Information for Health Professionals

Clinical features

Incubation period is typically 2–4 days. Campylobacter infection is characterized by diarrhea (frequently bloody), abdominal pain, fever, and occasionally nausea and vomiting. More severe illness can occur, including dehydration, bloodstream infection, and symptoms mimicking acute appendicitis or ulcerative colitis.

Etiologic agent

This scanning electron microscopic (SEM) image depicts a number of Gram-negative Campylobacter jejuni bacteria, magnified 9,951x. — This scanning electron microscopic (SEM) image depicts a number of Gram-negative *Campylobacter jejuni* bacteria, magnified 9,951x.

Campylobacter is a gram-negative, microaerophilic genus of bacteria of the family Campylobacteriacae. There are more than 20 species of Campylobacter, not all of which cause human illness. Approximately 90% of human illness is caused by one species, Campylobacter jejuni. Less common species, such as C. coli, C. upsaliensis, C. fetus and C. lari, also cause infection.

Campylobacter jejuni grows best at 37^°C to 42^°C, the approximate body temperature of a bird (41^°C to 42^°C), and seems to be well-adapted to birds, which carry the bacteria without becoming ill. These bacteria are fragile. They cannot tolerate drying. Freezing reduces the number of Campylobacter bacteria on raw meat.

Incidence

Active surveillance through the Foodborne Diseases Active Surveillance Network (FoodNet> indicates that about 14 cases per 100,000 people are diagnosed each year. Many more cases go undiagnosed or unreported. CDC estimates that Campylobacter infection affects more than 1.3 million people in the United States every year.

Outcomes

Most people who get Campylobacter infection recover completely within two to five days, although recovery can take up to 10 days. Campylobacter infection can result in long-term consequences such as arthritis, irritable bowel syndrome (IBS), or Guillain-Barré syndrome (GBS). CDC estimates about 1 in every 1,000 reported Campylobacter illnesses leads to GBS.

Transmission

Most cases of Campylobacter infection occur after someone eats raw or undercooked poultry or eats another food that has been contaminated by raw or undercooked poultry. Outbreaks of Campylobacter infection are infrequently reported relative to the number of illnesses. Outbreaks have been associated with unpasteurized dairy products, contaminated water, poultry, and produce. People also can get infected from contact with the feces of a dog or cat. Person-to-person spread of Campylobacter is uncommon.

Diagnosis

A confirmed case is the isolation of Campylobacter spp. from a clinical specimen. A probable case is the detection of Campylobacter spp. in a clinical specimen using a culture-independent diagnostic test (CIDT), such as a polymerase chain reaction test.

The use of CIDTs as stand-alone tests for the direct detection of Campylobacter in stool is increasing. Data indicate that the sensitivity, specificity, and positive predictive value of these assays vary, depending on the manufacturer (CDC unpublished data). Culture confirmation of CIDT-positive specimens (called reflex culture) is ideal. It can be used to obtain the whole genome sequence, which can provide antimicrobial susceptibility data and molecular subtyping, but reflex culture is not practical in most locations.

Treatment

Most infections are self-limited. Patients should drink extra fluids as long as the diarrhea lasts. Antimicrobial therapy is needed only for patients with severe disease or those at high risk for severe disease, such as people with immune systems that are severely weakened from medications or other illnesses. Azithromycin and fluoroquinolones (e.g., ciprofloxacin) are commonly used for treatment, but resistance to fluoroquinolones is common. Antimicrobial susceptibility testing can help guide appropriate therapy.

Risk groups

Anyone can become infected with Campylobacter but campylobacteriosis is more common in males, children younger than 5 years, and people 65 years and older.

Surveillance

Campylobacter infections have been tracked passively through the National Notifiable Disease Surveillance System (NNDSS) since 1993 and actively since 2015 when these infections became nationally notifiable. The Foodborne Diseases Active Surveillance Network (FoodNet) has conducted active surveillance for Campylobacter infections in sentinel sites since 1996. The National Antimicrobial Monitoring System (NARMS) monitors antimicrobial susceptibility to a range of antibiotics for a convenience sample of Campylobacter isolates from people. Campylobacter outbreaks are reported to the National Outbreak Reporting System (NORS).

Trends

The Foodborne Diseases Active Surveillance Network (FoodNet) has tracked trends in Campylobacter infection since 1996. Campylobacter infections increased by 13% in 2014, when compared with 2006-2008. Use of culture-independent tests (CIDTs) to diagnosis Campylobacter infection increased by 14% in 2014, typically replacing traditional culture-based methods.

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