Browsing by Author "Castro-Gutierrez, Víctor"

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    Dissemination of metaldehyde catabolic pathways is driven by mobile genetic elements in Proteobacteria
    (The Microbiology Society, 2022-10-27) Castro-Gutierrez, Víctor; Fuller, Edward; Garcillán-Barcia, María Pilar; Helgason, Thorunn; Hassard, Francis; Moir, James
    Bioremediation of metaldehyde from drinking water using metaldehyde-degrading strains has recently emerged as a promising alternative. Whole-genome sequencing was used to obtain full genomes for metaldehyde degraders Acinetobacter calcoaceticus E1 and Sphingobium CMET-H. For the former, the genetic context of the metaldehyde-degrading genes had not been explored, while for the latter, none of the degrading genes themselves had been identified. In A. calcoaceticus E1, IS91 and IS6-family insertion sequences (ISs) were found surrounding the metaldehyde-degrading gene cluster located in plasmid pAME76. This cluster was located in closely-related plasmids and associated to identical ISs in most metaldehyde-degrading β- and γ-Proteobacteria, indicating horizontal gene transfer (HGT). For Sphingobium CMET-H, sequence analysis suggested a phytanoyl-CoA family oxygenase as a metaldehyde-degrading gene candidate due to its close homology to a previously identified metaldehyde-degrading gene known as mahX. Heterologous gene expression in Escherichia coli alongside degradation tests verified its functional significance and the degrading gene homolog was henceforth called mahS. It was found that mahS is hosted within the conjugative plasmid pSM1 and its genetic context suggested a crossover between the metaldehyde and acetoin degradation pathways. Here, specific replicons and ISs responsible for maintaining and dispersing metaldehyde-degrading genes in α, β and γ-Proteobacteria through HGT were identified and described. In addition, a homologous gene implicated in the first step of metaldehyde utilisation in an α-Proteobacteria was uncovered. Insights into specific steps of this possible degradation pathway are provided.
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    Wastewater-based epidemiology for surveillance of infectious diseases in healthcare settings
    (Lippincott, Williams & Wilkins, 2023-06-02) Hassard, Francis; Bajón Fernández, Yadira; Castro-Gutierrez, Víctor
    Purpose of review: Wastewater-based surveillance (WBS) (epidemiology) using near-source sampling (NSS) in large buildings, hospitals and care homes is reviewed covering three main areas: state-of-the-art WBS, benefits/opportunities NSS has for hospital infection control systems and new insights from hospital wastewater surveillance and policy implications. Recent findings: Wastewater provides aggregate, anonymous sources of data where the spatial resolution can be linked to populations being served. In hospitals, clear links established between wastewater RNA-fragments signal to nosocomial COVID-19 cases/outbreaks. Detecting other targets from hospital wastewater such as antimicrobial resistance markers is considered a substantial opportunity for this technology. Other clinically relevant infections, that is influenza and monkeypox, can be perceived, and sub-variant resolution to target public health response in near real time to benefit hospital infection control. WBS can reduce hospitals’ clinical testing requirements, as diagnostic costs are aggregated into fewer samples while still detecting single cases. Summary: WBS using NSS can inform infectious disease monitoring earlier, faster and cheaper than conventional monitoring. Routine sampling using wastewater provides a platform for risk-based sampling and enables smarter allocation of resources. Finally, hospital wastewater can be used for the benefit of the wastewater surveillance field as a promising source to monitor emerging threats and resolve longstanding questions on faecal shedding. Hospital monitoring in low-income settings is considered a priority for future research.