ICEs in Vibrio cholerae from water samples from France: Occurrence, diversity and impact for human health - Anses - Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail Accéder directement au contenu
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ICEs in Vibrio cholerae from water samples from France: Occurrence, diversity and impact for human health

Résumé

Vibrio cholerae is found in aquatic ecosystems throughout the world. While isolates of the O1/O139 serogroup are capable of causing cholera due to the presence of cholera toxin (CTX) and toxin coregulated pilus (TCP) as primary virulence factors, isolates of other serogroups (non-O1/O139) are usually considered less harmful. However, some of them have been shown to be involved in intestinal and extra-intestinal infections (i.e., wound, soft tissue and ear infections or bacteraemia) due to a wide range of virulence factors (i.e., mannose-sensitive haemagglutinin pilus (MSHA), various hemolysins, repeat toxin clusters (RTX), outer membrane proteins and the type III secretion system (TTSS)) that usually act synergistically during the infection process. Besides pathogenicity, self-transferring integrative conjugative elements (ICEs) gain further importance as they represent large genomic segments carrying several bacterial adaptive functions including antimicrobial resistance (AMR). In this study the occurrence and diversity of ICE-carrying V. cholerae from France and their impact for human health was studied. V. cholerae isolation was conducted from water/sediment samples (total: n=586) collected along a salinity gradient under a temperate climate (France): freshwater (2 sites: n=49 and n=91), brackish water (n=207) and sediments (n=41) from brackish areas, seawater (n=59) and wastewater (n=139) between June 2000 and September 2001. In addition, 49 samples of cockles were also investigated. Isolates from different sources were subjected to a molecular survey on the presence of ICE. ICE-carrying isolates (n=64) were further subjected to paired-end, short read whole-genome sequencing (WGS) for in depth characterization. Non-O1/O139 isolates were successfully recovered by cultivation from all sources investigated in this study. Molecular detection on ICE revealed substantial differences between the different water types, while samples from brackish and seawater exhibited the highest number of ICE-carrying V. cholerae in comparison to freshwater samples. Bioinformatic analysis revealed 21 different MLST allele compositions among 64 V. cholerae isolates, of which 11 belong to unassigned sequence types (ST). The AMR genes detected were linked to chromosomal contigs and conferred resistance to carbapenems (varG), colistin (almG) and phenicol (catB9). The number of virulence factors among the isolates ranged from 151 to 166 and were involved in adherence, biofilm formation, effector delivery systems, exoenzymes, exotoxins, immune modulation, motility, and nutritional/metabolic factors. The detection of ICE-carrying isolates in about 10% of the analyzed V. cholerae provides a first insight into the presence of self-transmissible sequence regions in naturally occurring isolates. The genomes of the isolates found so far are not heavily loaded with AMR, but may represent a hot spot for the acquisition of insertional elements carrying medically important resistance genes. Selective pressures on the bacteria, such as exposure to antimicrobials or residues in water (wastewater), may force their spread and adaptation, but will also hamper medical treatment purposes against V. cholerae infections. Further surveillance and characterization data is needed and will provide information about diversity of ICE in V. cholerae and their specific mechanisms for acquiring and spreading AMR.
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Dates et versions

anses-04167919 , version 1 (21-07-2023)

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  • HAL Id : anses-04167919 , version 1

Citer

Sandrine Baron, Laetitia Le Devendec, Jean Lesne, Xavier Bellanger, Claudia Jäckel, et al.. ICEs in Vibrio cholerae from water samples from France: Occurrence, diversity and impact for human health. 9. Symposium on Antimicrobial Resistance in Animals and the Environment (ARAE), Jul 2023, Tours (France), France. 2023. ⟨anses-04167919⟩
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