Antibiotic resistance to colistin – UPSC GS3

India’s poultry farms are spawning global superbugs by giving medicines to the birds to protect them against diseases or to make them gain weight faster so more can be grown each year at greater profit. One drug typically given this way is colistin.

Researchers who tested meat from supermarkets in the country in 2014 found residues of six antibiotics, suggesting they were being used liberally on farms.

Doctors call it the ‘last hope’ antibiotic because it is used to treat patients critically ill with infections which have become resistant to nearly all other drugs.

The World Health Organisation has called for the use of such antibiotics, which it calls “critically important to human medicines”, to be restricted in animals and banned as growth promoters.

Their continued use in farming increases the chance that bacteria will develop resistance to them, leaving them useless when treating patients.

Thousands of tonnes of veterinary colistin was shipped to countries including Vietnam, India, South Korea and Russia in 2016, the Bureau of Investigative Journalism can reveal. In India, at least five animal pharmaceutical companies are openly advertising products containing colistin as growth promoters.

A colistin-resistant gene was discovered in Chinese pigs in 2015.

The gene, mcr-1, could be transferred within and between species of bacteria. That meant that microbes did not have to develop resistance themselves, they could become resistant just by acquiring the mcr-1 gene.

The discovery was met with worldwide panic in the medical community as it meant the resistance could be passed to bugs which are already multi-drug resistant, leading to untreatable infections.

Rampant use of the drug in livestock farming has been cited as the most likely way mcr-1 was spread. It has been detected in bacteria from animals and humans in more than 30 countries, spanning four continents. Another four colistin resistant genes (mcr-2 to mcr-5) have been discovered.

Bugs bred in the country spread globally. One which particularly worried scientists is a gene called New Delhi metallo-beta-lactamase 1 (NDM-1), which makes bugs resistant to carbapenem antibiotics.

This has been dubbed “the nightmare bacteria” by the Centers for Disease Control and Prevention in the U.S. because it kills half the patients who develop a bloodstream infection.

NDM-1 was first found in a patient who acquired it in India in 2008 and has since spread all over the world, with over 1,100 laboratory-confirmed cases in the U.K. since 2003.

Unregulated sale of the drugs for human or animal use — accessed without prescription or diagnosis — has led to unchecked consumption and misuse.

Overuse of the drugs in hospitals has created antibiotic resistant hotspots, and poor infection control means these bugs spread within the hospital and into the community. Some of the pharmaceutical companies manufacturing antibiotics have also failed to dispose of antibiotic-ridden waste properly, fuelling the spread of resistant bugs in the environment.

All of these factors have led to high rates of resistance. In India, 57% of the Klebsiella pneumoniae bacteria — which commonly cause urine, lung and bloodstream infections — are resistant to last-line antibiotics known as carbapenems.

There is no legal requirement for one in the country as Colis V was bought over the counter from a poultry feed and medicines shop in Bangalore without a prescription.

In 2014 the Agriculture Ministry sent an advisory letter to all State governments asking them to review the use of antibiotic growth promoters. However, the directive was non-binding, and none have introduced legislation to date.

In its National Action Plan on AMR published in 2017, the Centre banned using antibiotics as growth promoters. The plan is not currently linked to any regulatory action.

The World Health Organisation released guidelines in November 2017 recommending reducing use of critically important antibiotics in food-producing animals and banning their use as growth promoters. It also recommended banning the mass medicating of livestock with antibiotics to prevent disease.

Using antibiotics as growth promoters has been banned in the European Union since 2006, and was made illegal in the U.S. in 2017.

In Europe, colistin is available to farmers only if prescribed by a vet for the treatment of sick animals.