Clinical and microbiological characteristics of MRSA pneumonia in ICU patients and therapeutic effect of linezolid

The clinical and microbiological features of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia among intensive care unit (ICU) patients were assessed in this study, as well as the relationship between linezolid treatment and outcomes. Of 282 ICU patients (January 2019-March 2024), 176 survived and 106 passed away. Independent predictors of death were age >60 years, tracheal intubation, central venous catheterization, ?3 comorbidities and elevated procalcitonin (PCT). Seventy-two sputum representative MRSA isolates were analyzed for resistance determinants (mecA, SCCmec) and prevalent virulence genes (sea, hla,tsst-1,icaA,pvl). Linezolid therapy was associated with improved survival, reduced PCT levels and reduced prevalence of sea, tsst-1 and icaA. pvl co-presence with other virulence genes was related to poor outcomes. Including use of linezolid in predictive models improved discrimination (ROC AUC 0.805) .Transfusion recipients frequently present with independent risk factors associated with mortality in ICU patients diagnosed with MRSA pneumonia. Prognosis for ICU MRSA pneumonia is based on clinical risk factors, virulence gene carriage and transfusion status. Limitations are the retrospective study design and that sputum samples were used, which may result in misclassification.