Antimicrobial therapy of postpartum endomyometritis

Seventy patients with postpartum endomyometritis were treated with either intravenous mezlocillin (16 gm/day) or ampicillin (8 gm/day) in a prospective, randomized, double-blind comparison. Endocervical dilatation was routinely performed. Clindamycin (2 gm/day) was added if patients failed to improve within 48 hours of beginning therapy. Pretreatment clinical and microbiologic profiles were comparable in the two groups. Bacteremia was documented in 21 patients (30%). Anaerobic cocci and Bacteroides spp. (non- B. fragilis ) comprised 19 of 29 (65%) blood isolates. Thirty of 33 mezlocillin-treated patients (91%) and 30 of 37 ampicillin-treated patients (81%) responded to initial therapy (P>0.4). Resolution was need after the addition of clindamycin in all ten nonresponders; two of these patients also required surgical wound debridement. Objective parameters of clinical response were not significantly different in the two treatment groups. Side effects of mezlocillin therapy were minimal. We conclude that mezlocillin and ampicillin are equally effective and sate for therapy of postpartum endomyometritis. That mezlocillin was not superior to ampicillin, despite expanded activity against B. fragilis end members of Enterobacteriaceae , suggests that these pathogens are less important than was previously considered in postpartum endomyometritis.