STREAM

Hospital effluents are emerging hotspots for antimicrobial resistance, yet the ecological and chemical factors that sustain resistance genes remain poorly understood. The bla_IMP-29 carbapenemase gene was first identified in 2010 in a Pseudomonas aeruginosa strain at Besançon University Hospital and has not been detected in patients since 2013. Surprisingly, a 2025 survey of hospital effluents revealed numerous bacteria from diverse genera carrying blaIMP-29. Outside Besançon, this gene has been reported only twice worldwide (Sweden, 2015; Spain, 2021). These effluents therefore provide a unique model to study the persistence and dissemination of a resistance gene in the apparent absence of external inputs.

The STREAM project (Spread and TRansfer of blaIMP-29 in hospital effluents Across Microbiota) aims to identify the ecological, microbiological, and chemical factors that sustain and spread bla_IMP-29 in hospital wastewater. It will characterize the bacterial diversity of environmental carriers and the associated mobile genetic elements, including plasmids, integrons, and transposons. The project will also investigate horizontal gene transfer mechanisms and identify in situ bacterial reservoirs using the Hi-C method (High-Resolution Chromatin Conformation Capture). In addition, STREAM will assess the influence of chemical contaminants, such as antibiotics, biocides, and heavy metals, on plasmid stability using UPLCHRMS and ICP-MS analyses.

Led jointly by UMR CNRS 6249 and UMR INSERM 1231, STREAM combines genomic, microbiological, and environmental approaches while expanding the teams’ expertise with Hi-C and biocide quantification.

The project is expected to reveal the drivers of co-selection in hospital effluents, and enhance environmental surveillance of critical resistance genes. STREAM is dedicated to understanding the ecology and spatio-temporal dynamics of microbial communities and will contribute to the development of integrated One Health strategies for preventing antimicrobial resistance in the environment.