Penicillin-Resistant Bacteroides melaninogenicus

Abstract

<h3>To the Editor.—</h3> The choice of antimicrobial therapy for anaerobic lung infections remains controversial. These infections usually result from penicillin-sensitive oral flora. However, isolates of penicillin-resistant<i>Bacteroides fragilis</i>and<i>Bacteroides melaninogenicus</i>from such cases have been reported.¹Despite these resistant organisms, several reports have indicated that such infections may respond as well to penicillin as to clindamycin or other antimicrobial drugs directed against the penicillin-resistant species.² We recently treated a cavitating anaerobic pneumonia that did not respond to penicillin or to ampicillin in one of our patients. Clinical response occurred only after administration of clindamycin phosphate was begun. <h3>Report of a Case.—</h3> A 68-year-old diabetic man had development of rigors, fever, and a productive cough. After seven days of illness, a chest roentgenogram disclosed a right lower lobe pneumonia. After hospitalization, intravenous (IV) administration of penicillin G sodium, 600,000 units every six hours for four days, followed by