Perineal Crohn's Disease Complicated by nic Liver Abscess During Metronidazole Therapy

Abstract

A patient with ileal and perineal Crohn's disease developed a pyogenic liver abscess caused by Streptococcus milleri. The perineal process had been treated with high-dose metronidazole for the preceding 6 mo, and culture of a perianal abscess 2 mo before admission revealed heavy growth of Streptococcus milleri (which was misidentified as an anaerobic Peptostreptococcus). This case illustrates the difficulty in correctly identifying Streptococcus milleri, the most frequent isolate from pyogenic liver abscesses. Furthermore, the events suggest that metronidazole therapy can allow overgrowth of this organism in perineal abscesses which, in turn, may predispose to the development of purulent foci such as liver abscesses. This effect on the bacterial ecology of the perineum should be considered when opting for metronidazole therapy of perineal Crohn's disease.