Genotypic diversity among multi-drug-resistant (MDR) aquatic E. coli isolated from different sites of Yamuna River was analyzed using repetitive element PCR (rep-PCR) methods viz. ERIC-PCR and (GTG)₅-PCR and compared with the MDR animal fecal isolates. The 97 E. coli isolates belonging to different serotypes, phylogroups, and multi-drug resistance patterns were analyzed. High genetic diversity was observed by both the methods; however, (GTG)₅ typing showed higher discriminating potential. Combination of ERIC types (E1–E32) and (GTG)₅ types (G1–G46) generated 77 genotypes. The frequency of genotypes ranged from 0.013 to 0.065. The genotype composition of E. coli isolates was highly diverse at all the sampling sites across Yamuna River except at its entry site in Delhi. The sampling sites under the influence of high anthropogenic activities showed an increase in number of unique genotype isolates. These sites also exhibited high multiple antibiotic resistance (MAR) indexes (above 0.25) suggesting high risk of contamination. Principal coordinate analysis (PCoA) showed limited clustering of genotypes based on the sampling sites. The most frequent genotypes were grouped in the positive zone of both the principal coordinates (PC1 and PC2). The genotypes of most of the animal fecal isolates were unique and occupied a common space in the negative PC1 area forming a separate cluster. High genotypic diversity among the aquatic E. coli and the drain isolates, discharging the untreated municipal waste in the river, was observed, suggesting that the sewage effluents contribute substantially to contamination of this river system than animal feces. The presence of such a high diversity among the MDR E. coli isolates in the natural river systems is of great public health significance and highlights the need of an efficient surveillance system for better management of Indian natural water bodies.

使用重复元素PCR（rep-PCR）方法分析了从亚穆纳河不同地点分离的多药耐药（MDR）水生大肠杆菌中的基因型多样性。ERIC-PCR和（GTG）₅ -PCR并与MDR动物粪便分离株进行比较。分析了97种大肠杆菌分离物，它们分别属于不同的血清型，系统群和多药耐药性。两种方法均观察到高遗传多样性。但是，（GTG）₅分型显示出更高的识别潜力。ERIC类型（E1-E32）和（GTG）₅种类型（G1-G46）的组合产生了77个基因型。基因型的频率范围为0.013至0.065。大肠杆菌的基因型组成除了在德里的入口处外，亚穆纳河上所有采样点的分离株高度多样化。在高人为活动影响下的采样地点显示出独特的基因型分离株数量增加。这些部位还表现出较高的多重抗生素抗性（MAR）指数（高于0.25），表明存在高污染风险。主坐标分析（PCoA）显示基于采样位点的基因型有限聚类。最常见的基因型在两个主坐标（PC1和PC2）的阳性区域中分组。大多数动物粪便分离株的基因型是独特的，并在阴性PC1区域占据一个公共空间，形成一个单独的簇。水生大肠杆菌中的高基因型多样性观察到的污水隔离物将未经处理的城市废物排放到河中，这表明污水比动物粪便对河水系统的污染要大得多。在天然河系中，耐多药大肠埃希菌分离株之间如此高度的多样性具有重大的公共卫生意义，并突出显示了需要有效监控系统以更好地管理印度天然水体的需求。