New Delhi, April 17: The seawater near some of Mumbai's popular beaches carries antibiotic-resistant bacteria that could endanger public health and may have emerged from poorly treated sewage, government scientists have said.

Scientists from the National Institute of Oceanography's regional centre in Mumbai claim to have detected faecal bacteria called E. coli in seawater and sediment samples from Chowpatty, Dadar, Mahim, Juhu and Versova beaches.

They said the bacteria were resistant to multiple antibiotics and their count was higher than permissible limits.

The study underscores the need for government and municipal authorities to bolster sewage treatment and coastal management to prevent "serious health risks associated with these contaminated coastal waters", the researchers said.

The NIO scientists and a clinical microbiologist not associated with the study have said the findings are not surprising and should be seen as a fresh reminder of the need to curb antibiotic abuse.

But they have also asserted that there is no cause for panic because there is no evidence yet to link the E. coli from the beaches to infections in Mumbai.

Some faecal bacteria may cause no symptoms at all but others can cause severe gastrointestinal, respiratory, eye, nose, ear and skin infections, the researchers have said, describing their findings in the journal Environmental Science and Pollution Research.

An independent study by a US-based scientist had in 2003 estimated that swimming and bathing in wastewater-polluted coastal waters contributed to over 120 million cases of gastrointestinal disease and 50 million cases of severe respiratory disease.

Scientists say that swimmers and recreational beach users do not need to gulp seawater to expose themselves to the bacteria.

"Exposure may also occur through direct skin contact with the polluted beach water," said Abhay Fulke, a microbiologist at the NIO who led the study.

The researchers cited a 2014 study that estimated that about two million cubic metres of partially treated or largely untreated domestic sewage generated by Mumbai city enters the sea each day and tidal currents push the pollutants back towards the beaches.

Fulke and his colleagues studied the E. coli because this bacteria has long been considered an indicator of faecal contamination of seawater. They found isolates of E. coli resistant to more than seven antibiotics at all the five beaches studied.

All the 38 E. coli samples they studied were resistant to an antibiotic called augmentin, used most commonly to treat urinary tract infections. The 100 per cent resistance to augmentin is "a cause for concern", the scientists said.

Several of the E. coli isolates were also resistant to other antibiotics, including ampicillin, nalidixic acid, cephalothin, cefixime, ciprofloxacin, cefuroxime and cefpodoxime.

The NIO scientists have speculated that the observed patterns of resistance may reflect a trend of growing antibiotic resistance through the over-prescription and abuse of antibiotics.

"This is a reminder that we need urgent interventions to stop the abuse of antibiotics," said Chand Wattal, a senior consultant microbiologist at the Sir Ganga Ram Hospital, New Delhi, who was not associated with the study.

"However, I would not worry too much about drug-resistant E. coli in the water unless we have evidence through genotyping studies that they are connected to infections or outbreaks in Mumbai," he said.

To gather such evidence, scientists would need to compare E. coli from patients' infections and the seawater.

A senior NIO scientist who collaborated with Fulke in analysing the E. coli said the observation was unlikely to be unique to Mumbai.

"Along the coastline, wherever we have inadequately treated sewage discharged into the sea, we're likely to find similar antibiotic resistance," the scientist said.

Health experts have been urging the Indian government to crack down on antibiotic abuse for over a decade.

The Union health ministry has initiated what officials have said will be a coordinated programme involving the health, pharmaceuticals and the animal husbandry departments to curb antibiotic abuse.