Infecção multissistêmica por Rhodococcus equi em um caprino: relato de caso

Abstract

Isdescribed a case of multisystemic infection by Rhodococcus equi in a goat in thestateof Bahia, northeastern Brazil. The animal had paralysis of the hind limbs, apathy, pale mucous membranes, persistent sternal decubitus and hypersensitivity to the palpation of the dorso-lumbar region. Therapeutic protocols based on antimicrobials and corticosteroids were administered, unsuccessfully, after two weeks the animal died. At necropsy, there was moderate hepatomegaly, and in the parenchyma multiple firm nodules, with abscessing to granulomatous aspect, multifocal to coalescing. Similar nodules were observed in the spleen and mesenteric lymph nodes, in addition to other lesions to the femoral head, and lumbar vertebrae (L3-L5). Microscopically, there were multiple granulomas/piogranulomas characterized by central areas of necrosis, containing cellular debris, some neutrophils, and marked infiltration of adjacent macrophages, limited by fibrous tissue. In the macrophage cytoplasm there was structures with granular aspect, morphologically consistent with basophilic coccobacilli. The diagnosis was made by histological characteristics and confirmed by positive marking in the immunohistochemistry technique, using a polyclonal primary antibody produced from the ATCC of Rhodococcus equi in rabbits. In the Northeast, infection by R. equi should be included in the differential diagnoses of multisystemic granulomatous and piogranulomatous diseases affecting goats, especially caseous lymphadenitis and tuberculosis.