Characterization of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli Isolates from Jurong Lake, Singapore with Whole-Genome-Sequencing

: The fast-spreading of Extended-Spectrum Beta-Lactamase-Producing (ESBL-producing ) and ESBL genes has become a big challenge to public health. The risk of spreading ESBL genes and pathogens in the environment and community has raised public health concern. The characterizing and whole-genome sequencing studies of ESBL-producing bacteria from reservoir water in Singapore is still limited. : The reservoir water sample was taken from two randomly selected sampling points of the Chinese Garden (Jurong river reservoir), which is a popular reservoir park in Singapore. The bacteria of the water sample were collected with 0.45 µm filter membranes and enriched before processing with ESBL-producing screening. The collected ESBL positive isolates were further characterized by both phenotypic tests including disc diffusion and microdilution Minimum Inhibitory Concentration (MIC) test, and also genotypic test as whole-genome sequencing analysis. Besides, to investigate the transferability of the resistance gene, a conjugation test was performed with the J53 strain as the gene receptor. Nine ESBL-producing isolates were collected and confirmed as ESBL-producing with both phenotypic and genotypic tests. A potential pathogen as ST131 clade A isolate was identified, and all isolates were determined to harbor a gene. Among them, strain J1E4 was resistant to polymyxin E and confirmed to harboring a conjugatable mcr-1 gene. Further genetic environment analysis has reflected a conversed gene cluster formed by insert sequence (IS), , and family cupin-fold metalloprotein, which may potentially jump from the plasmids to the chromosome. : The first time we reported the whole genome sequencing (WGS) data of ESBL-producing including potential pathogen (ST131) present in reservoir water in Singapore. The ESBL-producing from reservoir water also carrying conjugatable colistin resistance genes which may become a risk to human health.