Genomic Analysis of Multiresistant Staphylococcus capitis Associated with Neonatal Sepsis.

Coagulase-negative staphylococci (CoNS), such as , are major causes of bloodstream infections in neonatal intensive care units (NICUs). Recently, a distinct clone of (designated NRCS-A) has emerged as an important pathogen in NICUs internationally. Here, 122 isolates from New Zealand (NZ) underwent whole-genome sequencing (WGS), and these data were supplemented with publicly available sequence reads. Phylogenetic and comparative genomic analyses were performed, as were phenotypic assessments of antimicrobial resistance, biofilm formation, and plasmid segregational stability on representative isolates. A distinct lineage of was identified in NZ associated with neonates and the NICU environment. Isolates from this lineage produced increased levels of biofilm, displayed higher levels of tolerance to chlorhexidine, and were multidrug resistant. Although similar to globally circulating NICU-associated strains at a core-genome level, NZ NICU isolates carried a novel stably maintained multidrug-resistant plasmid that was not present in non-NICU isolates. Neonatal blood culture isolates were indistinguishable from environmental isolates found on fomites, such as stethoscopes and neonatal incubators, but were generally distinct from those isolates carried by NICU staff. This work implicates the NICU environment as a potential reservoir for neonatal sepsis caused by and highlights the capacity of genomics-based tracking and surveillance to inform future hospital infection control practices aimed at containing the spread of this important neonatal pathogen.