Better Surveillance Could Have Delayed a Deadly XDR-TB Outbreak

HIV and tuberculosis (TB) will cause the deaths of so many people not only in Africa but also in India and China, that it will change the shape of these societies. Now, researchers have found that better tuberculosis surveillance programmes could have delayed the emergence of extensively drug-resistant strains of TB called Mycobacterium tuberculosis (XDR-TB).

During the study, researchers at the University of KwaZulu-Natal in South Africa found that the failure to test patients with tuberculosis for drug-resistant strains might have encouraged the development of the deadly antibiotic-resistant outbreak of XDR-TB.

The findings have suggested that had better tuberculosis surveillance programmes been in place, antibiotic treatments could have been better tailored to patients.

“The main message to any public health programme anywhere in the world is that you cannot control infectious disease without a surveillance programme,” Nature quoted Willem Sturm, a doctor and microbiologist at the University of KwaZulu-Natal in South Africa and an author on the study, as saying.

XDR-TB is a fatal descendant of the multidrug-resistant strains of tuberculosis that emerged in the 1990s. While multidrug-resistant strains are resistant to the two antibiotics that have traditionally been used as a first line of defence, XDR-TB is resistant to both the first-line antibiotics and at least three of the six remaining second-line drugs. The resulting infection is extremely hard to treat.

The strain was first observed in patients with HIV in KwaZulu-Natal in 2005. Since then, it has infected patients with and without HIV around the globe. Almost 10 percent of cases of multidrug-resistant tuberculosis are now believed to be XDR-TB1.

“Between HIV and TB — not only in Africa but in parts of India and China — there are going to be so many deaths that it will change the shape of those societies,” said Michael Iseman, a doctor at the University of Colorado School of Medicine in Denver, who was not affiliated with the study.

A new survey of drug resistance in tuberculosis cultures taken from infected patients between 1994 and 2005 has revealed that strains found more than a decade ago in the KwaZulu-Natal area were already resistant to several of the antibiotics being used to treat the disease.

Researchers found that the failure to test patients with tuberculosis for drug-resistant strains might have spurred the development of a deadly antibiotic-resistant outbreak by making the local tuberculosis became resistant.

The spread of HIV in the area provided an increasing population of particularly susceptible patients, worsening the problem. Most of the developing countries can’t afford to routinely test tuberculosis cultures, and diagnosis is often based solely on microscopic examination of sputum taken from patients.

“They have no laboratory services. If the smear is positive they treat the patient,” Iseman said. Sturm said that the results have implications for all infectious disease programmes, from malaria to HIV.

"The main point is that we must learn to prioritize surveillance," Sturm said.

Source-ANI
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