Extensive Subcutaneous Abscess due to Panton-Valentine Leucocidin-Positive Community-Associated Methicillin-Resistant Staphylococcus aureus in an Infant.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections have increased worldwide in people without underlying diseases. CA-MRSA can often cause serious bacterial infections, especially skin and soft tissue infections (SSTI). Here, we describe a case of severe subcutaneous abscess due to Panton-Valentine leucocidin (PVL)-positive CA-MRSA in an infant without underlying diseases. A 4-month-old girl presented with a 4-day history of fever, with extensive redness and swelling of the lumbar region and buttocks. She was diagnosed with extensive subcutaneous abscess of the lumbar region and buttocks. Surgical drainage was performed, and a substantial volume of pus was drained. MRSA was detected in the pus on culture. Antibiotic therapy that covered MRSA was also administered for 3 weeks, and the abscess healed. As it was a severe SSTI due to MRSA, analysis of MRSA revealed PVL-positive MRSA. This patient had no underlying disease or history of antibiotic administration, and as MRSA was present in the nasopharyngeal cavity, it was considered a case of CA-MRSA. Furthermore, the prevalence of PVL-positive CA-MRSA in MRSA isolated from patients with SSTI has also increased in Japan. The Infectious Diseases Society of America recommends surgical intervention and empirical antibiotic therapy for MRSA-complicated SSTI cases in an era of CA-MRSA. Pediatricians must strongly consider the possibility of MRSA in children with severe SSTIs.