Internal obturator muscle abscess caused by Klebsiella pneumoniae.

Obturator internus muscle abscess is an infrequent form of pyomyositis. To date, this disease has been described almost exclusively in children and young adults, and in most cases the causative agents are Gram-positive bacteria. We present the first report of obturator internus muscle abscess caused by a highly antibiotic resistant Klebsiella pneumoniae, in an elderly diabetic patient. Once considered very rare, Gram-negative pyomyositis is increasingly reported, and is an important concern in diabetic patients. Since pyomyositis can easily be missed if not considered, physicians should become familiar with this condition, and consider it in the differential diagnosis of septic diabetic patients.