Campylobacter infection is an illness caused by bacteria of the genus Campylobacter, with Campylobacter jejuni and Campylobacter coli among the most important human pathogens. Campylobacters are Gram-negative, curved or spiral-shaped bacteria with distinctive motility and generally require reduced-oxygen conditions for growth. Human infection most commonly produces acute gastroenteritis characterised by diarrhoea, abdominal pain and fever. Campylobacteriosis is an important foodborne disease and can occur worldwide. The organisms are strongly associated with poultry and other animal reservoirs, making food production, handling and cooking central to prevention.
Transmission is usually faecal-oral and frequently involves consumption of contaminated food or water. Undercooked poultry is a major source because poultry can carry Campylobacter in the intestinal tract without obvious disease. Cross-contamination can occur when raw poultry juices contact ready-to-eat foods, utensils or preparation surfaces. Unpasteurised milk and untreated water can also transmit infection. Direct contact with infected animals or their faeces is another possible route. Because relatively small amounts of contamination can cause illness, careful food hygiene is important even when food appears normal in smell, appearance and taste.
Campylobacteriosis commonly produces diarrhoea that may be watery or bloody, accompanied by abdominal cramping, fever and malaise. Symptoms often begin several days after exposure, and illness commonly resolves over approximately a week, although duration varies. Dehydration is an important concern, especially in vulnerable people. Vomiting can occur but is generally less prominent than diarrhoea. The clinical presentation can resemble other bacterial gastroenteritides, so laboratory testing may be necessary when identifying the organism is important for patient management, outbreak investigation or surveillance.
Most Campylobacter infections are self-limited, but complications can occur. Bacteraemia is uncommon but more likely in people with significant immune compromise. Post-infectious complications include reactive arthritis and Guillain–Barré syndrome, an acute immune-mediated neuropathy that can cause progressive weakness and, in severe cases, respiratory compromise. The absolute risk of Guillain–Barré syndrome following Campylobacter infection is low, but the association is scientifically important because specific Campylobacter surface structures can resemble components of peripheral nerve gangliosides, potentially contributing to molecular mimicry and autoimmune nerve injury.
Diagnosis is commonly established through stool testing using culture or molecular methods. Culture provides an organism for identification and antimicrobial susceptibility testing, while molecular assays can offer rapid detection of bacterial genetic material. Not every patient with uncomplicated diarrhoea requires laboratory testing, but testing becomes particularly relevant for severe disease, prolonged symptoms, bloody diarrhoea, outbreaks, vulnerable patients and public-health investigations. Campylobacter can be difficult to culture because it has specialised atmospheric and temperature requirements, so laboratory handling differs from routine enteric bacteria.
Treatment of uncomplicated Campylobacter infection is usually supportive, particularly replacement of fluids and electrolytes. Antibiotics may be considered for severe disease, prolonged illness or people at increased risk of complications. Macrolides such as azithromycin are commonly used when antimicrobial treatment is indicated, while resistance patterns and local guidance must be considered. Fluoroquinolone resistance is widespread in many regions, limiting their usefulness. Antibiotic therapy does not remove the need for hydration and supportive care, and unnecessary antimicrobial treatment can contribute to resistance.
Prevention centres on reducing contamination and thoroughly cooking poultry and other relevant foods. Raw poultry should be kept separate from ready-to-eat food, hands and kitchen surfaces should be washed appropriately after handling raw meat, and cooked food should not be placed on surfaces contaminated by raw products. Pasteurisation reduces the risk associated with milk, while treatment of drinking water reduces waterborne transmission. Because poultry colonisation can occur without visible illness, consumers cannot reliably identify contaminated meat by appearance alone. Food safety practices are therefore more dependable than visual inspection.
Campylobacter differs from Salmonella and E. coli Infection even though all can cause foodborne diarrhoeal illness. The organism's curved morphology, specialised growth requirements and strong association with poultry are distinctive features. “Campylobacter” refers to a genus rather than a single species, and different species have different host associations and clinical significance. The infection is also important because the immediate gastrointestinal illness can occasionally be followed by neurological or rheumatological complications. Its public-health control consequently requires both prevention of food contamination and awareness of possible post-infectious disease.
