A case of Panton–Valentine leucocidin toxin-positive staphylococcus aureus-mediated neonatal mastitis

Introduction: Neonatal mastitis is an inflammatory condition of the breast frequently associated with Staphylococcus aureus. While Panton–Valentine leucocidin (PVL), a B-pore-forming cytotoxin, is commonly associated with enhanced virulence in community-acquired methicillinresistant S. aureus isolates, this is the first report to our knowledge of neonatal mastitis caused by PVL-positive S. aureus. Case presentation: A 20-day-old full-term female neonate presented with bilateral mastitis, complicated by bilateral abscess formation. PVL toxin-positive S. aureus was cultured from aspirates of both breasts. All family members, none of whom presented with symptoms of infection, and, specifically, maternal vaginal samples proved negative for PVL-positive S. aureus. Successful resolution involved surgical drainage and clindamycin therapy. Conclusion: While PVL toxin-positive S. aureus has previously been implicated in bovine and ovine mastitis, there may now be a need for vigilance with respect to human incidence. Due to PVL-mediated tissue necrosis, breast abscess formation and poor response to conventional antimicrobial therapy should, perhaps, be a cause for suspicion of PVL-bearing S. aureus and expediting of appropriate therapy to avoid potential for long-term consequences such as abnormal breast development.