurs 2 to 5 days after infection and symptoms often include watery or bloody diarrhea, fever, and abdominal cramps. The most serious cases of campylobacteriosis occur in young children and elderly adults, with some patients developing a more serious side effect called Guillain Barré syndrome. The CDC estimates that Campylobacter causes an estimated 1.5 million cases each year in the United States.

Clostridium difficile toxin A/B

Clostridium difficile is a gram-positive, anaerobic, rod-shaped, spore forming bacterium that produces two exotoxins A and B. C. diff is the most common cause of hospital acquired infectious disease in the United States, and is often acquired while, or shortly after, taking antibiotics. Symptoms may develop a few days after you begin taking antibiotics and include: diarrhea, fever, abdominal cramps, nausea, and may result in death. 1 in 6 individuals who have had C. diff will get it again in the next 2-8 weeks. It is estimated to cause almost half a million cases in the United States each year, and those over the age of 65 are at highest risk of death, with 1 in 11 dying within one month of diagnosis.

E. coli and Shigella

E. coli are gram-negative, rod-shaped bacteria that live in the intestines of humans and animals. Shigella are gram-negative, non-spore forming, rod-shaped bacteria closely related to E. coli. Most types of E. coli are harmless and an important part of our digestive system, but some strains are pathogenic causing illness when ingested after consuming contaminated food, and water, and direct contact with infected individuals and animals. Pathogenic E. coli can be classified into several different pathotypes, each with its own toxins and mechanisms of action.

Sterling Pathology tests for five different E. coli pathotypes: Enteroaggregative coli (EAEC), Enterotoxigenic E. coli (ETEC), Shiga-like toxin-producing E. coli (STEC), E. coli 0157, and Shigella spp./Enteroinvasive E. coli (EIEC).

Enterotoxigenic E. coli LT/ST (ETEC)

Enterotoxigenic E. coli contain heat-labile (LT) or heat-stable (ST) enterotoxins, that are released after the bacteria attaches to the intestinal epithelium and cause the intestinal cells to secrete fluids that lead to diarrhea.

Enteroaggregative E. coli (EAEC)

Enteroaggregative E. coli are defined by their “stacked brick” pattern of adhesion to the intestinal lining. Once adhered they release enterotoxins and cytotoxins that damage the intestinal cells that cause inflammation and lead to watery or bloody diarrhea, fever, vomiting, and abdominal cramps.

E. coli O157

coli O157 is a Shiga-like toxin producing (STEC) E. coli strain. STEC O157 causes illness after ingesting contaminated food like raw milk, ground beef, and leafy greens. Infection with this subtype can cause hemorrhagic diarrhea and kidney failure, which have caused the deaths of children under the age of 5, and elderly adults.

Shiga-like toxin producing E. coli stx1/stx2 (STEC)

Shiga-like toxin-producing E. coli may contain either one or both of the Shiga-like toxins Stx1 and Stx2. Infection occurs after eating any product contaminated with the bacteria, these commonly include: raw or undercooked meat, raw milk, lettuce, and other produce items. This bacterium is an important cause of traveler’s diarrhea. Symptoms begin 3 to 4 days after eating a contaminated food item and include: vomiting, abdominal cramps, and diarrhea that is often bloody, with little to no fever. Young children and elderly adults are at a higher risk of developing hemolytic uremic syndrome (HUS), a potentially fatal disease where red blood cells damaged by Shiga-like toxins clog the kidneys, leading to renal failure. STEC causes about 265,000 illnesses each year in the United States with 30 deaths.

Shigella/ Enteroinvasive E. coli (EIEC)

Shigella and enteroinvasive E. coli both contain the same gene, which allows them to invade host cells. Infection occurs after touching a contaminated object then placing your hands in or near your mouth, you can also become sick after eating food prepared by someone who is/was sick, and swallowing contaminated recreational/drinking water. Symptoms caused by infection with either bacterium include profuse diarrhea and a high fever. There are an estimated 500,000 infections each year with most cases occurring in children under 10 years old.

Salmonella spp.

Salmonella spp are gram-negative, motile, and rod-shaped bacteria that are classified as either typhoidal or non-typhoidal. Typhoidal Salmonella causes typhoid fever, a serious disease, and non-typhoidal Salmonella causes stomach cramps, fever, and diarrhea that can sometimes be bloody. Salmonella is found in the intestines of humans and animals, and transmission occurs after consuming contaminated food and water, and touching infected animals, their feces, and their environment. Symptoms usually begin a few hours to a few days after infection and can last for 4 to 7 days. There are about 1.35 million Salmonella infections per year that result in about 420 deaths, children and elderly adults are at highest risk of serious illness.

Vibrio spp.

Vibrio spp. are gram-negative, comma-shaped, non-spore forming motile bacteria found in coastal waters, particularly during warmer months when the water is warmer. Illness occurs after consumption of raw or undercooked shellfish, especially oysters. After consumption, symptoms usually begin within 24 hours and include watery diarrhea, abdominal cramping, fever, nausea, vomiting, and chills, and can last for 3 days. The CDC estimates that there are about 80,000 cases of vibriosis each year in the United States.

Sterling Pathology tests for different Vibrio species including, V. parahaemolyticus, V. vulnificus, and V. cholerae, and specifically identifies V. parahaemolyticus.

Vibrio parahaemolyticus

parahaemolyticus is found in brackish saltwater and is the most common cause of vibriosis in the United States, and is associated with eating raw and undercooked seafood, especially raw oysters. Symptoms include watery diarrhea, abdominal cramps, nausea, and vomiting. V. parahaemolyticus is estimated to cause 45,000 illnesses each year.

Other Vibrio species

There are several non-parahaemolyticus Vibrio species, including V. vulnificus and V. cholerae. V. cholerae is responsible for endemic, epidemic, and pandemic cholera. Symptoms include profuse watery diarrhea that can lead to death from severe dehydration if not treated. It has been estimated that between 1.3 million and 4 million cholera cases occur worldwide each year with between 21,000 and 143,000 fatalities. V. vulnificus illness occurs when an open wound comes into contact with raw or undercooked shellfish, or with saltwater or brackish water. V. vulnificus infection can lead to necrotizing fasciitis that require intensive care or amputations, 1 in 5 people die with this infection.

Yersinia enterocolitica

Yersinia enterocolitica is a gram-negative rod-shaped bacterium. This bacterium is frequently associated with the consumption of raw and undercooked pork, or through close contact with someone who has handled pork. The symptoms of Yersiniosis vary depending on the age of the person infected. Young children are most commonly infected, and their symptoms include fever, abdominal pain, and diarrhea that is often bloody. Symptoms in older children and adults include: fever and right-side abdominal pain which is often mistaken for appendicitis. Y. enterocolitica causes 117,000 infections, and 35 deaths per year in the United States.