Lung abscess caused by Eikenella corrodens: report of a case.

Eikenella corrodens is a slow-growing, facultatively anaerobic, gram-negative bacillus. It is part of the normal flora of the human upper respiratory tract. We report a 68-year-old man who developed lung abscesses caused by E. corrodens while on long-term corticosteroid therapy for polymyositis. It was isolated by percutaneous transthoracic aspiration of an abscess under real-time sonographic guidance. The organism has a very unusual antimicrobial susceptibility: sensitive to penicillin, ampicillin, cephapirin, chloramphenicol, minocycline and erythromycin but resistant to clindamycin, oxacillin and gentamicin. The patient was treated empirically with penicillin G and gentamicin. The latter was discontinued after the results of the bacterial culture and sensitivity test were available. He was discharged one month later with marked improvement. Our report clearly demonstrates that E. corrodens can be the sole pathogen of a respiratory tract infection.