title: Evaluation of the GenoType Mycobacteria Direct assay for the simultaneous detection of the Mycobacterium tuberculosis complex and four atypical mycobacterial species in smear-positive respiratory specimens.
abstract: A novel, commercially available reverse hybridization assay [GenoType Mycobacteria Direct (GTMD), version 2.0; Hain Lifescience] was evaluated for the direct detection of five clinically relevant mycobacterial species [Mycobacterium tuberculosis complex (MTBC), Mycobacterium avium, Mycobacterium malmoense, Mycobacterium kansasii and Mycobacterium intracellulare] from 54 smear-positive respiratory specimens and the findings were compared with culture results. Three approaches were used for specimen preparation using either whole or 'split' sample volumes and N-acetyl-l-cysteine/3 % NaOH or 4 % NaOH as decontamination chemicals. Forty-three out of 52 samples in which RNA amplification was successful gave GTMD results that concurred with the identification of the cultured isolate. All cases of MTBC were detected. Twenty-two samples contained M. tuberculosis complex, seven had M. kansasii, four had M. malmoense, seven contained atypical mycobacteria other than those detectable using the GTMD assay and three specimens contained no viable mycobacteria. The assay is easy to use and can be completed in one working day. Results interpretation is facilitated by the inclusion of an internal amplification control with each sample to allow identification of specimens containing amplification inhibitors. A positive GTMD result will quickly identify patients with MTBC infection or provide specific identification of four other atypical mycobacteria from the same specimen. This allows more rapid drug susceptibility testing, treatment, and public health and infection control decisions.
authors.affiliation: Scottish Mycobacteria Reference Laboratory, Department of Laboratory Medicine, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, UK.
authors.forename: A-Louise
authors.initials: AL
authors.lastname: Seagar
authors.affiliation: Microbiology Department, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
authors.forename: Carmel
authors.initials: C
authors.lastname: Prendergast
authors.affiliation: Scottish Mycobacteria Reference Laboratory, Department of Laboratory Medicine, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, UK.
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Emmanuel
authors.affiliation: Scottish Mycobacteria Reference Laboratory, Department of Laboratory Medicine, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Rayner
authors.affiliation: Mast Group Ltd, MAST House, Derby Road, Bootle, Merseyside L20 1EA, UK.
authors.forename: Susan
authors.initials: S
authors.lastname: Thomson
authors.affiliation: Scottish Mycobacteria Reference Laboratory, Department of Laboratory Medicine, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, UK.
authors.forename: Ian F
authors.initials: IF
authors.lastname: Laurenson
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D005838:Genotype; D006801:Humans; D025202:Molecular Diagnostic Techniques; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis* / Q000382:microbiology; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D009170:Nontuberculous Mycobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D011933:Reagent Kits, Diagnostic