Rapid De-escalation of Anti-MRSA Therapy Guided by S. Aureus Nares Screening in Case of Pneumonia

The current IDSA/ATS guidelines recommend Linezolid and Vancomycin for MRSA coverage in hospitalized patients with pneumonia, which is common clinical practice in Italy. However, a nasal PCR-assay for MRSA has a high negative predictive value and can facilitate rapid antibiotic de-escalation, thereby avoiding unnecessary anti-MRSA treatments. The indiscriminate use of these drugs has contributed to the emergence of resistant S. aureus strains and has led to significant adverse effects, without providing any survival benefits. Additionally, it has increased hospital stays and associated costs. The proposed study aims to use this diagnostic tool to shorten empirical anti-MRSA treatment duration in pneumonia patients, focusing on reducing antimicrobial therapy days while measuring in-hospital mortality, length of stay and adverse drug event incidence.