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Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in neonatal intensive care units (NICU) that confers significant morbidity and mortality.Improving our understanding of MRSA transmission dynamics, especially among high-risk patients, is an infection prevention priority.We investigated a cluster of clinical MRSA cases in the NICU using a combination of epidemiologic review and whole-genome sequencing (WGS) of isolates from clinical and surveillance cultures obtained from patients and healthcare personnel (HCP).Phylogenetic analysis identified 2 genetically distinct phylogenetic clades and revealed multiple silent-transmission events between HCP and infants. The predominant outbreak strain harbored multiple virulence factors. Epidemiologic investigation and genomic analysis identified a HCP colonized with the dominant MRSA outbreak strain who cared for most NICU patients who were infected or colonized with the same strain, including 1 NICU patient with severe infection 7 months before the described outbreak. These results guided implementation of infection prevention interventions that prevented further transmission events.Silent transmission of MRSA between HCP and NICU patients likely contributed to a NICU outbreak involving a virulent MRSA strain. WGS enabled data-driven decision making to inform implementation of infection control policies that mitigated the outbreak. Prospective WGS coupled with epidemiologic analysis can be used to detect transmission events and prompt early implementation of control strategies.

IntroductionMethicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in neonatal intensive care units (NICU) that carries significant morbidity and mortality. Improving our understanding of MRSA transmission dynamics, especially among high risk patients, is an infection prevention priority.MethodsWe investigated a cluster of clinical MRSA cases in the NICU using a combination of epidemiologic review and whole genome sequencing (WGS) of isolates from clinical and surveillance cultures obtained from patients and healthcare personnel (HCP).ResultsPhylogenetic analysis identified two genetically distinct phylogenetic clades and revealed multiple silent transmission events between HCP and infants. The predominant outbreak strain harbored multiple virulence factors. Epidemiologic investigation and genomic analysis identified a HCP colonized with the dominant MRSA outbreak strain who cared for the majority of NICU patients who were infected or colonized with the same strain, including one NICU patient with severe infection seven months before the described outbreak. These results guided implementation of infection prevention interventions that prevented further transmission events.ConclusionSilent transmission of MRSA between HCP and NICU patients likely contributed to a NICU outbreak involving a virulent MRSA strain. WGS enabled data-driven decision making to inform implementation of infection control policies that mitigated the outbreak. Prospective WGS coupled with epidemiologic analysis can be used to detect transmission events and prompt early implementation of control strategies.SummaryWhole genome sequencing identified a NICU outbreak of MRSA preceded by silent transmission between health care personnel and patients seven months prior to outbreak detection. This study suggests prospective genomic analysis may identify isolates with high virulence potential, offering an early opportunity for intervention.

This cohort study examines the rate of positive test results for severe acute respiratory syndrome coronavirus 2 in children without symptoms who were treated in US hospitals for other conditions.

Candida auris is an emerging multidrug-resistant yeast with high mortality. We report the sentinel C. auris case on the United States West Coast in a patient who relocated from India. We identified close phylogenetic relatedness to the South Asia clade and ERG11 Y132F and FKS1 S639Y mutations potentially explaining antifungal resistance.

During August 2017, two separate clusters of platelet transfusion-associated bacterial sepsis were reported in Utah and California. In Utah, two patients died after platelet transfusions from the same donation. Clostridium perfringens isolates from one patient's blood, the other patient's platelet bag, and donor skin swabs were highly related by whole genome sequencing (WGS). In California, one patient died after platelet transfusion; Klebsiella pneumoniae isolates from the patient's blood and platelet bag residuals and a nontransfused platelet unit were matched using WGS. Investigation revealed no deviations in blood supplier or hospital procedures. Findings in this report highlight that even when following current procedures, the risk for transfusion-related infection and fatality persists, making additional interventions necessary. Clinicians need to be vigilant in monitoring for platelet-transmitted bacterial infections and report adverse reactions to blood suppliers and hemovigilance systems. Blood suppliers and hospitals could consider additional evidence-based bacterial contamination risk mitigation strategies, including pathogen inactivation, rapid detection devices, and modified screening of bacterial culture protocols.