Hyderabad, March 22 Researchers from CSIR-CCMB, along with partner institutions, have uncovered widespread patterns of antimicrobial resistance (AMR) genes in bacteria across major Indian cities, offering new insights into a growing global health threat.
Antimicrobial resistance occurs when bacteria evolve mechanisms to survive drugs designed to kill them, such as antibiotics. This phenomenon is already responsible for millions of deaths worldwide each year and poses a serious challenge to modern medicine, a press release from the Centre for Cellular and Molecular Biology (CCMB) said.
In one of the most comprehensive studies of its kind in India, the findings, published in Nature Communications, provide the first large-scale map of AMR genes in urban wastewater.
Beyond identifying threats, the researchers propose using wastewater-based pathogen surveillance more widely in the country. They have provided a practical path forward for public health despite the infrastructural challenges in various regions of the country.
The study analyzed 447 wastewater samples collected between March 2022 and March 2024 from 19 sites across four major metropolitan cities—Delhi, Mumbai, Kolkata, and Chennai.
Using advanced "shotgun metagenomics" techniques, researchers examined bacterial genetic material to understand how resistance develops and spreads.
"The study finds that the microbial communities shifted based on local environmental factors. For example, Klebsiella pneumoniae is more abundant in Chennai and Mumbai, and Pseudomonas aeruginosa in Kolkata. But the genes conferring resistance to various antibiotics remained consistent across all four metro cities," it said.
Antibiotics also belong to different chemical classes, such as tetracyclines, beta-lactams, and macrolides.
The researchers also found that bacteria share resistant genes against tetracyclines and beta-lactams far more easily than against macrolides.