Breaking News

XDR TB in South Africa traced to lack of drug susceptibility testing / inadvertently helped to create a new strain of TB

Public release date: 22-Oct-2007

XDR TB in South Africa traced to lack of drug susceptibility testing

In South Africa, the 2001 implementation of the World Health Organization’s anti-tuberculosis program may have inadvertently helped to create a new strain of extensively drug-resistant tuberculosis (XDR TB). In a new study published in the December 1 issue of Clinical Infectious Diseases, currently available online, researchers tracked the developing drug resistance of one particular strain of Mycobacterium tuberculosis over 12 years. They found that at the time of the 2001 adoption of the DOT+ strategy for multi-drug resistant strains, the strain was already resistant to one or more of the drugs mandated by that strategy, thus allowing the strain to survive and develop resistance to additional drugs.

The spread of a highly transmissible strain of drug-resistant tuberculosis has been facilitated by applying standard treatment regimens for susceptible and multi-drug resistant tuberculosis in the absence of drug resistance surveillance,” said one of the authors, A. Willem Sturm, MD, of the University of KwaZulu-Natal’s Nelson R. Mandela School of Medicine in South Africa. “Public health programs for the treatment and control of infectious diseases need to be supported by drug resistance surveillance programs.”

Unfortunately, at least one strain of M. tuberculosis in South Africa had already developed resistance to one or more of these second-line drugs by the time they were introduced. Drug susceptibility tests would have warned doctors that the standard second-line regimen was unlikely to help the patient but was likely to lead to additional drug-resistance, but these tests were not performed or were not available. Indeed, the reduced efficacy of the regimen allowed the strain to survive and, over time, develop resistances to other drugs

%d bloggers like this: