Background: The fast-spreading of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli (ESBL-producing E. coli) 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. Materials and methods: 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 E. coli 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 E. coli strain as the gene receptor. Result: Nine ESBL-producing E. coli 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 bla_CTX-M 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), bla_CTX-M-15, and WbuC family cupin-fold metalloprotein, which may potentially jump from the plasmids to the chromosome. Conclusion: The first time we reported the whole genome sequencing (WGS) data of ESBL-producing E. coli including potential pathogen (ST131) present in reservoir water in Singapore. The ESBL-producing E. coli from reservoir water also carrying conjugatable colistin resistance genes which may become a risk to human health.

中文翻译：

---

使用全基因组测序对来自新加坡裕廊湖的产超广谱 β-内酰胺酶的大肠杆菌分离株进行表征

背景：产超广谱β-内酰胺酶的大肠杆菌（产ESBL的大肠杆菌）和ESBL基因的快速传播已成为公共卫生的一大挑战。ESBL 基因和病原体在环境和社区中传播的风险已引起公众健康关注。新加坡水库水中产 ESBL 细菌的表征和全基因组测序研究仍然有限。材料与方法：水库水样取自新加坡著名的水库公园——华人花园（裕廊河水库）的两个随机采样点。用 0.45 µm 滤膜收集水样中的细菌，并在使用产 ESBL 处理前进行富集大肠杆菌筛选。收集的 ESBL 阳性分离物通过包括圆盘扩散和微稀释最小抑制浓度 (MIC) 测试在内的表型测试以及作为全基因组测序分析的基因型测试进一步表征。此外，为了研究抗性基因的可转移性，以J53大肠杆菌菌株作为基因受体进行了结合试验。结果：收集到9 株产 ESBL大肠杆菌，经表型和基因型试验证实为产 ESBL。鉴定出一种潜在的病原体为 ST131 进化枝 A 分离株，所有分离株都被确定为含有bla _CTX-M基因。其中，菌株J1E4对多粘菌素E具有抗性，并证实含有可结合的mcr-1基因。进一步的遗传环境分析反映了由插入序列 (IS)、bla _CTX-M-15和WbuC家族杯形折叠金属蛋白形成的转换基因簇，其可能从质粒跳转到染色体。结论：我们首次报道了新加坡水库水中存在的潜在病原体 (ST131)的产 ESBL大肠杆菌的全基因组测序 (WGS) 数据。水库水中产生 ESBL 的大肠杆菌也携带可结合的粘菌素抗性基因，这可能对人类健康构成威胁。