RESUMO
SETTING: Quality assurance for the World Health Organization (WHO)/International Union Against Tuberculosis and Lung Disease (The Union) global tuberculosis (TB) drug resistance surveillance programme. OBJECTIVE: To monitor the quality of drug susceptibility testing (DST) in different countries. METHODS: In 2002-2003 and 2005-2006, 20 Mycobacterium tuberculosis strains were sent by the WHO/Union Supranational Reference Laboratory of Rome to TB reference laboratories in Albania, Bahrain, Kosovo, Mozambique, Oman, Qatar and Turkey for external quality control (EQC). RESULTS: In 2002-2003, the specificity, sensitivity, efficiency, reproducibility and predictive values for resistance/susceptibility were >or=90% for streptomycin (SM), isoniazid (INH) and ethambutol (EMB). In 2005-2006, all statistical values were >or=96% for SM, INH, rifampicin and EMB. CONCLUSION: EQC improved the quality of M. tuberculosis DST in the participating countries.
Assuntos
Antituberculosos/farmacologia , Testes de Sensibilidade Microbiana/normas , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose Pulmonar/tratamento farmacológico , Humanos , Controle de Qualidade , Sensibilidade e Especificidade , Tuberculose Pulmonar/epidemiologiaRESUMO
There is still an urgent requirement for more sensitive, cost-effective methods for detection and susceptibility testing of mycobacteria in clinical samples. We have been investigating a simple bacteriophage-based system which could be used for both purposes. As this depends upon the detection of phages which have successfully infected cells, a key step is the efficient removal or inactivation of phages remaining free in the culture medium. We demonstrate here the use of ferrous ammonium sulphate as an effective agent for the inactivation of mycobacteriophage D29 without impairing phage replication in previously infected host bacteria. Using this property, we report the detection of viable Mycobacterium smegmatis, M. bovis BCG and M. tuberculosis using simple low-cost technology. The method is highly sensitive, since it is able to detect 10 colony-forming units of M. smegmatis. It is also rapid, with the detection of M. tuberculosis in sputum specimens within 48 h.
