Incidence of Community-associated Methicillin-resistant Staphylococcus aureus Infections in a Regional Hospital

Since the early 2000s, the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections among the community of people lacking known healthcare risk factors has increased. This MRSA infection is referred to as community-associated MRSA (CA-MRSA) infection and is distinct from hospital-associated MRSA (HA-MRSA) infection, which occurs among people with known healthcare risk factors. Understanding the epidemiology of CA-MRSA infections is critical; however, this has not been investigated in detail in Japan. Our objective was to investigate the incidence of CA-MRSA infections in a regional hospital.

We investigated CA-MRSA isolates and infections in a rural regional hospital by reviewing medical records of one year. Infections were classified as CA-MRSA if no established risk factors were identified.

During 2008, 31 Staphylococcus aureus (S. aureus) isolates were detected in 29 unique patients, with 1 methicillin-sensitive S. aureus (MSSA) isolates obtained from 19 patients (66%) and MRSA obtained from 10 patients (34%). In the 10 patients with MRSA, the number of HA-MRSA and CA-MRSA cases were nine (32% of patients with S. aureus isolates) and one (3%), respectively. The patient with CA-MRSA was diagnosed with cellulitis due to CA-MRSA. All nine patients with HA-MRSA exhibited colonization.

We observed a CA-MRSA case in a regional hospital in Japan, suggesting that incidence trends of CA-MRSA should be considered in future research and treatment.