The challenges of diagnosis and treatment of the rare Prevotella induced breast abscess: A retrospective cohort study

Objective: Although the genus Prevotella is part of the general human flora, species of this anaerobic gramnegative bacteria have been described as cause of persisting nonpuerperal breast abscesses. Collecting punctate samples and testing these samples for anaerobic bacteria, is not part of the common diagnostic workflow in atypical breast abscesses. The causative anaerobic micro-organism can remain unclear and patients can be treated with multiple inadequate antibiotics and/or extensive surgical procedures. The aim of this cohort study of Prevotella induced breast abscesses is to gain more insights into the diagnostic procedures and treatment. Methods: Medical charts of patients with a Prevotella induced breast abscess between 2015 and 2021, were retrospectively reviewed on patient characteristics, diagnostic procedures, treatment and outcome. Results: Twenty-one patients were included. Six subspecies of Prevotella were determined by culturing. High susceptibility was observed for amoxicillin/clavulanic acid (100%, n = 12). Nine patients (43%) were treated with antibiotics, eight patients (38%) with antibiotics and incision and drainage, and four patients (19%) with only incision and drainage. Recurrence was observed in nine patients (43%), of whom five patients were treated with antibiotics and three patients had surgery. The mean duration of antibiotic administration in patients with recurrence was significantly shorter compared to those without recurrence (5.6 days vs. 19.5 days, p = 0.039). Conclusion: Specific anaerobic culturing should be common practice in atypical breast abscesses to confirm Prevotella species. The high recurrence rate emphasizes the need of further research for optimal treatment. Prolonged duration of antibiotics could be considered and amoxicillin/clavulanic acid seems to be the first choice.