[Advantages and drawbacks of expectoration decontamination methods for tuberculosis and anti-tuberculosis drug resistance diagnosis]

Abstract

In the actual context of increasing tuberculosis and anti-tuberculosis drug resistance, the laboratory diagnosis of Mycobacterial infections remain the primordial objective of control and surveillance of human tuberculosis. The diagnosis and following of tuberculosis in resource limited settings are done by microscopy Ziehl-Neelsen method which is poor sensitive (20-53%) and have poor specificity because it's can't distinguish tuberculosis mycobacterium and atypical tuberculoid mycobacterium. Mycobacterium culture on solid media is the gold standard method for tuberculosis and anti-tuberculosis drug resistance diagnosis. Here, the challenge is that expectorations using for culture contain mycobacterium and others contaminating bacteria responsible of culture contamination. Many different methods of homogenization and decontamination of sputum specimens for culturing exist and each laboratory had to do a choice of the better method to optimize isolating of mycobacterium. This review is a summary of homogenization and decontamination methods described in literature and used by certain laboratories for diagnosis of TB by culture. However, it's essential for each laboratory to conduct evaluation of the different methods and do the choice of the appropriate one by taking into account factors such as the feasibility and cost effectively. Nine methods of decontaminations are described in this review taking account of their advantages, drawbacks and their feasibility in resource limited settings.

Keywords: culture; decontamination; mycobacterium; sputum; tuberculosis.