Antimicrobial Selection in the Face of Nasal Methicillin-Resistant Staphylococcus aureus-Polymerase Chain...

Emergence of resistance to vancomycin and the increasing incidence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) warrant careful initiation of antimicrobial agents after nasal swab polymerase chain recombination (PCR) MRSA positive screen. Current MRSA PCR nasal swab (PCR) screening does not distinguish non-hospital-acquired strains. A retrospective, institutional review board-approved study of collected PCR screenings among 826 burn center admissions over a 23-month period assessed culture results, antimicrobial agents chosen, and patient demographics. Seventy-seven of the 826 were known chronic carriers (n = 11); had MRSA on initial PCR (n = 48); or converted to positive PCR screen on later testing (n = 18). The 48 patients with initial positive PCR were decolonized with mupirocin. MRSA carriers were not decolonized. The 18 patients who became PCR positive were also not decolonized with 10 having positive cultures. The 48 initial PCR nasal swab positive patients represented 5.8% of admissions. Demographic data did not differ among chronic carriers, initial PCR positive patients, nor those converting to PCR positive. Length of stay was shorter for initial PCR positive decolonized patients (P << .05) and they had a 35% of decrease in MRSA infection. All 11 chronic carriers became infected with MRSA; however, five had non-hospital-acquired MRSA and two solely non-hospital-acquired MRSA. For the 48 PCR positive patients, 17 had isolated MRSA and one having exclusively non-hospital-acquired MRSA. Of the 39 patients with isolated MRSA, 20 (43%) non-hospital-acquired MRSA. Non-hospital-acquired MRSA was 43%, however PCR fails to distinguish hospital-acquired MRSA from community-acquired MRSA.