A study published in Nature Communications analysed wastewater from four major Indian cities: Delhi, Mumbai, Kolkata and Chennai. The team collected 447 samples from 19 sites between 2022 and 2024 and used sequencing to map microbes, resistance genes and mobile elements that help resistance spread.
Researchers found many resistance genes across the cities. Bacterial communities differed, but many resistance genes were similar, suggesting common mechanisms. Klebsiella pneumoniae was more common in Chennai and Mumbai, while Pseudomonas aeruginosa dominated in Kolkata, yet overall resistance patterns stayed consistent.
Scientists call sewage an important interface for human activity, antibiotic use and microbial diversity. The 2025 National Action Plan and the One Health approach promote wastewater surveillance. The Indian Council of Medical Research plans to expand surveillance to 50 cities after a pilot in five cities. Critics point to state-level gaps and weak enforcement as obstacles.
Difficult words
- wastewater — used water from homes and cities
- sequence — method to read the order of DNAsequencing
- resistance — ability of bacteria to survive antibiotics
- mobile element — a DNA piece that moves between organismsmobile elements
- surveillance — system for regularly watching public health data
- interface — place or point where different things meet
- enforcement — official action to make rules followed
- pilot — small initial test before larger project
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Do you think wastewater surveillance is useful for public health in your city? Why or why not?
- What challenges might authorities face when they expand surveillance from five to fifty cities?
- How could communities help reduce antibiotic resistance seen in sewage?
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