Role of the Clinical Mycobacteriology Laboratory in Diagnosis and Management of Tuberculosis in Low-Prevalence Settings

Johns Hopkins Medical Institutions, Baltimore, Maryland, Baltimore, Maryland, USA.
Journal of clinical microbiology (Impact Factor: 4.23). 12/2010; 49(3):772-6. DOI: 10.1128/JCM.02451-10
Source: PubMed

ABSTRACT Tuberculosis (TB) remains a global epidemic, despite a significant decline in reported cases in the United States between 2008 and 2009. While the exact nature of this decline is unclear, one thing remains certain: TB, including multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB, is no longer restricted to developing regions of the globe. It is of vital importance that both public and private mycobacteriology laboratories maintain the ability to detect and identify Mycobacterium tuberculosis from patient specimens, as well as correctly determine the presence of antibiotic resistance. To do this effectively requires careful attention to preanalytical, analytical, and postanalytical aspects of testing. Respiratory specimens require digestion and concentration followed by fluorescence microscopy. The Centers for Disease Control and Prevention (CDC) recommends the performance of a direct nucleic acid amplification method, regardless of smear results, on specimens from patients in whom the suspicion of tuberculosis is high. Liquid-based technologies are more rapid and sensitive for the detection of M. tuberculosis in culture and nucleic acid probes, but biochemicals are preferred for identification once growth is detected. Susceptibility testing is most often done using either the agar proportion method or a commercial broth system. New genotypic and phenotypic methods of susceptibility testing include first- and second-line agents and are promising, though not yet widely available. Finally, gamma interferon release assays are preferred to the tuberculin skin test for screening certain at-risk populations, and new CDC guidelines are available that assist clinicians in their use.

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    • "La plupart des milieux liquides sont couplés à une détection automatique de la croissance. L'usage des automates avec incubateurs incorporés développés fin des années 1990 (mycobacteria growth indicator tube [Bactec MGIT960 ® ], [Becton Dickinson], VersaTREK ® [Trek Diagnostics] ou BacT/ALERT ® [BioMérieux]) présente l'avantage de réduire significativement le délai de positivité de 10 à 14 jours en moyenne par rapport aux cultures en milieu solide [14] "
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    • ") Among these, Amplicor M. tuberculosis test and AMTD based on 16S rRNA gene have been approved by the US Food and Drug Administration (FDA) for the diagnosis of PTB only (Brodie & Schluger, 2009), and none of these commercial tests have been approved by FDA for the diagnosis of EPTB (Parrish & Carroll, 2011). However, the utility of these commercial tests has been extensively explored in the diagnosis of EPTB (Honore-Bouakline et al., 2003; Causse et al., 2011). "
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