Campylobacter Concisus: Symptoms, Causes, and Treatment

Campylobacter concisus is a species of bacteria that scientists are studying with increasing interest. It was long known as a common inhabitant of the human oral cavity, found in dental plaque and saliva. However, researchers now recognize it as an emerging pathogen, as it is being identified more frequently as a cause of intestinal disease. Certain strains can cause illness if they move to the digestive tract.

Sources and Transmission of Campylobacter Concisus

The primary habitat for Campylobacter concisus is the human mouth. It is a regular member of the microbial community in saliva and dental plaque, even in healthy individuals. Because of its prevalence in the oral cavity, the main way the bacterium spreads is thought to be through direct oral contact, such as sharing utensils or kissing.

Another significant route of transmission is the oral-fecal pathway. This occurs when the bacteria are swallowed and travel from the mouth to the gastrointestinal system, eventually being shed in feces. Poor hygiene can then lead to the contamination of surfaces, food, or water, allowing the bacteria to be ingested by another person.

While other species of Campylobacter are well-known foodborne pathogens linked to undercooked poultry, C. concisus is less commonly transmitted this way. There have been some instances of it being found in contaminated water or food, but its main reservoir is considered to be humans. The bacterium’s ability to form biofilms, which are protective communities of microorganisms, helps it survive in the oral cavity before being transmitted.

Associated Symptoms and Conditions

When Campylobacter concisus causes an acute infection in the gut, it results in gastroenteritis. The symptoms of this condition include prolonged diarrhea, which can sometimes be bloody, along with abdominal pain and cramping. The diarrhea is often noted to have a milder course compared to infections caused by its more well-known relative, Campylobacter jejuni.

Beyond acute illness, C. concisus is drawing attention for its association with chronic inflammatory diseases of the digestive system. There is a strong link between the presence of this bacterium in the gut and Inflammatory Bowel Disease (IBD), which includes both Crohn’s disease and ulcerative colitis. Studies have found C. concisus more often in intestinal biopsies from people with these conditions compared to healthy individuals.

It is important to understand that this is currently viewed as an association, not a definitive cause. The thinking is that for some people, the translocation of certain strains of C. concisus from the mouth to the gut may trigger or worsen an inflammatory response in those genetically predisposed to IBD. The bacterium has also been linked to esophageal conditions, including esophagitis and Barrett’s esophagus.

Diagnosis and Testing

Identifying a Campylobacter concisus infection begins with collecting a biological sample, most often a stool sample from a patient experiencing diarrhea. In cases where a chronic condition like IBD is suspected, physicians might collect tissue samples, known as biopsies, during an endoscopic procedure. These samples are then sent to a laboratory for analysis.

Historically, identifying C. concisus has been challenging because it is a fastidious organism with complex nutritional requirements, making it difficult to grow in a standard laboratory culture. Traditional culture methods are often unreliable for C. concisus, leading to it being overlooked. The bacteria can be sensitive to antibiotics used in the culture media, preventing it from growing.

To overcome these difficulties, diagnostic methods have shifted toward more advanced molecular techniques. The most prominent of these is the Polymerase Chain Reaction (PCR) test. This method is highly sensitive and specific, allowing labs to find C. concisus even when the number of bacteria is low and providing a much more accurate diagnosis.

Treatment and Management

The approach to treating a Campylobacter concisus infection depends on the severity of the illness. For cases of acute gastroenteritis that are mild, the infection is often self-limiting and resolves on its own within about a week. Treatment is primarily supportive, focusing on preventing dehydration by encouraging the patient to drink plenty of fluids.

Antibiotics are generally reserved for more specific circumstances. A doctor might prescribe them for patients who have a severe or persistent infection, exhibit symptoms like a high fever or bloody diarrhea, or for individuals with weakened immune systems. Antibiotics are also considered when the infection is believed to be contributing to a flare-up of a chronic condition like IBD.

When antibiotics are necessary, macrolides such as azithromycin are often the treatment of choice. However, there is a growing global concern about antibiotic resistance in Campylobacter species, which can make treatment more complicated. Healthcare providers aim to use antibiotics judiciously and may order susceptibility testing to determine which medication will be most effective.