Drug resistant cholera in India attributed to antibiotic misuse

Indian microbiologists have said that the widespread misuse of antibiotics in India has led to the emergence of drug resistant cholera, in a rerun of events that involved typhoid a decade ago.

Strains of Vibrio cholerae in India have become resistant to several antibiotics, and multidrug resistance is increasing, researchers at the National Institute of Cholera and Enteric Diseases in Calcutta said. Studies on V cholerae strains isolated from patients in eastern India over the past six years show that the bacilli are resistant to several old as well as new antibiotics, including ampicillin, tetracycline, furazolidone, norfloxacin, and ciprofloxacin.

“Our list of antimicrobial agents still effective against cholera is shrinking,” said Dr Sujit Bhattacharya, director of the National Institute of Cholera. “The emergence of resistance to specific antibiotics almost parallels the sequence in which the drugs were introduced in the marketplace.” Enteric infections represent a major public health problem in India, with diarrhoeal diseases accounting for an estimated 600 000 deaths each year in children aged under 5 years.

The Indian health ministry has periodically issued advice to doctors and the public against the routine use of antimicrobial agents in diarrhoea, but microbiologists say that the use of antibiotics is still “capricious.” Government surveys show that nearly 50% of patients with diarrhoea in India are treated with antimicrobial agents, although less than 15% actually need them.

The emergence of multidrug resistant Salmonella typhi across India during the early 1990s had also been attributed to the indiscriminate use of antibiotics. “Lessons clearly haven't been learnt,” said Dr Maharaj Kishen Bhan, professor of paediatrics at the All India Institute of Medical Sciences in New Delhi. “Things seem to have actually become worse,” he said.

Microbiologists point out that pharmaceutical companies produce drugs containing two antimicrobial agents—for example, combinations of norfloxacin and metronidazole, or ciprofloxacin and tinidazole. “The market is flooded with such irrational combinations that are often wrongly prescribed for diarrhoea,” said Dr Bhattacharya. The new study, published in the latest issue of the Indian Journal of Medical Research (2000;112:78-85), says that V cholerae strains may be transferring multidrug resistant traits among each other.

“A chronological analysis suggests that resistance has moved from Vibrio cholerae serotypes non-01 and non-0139, associated with sporadic cases of cholera, to serotypes 01 and 0139, which are associated with epidemics,” said Thandavarayan Ramamurthy, assistant director at the National Institute of Cholera and Enteric Diseases.

Last week the institute began to train microbiologists from across India in molecular epidemiology techniques to correlate different serotypes of V cholerae with drug susceptibility in an attempt to track drug resistance nationwide.