A prospective bacterial whole-genome-sequencing-based surveillance programme for comprehensive early detection of healthcare-associated infection transmission in paediatric oncology patients.

BACKGROUND: Bacterial whole-genome sequencing (WGS) and determination of genetic relatedness is an important tool for investigation of epidemiologically suspected outbreaks. AIM: This prospective cohort study evaluated a comprehensive, prospective bacterial WGS-based surveillance programme for early detection of transmission of most bacterial pathogens among patients at a paediatric oncology hospital. METHODS: Cultured bacterial isolates from clinical diagnostic specimens collected prospectively from both inpatient and outpatient encounters between January 2019 and December 2021 underwent routine WGS and core genome multi-locus sequence typing to determine isolates' relatedness. Previously collected isolates from January to December 2018 were retrospectively analysed for identification of prior or ongoing transmission. Multi-patient clusters were investigated to identify potential transmission events based on temporal and spatial epidemiological links and interventions were introduced. FINDINGS: A total of 1497 bacterial isolates from 1025 patients underwent WGS. A total of 259 genetically related clusters were detected, of which 18 (6.9%) multi-patient clusters involving 38 (3.7%) patients were identified. Sixteen clusters involved two patients each, and two clusters involved three patients. Following investigation, epidemiologically plausible transmission links were identified in five (27.8%) multi-patient clusters. None of the multi-patient clusters were suspected by conventional epidemiological surveillance. CONCLUSION: Bacterial WGS-based surveillance for early detection of hospital transmission detected several limited multi-patient clusters that were unrecognized by conventional epidemiological methods. Genomic surveillance helped efficiently focus interventions while reducing unnecessary investigations.

Differential response of buddleia (Buddleia davidii Franch.) to ozone.

Five cultivars of buddleia, Buddleia davidii Franch., were exposed to sub-ambient, ambient, and twice-ambient levels of ozone in open-top chambers for 8 weeks (June-August) during 1995: Plants were evaluated for foliar injury, growth index, and inflorescence characteristics during and following exposure. Destructive harvests were conducted at the end of the exposure period to determine dry weights of both above- and below-ground plant components. All cultivars had symptoms of visible injury in the twice-ambient treatment at both three and eight weeks after exposures began. No visible symptoms were observed at ambient ozone concentrations. At three weeks of exposure, 'Pink Delight' had the highest percentage of the leaves injured (PLI), 46.2%, followed by 'Opera' with a PLI of 23.3%. The other three cultivars had similar PLIs of less than 15%. After eight weeks of exposure, visible injury was equally severe on all cultivars with a mean PLI of 50.2% and mean Horsfall-Barratt rating of 5.4, indicating 12 to 25% of the leaf area was injured. No ozone x cultivar interaction was found for any growth variable measured. Across cultivars, growth index was reduced by 6%, total dry weight by 35%, and the number of developing floral buds and inflorescences by 29% for plants in twice-ambient ozone concentrations compared to ambient ozone concentrations. Percent biomass allocated to inflorescences was significantly greater for plants exposed to sub-ambient levels compared to those exposed to ozone at either ambient or twice-ambient concentrations. Results indicate that ozone levels similar to those in large urban areas in the southeastern United States have the potential to reduce growth and flowering of this important landscape plant.

Odontogenic adenomatoid tumors associated with orthodontic treatment.

Because of a predilection for occurrence in the anterior jaw in association with an unerupted tooth, the odontogenic adenomatoid tumor (OAT) will sometimes be discovered in the context of an orthodontic procedure to promote and guide eruption of the tooth. Two cases illustrate this situation. Some other lesions that might have a clinical presentation similar to the OAT are named.