Acute peritonsillar abscess caused by Arcanobacterium haemolyticum.

A patient is reported with a peritonsillar abscess yielding Arcanobacterium haemolyticum. This appears to be only the fifth such case described in the medical literature and the first from Europe. The organism has been reported as an occasional cause of tonsillopharyngitis with rash, resembling infection with Streptococcus pyogenes but often unresponsive to penicillin therapy. A. haemolyticum easily passes unrecognized in bacteriological cultures as a result of its slow growth, coryneform appearance in the Gram's stain and weak haemolytic activity on conventional laboratory media.