The discovery of the New Delhi mettallo-beta-lactamase-1 (NDM-1) in 51 of 151 sewage samples and two of 50 drinking water samples taken from India's capital indicates that the superbug is present in the environment and is no longer a hospital-born infection. The study published online in The Lancet Infectious Diseases journal (“Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health: an environment point prevalence study,” by Timothy R. Walsh et al .) found that the NDM-1 gene has spread to families of gram-negative bacteria like E. coli that populate the human gut. The drug-resistant gene has been found even in pathogenic bacteria that cause cholera and dysentery. Transfer of the NDM-1 gene to bacteria belonging to a different species is possible as it is carried in the plasmids, which are capable of moving from one bacterium to another. Transfer of the plasmids carrying the NDM-1 gene was highest at 30°C, the average peak temperature, and within the daily temperature range of New Delhi from April to October. Most importantly, the transfer has been facilitated by poor sanitation, as reflected by the oral-faecal route of transmission.
It is clear that the two papers (August 2010 and April 2011) have at last shaken the government, which has initially been in denial, out of its slumber and inaction. The Indian Council of Medical Research has invited research proposals from scientists to generate scientific evidence on antimicrobial resistance. This move indicates that the apex medical research body has finally realised there is no place for jingoism in matters of science, and that the latest findings must be taken seriously and verified scientifically. The exercise will prove useful only if researchers are truly free to report the presence of the superbug and the extent of its spread. The second important development has been the drafting of the much-needed national policy for containment of antimicrobial resistance. The policy admits that the use of antibiotics is inappropriate in 20 per cent to 50 per cent of cases. It targets the indiscriminate use of antibiotics in food animals and intends to curb the practice since it ultimately causes drug resistance in humans. Most importantly, access to third generation antibiotics like carbapenems is to be restricted to tertiary hospitals. But even in these hospitals, efforts must be directed toward restricting its use to patients with severe infections. The government should waste no time in creating a national surveillance system for measuring antibiotic resistance if it is serious about getting on top of the problem.
Correction
(* * The editorial, “The superbug effect” (April 23, 2011), said: “The discovery of the New Delhi mettallo-beta-lactamase-1 (NDM-1) in 51 of 151 sewage samples and two of 50 drinking water samples taken from India's capital indicates that the superbug is present in the environment and is no longer a hospital-born infection.” It should have been 71 of 151 sewage samples.)
