Common AMR genes found across Indian cities, reveals CCMB study
Hyderabad: Scientists have identified similar antimicrobial resistance (AMR) genes in bacteria across major Indian cities, highlighting the growing threat of drug-resistant infections and the need for wider surveillance.
Wastewater surveillance proposed as cost-effective public health tool
Researchers from the CSIR-Centre for Cellular and Molecular Biology (CCMB) and partner institutions have published a study in Nature Communications that presents the first comprehensive AMR map in Indian urban wastewater.
Antimicrobial drugs such as antibiotics are used to treat bacterial infections. However, many bacteria are becoming resistant, making treatment less effective. This condition, known as antimicrobial resistance, is linked to millions of deaths globally each year. Despite the risk, India has limited data on local AMR prevalence.
The study used a shotgun metagenomics approach to examine bacterial genes and understand resistance mechanisms. Researchers analysed 447 wastewater samples collected from 19 sites across Delhi, Mumbai, Kolkata and Chennai between March 2022 and March 2024.
Findings showed that while different bacterial species dominate in different cities, the genes responsible for antibiotic resistance were largely similar across locations. Microbial communities varied due to local environmental factors.
For instance, Klebsiella pneumoniae was more abundant in Chennai and Mumbai, while Pseudomonas aeruginosa was more prevalent in Kolkata. However, resistance-conferring genes were consistently detected across all four metro cities.
Scientists noted that bacteria develop resistance through specific genes. These genes can strengthen bacterial cell walls, enable microbes to expel or break down antibiotic molecules, or alter metabolic pathways. Such genes can spread not only to offspring but also to neighbouring bacteria.
The study also examined resistance patterns against different antibiotic classes, including tetracyclines, beta-lactams and macrolides. Researchers found that resistance genes against tetracyclines and beta-lactams are more easily shared among bacteria than those against macrolides.
Standard protocol enables wider surveillance despite infrastructure gaps
Beyond mapping risks, the researchers recommended expanding wastewater-based pathogen surveillance across the country. They suggested this approach could help detect outbreaks early and monitor the spread of drug-resistant pathogens in real time.
“We have developed and validated a Standard Operating Procedure that allows effective sample storage at 4°C for up to seven days without compromising data quality. The samples can be sent to common testing hubs, which suits resource-limited settings,” said Vinay K Nandicoori, director, CSIR-CCMB.
He added that broader participation in wastewater-based surveillance could strengthen public health preparedness despite infrastructural challenges.
