Résumé
A total of 54 rapidly growing mycobacteria (RGM) isolated from patients attended in the two hospitals of Cádiz Bay (Spain) were selected during a seven-year-period (2000-2006) in order to evaluate the INNO-LiPA Mycobacteria v2 assay for mycobacterial identification, based on the reverse hybridization principle. The strains were cultured in Lõwenstein-Jensen and Middlebrook 7H9 media and identified to the species level by sequencing of the 16S rRNA, PCR-restriction enzyme analysis of the hsp65 gene, conventional tests and INNO-LiPA Mycobacteria v2 assay. By the molecular methods we identified a total of 12 different species: 23 Mycobacterium fortuitum, 11 M. chelonae, 10 M. abscessus, 2 M. senegalense, 1 M. alvei, 1 M. brumae, 1 M. mageritense, 1 M. mucogenicum, 1 M. neoaurum, 1 M. peregrinum, 1 M. septicum and 1 M. smegmatis. Fifty two strains (96.3 percent) were correctly identified by conventional techniques and 47 strains (87.0 percent) by INNO-LiPA Mycobacteria v2 assay. We find INNO-LiPA Mycobacteria v2 assay simple to perform but it provides few advantages in comparison with conventional methods and sometimes needs complementary tests to identify Mycobacterium fortuitum complex, M. chelonae complex and specific species due to the great heterogeneity in the RGM group.
Sujets)
Humains , Séquence nucléotidique , DNA restriction enzymes , Activation enzymatique , Hybridation génétique , Techniques in vitro , Mycobactéries non tuberculeuses/génétique , Mycobactéries non tuberculeuses/isolement et purification , Réaction de polymérisation en chaîne , Marqueurs génétiques , Génétique microbienne , Méthodes , Patients , MéthodesRésumé
ELISAs for paratuberculosis employ a preadsorption step with Mycobacterium phlei to diminish unspecific reactions As M. fortuitum is one of the most frequent environmental mycobacteria, the purpose of this pilot study was to evaluate its use as an alternative for the preadsorption in ELISAs for paratuberculosis. Results suggest that M. fortuitum can be an alternative instead of or associated to M. phlei with comparable results (κ > 0.8) to conventional ELISAs using M. phlei as a preadsorption antigen.
Ensaios de sorodiagnóstico de paratuberculose (ELISA) utilizam Mycobacterium phlei na etapa de pré-adsorção para diminuir reações inespecíficas. Uma vez que M. fortuitum é uma das micobactérias atípicas mais isoladas no Brasil, o objetivo central deste estudo foi averiguar a possibilidade de sua utilização como antígeno da etapa de pré-adsorção destes testes. Os resultados sugerem que M. fortuitum apresentou resultados comparáveis (κ > 0.8) aos alcançados com M. phlei e que, portanto poderia ser uma alternativa ao invés ou associado a M. phlei na etapa de pré-adsorção de ELISAs para paratuberculose.