Clinical and Microbiological Characteristics of Hospital-Acquired Methicillin-Resistant Bacteremia Caused by a Community-Associated PVL-Negative Strain.

Background: ST72-SCCIV, a community-associated methicillin-resistant (CA-MRSA) strain in Korea, originated in the community and has been spreading in health care settings. Herein, we describe the clinical and microbiological characteristics of patients with hospital-acquired MRSA bacteremia (MRSAB) caused by community-associated strains.

Methods: We analyzed hospital-acquired MRSAB cases caused by ST72-SCCIV using a prospective cohort of patients with SAB in a tertiary hospital in Korea from July 2008 to December 2018. We compared the clinical and microbiological characteristics of ST72-SCCIV with ST5-SCCII, a representative hospital-associated genotype strain.

Results: Of the 1782 bacteremia (SAB) cases, 628 (35.2%) were hospital-acquired MRSAB. Of the 628 isolates, 431 (68.6%) were ST5-SCCII and 152 (24.2%) were ST72-SCCIV. Patients with ST72-SCCIV were younger than those with ST5-SCCII and less likely to have a history of recent surgery, antibiotic treatment, nasal MRSA colonization, and central venous catheter placement. Compared with ST5-SCCII, ST72-SCCIV isolates were more likely to have vancomycin MICs ≤1.0 mg/L ( < .001). Osteoarticular infection as the site of infection (7.2% [11/152] vs 1.4% [6/431]) was more common in patients with ST72-SCCIV. There were no significant differences in the rate of recurrence (≤90 days), persistent bacteremia (≥7 days), or 30- and 90-day mortality rates between the 2 groups.

Conclusions: Osteoarticular infections were more prevalent in ST72-SCCIV MRSAB. Mortality rates between the ST72-SCCIV and ST5-SCCII groups were not significantly different.