Human lymphadenitis due to Corynebacterium pseudotuberculosis: report of ten cases from Australia and review

Corynebacterium pseudotuberculosis commonly causes caseous lymphadenitis in Australian sheep. We describe 10 cases of human lymphadenitis due to C. pseudotuberculosis; in all cases, isolates were submitted to a reference laboratory in Victoria, Australia. Most of the patients were occupationally exposed to sheep. We also review the 12 previously published cases of this infection, most of which were reported from Australia. No patient had any underlying disease or predisposing condition. Surgical excision of the affected lymph glands is the mainstay of management, and antibiotic therapy is supplementary treatment. Diagnosis was delayed for some patients, and some patients had a protracted or recurrent clinical course and/or a slow recovery. These 10 additional cases from one Australian state indicate that human lymphadenitis caused by C. pseudotuberculosis has not been as rare as the number of published reports indicates, at least in Australia. However, the increasing use of a vaccine against caseous lymphadenitis in sheep in Australia should result in the decreasing human incidence of this zoonosis.