Suppurative Adenitis of Preputial Glands Associated with Corynebacterium mastitidis Infection in Mice

Suppuration of the preputial gland in mice occurs as a septic complication of fight wounds around the external genitalia. Currently reported bacterial isolates from these lesions are limited to Staphylococcus aureus, Pasteurella pneumotropica, and Klebsiella oxytoca. In the context of a pilot experiment aimed at defining the aging phenotype of estrogen receptor beta knockout (BERKO) mice, 2 male mice (1 of the BERKO line and the other from the age- and sex-matched wild-type control group) were discovered at necropsy to have preputial gland lesions. In both cases, histopathologic examination confirmed severe suppuration and abscesses of the preputial glands associated with systemic reactive (secondary) amyloidosis. Both Gram staining and Bacillus Calmette-Guérin immunohistochemistry highlighted the presence of numerous bacillary to rod-shaped bacteria within the preputial lesions. Subsequent PCR analysis coupled with denaturing gradient gel electrophoresis identified Corynebacterium mastitidis in the preputial gland abscesses. This organism is isolated infrequently from the milk of sheep with subclinical mastitis and was identified as part of the normal microflora of the human ocular surface. No information regarding the epidemiology and pathogenesis of C. mastitidis infection in laboratory animals is currently available, and to our knowledge this report is the first description of C. mastitidis infection in mice.