Predictive value of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab PCR assay for MRSA infection in critically ill pediatric patients

Authors

Lexi Crawford, Division of Critical Care Medicine, Children's National Hospital, Washington, DC.
Vera Pertsovskaya, The George Washington University School of Medicine and Health Sciences, The George Washington University, Washington, DC.
Alice Shanklin, Division of Critical Care Medicine, Children's National Hospital, Washington, DC.
Anqing Zhang, The George Washington University School of Medicine and Health Sciences, The George Washington University, Washington, DC.
Rana F. Hamdy, The George Washington University School of Medicine and Health Sciences, The George Washington University, Washington, DC.

Document Type

Journal Article

Publication Date

12-9-2023

Journal

Journal of the Pediatric Infectious Diseases Society

DOI

10.1093/jpids/piad111

Abstract

OBJECTIVES: Critically ill pediatric patients are frequently initiated methicillin-resistant Staphylococcus aureus (MRSA) active antibiotics during infection evaluation even though MRSA infections are rare in many patient populations. The MRSA nasal swab polymerase chain reaction assay (MRSA-NS-PCR) is a test that has been shown to have a high negative predictive value (NPV) for MRSA infection in adults. This study evaluated the diagnostic test characteristics of the MRSA-NS-PCR in predicting the presence of MRSA infection in critically ill pediatric patients. STUDY DESIGN: A retrospective cohort study was performed in a 44-bed pediatric intensive care unit (PICU) between 2013-2017. 3,860 pediatric patients (54% male, median age 4 years [IQR 1-11 yrs.]) admitted to the PICU who met pediatric systemic inflammatory response syndrome (pSIRS) criteria, were screened with a MRSA-NS-PCR, and had cultures obtained within seven days of MRSA-NS-PCR collection were included. Predictive values and post-test probabilities of the MRSA-NS-PCR for MRSA infection were calculated. RESULTS: MRSA-NS-PCR was positive in 8.6% of patients. MRSA infection was identified in 40 patients, equaling an incidence rate of 2 per 1,000 patient days. The MRSA-NS-PCR demonstrated a positive predictive value (PPV) of 9.7%, a NPV of 99.8%, and a post-test probability for a negative test of 0.2% for MRSA infection. CONCLUSIONS: The MRSA-NS-PCR has a poor PPV but a high NPV for MRSA infection in PICU patients when the incidence of MRSA infection is low. Creation of protocols to guide antimicrobial selection based on MRSA-NS-PCR results may lead to improved antimicrobial stewardship and significant risk reduction.

APA Citation

Crawford, Lexi; Pertsovskaya, Vera; Shanklin, Alice; Zhang, Anqing; and Hamdy, Rana F., "Predictive value of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab PCR assay for MRSA infection in critically ill pediatric patients" (2023). GW Authored Works. Paper 3988.
https://hsrc.himmelfarb.gwu.edu/gwhpubs/3988

Department

Pediatrics