Bacteriology of non-oncologic post-operative breast infections: A retrospective cross-sectional study to guide empiric antibiotic coverage.

[BACKGROUND] Antibiotic prophylaxis for non-oncologic breast surgeries is not well described by procedure type. This study identified the underlying microbiological etiologies and antibiotic sensitivities of culture-positive infections from non-oncologic breast surgeries that were performed at a major medical center to guide specific empiric antibiotic coverage.

[METHODS] A retrospective cohort study was conducted at a tertiary hospital from November 2018 to January 2024. Patients aged ≥18 years who underwent non-oncologic breast surgery with culture-confirmed infections were included. Procedures analyzed included mastopexy, augmentation, reduction, gender-affirming surgery, and prophylactic mastectomies with and without reconstruction. Organism profiles from the procedures with >1 culture-positive infection were compared with their antibiogram to guide empiric treatment.

[RESULTS] Among the 3457 non-oncologic breast procedures, 37 resulted in culture-positive infections (1.07%). Infected patients were older (mean age 44 vs 37 years, p<0.05), but no significant differences in sex, body mass index, tobacco use, or comorbidities were noted. Infection rates were similar between prosthetic (1.04%) and non-prosthetic (1.08%) procedures (p=0.94) but were significantly higher in the risk-reducing mastectomy cohort (3.65% vs 0.92%, p<0.01). Organism profiles varied with the procedure. Organisms isolated from all procedures were sensitive to vancomycin. Empiric treatment recommendations included vancomycin plus ciprofloxacin, piperacillin-tazobactam, levofloxacin, or ceftazidime depending on the procedure type.

[CONCLUSIONS] Microbial etiologies of surgical site infections following non-oncologic breast surgery differed with the procedure. Procedure-specific empiric antibiotic regimens may improve infection management. Institutional and regional antibiotic susceptibility should be investigated to inform clinical guidelines on antibiotic use.