Clinical Characteristics, Risk Factors and Outcomes of MRSA Pneumonia with Secondary MRSA Bloodstream Infection

Abstract BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) pneumonia (MP) and MRSA bloodstream infections (MRSA-BSI) are relatively often described, but MP with secondary MRSA-BSI (termed as MP-BSI) is few reported. Herein, we attempted to investigate the clinical features, risk factors and outcomes of MP-BSI in comparison with MP alone.MethodsClinical data from patients with MP was retrospectively collected. The cases were divided into groups of MP alone and MP-BSI. Determination of independent risk factors for MP-BSI relied on binomial logistic regression analysis. In addition, the outcomes were also compared.ResultsA total of 435 patients with MP were recruited, 18.9% (82/435) of whom was MP-BSI. The median age was 62 (interquartile range,51,72) years, and 74.5% were male. Multivariate analysis revealed that high SOFA score, immunosuppression, community-acquired MRSA pneumonia (CA-MP), time from initial to targeted antibiotics, accelerated respiratory rate, elevated γ-GT (all p<0.05) were independent risk factors for MP-BSI, while targeted treatment with linezolid was a protective factor. The median length of hospitalization, 28-day mortality, and in-hospital mortality among total patients were 26 days, 13.6%, and 17.0%, respectively. Patients with MP-BSI had longer length of hospitalization, higher 28-day mortality and in-hospital mortality (all p<0.05).ConclusionsSecondary MRSA-BSI among MRSA pneumonia is not uncommon. High SOFA score, immunosuppression, CA-MP, time from initial to targeted antibiotics, accelerated respiratory rate and elevated γ-GT are independent risk factors for MP with secondary MRSA-BSI; importantly, linezolid as targeted antibiotic is a protective factor. In addition, patients with MP have worse clinical outcomes when they are developed with MRSA-BSI.