# A Single-Center Retrospective Study on the Bacteriological Profile of Breast Abscesses

## TL;DR

This study identifies common bacteria causing breast abscesses and highlights antibiotic resistance patterns to guide effective treatment.

## Contribution

The study provides updated insights into the microbiological profile and antibiotic resistance of breast abscesses in a clinical setting.

## Key findings

- Staphylococcus aureus was the most common pathogen, with 15% being methicillin-resistant.
- Polymicrobial infections were found in 8.33% of cases, involving both aerobic and anaerobic organisms.
- High antibiotic resistance was observed in Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis.

## Abstract

Introduction: Breast abscesses are a common clinical condition, primarily affecting lactating women as a result of mastitis. It can also occur in non-lactating women due to a variety of factors such as diabetes, immunosuppression, and trauma. The microbiological etiology of breast abscesses is important for determining effective antibiotic therapy and preventing complications. This study aims to identify the microbiological profile of breast abscesses, characterize the common pathogens, and analyze their antibiotic resistance patterns.

Methods: A retrospective analysis was conducted on 108 patients diagnosed with breast abscesses between June 2023 and January 2025. Hospital records were retrieved and reviewed. Demographic data, microbiological findings and antibiotic treatment outcomes were extracted. The primary objective was to identify the main pathogens causing breast abscess. The secondary objective was to understand the antibiotic resistance patterns and the prevalence of coagulase-negative staphylococci (CoNS) in breast abscesses. Microbiological cultures were obtained from abscess aspirates or purulent drainage material. The bacterial isolates were identified using standard microbiological techniques. Antibiotic susceptibility testing was performed using the disk diffusion method.

Results: The mean age of participants in the study was 26±2 years. Of the 108 women, approximately 84% had lactational breast abscesses, and the remaining 16% had non-lactational breast abscesses. The most frequently isolated microorganism was Staphylococcus aureus (41.67%), with 15% of isolates being methicillin-resistant (MRSA). Other common pathogens included Streptococcus pyogenes (13.89%), Escherichia coli (9.26%), and Enterococcus faecalis (7.41%). Polymicrobial infections, including both aerobic and anaerobic organisms, were identified in 8.33% of cases. Antibiotic resistance was notably high for Staphylococcus aureus, Escherichia coli (10% extended-spectrum beta-lactamase (ESBL)-producing), and Enterococcus faecalis (5% vancomycin-resistant). Five patients (4.63%) had no microbial growth. The majority of patients were treated with empirical antibiotics, and therapy was adjusted based on culture results, with good clinical outcomes in most cases.

Conclusion: The microbiological profile of breast abscesses is diverse, with Staphylococcus aureus being the predominant pathogen, followed by Streptococcus pyogenes and Escherichia coli. Antibiotic resistance, particularly in MRSA, poses a significant challenge in treatment. Empiric antibiotic therapy should be tailored according to local resistance patterns to ensure effective treatment and reduce the risk of complications.