Ayushi Jain, Sanju Kumari, Khem Raj Meena, Jitendra, Arvind Kumar
Ana Sagar Lake, despite its ecological, public health, and economic importance, has remained largely unexplored with respect to its bacterial diversity and antibiotic resistance. Therefore, the present study aimed to characterize the bacterial diversity of the lake and evaluate the antibiotic resistance profiles of the recovered isolates. Based on 16S rRNA gene sequencing, the bacterial isolates AL-1, AL-5, AL-6, and AL-9 were identified as Priestia sp. (GenBank accession: PX973463), Acinetobacter soli strain AL-5 (PX973464), Pseudomonas sp. AL-6 (PX973465), and Acinetobacter sp. AL-9 (PX973466), respectively. Among these, AL-1 (Priestia sp.) exhibited the highest level of resistance, showing resistance to chloramphenicol, streptomycin, cefepime, aztreonam, and cefoperazone. Interestingly, AL-9 demonstrated an inverse response to antibiotic exposure, with significantly enhanced biofilm formation in the presence of chloramphenicol compared with the untreated control. In addition, AL-1, AL-6, and AL-9 displayed increased intracellular accumulation of ethidium bromide (EtBr), indicating reduced efflux pump activity and a potential increase in antibiotic susceptibility. Chloramphenicol exerted the most pronounced effect on AL-9 cells among the antibiotics tested. To the best of our knowledge, this is the first study to characterize the antibiotic resistance profiles of bacterial isolates recovered from Ana Sagar Lake. These findings provide valuable baseline data for assessing the microbial quality of the lake, understanding the potential public and environmental health risks associated with its use, and supporting future monitoring and management strategies.