Corynebacterium ulcerans diphtheria in France; a dog as the culprit
Abstract number: 10.1111/j.1198-743X.2004.902_o207.x
A 47-year-old woman with typical laryngeal diphtheria was admitted to Bicêtre hospital (France) for severe dyspnoea. Throat swab grown on Loeffler's medium and blood agar gave of a gram-positive catalase positive-rod identified as Corynebacterium ulcerans by positive urease reaction, API Coryne system and sequencing of 16 sRNA gene. Disk diffusion test showed that this isolate was susceptible to most antibiotics including beta-lactams and macrolides. A PCR test was positive for the gene of diphtheria-like toxin that is usually quite invariable in Corynebacterium diphteriae. Sequencing identified a gene that encoded a toxin that had twenty-five amino acid substitutions as compared with diphtheria toxin. The patient was treated with amoxicillin-clavulanic acid (before identification of C. ulcerans) for 5 days, then penicillin G adapted to renal function for nine days and one dose of diphtheria antitoxin (40 000 U). She recovered without complication. She was immunocompromised (prednisone 6 mg/day, tacrolimus 12 mg/day, and mycophenolate nofetil 1 g/day) as she had underwent kidney graft and a retrospective analysis did not evidence detectable diphtheria antibodies in her serum.
Carriers of C. ulcerans in the immediate vicinity of the patient (family, patients and health care workers, n = 88) using a novel selective medium settled for this purpose [Columbia colistin-nalidixic acid (CNA) agar plates with 5% sheep blood plus fosfomycin 125 mg/L] were not identified. However, the exact same C. ulcerans isolate was found from throat, nostrils and labial ulceration of the companion dog of this patient. This dog had chronic cutaneous ulcerations, sneezing and rhinorrhea for years. Failure of an amoxicillin-containing treatment (2 g/day for 15 days) for eliminating the bacteria from the dog lead to his killing.
Although the main natural reservoir of C. ulcerans is cattle and cattle environment, this is the first report that suggests transmission from a dog to human of a coryneform bacteria as a source of diphtheria. In addition it raises the growing question of pets as a reservoir of zoonotic infection in immunocompromised patients."
|Session name:||XXIst ISTH Congress|
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