Pediatric Clinical Outcomes of Nasal Methicillin-resistant Staphylococcus aureus Polymerase Chain Reaction Utilization

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a clinical challenge in selecting empiric antimicrobials for pediatric infections. We implemented nasal MRSA polymerase chain reaction (nMRSA PCR) screening as a diagnostic tool and evaluated its impact on empiric antibiotic use and clinical outcomes. Methods: A retrospective single-center study of patients hospitalized with infections who were empirically prescribed anti-MRSA antibiotics was conducted prior to and following the initiation of nMRSA PCR screening. Electronic medical records, pharmacy data and bacterial cultures results were reviewed. Predictive values of nMRSA PCR testing were calculated and the duration of anti-MRSA empiric therapy and clinical outcomes preimplementation and postimplementation were compared. Results: During the preimplementation period, there were 382 distinct episodes (294 unique patients) that met the inclusion criteria and during post-nMRSA PCR implementation, 394 episodes (360 unique patients) were identified. The median time to discontinuation of anti-MRSA antibiotics and proportion of patients prescribed anti-MRSA antibiotics at discharge were significantly lower in postimplementation compared with preimplementation period; 48 versus 56 hours, P < 0.001 and 20.1% versus 40.3%, P < 0.001, respectively. The negative and positive predictive values of nMRSA PCR compared to clinical culture results were 95.6% and 51.2%, respectively. Predefined adverse outcomes were documented in 11 patients who had early anti-MRSA discontinuation with negative nMRSA PCR results but only 3 were restarted on anti-MRSA treatment and none grew MRSA in clinical cultures. Conclusions: Shortened anti-MRSA antibiotic duration, high negative predictive value and low adverse events provide promising evidence that nMRSA PCR is an effective, rapid antimicrobial stewardship tool for hospitalized children.