The challenge of tackling rising drug-resistant infections in India has just become more difficult.
Two new drug combinations, approved by the U.S. Food and Drug Administration (FDA) for their efficacy in treating infections resistant to even third-generation antibiotics — carbapenems — have been found to have limited efficacy in India.
For close to two months, microbiologists at the Christian Medical College (CMC), Vellore, have toiled to test the efficacy of two combination drugs — ceftazidime/avibactum and ceftolozane/tazobactum approved by FDA in February 2015 and December 2014 respectively — on samples collected from various hospitals from across the country. The drugs were given to CMC to check the response to them in India, as part of a global efficacy study before they are launched in the market.
“These are already approved by the FDA based on their study in America that found the drugs to be effective. But that may not apply to India where it will have limited effect. If the drugs work on 10 cases in the US, they will work on three or four cases in India,” said Dr. V Balaji, head of microbiology, CMC. The big concern is that carbapenems should be sparingly used to ensure they remain effective on infections resistant to the strongest antibiotics. “There are no new antibiotics hitting the market so we have to reduce the use of carbapenem and for that we need better combination drugs (to treat these infections),” said Dr. Balaji.
Doctors said the likelihood of death is higher in critically ill patients or those with suppressed immunity (following chemotherapy or organ transplants) if they acquire drug-resistant infections.
Enzyme causes failureIndia’s worry is rooted in the enzyme that makes the bacteria resistant here to the strongest antibiotics — the contentiously named New Delhi metallo-beta-lactamase-1 (NDM-1) and ‘Oxa-48-like-carbapenemase’. This is different from the resistance mechanism seen in the U.S. where the enzyme that makes the bacteria resistant to antibiotics is often KPC — Klebsiella Pneumoniae Carbapenemase. So while the combination drugs worked on KPC, they were not strong enough against the NDM-1 and Oxa-48-like carbapenemase.
“These two combination drugs may add valuable options for treating bacterial infections in North America and European countries where KPC is the predominant mechanism of resistance. In India, NDM-1 followed by Oxa-48-like carbapenemase is the common resistance mechanism. Therefore, these drugs may not help in the Indian setting,” the CMC said in an e-mail response to The Hindu .
Resistance to antibiotics has been rising in India, mainly because of their indiscriminate use to treat even routine infections. Earlier this year, economist Lord Jim O’Neill had said that India’s mounting drug-resistant infections could claim a million lives by 2050.
That India’s drug-resistance problem is a global concern became evident late last year when the U.S. government’s Global Health Security Agenda pumped in $8 million to map anti-microbial resistance and build capacities to tackle it better.
