Detection and characterization of ESBL-producing and additional co-existence with genes from river water in northern Thailand.

Background: Extended-spectrum β-lactamase producing (ESBL-producing ) have emerged, causing human and animal infections worldwide. This study was conducted to investigate the prevalence and molecular genetic features of ESBL-producing and multidrug-resistant (MDR) in river water.

Methods: A total of 172 samples were collected from the Kok River and Kham River in Chiang Rai, Thailand, during a 10-month period (2020-2021).

Results: We detected 45.3% of to be MDR. The prevalence of ESBL-producers was 22%. Among those ESBL-producing strains, CTX-M-15 (44.7%) was predominantly found, followed by CTX-M-55 (26.3%), CTX-M-14 (18.4%), and CTX-M-27 (10.5%). The and genes were found to be co-harbored with the genes. Mobile elements, ., IS1 and Tn, were observed. Twelve plasmid replicons were found, predominantly being IncF (76.3%) and IncFIB (52.6%). Whole genome sequencing of ten selected isolates revealed the co-existence of ESBL with genes in two ESBL-producing . A wide diversity of MLST classifications was observed. An -- gene cassette was found to disrupt the PUF2806 domain-containing gene, while an contig on another isolate contained the /-- core segment.

Discussion: In conclusion, our data provides compelling evidence of MDR and ESBL-producing , co-existing with genes in river water in northern Thailand, which may be disseminated into other environments and so cause increased risks to public health.