Bacteria That Cause Leprosy Are Undergoing Scary Mutations That Resist Drug Treatments

Leprosy has ravaged communities throughout history, dating back to ancient civilizations, but, thanks to modern medicine, it has become less of a threat in industrialized societies. But a new study reveals that the bacteria responsible for the disease, Mycobacterium leprae, may be mutating to become resistant to treatment.

Related: British Squirrels Carry Leprosy Strain that Plagued Medieval Humans 

1_30_2018_Leprosy A patient with Leprosy in his hospital room on January 30, 2017. Researchers say that the bacteria causing the disease appears to be mutating to become resistant to treatment. TAUSEEF MUSTAFA/AFP/Getty Images

For the study, published in Nature Communications, researchers analyzed 154 genomes of the bacteria from 25 countries. Among the samples, 147 were from human, six were from red squirrels and one came from an armadillo. The team found that eight strains of the bacteria had mutations, specifically to one particular gene that helps repair damage. These particular strains were also resistant to damage.

As study co-author Andrej Benjak of the research institute Ecole Polytechnique Fédérale de Lausanne in Lausanne, Switzerland told Cosmos magazine, the gene mutations represent a gamble for the bacteria. “It's a fascinating survival strategy against antibiotics,” he said. “Disrupting DNA repair will result in a storm of random mutations, increasing the chance that the right gene mutates at the right spot and lead to drug resistance. But random mutations can be deadly, so it's like a desperate, genetic Russian roulette for the bacterium.”

The researchers are concerned these mutations could make the disease more dangerous. 

“Drug resistance is alarming for leprosy control,” they write, further arguing that more research should be done to see how the mutations could contribute to the rise in drug-resistant strains.

They note in the report that while leprosy responds to treatment and isn't dehabilitating when caught early on, it is still a public health concern in South America, Africa and parts of Asia, which have more than 200,000 new cases each year.

Since the 1980s, doctors have used the medications rifampicin, dapsone and clofazimine, along with a few others like ofloxacin, minocycline and clarithromycin to treat leprosy. But more cases of bacteria resisting these treatments have been reported, making this discovery particularly important.

The researchers also discovered that leprosy might have originally hailed from Asia, but tracking down the disease’s origin will be tricky.

“We need more samples from Central Asia and the Middle East, but these are hard to get due to current geopolitical issues,” study co-author and infectious disease expert Charlotte Avanzi told Cosmos.

According to the World Health Organization, leprosy impacts the skin, peripheral nerves and eyes, but has typically been curable and long-term disability has for the most part been avoidable. Though the disease dates back to ancient times, the WHO explains that the medication, dapsone, was the first medication to treat M. leprae during the 1940s. By the 60s, however, the bacteria became resistant to what was then the only leprosy medication. New drugs, rifampicin and clofazimine, have since been discovered and supplemented the original treatment to form this multi-drug therapy.

The new study indicates that these drugs may also become less effective with time, making further research invaluable to controlling leprosy. 

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