Emerging Insights into Corynebacterium Kroppenstedtii Complex Associated Breast Abscesses: A Retrospective Study

Corynebacterium kroppenstedtii complex (CKC), including C. kroppenstedtii, C. parakroppenstedtii, and C. pseudokroppenstedtii, has been implicated in breast abscesses and granulomatous mastitis, presenting diagnostic and therapeutic challenges. Its lipophilic nature and association with specific populations necessitate targeted investigations.

This retrospective study was conducted at Hamad Medical Corporation, Qatar, including all CKC isolates from breast tissue collected between October 2016 and March 2024. Data from electronic medical records were collected and anonymized. Microbiological analysis involved standard culture techniques, Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) for identification, and antibiotic susceptibility testing per Clinical and Laboratory Standards Institute (CLSI) standards. Statistical methods included descriptive analyses, Pearson's correlation, and relative risk calculations.

Among 34 isolates, 31 were from breast tissue of pre-menopausal women, predominantly obese or overweight, with a median age of 33 years. Breast abscesses were typically unilateral, associated with axillary lymphadenopathy, and varied in size and complexity. Recurrence within six months occurred in 58% of cases. Prolonged antimicrobial therapy and, in some cases, surgical intervention were necessary. Most isolates were sensitive to vancomycin, linezolid, and rifampicin, but resistance to penicillin and daptomycin was noted.

CKC is an emerging pathogen in breast abscesses, requiring precise diagnostic approaches and individualized treatment strategies. Advanced genomic tools are recommended for species differentiation and resistance monitoring. Ongoing research is essential to optimize management and address rising antimicrobial resistance.