Campylobacter Infections

ByLarry M. Bush, MD, FACP, Charles E. Schmidt College of Medicine, Florida Atlantic University
Reviewed/Revised Jun 2024

Several species of the gram-negative bacteria Campylobacter (most commonly Campylobacter jejuni) can infect the digestive tract, often causing diarrhea.

  • People can be infected when they consume contaminated food or drink or have contact with infected people or animals.

  • These infections cause diarrhea, abdominal pain, and fever.

  • Identifying the bacteria in a stool sample confirms the diagnosis.

  • For some people, replacing lost fluids is all that is needed, but if symptoms are severe, antibiotics are also needed.

(See also Overview of Bacteria.)

Campylobacter bacteria normally inhabit the digestive tract of many farm animals (including cattle, sheep, pigs, and fowl). The feces of these animals may contaminate water in lakes and streams. Meat (usually poultry) and unpasteurized milk may also be contaminated. People may be infected in several ways:

  • Eating or drinking contaminated (untreated) water, unpasteurized raw milk, undercooked meat (usually poultry), or food prepared on kitchen surfaces touched by contaminated meat

  • Contact with contaminated food or water (for example, when handling contaminated food)

  • Contact with an infected person (through contamination of food with fecal material or sexual contact)

  • Contact with an infected animal (such as a puppy)

Campylobacter bacteria, usually Campylobacter jejuni, cause inflammation of the colon (colitis) that results in fever and diarrhea. These bacteria are a common cause of infectious diarrhea in the United States and among people who travel to countries where food or water may be contaminated.

Campylobacter jejuni affects people who are healthy and people who are ill and causes diarrhea in all age groups. It seems to mostly affect children 1 to 5 years of age.

Symptoms of Campylobacter Infections

Campylobacter symptoms usually develop 2 to 5 days after exposure and continue for about 1 week. Symptoms of Campylobacter colitis include diarrhea, abdominal pain, and cramps, which may be severe. The diarrhea may be watery and sometimes bloody and can be accompanied by nausea, vomiting, headache, muscle aches, and fever ranging from 100 to 104° F (38 to 40° C).


Complications of Campylobacter infection can include

Bacteremia occurs temporarily in some people with colitis. This infection usually causes no symptoms or complications. However, the bloodstream is repeatedly or continuously infected in a few people, usually those with a disorder that weakens the immune system, such as HIV/AIDS, diabetes, or cancer. This infection causes a long-lasting or recurring fever.

Other symptoms develop as the bloodstream carries the infection to other structures, such as the following:

Guillain-Barré syndrome (a nerve disorder) develops in about 1 of 1,000 of people in the United States with Campylobacter colitis because antibodies that the body makes to fight off the infection sometimes also attack the nerves. Guillain-Barré syndrome causes weakness or paralysis. Most people recover, but muscles may be greatly weakened. People may have difficulty breathing and need to use a mechanical ventilator. Weakness does not always completely resolve. About 20 to 50% of people who develop Guillain-Barré syndrome have had a previous Campylobacter infection.

Reactive arthritis may develop days to weeks after the diarrhea resolves. Usually, the disorder causes inflammation and pain in a knee or other joint.

Inflammation of the eyes (uveitis) and the urethra (causing painful urination) may also occur.

Diagnosis of Campylobacter Infections

  • Culture or PCR of a stool sample

  • Sometimes culture of a blood sample

Doctors may take a sample of stool and send it to a laboratory to grow (culture) and identify the bacteria. However, stool is not always tested. Stool cultures take days to complete, and doctors do not usually need to know which bacteria caused the diarrhea to effectively treat it. However, if people have bloody diarrhea or appear seriously ill, the stool is usually tested. A test that identifies genetic material of the bacteria in stool, called the polymerase chain reaction (PCR) technique, may be used so that the bacteria can be detected more quickly. The PCR technique increases the amount of the bacteria's DNA to make it easier to detect. Other tests may rapidly identify the bacteria (antigen) in the stool.

If the bacteria are identified, they are tested to see which antibiotics are effective (a process called susceptibility testing).

If doctors suspect that the bloodstream or other organs are infected, they take a sample of blood to be cultured.

Treatment of Campylobacter Infections

  • Usually no specific treatment

  • Sometimes an antibiotic such as azithromycin

Many people get better in a week or so without specific treatment.

Some people require extra fluids by vein (intravenously) or by mouth.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  1. Centers for Disease Control and Prevention (CDC): Campylobacter: A resource providing information about Campylobacter, including outbreaks and antibiotic resistance

Drugs Mentioned In This Article
Test your KnowledgeTake a Quiz!
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID