Infected breast cyst due to Prevotella buccae resistant to metronidazole.

Prevotella buccae is a Gram-negative anaerobic rod involved in some human infections. We report the first case of an infected breast cyst in a non-puerperal women due to this pathogen. A 53-year-old woman presented with pain and a cystic lesion in the right breast. Culture of abscess drainage resulted in isolation of P. buccae. High level of resistance to metronidazole was documented. Treatment with drainage and amoxicillin-clavulanate was established, and improvement of this infection was observed.