Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Viewer Question: Is it necessary to conduct a culture of feces or vomit
in order to determine that a patient suffers from food poisoning?
Doctor's Response: Food poisoning is a general term that refers to gastrointestinal illnesses
(usually diarrhea and/or
vomiting) caused by food that is contaminated with:
bacteria,
parasites,
viruses, or
toxic substances.
The actual cause of most individual
episodes of food poisoning,
however,
never is pursued (for example, a culture is not done) since most episodes are mild
or moderate in severity and are over in a few hours to a few days. In fact, the
diagnosis of food poisoning usually is made only
presumptively, based on the affected individual's symptoms and the circumstances. Even in
outbreaks of suspected food poisoning that involve many people, when careful studies
are done, a specific cause is found no more than half of the time.
Bacteria are the cause of most outbreaks of food poisoning for which a specific cause is
determined. Bacteria cause food poisoning in three ways.
Food poisoning is a common infection that affects millions of people in the
United States each year.
Most commonly, patients complain of vomiting, diarrhea, and crampy
abdominal pain.
People should seek medical care if they have an associated fever, blood
in their stool, signs and symptoms of dehydration, or if their symptoms do not
resolve after a couple of days.
Treatment focuses on keeping the patient well hydrated.
Most cases of food poisoning resolve on their own.
Prevention is key and depends upon keeping food preparation areas clean,
good hand washing, and cooking foods thoroughly.
What is food poisoning?
Food poisoning might be described as a food borne disease. Food that contains
a toxin, chemical or infectious agent (like a bacterium, virus, parasite, or
prion) and cause symptoms in the body are considered types of food poisoning by
most investigators. Those symptoms may be related only to the gastrointestinal
tract causing vomiting or diarrhea or may involve other organs
such as the kidney,
brain or muscle.
Typically most food borne diseases cause vomiting and diarrhea that tend to
be short lived and resolve on their own, but
dehydration and
electrolyte
abnormalities may develop. According to the Center for Disease Control and
Prevention, 76 million people become ill from food related diseases each year
resulting in 325,000 hospitalizations and 5,000 deaths.
What are the types of food poisoning?
Most frequently, food poisoning may be due to infection caused by bacteria,
viruses, parasites, and infrequently, prions. More than 200 infectious causes
exist. Sometimes it is not the bacteria that causes the problem but the toxin
that bacteria produce in the food before it is eaten. This is the case with
Staphylococcal food poisoning and with
botulism.
Other illnesses may involve chemical toxins that are produced in certain
foods that are poorly cooked or stored. For example, scombroid poisoning occurs
due to a large release of histamine chemical from the fish when it is eaten. It
causes facial swelling, itching, and difficulty breathing and swallowing
- just
like an allergic reaction. Scombroid poisoning is sometimes confused with a
shellfish allergy.
Some "food poisonings" may not be due to toxins or chemicals in food but
to infectious agents that happen to contaminate the food.
E. coli O157:H7 (hemorrhagic E. coli) usually occurs when contaminated food is eaten, but it
also can spread from contaminated drinking water, a contaminated swimming
pool, or child to child in a day care center. The goal of information included is to
introduce the major causes of food poisoning and is not meant to be all
inclusive.
Listeria is a
bacteria that has caused the two most deadly outbreaks of food poisoning in
United States history. In 1985, an outbreak in California was traced to eating a
type of fresh cheese, and in 2011, Listeria food poisoning was traced to a cantaloupe farm and processing operation in Colorado. It is most often associated with eating soft cheeses, raw milk, contaminated fruits, vegetables, poultry, and meats. Newborns, the elderly and others with compromised immune systems are at higher risk of becoming ill with
Listeria infections. Pregnant women are also at higher risk of contracting
Listeria infections and are recommended to avoid soft cheeses like brie, camembert, and blue (cream cheese is safe) to avoid infection and to prevent transmission to the fetus.
Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an organ. Abdominal pain can reflect a major problem with one of the organs in the abdomen such as the appendix, gallbladder, large and small intestine, pancreas, liver, colon, duodenum, and spleen.
