Anaerobic breast abscess caused by Prevotella bivia in non-lactating woman: A case report with diagnostic and clinical implications

Background and Clinical Significance: Prevotella bivia is an anaerobic Gram-negative bacillus commonly associated with pelvic and genital tract infections. Its isolation from breast abscesses, particularly in nonpuerperal women, is extremely uncommon. Case presentation: We report a unique case of a 40-year-old non- lactating woman presenting with a recurrent right breast abscess. The pa- tient experienced three episodes over three years (2022–2025); only the fourth episode was microbiologically confirmed as being caused by P. bivia, identi- fied using MALDI-TOF MS. Antimicrobial susceptibility testing revealed resistance to ampicillin and susceptibility to amoxicillin/clavulanic acid and other agents. Conclusion: The case underlines the critical role of anaerobic cultures and advanced identification techniques in recurrent breast infections. Although microbiological confirmation was achieved only in the latest episode, the recurrent clinical picture suggests a difficult-to-culture microbial aetiology.