Eikenella

Eikenella is a genus of Gram-negative bacteria within the family Neisseriaceae. The most notable species within this genus is Eikenella corrodens, which is known for its role in human infections, particularly in the context of human bite wounds and periodontal disease.

Characteristics

Eikenella species are small, non-motile, facultatively anaerobic, and rod-shaped bacteria. They are characterized by their ability to corrode or pit the agar on which they are grown, a feature that is particularly notable for Eikenella corrodens. These bacteria are oxidase-positive and catalase-negative, and they do not ferment carbohydrates.

Habitat

Eikenella corrodens is a commensal organism found in the oral cavity, gastrointestinal tract, and genitourinary tract of humans. It is part of the normal microbiota but can become pathogenic under certain conditions.

Pathogenicity

Eikenella corrodens is an opportunistic pathogen. It is commonly associated with infections following human bites, fist fights, and needle licks. It can also be involved in periodontal infections, endocarditis, osteomyelitis, and respiratory tract infections.

Infections

• Human Bite Wounds: Eikenella corrodens is frequently isolated from infections resulting from human bites. These infections can lead to cellulitis, abscess formation, and in severe cases, systemic infection.
• Periodontal Disease: As part of the oral microbiota, Eikenella corrodens can contribute to periodontal disease, particularly in cases of periodontitis.
• Endocarditis: Although rare, Eikenella corrodens can cause infective endocarditis, especially in individuals with pre-existing heart conditions.
• Osteomyelitis: This bacterium can be involved in bone infections, particularly following trauma or surgery.

Diagnosis

Diagnosis of Eikenella corrodens infections is typically made through culture of the organism from clinical specimens. The characteristic pitting of agar and the production of a bleach-like odor are indicative of Eikenella corrodens. Molecular methods, such as PCR, can also be used for identification.

Treatment

Eikenella corrodens is generally susceptible to a range of antibiotics, including penicillins, cephalosporins, and tetracyclines. However, it is resistant to clindamycin and metronidazole. Treatment typically involves the use of appropriate antibiotics based on susceptibility testing, along with surgical intervention if necessary to drain abscesses or debride infected tissue.

Prevention

Preventive measures include proper wound care and hygiene, especially in cases of human bites. Prompt medical attention and prophylactic antibiotics may be warranted in high-risk situations.

Research

Ongoing research is focused on understanding the pathogenic mechanisms of Eikenella corrodens and its role in polymicrobial infections. Studies are also exploring the development of vaccines and novel therapeutic approaches to manage infections caused by this organism.

See also

• Gram-negative bacteria
• Opportunistic infection
• Oral microbiota