Drinking India’s tap water can yield more than a bad case of Delhi belly.
Scientists testing water samples from New Delhi found more than a dozen species of bacteria, ranging from strains that cause pneumonia to cholera. The bugs had genes that enable them to resist almost all medicines, according to a study published today in the medical journal The Lancet.
The research exposes the role played by India, a booming economy with more mobile-phone subscribers than toilets, in fanning the development of drug-evading bacteria. As 30 million people fly out of the country annually, some are leaving with bowel-dwelling bugs that may cause deadly sepsis and defeat the most powerful antibiotic treatments.
“There is not even a light you can see at the end of this dark tunnel,” said Peter Collignon, an infectious diseases doctor who teaches at the Australian National University in Canberra. “People are dying from infections that are no longer treatable with available antibiotics.”
The researchers, led by Timothy Walsh of Cardiff University in Wales, collected 171 swabs from some of the drains that line New Delhi’s streets and 50 samples of public tap water in September and October. The samples were tested in the U.K. to identify the bacteria they contained and whether the germs had a gene known as NDM-1, which makes them resistant to a class of antibiotics-of-last resort known as carbapenems.
The gene was found in two of the drinking-water and 51 of the seepage samples, including in Vibrio cholerae, Shigella boydii and nine other bacteria species not previously reported to harbor the resistance mechanism.
Losing ‘Miracle Cures’
The bacteria have been detected in patients traveling to Europe, North America, Asia and Australia since 2008. Cases were often linked to hospitalization in India and neighboring countries, the authors said. Today’s paper points to the environment as a new route of infection.
Concern that antibiotics are becoming powerless weapons is growing, and the United Nations picked drug resistance as its theme for today’s World Health Day. Sixteen antibiotics were approved between 1983 and 1987, compared with only two since 2008, according to the Infectious Diseases Society of America.
“The world is on the brink of losing these miracle cures,” Margaret Chan, director-general of the World Health Organization, said in a statement today. “In the absence of urgent corrective and protective actions,” Chan said we may enter “a post-antibiotic era, in which many common infections will no longer have a cure and, once again, kill unabated.”
Escaping the Gut
More than 100 million Indians may possibly harbor bacteria with the NDM-1 resistance gene if the study’s findings reflect community-wide dissemination, Walsh said in an interview.
“They’re carrying it as normal flora” in their gastrointestinal tract, Walsh said, adding that surveys based on rectal swabs are needed to gauge prevalence. “I imagine it’s going to be alarmingly high from what we’re seeing.”
Eighteen percent of public water samples tested at more than 600 sites in New Delhi were tainted by E. coli, Salmonella, or some other disease-causing bacteria found in human excreta that made the water unfit for drinking, according to a survey this year by the Municipal Corporation of Delhi.
As long as the resistant bacteria remain in the bowel, most people have no symptoms. Complications occur when the germs escape from the bowel, entering other parts of the body, including the bloodstream.
Boil the Water
Bladder infections caused by the resistant bugs pose one of the biggest health threats as bowel bacteria commonly invade the urinary tract, particularly in women, Walsh said.
“If the bacteria is NDM-1 positive and shows the resistance profiles that we know it can, that virtually becomes untreatable,” Walsh said. Germs that migrate to the kidney may enter the bloodstream and cause sepsis, he said.
Boiling water for 10 to 15 minutes should kill most bacteria, according to Daniel Watts, a retired chemist who worked on pollution prevention strategies at the New Jersey Institute of Technology in Newark.
The findings expose the extent to which a lack of sanitation is holding back India’s economic development. A shortage of toilets and inadequate sewage treatment trimmed 6.4 percent from India’s gross domestic product in 2006, or the equivalent of $53.8 billion, a study by the World Bank’s Water and Sanitation Program found.
“You can’t just wish this away,” said Vinod Paul, professor of pediatrics at the All India Institute of Medical Sciences in New Delhi. Paul blames “rampant” resistance in Klebsiella, E. coli and Streptococcus bacteria for rising rates of hard-to-treat sepsis in newborns. “We don’t have a handle on how to tackle this.”
Fifty-four percent of the 1.2 billion people in India, the second-fastest growing of the world’s major economies, lacked a toilet in 2008 and were forced to defecate in fields, on riverbanks and railway tracks and other open spaces, according to a 2010 United Nations report. Only one in five people had water piped into the home.
Lack of sanitation and clean water indirectly challenge India’s hospitals -- even the private centers that undertake organ transplants and other sophisticated surgeries, said David Livermore, director of antibiotic resistance monitoring at the U.K.’s Health Protection Agency in London.
“How does the hospital isolate itself when its patients, staff and food all come from outside, where they are exposed to this soup of resistance?” Livermore said in an e-mail yesterday. “Combine sophisticated medicine, poor sanitation, and heavy antibiotic usage and you have a rocket fuel to drive the accumulation of resistance -- and that surely is what India has created.”
U.K. Issues Alert
Public water supplies in urban India typically run for only a few hours a day. Bacteria may concentrate in stagnant water inside pipes, according to Walsh. He also found that resistance genes passed among bacteria best at 30 degrees Celsius (86 degrees Fahrenheit), a temperature reached in New Delhi about seven months of the year.
Evidence of multidrug-resistant bacteria in tap water and drains “probably represent a huge environmental contamination,” said Robert Bonomo, professor of pharmacology and microbiology at Case Western Reserve University and a doctor at the Cleveland VA Medical Center in Ohio. “I bet a lot of people are not happy about that finding.”
Below the Waterline
Hospitals in the U.K. began reporting NDM-1 cases in mid-2008. In July 2009, the HPA issued an alert asking doctors to look out for the bacteria in patients who had visited hospitals in the Indian subcontinent. Last August, Walsh and colleagues reported that NDM-1 was present in 1.9 percent of bacteria samples from patients in the states of Tamil Nadu and Haryana.
India’s government in response created an expert group to advise doctors and the public on antibiotic usage.
“We misuse the drugs very often,” Vishwa Mohan Katoch, director-general of the Indian Council of Medical Research in New Delhi, said in an interview yesterday. “Resistance emerges and that antibiotic becomes useless,” limiting the choice of effective medicines and increasing the reliance on more expensive treatments, he said.
Improper use of antibiotics, including their sale without a doctor’s prescription, has probably helped drive the emergence of resistant bacteria, according to Walsh.
“This idea of stopping non-prescribed antibiotics is a good one, but it’s too late,” Walsh said. “The damage has been done. The part of the iceberg below the waterline is now massive.”