Cutaneous nocardiosis in a cat

A 4-year-old spayed female domestic shorthair cat was presented to us for swelling of all foot pads. The skin lesions were histopathologically diagnosed as suppurative pyogranulomatous panniculitis. The lesions did not respond to cephalexin, prednisolone or itraconazole. However, complete resolution of the skin lesions was obtained with doxycycline. A littermate living in the same household developed similar skin lesions that were also successfully treated with doxycycline. Polymerase chain reaction analysis detected the 16S ribosomal RNA gene of Nocardia spp. in DNA extracted from lesion pus, and direct nucleotide sequencing analysis revealed 100% homology with Nocardia elegans. We diagnosed this case as nocardiosis.