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: 3.99). 12/2010; 49(3):772-6. DOI: 10.1128/JCM.02451-10
Source: PubMed


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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    ABSTRACT: This review focuses on the role of new tools in the "modern" microbiological diagnosis of tuberculosis. Traditional techniques of microscopy and culture remain essential to diagnostic certainty, but some innovations replace daily the older techniques such as the identification of Mycobacterium tuberculosis complex by immunochromatography or mass spectrometry MALDI-TOF type from positive cultures, or susceptibility testing in liquid medium. New tools that use molecular techniques have become important. They all have in common to optimize the fight against tuberculosis by reducing diagnostic delay. They also allow rapid detection of drug resistance. However, the techniques of gene amplification directly from clinical samples are still less sensitive than culture. Bacteriological diagnosis of tuberculosis disease therefore still relies on the complementarities of different phenotypic and molecular techniques.
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    • "However, culture remains the gold standard method for the diagnosis of TB. Egg-based media such as Löwenstein-Jensen are widely used, but agar media such as Selective 7H11 and liquid-based media are now considered standard tools [7]. Several centers also use these systems to isolate rare mycobacterial species. "
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    ABSTRACT: The present study was conducted to assess the efficiency of using TK SLC-L (Salubris, Inc.) for the primary isolation of mycobacteria from clinical samples by comparing it to the MGIT detection system (Becton Dickinson Diagnostic Instrument Systems). Although TK SLC, a biphasic medium, has been evaluated previously, this is the first study to evaluate TK SLC-L, a liquid medium. Clinical specimens from a total of 146 clinically suspected cases of tuberculosis were studied. Each processed sample was evaluated by ZN staining and inoculated into TK SLC-L and MGIT tubes. The TK SLC tubes were incubated in a MYCOLOR TK while the MGIT tubes were incubated in a MGIT system. Growth, indicated by automated systems, was confirmed through production of a smear and microscopic evaluation after ZN staining. Mycobacterial growth was positive in 35 TK SLC-L and in 34 MGIT samples. Although the growth detection time was approximately 3 to 5 days shorter, on average, with the MGIT system, the contamination rate was significantly lower using TK SLC-L. The total time spent for the repetition of cultures for contaminated samples in MGIT make the total return time for culture results equal to or longer than the time required by TK SLC-L. The TK Culture System using TK SLC-L is an efficient system and possible alternative to other rapid mycobacterial culture systems.
    BMC Infectious Diseases 03/2014; 14(1):130. DOI:10.1186/1471-2334-14-130 · 2.61 Impact Factor
    • ") 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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    ABSTRACT: During the last two decades, the resurgence of tuberculosis (TB) has been documented in both developed and developing nations, and much of this increase in TB burden coincided with human immunodeficiency virus (HIV) epidemics. Since then, the disease pattern has changed with a higher incidence of extrapulmonary tuberculosis (EPTB) as well as disseminated TB. EPTB cases include TB lymphadenitis, pleural TB, TB meningitis, osteoarticular TB, genitourinary TB, abdominal TB, cutaneous TB, ocular TB, TB pericarditis and breast TB, although any organ can be involved. Diagnosis of EPTB can be baffling, compelling a high index of suspicion owing to paucibacillary load in the biological specimens. A negative smear for acid-fast bacilli, lack of granulomas on histopathology and failure to culture Mycobacterium tuberculosis do not exclude the diagnosis of EPTB. Novel diagnostic modalities such as nucleic acid amplification (NAA) can be useful in varied forms of EPTB. This review is primarily focused on the diagnosis of several clinical forms of EPTB by polymerase chain reaction (PCR) using different gene targets.
    FEMS Immunology & Medical Microbiology 05/2012; 66(1):20-36. DOI:10.1111/j.1574-695X.2012.00987.x · 3.08 Impact Factor
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