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Journal of Clinical Microbiology, September 2001, p. 3222-3227, Vol. 39, No. 9
Regional Mycobacteria Reference Centre,
Laboratory of Clinical Microbiology and Virology, San Bortolo
Hospital, Vicenza,1 and Department of
Clinical Microbiology, General Hospital Umberto I
Received 23 April 2001/Returned for modification 7 June
2001/Accepted 28 June 2001
The new INNO-LiPA Mycobacteria (Innogenetics,
Ghent, Belgium), a reverse-hybridization-based line probe
assay, and the AccuProbe assay (Gen-Probe Inc., San Diego, Calif.) were
applied to MB/BacT Alert 3D (MB/BacT) system (Organon Teknika, Boxtel,
The Netherlands) culture bottles and evaluated for mycobacterial
identification. From 2,532 respiratory and extrapulmonary specimens
submitted for culture, 168 were flagged positive by the MB/BacT system
and promptly evaluated for identification (within 24 h). Each of
163 vials grew one mycobacterial isolate, including Mycobacterium tuberculosis complex (n = 73), M. avium complex (n = 3), M. avium (n = 8), M. intracellulare
(n = 5), M. kansasii (n = 15),
M. gordonae (n = 8), M. malmoense (n = 3), M. chelonae
(n = 13), M. abscessus (n = 2), M. xenopi (n = 11), M. scrofulaceum (n = 2), M. fortuitum (n = 7), M. terrae (n = 3),
M. simiae (n = 2), M. celatum
(n = 3), M. flavescens (n = 1), M. interjectum (n = 1), M. bohemicum (n = 1), and M. pulveris
(n = 2). Five cultures yielded mixed growth of two
mycobacterial species: M. tuberculosis complex plus M. gordonae (n = 2), M. tuberculosis complex plus M. chelonae (n = 1), M. tuberculosis complex plus
M. xenopi (n = 1), and M. avium plus M. chelonae (n = 1). In
testing of one-isolate vials, both systems showed excellent sensitivity
and specificity for all species and complexes for which they are
licensed (nine for INNO-LiPA Mycobacteria versus six for AccuProbe).
There were minor discrepancies in results for two isolates identified
by INNO-LiPA Mycobacteria as M. avium - M. intracellulare - M. scrofulaceum (MAIS) complex and by AccuProbe as M. intracellulare. In testing of two-isolate vials, INNO-LiPA
Mycobacteria correctly identified all isolates, while the
AccuProbe assay failed to identify three M. tuberculosis
complex isolates and one M. avium isolate. The AccuProbe
assay was completed within 2 h, while INNO-LiPA Mycobacteria required a 6-h period. In our opinion, INNO-LiPA Mycobacteria offers
the following advantages: (i) it contains a genus-specific probe that,
in addition to being used in genus identification, may be used as an
internal control for both the amplification and hybridization steps;
(ii) it simultaneously identifies M. tuberculosis complex,
MAIS complex, and seven other mycobacterial species, even from mixed
cultures; (iii) its mycobacterial DNA amplification ensures reliable
results independent from the concentration of viable microorganisms;
and (iv) it genotypically identifies M. kansasii and
M. chelonae. In conclusion, even though INNO-LiPA Mycobacteria is considerably less easy to use than AccuProbe, requiring
personnel skilled in molecular biology techniques, it represents an
excellent approach for routine identification of frequently encountered mycobacteria.
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.9.3222-3227.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Direct Identification of Mycobacteria from MB/BacT
Alert 3D Bottles: Comparative Evaluation of Two Commercial
Probe Assays
Torrette,
Ancona,2 Italy
*
Corresponding author. Mailing address: Regional
Mycobacteria Reference Centre, Microbiology and Virology Laboratory,
San Bortolo Hospital, Viale Rodolfi 37, Vicenza I-36100, Italy. Phone:
39 0444 993507. Fax: 39 0444 993963. E-mail:
claudio.scarparo{at}tin.it.
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