War against diseases

When delegates at the 102nd Indian Science Congress in Mumbai last week were listening to the virtues of ancient Indian science and medicine, the world of science was celebrating the discovery of a new antibiotic. Scientists the world over are excited upon this discovery because the new antibiotic is not just the first one to emerge in the past 30 years, but it also promises to tackle the most feared health emergency of the century – antibiotic resistance. Teixobactin, discovered by a team of scientists led by the Northeastern University, is being dubbed a “game changer” because it actually opens up an innovative way of finding antibiotics and thus could spawn a totally new class of antibiotics in future. 

The development comes just when experts were writing epitaphs for antibiotics discovered in the 20th century because most of them have been rendered useless with disease-causing agents having become resistant to them. In many cases, antibiotic resistance is seen spreading faster than the introduction of drugs into clinical practice, forcing the World Health Organization to label drug resistance as a public health crisis. For instance, even the most potent drugs are not working against tuberculosis as the bacterium causing the disease has become resistant. Cases of multi drug-resistant (MDR) tuberculosis – and even extra MDR – have been reported from India. Ailments like urinary tract infections, previously treatable with available drugs, are becoming hard to treat. Many cancer surgeons report that while they are able to save their patients from cancer, their immuno-suppressed bodies are falling prey to drug-resistant infections.  

Teixobactin has raised hopes on several counts. We all know that most modern drugs and treatments have their origins in nature. Millions of bacteria and fungi thrive in nature, both living in harmony and fighting with each other for survival. Therefore, they possess compounds to ward off attacks and survive. If these compounds can be identified and copies made, they become drugs. The reservoir of potential drugs available in nature is so vast and varied that it could take decades to screen, isolate, test compounds and make synthetic copies to be sold as commercial drugs. Most of the currently available antibiotic drugs have been discovered this way, and are based on compounds found through screening of soil microorganisms. These microbes belong to a class that can be cultivated or cultured in lab for multiplication and research. It seems this source has been overmined in search of new drugs in the last half a century. Another source of potential drugs are microbes that are not amenable to culturing and can’t be grown in petri dish. They grow only in natural environments. The scientists behind the present discovery targeted this untapped natural resource successfully.

Second, the methodology deployed to screen microorganisms is also new. Scientists from the Northeastern University used a new technology called iChip that traps thousands of soil bacteria and is then inserted back in the soil for these bacteria to grow in natural environment. Microbes trapped in tiny holes in the chip grow and multiply in the soil, instead of petri dish. Later on when the chip is transferred to lab, it can be screened for potential drug candidates. One such bacteria — Eleftheria terrae — was found to produce the best antibiotic candidate that has been named teixobactin. This means that soil microorganisms that were previously unculturable could still be grown after an intermediary step of growth in an iChip buried in the soil. 

Third, what differentiates teixobactin is the hope that it won’t be rendered ineffective because it will be difficult for disease-causing bacteria to become resistant to it. Teixobactin works against disease agents by binding to fatty lipids that make up the bacterial cell wall, and it is difficult for a bacterium to alter such fundamental building blocks of the cell. This is different from existing antibiotics that target proteins, and it is relatively easy for a microbe to become resistant through mutations that change the shape of the protein. The mechanism of how Teixobactin works has been studied in laboratory mice that were infected with Staphylococcus aureus and Mycobacterium tuberculosis. It is a long way before this drug is tested in humans and if it is found effective, we will have a new weapon against deadly diseases.

While we celebrate the new discovery and hope that Teixobactin will hit the markets in the years to come, let’s not lose sight of the task at hand – fighting drug resistance. The emergence of NDM-1 (New Delhi Metallo-beta-lactamase) enzyme that rendered certain bacteria resistant to drugs a few years ago, raised a storm with both the Ministry of Health and corporate healthcare industry terming it as an attack on India’s medical tourism business. After living in denial for some time, India has finally come to terms with the problem and it is officially recognised that we need to act on this front. A five-year blueprint prepared by medical societies, Chennai Declaration, on curbing misuse of antibiotics in 2012 finally jolted the government into some action. As a first step, 46 antibiotics and anti-TB drugs have been placed under category of restricted drugs, meaning they can’t be sold over the counter. We are yet to see any impact of this measure which was taken in March 2014. Some hospitals, too, have evolved antibiotic policies as suggested in the blueprint. 

Still India has a long way to go when it comes addressing drug resistance given the fact that self medication is rampant.  Average practitioners prescribe antibiotics even for coughs and colds, and pharmacies are only too happy to home deliver drugs without bothering about any prescription. The use of antibiotics in the veterinary sector is completely unregulated. In Delhi’s Bhagirth Place wholesale market, one can buy antibiotics by the kilo. Pharmacies, drug companies as well as doctors represent strong lobbies. Patients too demand ‘strong medicine’ and are too happy to pop pills at will. Preventing misuse and overuse of antibiotics is in indeed a challenge.

That’s why Dr Abdul Ghafur, who first flagged off the NDM-1 threat in 2010 and later steered the Chennai Declaration, feels India needs an ‘implementable policy’ and not a ‘perfect policy’ on antibiotics. The discovery of Teixobactin is, undoubtedly, a giant step, but that should not deter us from acting now on stopping misuse of available antibiotics.

The writer is a columnist and author based in New Delhi