WHAT IS IT? Sudan strain of TB

What is it?

It’s a highly mutated strain of tuberculosis bacteria that was discovered in southeastern Sudan in 2015. According to the World Health Organisation, five people in the region had been diagnosed with the resistant strain, a type of TB in which the bacteria are resistant to at least two classes of antibiotics. A laboratory in Germany was able to test samples from four of those five, the most recent being from a 43-year-old woman in January this year. The combination of the two sets of bacteria made the woman resistant to treatment for both injectable treatment and a combination of antibiotics called nebulisation – a way of killing the bacteria by blowing certain substances into their lungs.

How common is it?

Less common than one in a million.

What causes it?

Dr Simon Eccles, a malaria expert at Imperial College London, told the Guardian this month that the experts involved in the Sudan study were “giddy at the prospect” that the strain might play a role in stopping transmission of the disease. It was clear that a different type of TB caused by multiple mutations would increase survival rates, but how “grand slam” the mutation was wasn’t clear, he said. As with most TB bacteria, it has developed resistance to a type of antibiotic called fluoroquinolones, a new class of agent in the class of carbapenems. Scientists have been working with the drug-resistant bacteria in an attempt to reverse the resistance by combining fluoroquinolones with other drugs.

Who’s at risk?

Dr Sebastien Delmas, a TB specialist at the Pasteur Institute in Paris, told the Guardian that while the strain is unlikely to kill people, it could affect new diagnoses of drug-resistant TB and “increase the uncertainty in terms of the current detection methods”.

Why was the strain discovered in Sudan?

There is little history of TB in Sudan, which is a mixed ethnic and geographic mix of Christians, Muslims and animists. The research was carried out to understand transmission patterns of the disease, particularly in the process of drug-resistant TB diagnosis. In May, Dr Ronny Shih, who is based at the International Centre for Diarrhoeal Disease Research, Bangladesh, told the Guardian that TB transmission in Sudan was expected to increase and adapt to new-age antibiotics. “The highest risk is the rapid spread of drug resistant TB into population. The lineages of these resistant TB strains are international and don’t require co-movement of people, such as with Middle East respiratory syndrome coronavirus.”

Is there an effective cure?

Research into how to develop a cure has previously shown signs of progress. Dr Michael Mendell, deputy director of the TB Centre of Excellence at the London School of Hygiene and Tropical Medicine, said in 2016 that early development of the second-line drugs had begun in Sudan. Several of the patients were on a cocktail of the treatments, he said, and the few remaining months left until treatment would be impossible for patients to get the cure.

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