Gastroenteritis (viral gastroenteritis, stomach flu) is an infection caused by a variety of viruses that results in vomiting and/or diarrhea. Even though it is often called the "stomach flu," it is not caused by the influenza viruses. Viruses that can cause gastroenteritis (stomach flu) include: rotaviruses, adenoviruses, caliciviruses, astroviruses, Norwalk virus, and a group of Noroviruses. Gastroenteritis is not caused by bacteria. The main symptoms of gastroenteritis include vomiting and watery diarrhea, however, headache, fever, and abdominal cramps (stomach ache) may also be present.
Staphylococcus or Staph is a group of bacteria that can cause a multitude of diseases. Staph infections can cause illness directly by infection or indirectly by the toxins they produce. Symptoms and signs of a Staph infection include redness, swelling, pain, and drainage of pus. Minor skin infections are treated with an antibiotic ointment, while more serious infections are treated with intravenous antibiotics.
Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.
Norovirus infection causes stomach flu, or gastroenteritis. It's a very contagious illness with symptoms that include nausea and vomiting, diarrhea, stomach cramps, fever, headache, chills, and muscle aches. Norovirus infection cannot be treated with antibiotics, so treatment focuses on maintaining proper hydration.
The most common food allergies are to eggs, nuts, milk, peanuts, fish, shellfish, strawberries and tomatoes. Symptoms and signs include nausea, vomiting, diarrhea, abdominal pain, itching, hives, eczema, asthma, lightheadedness, and anaphylaxis. Allergy skin tests, RAST, and ELISA tests may be used to diagnose a food allergy. Though dietary avoidance may be sufficient treatment for mild allergies, the use of an Epipen may be necessary for severe food allergies.
Inflammation of the inner lining of the colon is referred to as colitis. Symptoms of the inflammation of the colon lining include diarrhea, pain, and blood in the stool. There are several causes of colitis including infection, ischemia of the colon, inflammatory bowel disease (Crohn's disease, Ulcerative colitis, or microscopic colitis). Treatment depends on the cause of the colitis.
Salmonella bacteria are known to cause salmonellosis, typhoid fever, and paratyphoid fever in humans. Salmonella infection is usually caused by ingesting large amounts of the bacteria in contaminated food or water.
There are many types of E. Coli (Escherichia coli ). Pathogenic E. coli can cause urinary tract and bladder infections, or lead to sepsis. E coli O157:H7 (EHEC) causes bloody diarrhea and colitis. Complications of E. coli infection include hemorrhagic diarrhea, hemolytic-uremic syndrome, and thrombotic thrombocytopenic purpura. Symptoms include severe abdominal pain and bloody diarrhea. E coli O157:H7 commonly is due to eating raw or undercooked hamburger or raw milk or dairy products.
Botulism is an illness caused by a neurotoxin produced by the bacterium Clostridium botulinum. There are three types of botulism: food-borne, wound, and infant. Symptoms include muscle paralysis, dry mouth, constipation, slurred speech, and blurred vision. If food-borne and wound botulism are detected early enough, they may be treated with an antitoxin. Infant botulism is treated intravenously with BabyBIG (Botulism Immune Globulin).
Listeria is a type of bacteria that can cause food poisoning. Listeriosis symptoms include diarrhea, nausea and fever. Pregnant women are 20 times more likely than other healthy adults to get listeriosis. Listeria infection is treated with antibiotics.
Travelers' diarrhea is generally contracted by eating contaminated food or drinking contaminated water. Food is the primary source of travelers' diarrhea. Enterotoxigenic E. coli is the cause of up to 70% of all cases of travelers' diarrhea. There are five unique classes of E. coli that causes gastroenteritis. Other bacteria responsible for travelers' diarrhea include
Campylobacter, jejuni, shigella, and salmonella. Viruses such as rotavirus and Norwalk virus (norovirus) and giardia lamblia a parasite may cause travelers' diarrhea. Prevention is careful eating and drinking of water.
Trichinosis is a food-borne disease caused by ingesting parasites (roundworms) in undercooked pork or wild-game meat. Symptoms of trichinosis include diarrhea, nausea, muscle aches, itching, fever, chills, and joint pains. Trichinosis usually resolves without treatment, but more severe cases are treated with thiabendazole, albendazole, or mebendazole.
Cholera is an infectious disease characterized by intense vomiting and profuse watery diarrhea and that rapidly lease to dehydration and often death. Cholera is caused by infection with the bacteria Vibrio cholerae, which may be transmitted via infected fecal matter, food, or water.
