Penicillin-clavulanate susceptibility in clinical methicillin-resistant Staphylococcus aureus bloodstream infection strains from the CAMERA2 trial

The study examined the prevalence of penicillin-clavulanate susceptibility in 117 clinical methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection strains. Results showed that 62% of strains were susceptible to penicillin-clavulanate and 62% to oxacillin. Susceptibility to oxacillin and penicillin-clavulanate were highly correlated with sensitivity of 97.3% and specificity of 95.5%. Genome analysis revealed 8 alleles of the mecA gene. Penicillin-clavulanate susceptibility was strongly associated with community-associated MRSA sequence types (odds ratio 72.8), community acquisition of infection, and lower comorbidity and disease severity scores. Infections caused by susceptible strains occurred predominantly in younger patients with fewer comorbidities and milder clinical presentations.