Nosocomial SARS-CoV-2 infections have severely affected bed capacity and patient flow. We utilised whole genome sequencing (WGS) to identify outbreaks and focus infection control resources and intervention during the UK’s second pandemic wave in late 2020. Phylogenetic analysis of WGS and epidemiological data pinpointed an initial transmission event to an admission ward, with immediate prior community infection linkage documented. High incidence of asymptomatic staff infection with genetically identical viral sequences was also observed, which may have contributed to the propagation of the outbreak. WGS allowed timely nosocomial transmission intervention measures, including admissions ward point of care testing and introduction of portable HEPA14 filters. Conversely WGS excluded nosocomial transmission in two instances with temporospatial linkage, conserving time and resources. In summary, WGS significantly enhanced understanding of SARS-CoV-2 clusters in a hospital setting, both identifying high risk areas and conversely validating existing control measures in other units, maintaining clinical service overall.

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Background Carbapenemase Producing Enterobacterales (CPE) are a global health concern. Nosocomial outbreaks have been reported globally with patient-to-patient transmission felt to be the most frequent route of cross-transmission. Aim To describe the investigation and control of an outbreak of healthcare-associated New Delhi Metallo-beta-lactamase (NDM) CPE on a haematology ward, over 2 months. Methods Four patients acquired CPE; all had gastrointestinal tract colonisation with two subsequently developing bacteraemias. The outbreak team performed a retrospective review, prospective case finding and environmental sampling using swabs, settle plates, air and water sampling. Immediate control measures were implemented including appropriate isolation of cases and additional ward cleaning with chlorine disinfectant, ultra-violet light decontamination and hydrogen peroxide. Findings Following two cases of nosocomial acquired CPE prospective case finding identified two further cases. 4.6% of the initial environmental samples were positive for CPE including from waste water sites, the ward sluice and the ward kitchen. Three of the four CPE isolates were identical on pulse field gel electrophoresis (PFGE) typing. Detection of the CPE from the ward kitchen environmental samples suggests a possible role for cross transmission. Conclusion This is the first CPE outbreak report to highlight the role of a ward kitchen as a possible source of cross-transmission. In view of this we suggest ward kitchens are reviewed and investigated in nosocomial CPE outbreaks.

Background Nosocomial infections have posed a significant problem during the COVID-19 pandemic, affecting bed capacity and patient flow in hospitals. Effective infection control measures and identifying areas of highest risk is required to reduce the risk of spread to patients who are admitted with other illnesses. This is the first pandemic where whole genome sequencing (WGS) has been readily available. We demonstrate how WGS can be deployed to help identify and control outbreaks. Aims & Methods Swabs performed on patients to detect SARS-CoV-2 underwent RT-PCR on one of multiple different platforms available at Nottingham University Hospitals NHS Trust. Positive samples underwent WGS on the GridION platform using the ARTIC amplicon sequencing protocol at the University of Nottingham. Results Phylogenetic analysis from WGS and epidemiological data was used to identify an initial transmission that occurred in the admissions ward. It also showed high prevalence of asymptomatic staff infection with genetically identical viral sequences which may have contributed to the propagation of the outbreak. Actions were taken to help reduce the risk of nosocomial transmission by the introduction of rapid point of care testing in the admissions ward and introduction of portable HEPA14 filters. WGS was also used in two instances to exclude an outbreak by discerning that the phylotypes were not identical, saving time and resources. Conclusions In conjunction with accurate epidemiological data, timely WGS can identify high risk areas of nosocomial transmission, which would benefit from implementation of appropriate control measures. Conversely, WGS can disprove nosocomial transmission, validating existing control measures and maintaining clinical service, even where epidemiological data is suggestive of an outbreak.

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