Media statement

Rapid Diagnosis of MDR-TB

South African Medical Research Council (MRC), Foundation for Innovative New Diagnostics (FIND), the National Health Laboratory Service (NHLS) and Department of Health

Tuberculosis (TB), a preventable and curable disease, remains one of South Africa's biggest public health problems, with more than 500 000 cases expected this year.  South Africa is currently fourth on the WHO list of 22 high-burden countries responsible for 80% of the world's TB burden, and also has the second-highest prevalence of TB per capita in the world, at 998 cases per 100 000 population.  TB control is hampered by the dual HIV epidemic, and is one of the main reasons for the rapid increase in TB in South Africa. This is now compounded by escalating rates of multidrug resistance (MDR) and the emergence of extensively drug-resistant TB (XDR-TB) in all nine provinces.

More than 60% of TB patients in SA are co-infected with HIV, presenting unique challenges for patient management, disease control efforts, and infection control.  Spread of MDR-TB and XDR-TB to vulnerable populations such as HIV co-infected individuals can have devastating consequences - aside from a much reduced possibility of cure, HIV-infected patients who contract MDR-TB or XDR-TB may develop complications more easily and as a result the death rate is very high.

The diagnosis of MDR-TB is dependent on a laboratory result with current procedures often exceeding 2 months. Rapid diagnosis of drug-resistant TB has been identified as one of the key efforts to find a solution to the control of MDR-TB. A demonstration study under field conditions involving 20 000 TB patients at risk of MDR-TB was conducted in four provinces in South Africa, evaluating the effectiveness of a new molecular test for rapid diagnosis of MDR-TB. Outcomes of this study showed that the test has the potential to revolutionise the control of MDR-TB and its use in TB control programmes has been endorsed by the World Health Organization earlier this week.

Scientists from the South African Medical Research Council (SAMRC), the Foundation for Innovative New diagnostics (FIND), and the National Health Laboratory Service (NHLS) have combined efforts with National and Provincial Departments of Health to demonstrate the utility of the new molecular test, called 'line probe assays'.  The study from South Africa showed that the test is highly effective in diagnosing MDR-TB and can be used in laboratory settings in developing countries.
 
“The new rapid diagnostic test is a breakthrough that will reduce the delay in diagnosis of multidrug-resistant tuberculosis (MDR-TB) from three months to less than a week, thereby breaking the cycle of transmission of MDR-TB in communities and preventing premature death of patients while they wait for a diagnosis” says Dr Martie van der Walt, Acting Director of the TB Epidemiology and Intervention Research Unit of the South African Medical Research Council.

Acceleration of research into diagnostics, drugs and vaccines to meet the challenges of drug-resistant TB has been called for by many agencies.  “It is testimony to the dedication of scientists and public health officials that we now have a test that can confirm MDR-TB within a week and that South Africa has been in the forefront in the validation of this test under programmatic conditions,” says Dr Lindiwe Mvusi, from the National Department of Health.  She  also confirmed that the new line probe assay will be incorporated into the diagnostic algorithm for MDR-TB to enable early diagnosis and treatment of patients.

Although specialized laboratory facilities and specially trained personnel are required, the test is easy to perform in the laboratory and results are accurate and reproducible. “These tests are envisioned to make a dramatic impact on the early laboratory diagnosis of MDR-TB patients. Furthermore, utilization of this test in the field is envisioned to reduce overall laboratory costs to the National Tuberculosis Control Programme” says Dr Gerrit Coetzee, Head of the National TB Reference Laboratory of the National Health Laboratory Service.

A week ago WHO recommended line probe assays for rapid MDR-TB diagnosis worldwide. This policy change was driven by data from recent studies, mainly from the South African study, which produced evidence for the reliability and feasibility of using line probe assays under routine conditions. This is very likely one of few instances that global policy for poverty-related disease is driven by evidence generated by scientists and institutions from high-burden countries, such as South Africa, with full credit of the results. “Five months ago, WHO renewed its call to make MDR-TB an urgent public health priority”, said WHO Director-General Dr Margaret Chan, “and today we have evidence to guide our response. Based on that evidence, we are launching these promising initiatives”.

“This fruitful collaboration to study the impact of this new molecular test, demonstrates a real potential advancement in the global effort to better address the recent recognition of challenges posed by M(X)DR-TB” said FIND Chief Executive Officer, Dr Giorgio Roscigno. “We are now in a better position to quickly and more accurately detect drug-resistant forms of TB and look forward to pursuing our efforts here and in other countries facing similar health challenges.”

The study for the new test was funded by Geneva-based organization FIND Diagnostics, coordinated by the SAMRC and laboratory evaluation done by NHLS. The test will be rolled out to all provinces in South Africa following the acceptance of a new diagnostic algorithm by the National TB Control Programme.