Prevalence and Molecular Characterization of Extended-Spectrum Beta-Lactamase (ESBL) Carrying Escherichia Coli in Urban Aquatic Environments in Greater Noida, India

Objectives: To determine the prevalence and type of Extended-spectrum beta-lactamase (ESBL) in Escherichia coli (E.coli) isolated from water samples from urban aquatic environments in Greater Noida, India. Materials and methods: 100 ml water samples were collected from ten different aquatic environments including canals, drains, rivers flowing through Greater Noida, India. The water samples were serially diluted up to 100 ml to achieve countable plates. One ml of each dilution was pipetted onto Hi Chrome E.coli agar (Hi Media) and incubated at 37⁰C for 24 hrs. Screening for the presence of ESBL was carried out using 2nd and 3rd generation cephalosporins. Screen positive isolates were confirmed for ESBL production by Double Disk Diffusion test. ESBLs were characterized into blaTEM, blaCTX-M, and blaSHV  genes by Polymerase chain reaction(PCR). Results & Conclusion:  E.coli were isolated from all the 10 (100%) environmental aquatic sources. The range of colony count was 1.2 × 105 to 1.9 × 107. Seven E.coli isolates were ESBL positive. blaCTX-M and blaTEM were identified in 6 and 5 ESBL-positive isolates by PCR, respectively.   This study thus concludes that urban aquatic environments contain drug-resistant organisms that have the potential to cross over to urban human population leading to spread of antimicrobial resistance in the community.