Retrospective Evaluation of Empiric Vancomycin Therapy for Infectious Workups in Relation to Methicillin-Resistant Staphylococcus aureus (MRSA) Risk Factors in the Neonatal Intensive Care Unit.

Abstract

Objectives: This study evaluated empiric antibiotic prescribing patterns in relation to methicillin-resistant Staphylococcus aureus (MRSA) risk factors in infants with potential late-onset sepsis (LOS). Secondarily, this study evaluated rates of escalation and de-escalation from initial antibiotic choice in patients who received at least 5 days of therapy.

Methods: This was a retrospective study of infants admitted to the neonatal intensive care unit (NICU) from December 1, 2022, to May 31, 2023. Infants at least 3 days old who received antibiotics for an infectious workup were included. The prevalence of risk factors for MRSA, including low birth weight, prematurity, outborn status, length of stay, parenteral nutrition, presence of indwelling lines, and history of MRSA-positive blood culture or colonization, was compared between patients who received vancomycin empirically or an alternative agent.

Results: A total of 143 blood cultures were obtained from 95 patients who received antibiotics for an infectious workup during the study period. Group 1 received vancomycin and included 51 (36%) blood cultures. Group 2 received an alternative agent and included 92 (64%) blood cultures. Patients in group 1 had higher rates of every MRSA risk factor included in this study, except for patients who were outborn. Group 1 also averaged a higher total number of MRSA risk factors per patient than group 2 (4.88 vs 2.53; p < 0.001).

Conclusion: This institution uses MRSA risk factors to determine empiric antimicrobial therapy in suspected LOS. Further studies are needed to determine the relationship between the studied risk factors and incidence of MRSA infection.