Brucellosis is an infectious disease caused by the Brucella bacteria. Symptoms and signs include sweating, fever, fatigue, dizziness, headache, cough, chest, joint, and abdominal pain, and enlarged liver and/or spleen. Brucellosis is treated with antibiotics.
Anthrax is a deadly infectious disease that may be transmitted to humans by infected animals or by biological warfare. There are three types of anthrax: cutaneous, inhalation, and gastrointestinal. Symptoms of cutaneous anthrax include a swollen glands, muscle ache, headache, fever, nausea, vomiting, and a red-brown raised spot that enlarges, blisters, and hardens, forming an ulcer crater with black crust. Symptoms of inhalation anthrax are flulike and may progress to respiratory distress, shock, coma, and death. Symptoms of gastrointestinal anthrax include loss of appetite, bloody diarrhea, and abdominal pain. Treatment for cutaneous anthrax involves penicillin, tetracycline, erythromycin, and ciprofloxin. Inhalation anthrax necessitates treatment with IV therapy with antibiotics.
Shigellosis is a disease caused by the Shigella bacteria. Bloody diarrhea, stomach cramps and fever are common symptoms. Mild infections usually resolve on their own. Antibiotics are used to treat more severe cases.
Hepatitis means inflammation of the liver. Hepatitis A is one type of liver disease caused by a virus. Since hepatitis A is a virus, it can pass from person to person from eating or drinking contaminated food or coming into contact with contaminated materials containing the virus. Symptoms of hepatitis A include stomach pain, diarrhea, dark yellow urine, jaundice, and more. There is a vaccine to prevent contracting hepatitis A.
Hemolytic uremic syndrome (HUS) is a diseases in which blood clots within the capillaries. Causes associated with HUS include E. Coli, birth control pills, pneumonia, medications such as chemotherapy, Ticlid, and quinine. Symptoms of HUS include gastroenteritis, abdominal cramping, vomiting, and bloody diarrhea. Diagnosis of HUS includes medical history, physical examination, and medical tests. Treatment includes rest, fluids, possible hospitalization for blood transfusion or complications due to kidney failure.
Cryptosporidiosis is an intestinal disease caused by the Cryptosporidium parasite. Symptoms include watery diarrhea, stomach cramps, nausea and vomiting, fever, weight loss, dehydration, and weight loss. Antibiotics are used in the treatment of cyptosporidiosis.
Cysticercosis is an infection caused by Taenia solium, the pork tapeworm. Symptoms include seizures, lethargy, nausea and vomiting, headache, vision changes, weakness, and confusion. Treatment depends upon the individual's symptoms and the stage of the infection. Treatment may incorporate anthelmintics, corticosteroids, anticonvulsants, and/or surgery.
Enterovirulent Escherichia coli (E. coli) are strains of related bacteria that have a strong propensity to cause gastrointestinal tract infections. Examples of strains include: EHEC (enterohemorrhagic E. coli), ETEC (enterotoxigenic E. coli), EPEC (enteropathogenic E. coli), EIEC (enteroinvasive E. coli), EAEC (enteroadherent E. coli), and EAggEC (enteroaggregative E. coli). Symptoms may vary depending on the strain the individual contracts. Infection is spread generally through contaminated food or drink.
Mad cow disease (or bovine spongiform encephalopathy [BSE]) is a fatal disease that attacks the central nervous system of adult cattle. Though the specific cause isn't known, it is speculated that infectious prions are the likely cause. Creutzfeldt-Jacob disease is found in people and is similar to BSE. A variation of this disease is thought to be caused by eating beef products from BSE-infected cattle.
Enterovirulent E. coli (EEC) are bacteria that comprise several groups of
E. coli serovars, all of which may cause diarrhea and other problems in the
intestines.
EEC bacteria can cause a wide range of symptoms ranging from mild to bloody
diarrhea, nausea, vomiting, stomach cramping and dehydration. Different groups
often produce less (EAEC group) or more intense symptoms (EHEC group) and
complications.
Although investigators vary on the group structure and names, six groups
are currently presented in the medical literature, listed by their main symptoms
produced or other "unique" group feature:
EHEC (enterohemorrhagic E. coli): Shiga toxins; bloody diarrhea, 10% with
complications
ETEC (enterotoxigenic E. coli): secretory toxins; watery diarrhea