Outcomes associated with secondary Staphylococcus aureus infection in COVID-19 patients

ABSTRACT

Introduction: Among COVID-19 patients, bacterial infections are associated with significant morbidity and mortality. Staphylococcus aureus is the principal pathogen causing bacterial infections in COVID-19 patients. Typically, clinical outcomes between methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) infections have demonstrated worse outcomes with MRSA. Outcomes of MRSA vs. MSSA remain limited in COVID-19 patients. Research Question or Hypothesis: We sought to evaluate clinical outcomes among COVID-19 patients with MRSA vs. MSSA infections. Study Design: Observational, retrospective cohort Methods: Hospitalized adults with confirmed COVID-19 and secondary S. aureus infections were evaluated from January 2020 to July 2022. Secondary infection was defined as a positive culture 48-hours after COVID-19 diagnosis. Cohorts were stratified by S. aureus susceptibility and pandemic year. Primary outcome was in-hospital allcause mortality. Secondary outcomes included 30-day mortality, allcause intensive care unit (ICU) mortality, and 60-day hospital readmission. Result(s) A total of 108 adults met the study criteria, 33 (30.5%) MRSA and 75 (69.4%) MSSA patients. At baseline, 84 (78%) patients were in the ICU with a mean APACHE-II score of 34.21+/-19.53. Six patients (5.6%) received at least 1 dose of mRNA vaccine. Primary sources of infection included respiratory (68%) and blood (25%), with no differences between cohorts. There was no statistical difference in inhospital all-cause mortality (51.5% vs. 62.7%, p=0.37), 30-day mortality (60.6% vs. 66.7%, p=0.61), all-cause ICU mortality (51.5% vs. 62.7%, p=0.37) and 60-day readmission (6.1% vs. 6.7%, p=0.92) between MRSA and MSSA, respectively. Mortality remained high when stratified by pandemic year 56.2% (2020), 68.2% (2021), and 46.2% (2022);p=0.619. Conclusion(s) Unlike patients without COVID-19, no significant differences in MRSA and MSSA outcomes were found. Mortality remained high in patients with secondary S. aureus infections throughout the study period. Further investigations are warranted to determine if COVID-19 patients respond differently than non-COVID-19 patients regarding the type of S. aureus secondary infection.