For many tribal families across the forests and foothills of Kerala, Tamil Nadu, and Karnataka, access to safe drinking water remains uncertain, often purchased in cans, fetched from distant hand pumps, or drawn from sources about which they know little.
Published Dec 19, 2025 | 7:00 AM ⚊ Updated Dec 19, 2025 | 7:00 AM
Children drinking water from a hand pump.
Synopsis: A study from some of India’s most isolated tribal communities found that antimicrobial resistance is widely present even in populations with little or no exposure to antibiotics, challenging the assumption that resistance is driven primarily by clinical drug use. The study is significant since for many tribal families across the forests and foothills of Kerala, Tamil Nadu, and Karnataka, access to safe drinking water remains uncertain.
A study of gut microbiomes from some of India’s most isolated tribal communities has found that antimicrobial resistance (AMR) and antimicrobial resistance genes (ARGs) are widely present even in populations with little or no exposure to antibiotics, challenging the assumption that resistance is driven primarily by clinical drug use.
The findings suggest that everyday consumption of unprotected drinking water may be a key route through which resistant microbes and genes enter and persist in the human gut, highlighting the environment — rather than medicine alone — as a critical front in India’s growing AMR challenge.
For many tribal families across the forests and foothills of Kerala, Tamil Nadu, and Karnataka, access to safe drinking water remains uncertain, often purchased in cans, fetched from distant hand pumps, or drawn from sources about which they know little.
To understand how these daily realities shape health in these communities, South First spoke to members of two Particularly Vulnerable Tribal Groups (PVTGs) — the Irulas and the Kuruwas — who shared the concerns they live with but are rarely asked about.
The 2025 study titled “Antimicrobial resistance: A one health metagenomic study of Indian tribal gut”, led by SA Mollick and team, focused on 103 healthy adults from three Particularly Vulnerable Tribal Groups — Irula, Jenu Kuruba, and Kurumba — across Tamil Nadu, Karnataka, and Kerala.
Researchers combined stool sample metagenomic sequencing with socio-demographic data, including participants’ primary water source and residential context, to understand how environmental and lifestyle factors shape antimicrobial-resistance genes (ARGs) in the gut.
By sequencing the entire microbial DNA from each sample, the team was able to identify and quantify resistance genes, providing a detailed picture of how local environments influence gut resistomes even in communities with minimal antibiotic use.
One of the most striking findings was that the type of drinking water — stream or tubewell — strongly influenced the variety and nature of antimicrobial-resistance genes. Those relying on stream water carried a broader diversity of resistance determinants, particularly genes linked to metals, biocides, and multi-compound resistance.
In contrast, tubewell users showed higher levels of antibiotic-specific resistance genes. The researchers also observed that metal-resistance genes were significantly enriched in people consuming stream water, suggesting that exposure to heavy metals and other environmental factors can unintentionally select for antibiotic resistance, a process called co-selection.
Analysis using Principal Coordinates Analysis further confirmed a clear separation between the gut resistomes of stream-water and tubewell-water consumers, demonstrating how closely resistance patterns are tied to the environment and daily exposure.
At the same time, the study acknowledged important limitations. It did not directly examine water, soil, food, or livestock for resistance genes, and it measured only the presence of ARGs rather than their activity or potential for transfer between bacteria.
Even with minimal antibiotic use, environmental exposures alone can shape gut resistomes in isolated communities. The study highlights the need for safe water, monitoring, and integrated One-Health strategies.
Radha, an Irula resident of Puliyur in Thirukalukundram in the Chengalpattu district of Tamil Nadu, said her family has long relied on buying water cans because the local supply line has remained out of service.
“We get drinking water from the church,” she said, explaining that each 20-litre costs ₹30. Despite repeatedly approaching the village head and the local MLA, she said, “No one has done anything” to restore the government-provided water.
When deliveries are delayed, her children end up drinking whatever is available nearby. Radha said the water often contains insects and debris, and illnesses routinely follow.
“I get a fever,” she said. “My children get many diseases; we can’t say we won’t get sick, because we definitely do.” Treatment depends on what is accessible that day — sometimes a government hospital, sometimes a nearby medical shop.
Radha’s story is not an outlier. Across Irula and Kuruwa settlements in the region, families describe a cycle of poor water access, recurring illness, and fragile healthcare support that leaves them constantly vulnerable — long before any laboratory detects the rise of antimicrobial resistance.
In Kothimangalam, Vasantha, a member of the Irula community, said that the families there rely on water drawn from a nearby lake-fed well, despite its far-from-ideal conditions.
“There is always a little salt in the water,” she said. “And sand too — we can see it.” “It is the only source available, so everyone drinks from the well,” she explained.
When asked about illnesses, she insisted they “don’t get many diseases,” but quickly added that if anyone fell sick, they have no choice but to travel out.
Travelling for care is a struggle: “I have to take a bus or an auto to go to Nandambakkam,” she said — the closest point where treatment is accessible.
Beside her stood Ravi, from the Kuruwa community, who cut in and explained the broader issue: Their settlement still has no motorable road. “The road is closed”, he said.
Residents said they have repeatedly raised the issue with local elected representatives, including during election visits, but the situation has not improved.
“They came asking for votes,” Ravi said, “but nothing has changed.” The well water, he added, is entirely dependent on groundwater and rain.
“If it rains, there will be water,” he said. “If there is no rain, the water level gets worse.”
Taken together, the lived experiences of Radha, Vasantha, and Ravi underscore a simple but urgent reality: For many tribal communities, water is not just scarce or inconvenient — it is unpredictable, untreated, and often the first point of exposure to invisible risks.
Dr Rajeev Jayadevan, a gastroenterologist and a functionary of the Indian Medical Association, highlighted that AMR has multiple causes beyond antibiotic misuse.
“Untreated water can contain bacteria already resistant to antibiotics, either from prior human use or indirectly through contaminated food such as vegetables, fruits, or meat,” he explained.
Agricultural practices also contribute: Manure and runoff can carry antibiotic-resistant bacteria, while careless disposal of medical waste exposes environmental bacteria to drugs, gradually fostering resistance.
He further explained how resistance spreads among bacteria themselves. “Once bacteria develop resistance, they can transfer that ability to other bacteria nearby through horizontal gene transfer, using plasmids or other genetic material,” he said.
Environmental exposures also play a role: Bacteria develop pumps to expel toxic substances such as heavy metals, and resistance genes for metals and antibiotics often coexist. This means exposure to metals in polluted water can unintentionally select for antibiotic resistance, a process called co-selection.
Overuse of antibiotics remains the main driver of AMR. Patients with repeated hospitalisations or multiple rounds of antibiotics tend to have more resistant infections.
In India, over-the-counter antibiotic sales and self-medication exacerbate the problem, though measures like Kerala’s restriction on selling antibiotics without a prescription have proven helpful.
Dr Jayadevan stressed that public health measures beyond rational antibiotic use are equally critical. “Providing safe and clean drinking water reduces waterborne diseases and limits exposure to resistant bacteria. Unless we address all contributing factors, from unsafe water to misuse of antibiotics, we cannot effectively control AMR.”
(Edited by Muhammed Fazil.)
