Armand Van Deun

Twenty Years of Global Surveillance of Antituberculosis-Drug Resistance

The emergence and dissemination of drug-resistant Mycobacterium tuberculosis is a global threat to health. In this report, surveillance of drug-resistant tuberculosis during the past 20 years is described.

Rifampicin-resistant Mycobacterium tuberculosis: susceptibility to isoniazid and other anti-tuberculosis drugs

Based on data from 14 Supranational Tuberculosis (TB) Reference Laboratories worldwide, the proportion of rifampicin (RMP) resistant isolates that were isoniazid (INH) susceptible by phenotypic drug susceptibility testing varied widely (0.5-11.6%). RMP-resistant isolates that were INH-susceptible had significantly lower rates of resistance to other first- and second-line anti-tuberculosis drugs (except rifabutin) compared to multidrug-resistant isolates. RMP resistance is not always a good proxy for a presumptive diagnosis of multidrug-resistant TB, which has implications for use of molecular assays that identify only RMP resistance-associated DNA mutations.

Strategies of extensively drug-resistant TB risk management for health workers and other care givers

Extensive drug resistance in TB is not a new phenomenon. It is created when patients with multidrug-resistant TB (MDR-TB) are treated with second-line anti-TB drugs but fail to be cured. The first principle in managing the risk of extensively drug-resistant TB (XDR-TB) is ‘do not generate XDR-TB’. Once it is created, every effort must be made to prevent it from spreading. Health workers and care givers in long-term care facilities and prisons may have a considerable risk of exposure to TB, including XDR-TB. The principles in the control of TB transmission in healthcare settings, long-term care facilities and prisons include early identification and isolation of infectious TB patients, effective treatment of TB as soon as possible, environmental control with proper ventilation and personal protection of healthcare workers and others. Patients with the highest risk of developing XDR-TB are those MDR-TB patients who failed treatment using a second-line regimen and TB patients who have a history of contact with XDR-TB patients. The core principles in managing the risk of XDR-TB for health workers and care givers are reducing the risks of exposure to XDR-TB, becoming infected and developing XDR-TB. If TB has developed, the principles include promptly diagnosing XDR-TB and starting proper treatment.

Global laboratory initiative tool for a stepwise process towards tuberculosis laboratory accreditation.

made with this new test in detecting tuberculosis among patients excreting few bacilli and in identifying rifampicin resistance. For the reasons outlined above and in our article, sputum smear microscopy must be retained as a routine test at peripheral level in low-income countries, at least for the time being. We wish to emphasise the need for good operational research before recommending any replacement of smear microscopy. The old cloth must not be discarded without due assurance that the new cloth is affordable, durable and resistant to stormy weather!