Abstract: Water used for drinking, recreational purpose and irrigation if contaminated with opportunistic pathogenic environmental microorganisms may have health implications as it propagates and disseminates human pathogens. This study aimed to isolate, identify (molecular identification) environmental microorganisms from various River and Lakes in Bengaluru, India. The water samples from Kagglipura and Avalahalli lakes, Dakshina Pinakini and Vrishabhavathi rivers were analysed for the presence of faecal indicator bacteria as well as common aquatic bacteria like Aeromonas and Pseudomonas species. Following the molecular identification of the isolates using 16S rDNA and 18S rDNA sequencing, faecal and total coliforms were detected in the untreated water samples from the Dakshina Pinakini and Vrishabhavathi river, with E.coli, Fusarium oxysporum, and Alternaria burnsii being the most prevalent genera. The water samples from the Kagglipura and Avalahalli lakes showed the presence of opportunistic pathogenic microorganisms like Aeromonas aquariorum, Klebsiella pneumoniae, Citrobacter freundii, that may significantly affect human, animal and plant health. Hence, the study highlights that the water from these River and Lakes in Bengaluru contains various opportunistic microbial pathogens. Such waters must therefore be treated suitably to meet the human requirement.

Keywords: Molecular identification, opportunistic pathogens, River and Lakes.

| DOI: 10.17148/IARJSET.2022.9281