Eikenella infections
Eikenella infections are caused by the bacterium Eikenella corrodens, a gram-negative rod that is part of the normal flora found in the mouth, upper respiratory tract, and urogenital tract. E. corrodens is considered an opportunistic pathogen and can lead to various infections, including periodontal disease, pneumonia, cellulitis, and endocarditis. The infection risk is heightened by poor oral hygiene, which can lead to dental plaque buildup and subsequent gum damage, as well as by factors like a compromised immune system, underlying health conditions, and intravenous drug use.
Symptoms of Eikenella infections can vary based on the infection site but may include fever and malaise. Diagnosis typically involves isolating the organism from the infected area, particularly in patients with a history of dental work or human bites. Treatment often requires surgical intervention for abscesses and may involve antibiotics like ampicillin/sulbactam or amoxicillin/clavulanate, especially due to the emergence of resistant strains. Preventative measures include maintaining good dental hygiene and managing underlying health conditions. Understanding these aspects can be crucial for recognizing and addressing Eikenella infections effectively.
Eikenella infections
- ANATOMY OR SYSTEM AFFECTED: Genitalia, lungs, mouth, respiratory system, teeth
Definition
Eikenella infection is caused by E. corrodens, a facultative, anaerobic, gram-negative rod that is part of the normal flora of the oral cavity, upper respiratory tract, and urogenital tract. This bacterium is an opportunistic pathogen. E. corrodens has been implicated in many types of infections, including juvenile periodontal disease, head and neck infections, pneumonia, intra-abdominal infections, cellulitis, and endocarditis.
Causes
Poor oral hygiene will allow E. corrodens to build up in plaque and damage the surrounding gum tissue, leading to gingivitis or abscesses (or both). A weakened immune system may allow infections to spread to the middle ear and sinuses and then reach into the spinal fluid and cause meningitis. Dental extractions provide access to the bloodstream by E. corrodens, which can then infect damaged heart valves. Saliva from a human bite transfers this organism into the wound, where an infection may develop and lead to cellulitis. Virulence factors target macrophage activity and allow the organism to attach to epithelial cells. The cell wall of E. corrodens also has endotoxin activity.
Risk Factors
The following factors increase the chance of developing an Eikenella infection: poor oral hygiene; the presence of an underlying disease such as diabetes, rheumatoid arthritis, leukemia, and lung cancer; a compromised immune system; intravenous drug use; and preexisting heart valve damage.
Symptoms
Symptoms are not specific and depend on the site of infection. Infected persons may have a fever and a heart murmur and feel malaise.
Screening and Diagnosis
A doctor will suspect Eikenella infection if the patient has a history of recent dental work, has had a recent urologic procedure, has a history of intravenous drug abuse, or has wounds caused by a human bite. Diagnosis is made by isolating the organism from the infected site. E. corrodens is a fastidious organism (and a member of the slow-growing HACEK bacterial group) that requires agar for growth, supplemented with hemin and an atmosphere of 5 to 10 percent carbon dioxide. Colonies have a characteristic bleachlike odor, and most strains pit the agar.
Treatment and Therapy
Surgical drainage is required if an abscess is present. In severe hand infections, debridement may be needed. Because of the emergence of beta-lactamase-producing strains of E. corrodens, the antibiotics recommended for treatment of most infections are ampicillin/sulbactam or amoxicillin/clavulanate, unless susceptibility testing is performed. For treatment of endocarditis, effective drugs are ceftriaxone, cefotaxime, and cefepime.
Prevention and Outcomes
To help prevent Eikenella infections, one should practice good dental hygiene, have routine dental checkups, take prophylactic antibiotics before dental work (patients with underlying diseases), and properly identify and treat underlying diseases.
Bibliography
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Garrity, G. M. Bergy’s Manual of Systematic Bacteriology. 2d ed. New York: Springer, 2005.
Langlais, Robert P., and Craig S. Miller. Color Atlas of Common Oral Diseases. 4th ed. Philadelphia: Lippincott Williams & Wilkins, 2009.
Liang ZC, Ouyang H, Song XJ, Liang JX, Zheng WH, Chen JJ, Yin ZG, Chen SY. Eikenella corrodens isolated from pleural effusion: A case report. World J Clin Cases 2024; 12(18): 3596-3602 [PMID: 38983430 DOI: 10.12998/wjcc.v12.i18.3596]. Accessed 3 Feb. 2025.
Preus, Hans R., and Lars Laurell. Periodontal Diseases: A Manual of Diagnosis, Treatment, and Maintenance. Chicago: Quintessence, 2003.
Winn, W. C., et al. Koneman’s Color Atlas and Textbook of Diagnostic Microbiology. 6th ed. Baltimore: Lippincott Williams & Wilkins, 2006.