Capnocytophaga

Capnocytophaga is a genus of Gram-negative bacteria that are part of the normal oral flora in humans and animals. These bacteria are known for their gliding motility and are often associated with opportunistic infections, particularly in immunocompromised individuals.

Taxonomy

Capnocytophaga belongs to the family Flavobacteriaceae, within the order Flavobacteriales. The genus was first described in the 1970s and includes several species, some of which are pathogenic to humans.

Morphology

Capnocytophaga species are characterized by their fusiform shape and are typically 2-6 micrometers in length. They are non-spore-forming and exhibit a distinctive gliding motility, which is a key feature of their identification in the laboratory.

Physiology

Capnocytophaga are facultative anaerobes, meaning they can survive in both the presence and absence of oxygen. They are capnophilic, requiring increased levels of carbon dioxide for optimal growth. These bacteria are chemoorganotrophic, utilizing organic compounds as a source of energy.

Habitat

Capnocytophaga species are commonly found in the oral cavity of humans and animals, particularly dogs and cats. They are part of the normal microbiota but can become pathogenic under certain conditions.

Pathogenicity

While Capnocytophaga is generally harmless in healthy individuals, it can cause serious infections in those with weakened immune systems. Infections can occur following dog bites or cat bites, leading to conditions such as sepsis, endocarditis, and meningitis.

Risk Factors

Individuals at higher risk for Capnocytophaga infections include those with splenectomy, alcoholism, cancer, diabetes mellitus, and HIV/AIDS.

Clinical Manifestations

Infections with Capnocytophaga can present with a range of symptoms, from mild local infections to severe systemic illnesses. Common symptoms include fever, chills, muscle pain, and rash. In severe cases, it can lead to septic shock and disseminated intravascular coagulation.

Diagnosis

Diagnosis of Capnocytophaga infections is typically made through blood cultures or cultures from infected sites. The bacteria can be identified by their characteristic morphology and motility, as well as biochemical tests.

Treatment

Capnocytophaga infections are generally treated with antibiotics. The bacteria are usually susceptible to penicillin, amoxicillin, and clindamycin. In cases of severe infection, intravenous antibiotics may be required.

Prevention

Preventive measures include proper wound care following animal bites and avoiding contact with animals for individuals with known risk factors. Vaccination and prophylactic antibiotics may be considered for high-risk individuals.

See also

• Bacterial infection
• Opportunistic infection
• Oral microbiota