The emergence of resistance on exposure to pharmaceuticals among microorganisms has raised serious concern in the therapeutic approach against infectious diseases. Effluents discharge from hospitals, industries, and urban settlements containing pharmaceuticals and other toxic compounds into the aquatic ecosystem selects bacterial population against them; thereby promotes acquisition and dissemination of resistant traits among the inhabitant microbiota. The present study was aimed to determine the prevalence and multidrug resistance pattern of Extended Spectrum β-lactamase (ESBL) producing and non-producing bacterial isolates from the heavily polluted Delhi stretch of river Yamuna, India. Additionally, the role of abiotic factors in the dissemination of conjugative plasmids harbouring resistance genes was also studied using E. coli J53 as recipient and resistant E. coli isolates as donor strains. Of the 227 non-duplicate bacterial isolates, 60% (136) were identified as ESBL⁺ and 40% (91) as ESBL. ESBL⁺ isolates were found highly resistant to β-lactam and non-β-lactam classes of antibiotics compared with the ESBL⁻ isolates. 68% of ESBL⁺ and 24% of ESBL⁻ isolates showed an MAR index of ≥0.5. Surprisingly, multidrug resistance (MDR), extensively drug resistance (XDR), and pandrug resistance (PDR) phenotype were observed for 78.6%, 16.9%, and 0.7% of ESBL⁺ and 90%, 3%, and none for PDR among ESBL⁻ isolates. Conjugation under different conditions showed a higher mobilization rate at neutral pH (7–7.5) for ESBL⁺ isolates. Conjugation frequency was maximum at 40 °C for the isolate E. coli MRB6 (4.1 × 10⁻⁵) and E. coli MRE32 (4.89 × 10⁻⁴) and at 35 °C for E. coli MRA11 (4.89 × 10⁻⁵). The transconjugants obtained were found tolerating different concentrations of mercuric chloride (0.0002–0.2 mg/L). Increased biofilm formation for ESBL⁺ isolates was observed on supplementing media with HgCl₂ (2 μg/mL) either singly or in combination with CTX (10 μg/mL). The present study demonstrates that anthropogenically influenced aquatic environments act as a reservoir of MDR, XDR, and even PDR strains; thereby posing a potent public health risk.

微生物对药物接触的抗药性的出现引起了对传染病治疗方法的严重关注。含有药物和其他有毒化合物的废水从医院，工业和城市居民区排放到水生生态系统中，从而选择了针对它们的细菌种群；从而促进居民微生物群中抗性性状的获得和传播。本研究旨在确定来自印度亚穆纳河污染严重的德里河段的扩展谱β-内酰胺酶（ESBL）产生菌种和不产生菌群的患病率和多药耐药模式。此外，还使用以下方法研究了非生物因子在携带抗性基因的结合质粒的传播中的作用大肠杆菌J53作为受体，抗性大肠杆菌分离株作为供体菌株。在227个非重复细菌分离株中，60％（136）被鉴定为ESBL ⁺，40％（91）被鉴定为ESBL。ESBL ⁺分离物中发现具有很高的耐β-内酰胺与ESBL相比抗生素和非β内酰胺类^-分离物。ESBL的68％⁺和ESBL的24％^-分离株显示出一个≥0.5MAR索引。令人惊讶的是，在ESBL ⁺中观察到多药耐药性（MDR），广泛耐药性（XDR）和泛药耐药性（PDR）表型分别为ESBL ^+的78.6％，16.9％和0.7％，ESBL中的PDR为90％，3％，而没有^-隔离株。在不同条件下的缀合显示ESBL ⁺分离株在中性pH（7–7.5）下的迁移率更高。缀合频率为在40℃下为分离物最大大肠杆菌MRB6（4.1×10 ^-5）和大肠杆菌MRE32（4.89×10 ^-4），并在35℃下为大肠杆菌MRA11（4.89×10 ^-5）。发现获得的转导结合剂可耐受不同浓度的氯化汞（0.0002-0.2 mg / L）。在添加HgCl _2的培养基上观察到ESBL ⁺分离株的生物膜形成增加（2μg/ mL）单独或与CTX（10μg/ mL）组合使用。本研究表明，人为影响的水生环境可作为MDR，XDR甚至PDR菌株的库。从而构成潜在的公共健康风险。