Merck Manual

Please confirm that you are not located inside the Russian Federation

Microorganisms That Cause Gastroenteritis

Microorganisms That Cause Gastroenteritis

Microorganism

Common Sources

Symptoms

Antimicrobial Use

Astrovirus

Epidemic and often seasonal

Milder watery diarrhea

Vomiting and fever

Symptoms begin 3 to 4 days after infection

Usually lasts 2 to 7 days

Similar to rotavirus

Antibiotics and antiviral drugs are not given.

Eating contaminated meat (especially undercooked poultry)

Drinking contaminated water or unpasteurized milk

Often bloody, sometimes watery diarrhea lasting 1 day to a week or more

Antibiotics given in the early stages of illness may shorten the duration of symptoms (for example, azithromycin or ciprofloxacin).

Usually due to bacterial overgrowth in people who have been taking antibiotics

Diarrhea

Antibiotic that caused the illness is stopped.

Vancomycin or fidaxomicin is given by mouth.

Metronidazole may be given to people who cannot tolerate vancomycin and fidaxomicin.

Drinking contaminated water

Person-to-person contact

Recreational water exposure

People with impaired immune systems are particularly susceptible

Watery diarrhea, crampy abdominal pain, nausea, fatigue, and vomiting

Usually lasts about 2 weeks

Antiparasitic drugs are sometimes given (for example, nitazoxanide).

Eating or drinking contaminated food or water

Bloody diarrhea, abdominal pain, weight loss lasting 1 to 3 weeks

Can cause infection in liver and other organs

Antiparasitic drugs are given (for example, metronidazole, iodoquinol, or paromomycin).

Enterohemorrhagic Escherichia coli (most commonly E. coli O157:H7―see Hemorrhagic Colitis)

Eating undercooked ground beef or drinking unpasteurized milk or juice

Swimming in contaminated pools

Person-to-person contact

Touching infected animals and then putting fingers in the mouth

Sudden abdominal cramps, watery diarrhea that usually becomes bloody within 1 to 3 days, and hemolytic-uremic syndrome in about 5% of people

Antibiotics are not given because they increase the risk of developing hemolytic-uremic syndromehemolytic-uremic syndrome.

Enterotoxigenic Escherichia coli (causes traveler’s diarrhea)

Eating or drinking contaminated food or water

Frequent watery diarrhea

Usually lasts 3 to 5 days

Antibiotics (for example, ciprofloxacin or levofloxacin) may help shorten duration of illness.

Azithromycin is given to children.

Drinking contaminated water

Person-to-person contact, particularly in day care centers

Diarrhea, nausea, and loss of appetite

More long-term illness (lasting several days to several weeks) may occur, with greasy stools, abdominal bloating, gas, fatigue, and weight loss

Antiparasitic drugs are given (for example, metronidazole or nitazoxanide).

Intestinal adenovirus

Epidemic and often seasonal

Frequent watery diarrhea lasts 1 to 2 weeks

Mild vomiting begins 1 to 2 days after diarrhea

Fever affects 50% of people

Symptoms begin 3 to 10 days after infection

Usually lasts 10 days or more

Antibiotics and antiviral drugs are not given.

Norovirus

Epidemic and often seasonal

Frequent watery diarrhea

Vomiting, especially in children

Stomach cramps, headache, and aches and pains

Fever higher than 102° F (about 39°C) occurs in about 30% of people

Diarrhea usually affects adults

Symptoms begin 1 to 2 days after infection

Usually lasts 2 to 7 days

Antibiotics and antiviral drugs are not given.

Epidemic and often seasonal

Frequent watery diarrhea

Vomiting and fever higher than 102° F (about 39°C)

Symptoms begin 1 to 3 days after infection

May last 5 to 7 days

Antibiotics and antiviral drugs are not given.

Vaccines are available for infants.

Eating contaminated food

Contact with reptiles (for instance, iguanas, snakes, and turtles), birds, or amphibians (for instance, frogs and salamanders)

High fever, exhaustion, abdominal cramps, nausea, vomiting, diarrhea that may or may not be bloody

Symptoms usually last 3 to 7 days

Antibiotics usually are not given.

Person-to-person contact, especially in day care centers

May be mild or severe

In mild cases, watery, loose stools

In severe cases, high fever, exhaustion, severe abdominal cramps, painful passage of stool containing blood and mucus

Symptoms usually last about a week without treatment

Antibiotics shorten the duration of the illness and decrease chance of spread to another person (for example, ciprofloxacin or trimethoprim-sulfamethoxazole).

Bacillus cereus

Eating food contaminated by toxins produced by bacteria

Severe nausea, vomiting, and diarrhea

Symptoms begin within 12 hours after eating contaminated food and lessen within 36 hours

Antibiotics are not given.

Eating or drinking contaminated food or water

Painless, watery diarrhea and vomiting

Can lead to massive fluid loss and shock

Antibiotics are given (for example, ciprofloxacin or doxycycline).

Other types of Vibrio

Shellfish

Watery diarrhea, often with little nausea or vomiting

Antibiotics are given (for example, ciprofloxacin, doxycycline, or trimethoprim/sulfamethoxazole).