TB bugs outsmart docs

02 June 2014 - 02:13 By Kim Cloete
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Mycobacterium tuberculosis Ziehl-Neelsen stain. The bacteria has been stained red to show up against the blue tissue.
Mycobacterium tuberculosis Ziehl-Neelsen stain. The bacteria has been stained red to show up against the blue tissue.
Image: CDC

Medical science is in danger of losing the fight against drug-resistant TB because too many doctors are prescribing the wrong medication or too little of the correct drugs.

"We're running into an era in which we won't have drugs available because organisms such as TB have developed resistance to them," said Professor Simon Schaaf, a paediatric researcher at the Desmond Tutu TB Centre, at Stellenbosch University.

Schaaf said it is essential that TB drugs be prescribed with great care so that they do not lose their efficacy.

"We're now at the stage we were in in the early 1990s, when we were waiting for new drugs with which to treat multidrug-resistant TB.

"Now we've used up our chances. We need to help the patients but also protect the efficacy of the drugs," he said.

Schaaf, who was recently awarded the National Order of Mapungubwe (silver) by President Jacob Zuma for his ground-breaking work on drug-resistant TB, said doctors must have a better understanding of TB treatment.

"We are not thinking carefully enough about what we are doing, largely because of ignorance. If you're only giving one, or too few drugs, resistance can develop."

He said doctors and nurses needed to be careful about monitoring whether the medication was working.

Patients can become drug-resistant if they do not take their medication exactly as prescribed.

"Sometimes, when patients fail to respond to ordinary treatment after six months, they're put on the same medication again, adding only one drug. By doing this, they become resistant to all TB drugs.

"This has caused a huge problem and cases of extensive drug-resistant TB, which can be fatal."

Schaaf said a combination of drugs was essential. He recommends that at least four drugs be prescribed for someone with drug-resistant TB.

"You need the combination of drugs so that the drugs can protect each other from resistance mutations. If one doesn't work, the others might," he said.

Schaaf's work has proved that multidrug-resistant TB can be treated successfully. Children with multidrug-resistant TB have a cure rate of 90%, compared with a 50% to 60% rate for adults.

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