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Ocular Capnocytophaga infection in an edentulous, immunocompetent host
L D Ormerod1, C S Foster, B G Paton
1Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114.
Abstract:
Severe microbial keratitis developed in a 74-year-old women receiving long-term corticosteroids. Corneal smears revealed slender, fusiform gram-negative bacilli, but the lesion continued to worsen despite intensive antibiotic treatment. After several days, Capnocytophaga sputigena was identified on culture. Specific antimicrobial therapy was instituted, supplemented with corneal cryotherapy. There was gradual clinical improvement. However, a sterile corneal melt led to the late loss of the eye. Although Capnocytophaga are gingival organisms and usually implicated as opportunists in severely ill, neutropenic patients with oral ulcerations, our patient was edentulous and without systemic immunosuppression. An increased awareness of Capnocytophaga is justified because of their widespread antibiotic resistance, capnophilic cultural requirements, and unusual microscopic and cultural morphology.
Insights
A severe eye infection caused by Capnocytophaga sputigena, a rare bacterial pathogen, occurred in an elderly woman on corticosteroids. Despite treatment, the infection led to the loss of her eye, highlighting the need for awareness of this resistant organism.
Area of Science:
- Ophthalmology
- Microbiology
Background:
- Corticosteroid use can predispose individuals to severe microbial keratitis.
- Capnocytophaga species are typically found in the gingival flora and act as opportunistic pathogens.
Observation:
- A 74-year-old woman on long-term corticosteroids developed severe microbial keratitis.
- Initial corneal smears showed gram-negative bacilli, but the infection worsened despite antibiotics.
- Capnocytophaga sputigena was identified on culture, prompting specific antimicrobial therapy and cryotherapy.
Findings:
- The patient experienced gradual clinical improvement after targeted therapy.
- A sterile corneal melt ultimately resulted in the loss of the eye.
- The patient was edentulous and not systemically immunosuppressed, an atypical presentation for Capnocytophaga infection.
Implications:
- Capnocytophaga sputigena can cause severe keratitis even in non-neutropenic patients without oral ulcerations.
- The widespread antibiotic resistance and unique cultural needs of Capnocytophaga warrant increased clinical awareness.
- This case underscores the importance of considering unusual pathogens in refractory microbial keratitis.