Table_5_Distribution of Antibiotic-Resistant Enterobacteriaceae Pathogens in Potable Spring Water of Eastern Indian Himalayas: Emphasis on Virulence Gene and Antibiotic Resistance Genes in Escherichia coli.XLSX

Every year millions of people die due to fatal waterborne diseases around the world especially in developing countries like India. Sikkim, a northeastern state of India, greatly depends on natural water sources. About 80% of the population of Sikkim depends on natural spring water for domestic as well as agricultural use. Recent waterborne disease outbreaks in the state raises a concerning question on water quality. In this study, we analyzed water quality especially for the detection of Enterobacteriaceae members from four districts of the state. Isolation with selective culture media techniques and taxonomic characterization of Enterobacteriaceae bacteria with 16S rRNA gene showed the prevalence of Escherichia coli (37.50%), Escherichia fergusonii (29.41%), Klebsiella oxytoca (36.93%), Citrobacter freundii (37.92%), Citrobacter amalonaticus (43.82%), Enterobacter sp. (43.82%), Morganella morganii (43.82%), Hafnia alvei (32.42%), Hafnia paralvei (38.74%), and Shigella flexneri (30.47%) in the spring water of Sikkim. Antibiotic susceptibility test (AST) showed resistance of the isolates to common antibiotics like ampicillin, amoxicillin as well as to third generation antibiotics like ceftazidime and carbapenem. None of the isolates showed resistance to chloramphenicol. E. coli isolated from spring water of Sikkim showed presence of different virulence genes such as stx1 (81.81%), elt (86.66%), and eae (66.66%) along with resistance gene for ampicillin (CITM) (80%), quinolones (qnrB) (44.44%), tetracycline (tetO) (66.66%), and streptomycin (aadA1) (66.66%). The data indicates a high incidence rate of multiple antibiotic resistant enteric bacteria in the spring water of Sikkim. Additionally, the presence of enteric bacteria in the water samples indicates widespread fecal contamination of the spring water.

全球每年有数百万人因致命性水源传播疾病离世，其中尤以印度等发展中国家情况严峻。锡金作为印度东北部的一个邦，高度依赖天然水源，该邦约80%的人口依靠天然泉水满足生活及农业生产用水需求。近期该邦暴发的水源传播疾病疫情，引发了学界对当地水质安全的高度关注。本研究针对锡金四个地区的泉水开展水质分析，重点聚焦肠杆菌科（Enterobacteriaceae）菌群的检测。本研究采用选择性培养基分离技术，结合16S rRNA基因对肠杆菌科细菌进行分类鉴定，结果检出以下菌群及其对应检出率：大肠埃希氏菌（Escherichia coli，37.50%）、弗格森埃希氏菌（Escherichia fergusonii，29.41%）、产酸克雷伯氏菌（Klebsiella oxytoca，36.93%）、弗氏柠檬酸杆菌（Citrobacter freundii，37.92%）、无丙二酸柠檬酸杆菌（Citrobacter amalonaticus，43.82%）、肠杆菌属（Enterobacter sp.，43.82%）、摩根摩根氏菌（Morganella morganii，43.82%）、蜂房哈夫尼菌（Hafnia alvei，32.42%）、副蜂房哈夫尼菌（Hafnia paralvei，38.74%）以及福氏志贺氏菌（Shigella flexneri，30.47%）。抗生素敏感性试验（Antibiotic Susceptibility Test, AST）结果显示，分离株对氨苄西林、阿莫西林等常见抗生素，以及头孢他啶、碳青霉烯类等第三代抗生素均表现出耐药性；但所有分离株均未对氯霉素产生耐药性。从锡金泉水中分离得到的大肠埃希氏菌携带多种毒力基因，包括stx1（81.81%）、elt（86.66%）与eae（66.66%）；同时携带多种耐药基因：氨苄西林耐药基因CITM（80%）、喹诺酮类耐药基因qnrB（44.44%）、四环素耐药基因tetO（66.66%）以及链霉素耐药基因aadA1（66.66%）。本研究数据表明，锡金泉水中多重耐药肠道细菌的检出率较高；此外，水样中肠道菌群的存在也提示当地泉水存在广泛的粪便污染。