When the researchers conducted tests to find out the average number of colony forming units, or CFU, (the unit used to measure the number of bacteria in a sample) in the water, they found it was ten times higher than the permissible limit of 100CFU/100ML. In Mumbai, it was more than 1,000CFU/100ML. Scientists said this was because of the high levels of untreated faecal matter that is released into the sea.
The team also found 54%, or 67 of the samples, tested positive for at least one virulent gene (VG) — which means the organism has the capacity to cause a more complicated form of diseases resistant to drugs. They found all of these VGS were Multiple Antibiotic Resistant, resistant to more than 12 groups of antibiotics that are available to treat them.
The findings are a cause for concern, as certain strains of E-coli possess virulence properties that allow them to cause a wide spectrum of infections in gastrointestinal, urinary, and the central nervous systems (CNS). Every year, more than 120 million cases of gastrointestinal disease, and 50 million cases of severe respiratory diseases are caused worldwide by swimming and bathing in coastal waters that are polluted with sewage.
The research team, headed by Dr Abhay Phulke, collected samples in the pre-monsoon, monsoon and post-monsoon periods in 2015-16. “Dadar had the highest resistance index, followed by Versova, Mahim, Juhu and Girgaum. The multiple antimicrobial resistances among 100% of the virulence genes is worrisome as disease caused by these organisms will be very difficult to treat. These bacteria are the main cause of childhood diarrhoea worldwide, causing more than two million deaths a year,” said Dr Phulke.
Citing previous studies, the scientists said despite the many laws and regulations of the Coastal Zone Management, Environmental Protection Agency and the Pollution Control Boards, partially treated or untreated waste from the city’s septic systems, and storm water run-off from urban and rural areas was finding its way into the sea, degrading the shoreline.
“Overall, it can be concluded that waters in the beaches of Mumbai are of microbiologically poor quality and therefore, effective measures such as proper sanitation, efficient disposal facilities, and wastewater treatment must be taken,” Dr Phulke said