Risk Factors for Nosocomial Methicillin Resistant Staphylococcus aureus (MRSA) Colonization in a Neonatal Intensive Care Unit: A Case-Control Study

Am J Infect Control. 2021 Apr 30:S0196-6553(21)00277-7. doi: 10.1016/j.ajic.2021.04.082. Online ahead of print.


AIM: To determine risk factors for MRSA colonization in a Level IV Neonatal Intensive Care Unit (NICU) independent of length of stay and gestational age in the context of a persistently circulating MRSA clone.

DESIGN: Retrospective matched case-control study.

SETTING: Level IV NICU PATIENTS: Infants admitted between April 4,2017- March 31,2018.

METHODS: Based on weekly surveillance cultures, infants who acquired MRSA were matched 1:1 with MRSA-negative control infants by duration of exposure (length of stay) and gestational age to determine risk factors for acquisition.

RESULTS: Fifty case infants were matched with controls. Isolates from 45 of the 50 cases were mupirocin-resistant and related by pulse-field gel electrophoresis. On matched univariable analysis, the following were significantly associated with a risk for MRSA acquisition: 1.Bed location in the acute area(p=0.03), 2.Requirement of any level of respiratory support during the week prior to MRSA detection(p=0.04), 3.Higher ATP pass rate (a measure of effectiveness of cleaning) during the week of and week prior(p=0.01), 4.Higher MRSA colonization pressure during the week of and week prior(p<0.0001), 5.Not having a hearing test during the time between the previous negative culture and MRSA acquisition(p=0.01). A multivariable conditional logistic regression model (that excluded ATP pass rate) found that only colonization pressure was associated with acquisition of MRSA colonization.

CONCLUSIONS: In an outbreak setting, MRSA colonization pressure is significantly associated with MRSA acquisition in the NICU independent of length of stay and gestational age.

PMID:33940064 | DOI:10.1016/j.ajic.2021.04.082