Familial and Environmental Impact on Colonization with Antibiotic-resistant Organisms in the Neonatal Intensive Care Unit

Abstract

Colonization with antibiotic-resistant organisms (AROs), including methicillin-resistant S. aureus (MRSA), places neonatal intensive care unit (NICU) patients at increased risk for infection. Infants are routinely screened for MRSA colonization, but reservoirs for ARO acquisition in the NICU are poorly understood. Infants with known MRSA nasal colonization and a control group of infants with negative MRSA screening swabs, and their parents, were enrolled in a prospective cohort study. Weekly swabs were obtained to identify AROs from 4 infant body sites, 3 parental body sites, and 5 high-touch environmental surfaces in the NICU. Culture-based methods were used to identify AROs. Samples were collected 1–14 times (median 7) from 11 MRSA-colonized infants, 7 control infants, 17 mothers, and 9 fathers. Of MRSA-colonized infants, 9 (82%) were colonized with MRSA in the nares, 6 (55%) in the umbilicus, 8 (73%) in the inguinal folds, and 6 (55%) in the rectum over the study period. Six (55%) MRSA-colonized infants had persistent colonization (i.e., 3 consecutive positive samplings) despite receiving decolonization measures. One (14%) control infant was colonized with MRSA during longitudinal sampling. Sixteen (89%) infants were colonized with ceftriaxone-non-susceptible Gram-negative bacteria. Of 110 Enterobacteriaceae isolates recovered from infants, 22% were non-susceptible to gentamicin, 80% to ceftazidime, 33% to cefepime, 2% to meropenem, and 56% to ceftolozane/tazobactam. Six (33%) infants were colonized with Pseudomonas species and 2 (11%) infants were colonized with Acinetobacterspecies. An ARO was recovered at least once from the environment for 13 (72%) infants and from a parent for 13 (72%) infants. Twelve (67%) infants and an environmental surface, and 11 (61%) infants and a parent, were colonized with the same ARO at some point. An environmental surface was colonized with MRSA for 9 (82%) MRSA-colonized infants compared with 3 (43%) controls (P = 0.14). A parent was colonized with MRSA for 9 (82%) MRSA-colonized infants compared with 1 (14%) control (P = 0.01). Extranasal body sites, parents, and environmental surfaces serve as potential reservoirs of ARO acquisition and transmission in NICU infants. All authors: No reported disclosures.