Feline pyothorax caused by a Borrelia-like organism and Corynebacterium pyogenes.

A 2-year-old, neutered, male cat was euthanatized because of difficult repiration and inability to rise. Necropsy revealed pyothorax. Corynebacterium pyogenes was grown from the purulent thoracic exudate. A Borrelia-like microorganism was demonstrated in the exudate, using phase-contrast microscopy.