Test of Bengaluru's open drains reveals major safety hazard

A recent study has discovered large levels of antibiotic-resistant bacteria in Bengaluru’s open drains that cause longer hosiptalisation and higher mortality.

Water samples from 66 sites across all BBMP zones were tested for the study by Precision Health, towards the end of 2021, which looked at how bacteria in the samples responded to five common antibiotics.

The test discovered that 51 per cent of all samples tested against the antibiotic ertapenem were resisting it, meaning the bacteria grew despite the presence of the antibiotic. Similarly, 46 per cent of samples were resistant to the antibiotic ciprofloxacin, 39 per cent to cefixime, 24 per cent to meropenem, and 28 per cent to piperacillin/tazobactam.

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Klebsiella pneumoniae and E. coli were the most commonly detected bacteria, and they were found to have high resistance to antibiotics.

Antimicrobial resistance (AMR) is a global health problem, largely caused by misuse and indiscriminate use of antibiotics.

“The study shows there is a high number of resistant bacteria in the environment, which has safety implications. Water from open drains is used for irrigation downstream or enters lakes, and later comes back to us through the water, crops, or fish we consume,” says Dr Varsha Sridhar, CEO of Molecular Solutions Care Health, which is part of the Precision Health coalition, stressing on the need for community-level surveillance for AMR.

The study also showed that AMR varies widely across different zones, and even among different wards of the same zone.

For example, in the West Zone, the samples collected from Govindarajanagar ward were susceptible to all five antibiotics, whereas those from Nandini Layout were resistant to all.

Among all eight zones, samples from RR Nagar had the highest levels of AMR, and East Zone the least.

These variations show the need for hyperlocal data, which should influence local doctors’ antibiotic prescriptions and drug purchase policies. Currently, most data are from tertiary hospitals only.

As per guidelines, Indian hospitals must review the AMR cases in their labs bi-annually and alter prescriptions, accordingly, says Dr Sridhar.

For example, if a particular bacterium has been showing resistance to an antibiotic, more of another antibiotic can be prescribed.

“I’m not sure how many hospitals actually do this, because lab systems are overworked. Besides, national-level data won’t hold true for a primary health care (PHC) doctor prescribing at the local level,” says Dr Sridhar.

Shirish Harshe, programme lead at Precision Health, says that as per WHO’s global action plan on AMR in 2016, each Indian state is to have a separate plan.

“If Karnataka is going to have a plan, wastewater surveillance will give enough data for the government to make policy decisions about drug prescriptions and people’s drug consumption behaviours,” he says.