IV: intravenous; GBS: group B Streptococcus; B. fragilis: Bacteroides fragilis; IgE: immunoglobulin E. * We suggest clindamycin plus gentamicin for initial therapy. Alternatives include ampicillin-sulbactam, cefotetan, cefoxitin, ceftizoxime, and piperacillin with or without tazobactam; these drugs, particularly ampicillin-sulbactam, are used as the initial antibiotic choice in some hospitals. However, the trials supporting use of these drugs have been small; thus, they may not have been able to determine statistically significant differences in efficacy. For those patients who are known to be colonized with GBS as a result of universal screening, addition of ampicillin (2 g IV every 6 hours) to a clindamycin plus gentamicin regimen or use of ampicillin-sulbactam (3 g IV every 6 hours) monotherapy is recommended for initial therapy. In geographic regions or institutions where B. fragilis has significant clindamycin resistance, ampicillin-sulbactam (3 g IV every 6 hours) is a reasonable alternative to clindamycin plus gentamicin. ¶ The rationale for adding ampicillin to the regimen is that 20% of treatment failures are due to resistant organisms, such as enterococci. Alternatively, the initial antibiotics can be discontinued, and ampicillin-sulbactam (3 g IV every 6 hours) can be initiated. Vancomycin can be used instead of ampicillin in penicillin-allergic patients with IgE-mediated, immediate allergic reactions, including anaphylaxis. If blood cultures were performed, antibiotic treatment decisions are based on drug sensitivity results for any organisms identified. Δ Refer to UpToDate content on evaluation and management of patients with persistent postpartum fever during treatment for postpartum endometritis for more detailed information.