Methicillin-resistant staphylococcus aureus breast abscesses: Risk factors and outcomes from a tertiary care center of a lower-middle-income country

Document Type

Article

Department

Surgery; Pathology and Laboratory Medicine

Abstract

Background and objectives: Breast abscesses are a common complication of mastitis, traditionally caused by methicillin-sensitive Staphylococcus aureus (MSSA). Recent global reports, however, indicate a rising prevalence of methicillin-resistant Staphylococcus aureus (MRSA), with limited data from South Asia. The objective of this study was to determine the prevalence, risk factors, antibiotic susceptibility patterns, management strategies, and clinical outcomes of MRSA breast abscesses at a tertiary-care center in Pakistan.
Methodology: A retrospective cross-sectional study was conducted at Aga Khan University Hospital, Karachi, from January 2010 to December 2024. All culture-positive breast abscesses with S. aureus growth were included. Patient demographics, clinical features, microbiological data, management, and outcomes were analyzed using descriptive statistics.
Results: Of 366 culture-positive breast abscesses, 326 (89.0%) yielded S. aureus, of which 274 (74.8% out of total) were MRSA, representing 74.5% of all isolates. A marked temporal shift was observed: MSSA remained relatively common from 2010-2019, but only 14 MSSA cases occurred from 2020-2024, with MRSA becoming the dominant pathogen. The mean age of MRSA patients was 29.4 ± 7.1 years; 88.7% were lactational. Key risk factors included prior antibiotic exposure (63.0%), recent hospitalization (55.9%), diabetes (18.6%), and history of previous abscess (14.4%). All MRSA isolates were vancomycin-susceptible; resistance rates were low for clindamycin (11.7%) and trimethoprim-sulfamethoxazole (9.8%). Initial ultrasound-guided aspiration was performed in 60.2%, with 20.6% requiring subsequent incision and drainage. Empirical clindamycin was used in 53.6%. Complete resolution was achieved in all patients with documented follow-up, with a recurrence rate of 3.3%. Among lactational cases, 91.4% successfully resumed breastfeeding.
Conclusion: This study reports one of the highest documented MRSA prevalence rates (74.5%) in breast abscesses worldwide, with a clear post-2020 dominance. Despite high MRSA burden, excellent outcomes were achieved with ultrasound-guided drainage and susceptibility-guided antibiotics. In high-prevalence settings, empirical therapy must cover MRSA, and routine culture with sensitivity testing is strongly recommended. Ultrasound-guided aspiration should remain first-line management, and continued breastfeeding is safe and encouraged after treatment.

Publication (Name of Journal)

Pakistan Journal of Medical Sciences

DOI

10.12669/pjms.42.(11AASC).15658

Link to Full Text

Share

COinS