MRSA Nasal PCR ’ s Role in Empiric Antibiotic Selection

Case A 67-year-old man with chronic obstructive pulmonary disease (COPD) was admitted to inpatient general medicine from his nursing home for pneumonia. He reported a 10-day history of an upper respiratory viral infection with symptoms improving until two days ago. Initial evaluation revealed a temperature of 100.5° F, heart rate of 95 beats per minute, blood pressure of 147/89 mmHg, respiratory rate of 25 per minute, and O2 saturation of 92% on room air. His white blood cell count was 14,000. Both a COVID-19 and methicillin-resistant Staphylococcus aureus (MRSA) nasal polymerase chain reaction (PCR) assay were negative. Chest X-ray revealed a right lower lobe opacity. Ceftriaxone and azithromycin were started to treat community-acquired pneumonia. Brief overview Staphylococcus aureus, and especially MRSA, are troublesome bacteria for the hospitalist. MRSA infections are associated with high mortality and morbidity risks, long treatment courses, and increased financial and physical strains on the patient.1 To reduce risks of infection and transmission, methods for rapid detection of MRSA are vital. Real-time PCR to detect MRSA in nasal swab specimens, with results available in approximately two hours, has become the test of choice for many institutions.2 The data supporting screening with the MRSA nasal PCR to reduce nosocomial transmission is mixed, but it is now well established that MRSA nasal colonization is a risk factor for invasive MRSA infections.1,3 Importantly, the...
Source: The Hospitalist - Category: Hospital Management Authors: Tags: Clinical Guidelines Interpreting Diagnostic Tests Source Type: research