A New Approach Towards Antibiotic Resistant Tuberculosis

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Mycobacterium tuberculosis is a deadly disease, and can be very resistant to antibiotics as well. Image courtesy of the US CDC

TB Treatment in 2012

Today, there is a growing incidence of multi-resistant tuberculosis, withstanding the best antibiotics, which is only treatable with costly toxic drugs, which patients in developing countries cannot afford.

According to WHO, of the 5 million or so multiresistant cases during the last decade, only one percent had access to treatment. In 1991, for example, a tuberculosis outbreak in New York was resistant to 11 antibiotics, and cases have also been reported where every antibiotic was ineffective.

Thankfully, these omniresistant bacilli perished with their hosts before they could spread.

In 2012, 1 in 30 of new TB cases worldwide were multiresistant, with some incidents of 1 in 3. Patients relapsed after a first treatment, with on average, 1 in 5 being multiresistant, with peaks up to 65%. The highest numbers were registered in the former Soviet Union.

Resistant cases, which do not react to normal treatments, need to be recognized as early as possible, and immediately treated with effective second-line antibiotics. The laboratory tests to identify resistant TB bugs are cumbersome – the WHO estimates that in 2009 only 11% of multiresistant cases were actually discovered.

Tuberculosis bacilli resistant to major antibiotics are a serious threat to world health, but now, scientists of the Antwerp Institute of Tropical Medicine have redeveloped a forgotten technique which detects resistant tuberculosis in circumstances where this was not previously feasible.

The Test for Multiresistant TB

Checking smears under the microscope remains the recommended technique for TB screening, but it cannot differentiate between living and dead bacilli, so the bacilli found may be the cadavers of a successful treatment, or resistant survivors. If the numbers don’t fall after multiple tests, then the bacilli is identified as a resistant strain, with the patient remaining contagious.

High-tech PCR technology immediately ascertains whether the bacillus is from a resistant strain, but in practice and certainly in resource-limited countries this is unfeasible. It also is impossible to cultivate every sample and then bombard it with every possible antibiotic to survey which ones still work for that individual patient.

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