[Contribution of PCR for detection of Mycobacterium tuberculosis complex in respiratory and nonrespiratory specimens].
OBJECTIVE
To evaluate the sensitivity of PCR versus culture of complex tuberculosis mycobacteria and to determine the delay between PCR results and identification of mycobacteria in culture.


METHODS
Ninety-nine pulmonary and 66 extrapulmonary specimens were analyzed. Samples were inoculated on liquid (MGIT, Bactec) and solid media (Coletsos) and respectively incubated 6 and 12 weeks. Identification was performed by reverse hybridization of PCR products to their complementary probes immobilized on membrane strips (Genotype MTBC, HAIN). Specimens DNA detection was realized by PCR (Cobas Amplicor Mycobacterium tuberculosis test, Roche).


RESULTS
Sensitivity of PCR for acid fast bacilli smear positive pulmonary (50/50) and extrapulmonary (7/7) specimens was 100%. Delay between PCR result and identification was 11 days for pulmonary specimens and 8 days for extrapulmonary specimens. Sensitivity of PCR for smear negative samples was, respectively, of 78.7% (37/47) and 51.8% (29/56) for pulmonary and extrapulmonary specimens. In case of PCR positive result of a smear negative sample, a gap of respectively 13 and 12 days was obtained for pulmonary and extrapulmonary specimens compared to identification.


CONCLUSIONS
Positive PCR result for respiratory specimens allows a gap of 11 to 13 days in diagnosis in comparison with identification of mycobacteria in culture.
Trombert-Paolantoni
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S
Laboratoire Pasteur-Cerba, rue de l'équerre, Z.I. des béthunes, 95066 Cergy Pontoise cedex 09, France. strombert@pasteur-cerba.com
Figarella
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Clairet
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D005838:Genotype; D006801:Humans; D008168:Lung / Q000382:microbiology*; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification*; D009928:Organ Specificity; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity