• Título:  APPLICATION OF MOLECULAR TECHNIQUES TO THE DIAGNOSTIC AND EPIDEMIOLOGY OF HAEMOPHILUS PARASUIS
• Autor:  Olvera van der Stoep, Alexandre
• Universidad:  Universidad Autónoma de Barcelona
• Departamento:  BIOLOGIA MOLECULAR Y BIOQUIMICA
• Fecha de Lectura:  16/01/2007
• Programa de doctorado:  BIOLOGIA MOLECULAR Y BIOQUIMICA
• Dirección: 
  • Aragón Fernández, Virginia (DIRECTOR)
• Tribunal: 
  • RODRÍGUEZ FERRI, ELÍAS FERNANDO (PRESIDENTE)
  • Barceló Vernet, Anna (SECRETARIO)
  • BLANCH GISBERT, ANICET (VOCAL)
  • BENSAID, ALBERT (VOCAL)
  • DE LA FUENTE, RICARDO (VOCAL)
• Descriptores: 
  • CIENCIAS AGRARIAS
  • MICROBIOLOGIA VETERINARIA
  • CIENCIAS VETERINARIAS
• Localización:  Biblioteca de comunicacions i hemeroteca general. Universitat Autonoma de Barcelona. 08193, Bellaterra (Barcelona) España
• Resumen:
  Haemophilus parasuis is the etiological agent of Glässer's disease, but this bacterium causes other clinical outcomes and can also be isolated from the upper respiratory tract of healthy pigs. Isolates of H. parasuis differ in phenotypic features (e.g. protein profiles, colony morphology or capsule production) and pathogenic capacity. Differences among strains have also been demonstrated at the genetic level. Several typing methods have been used to classify H. parasuis field strains, but they showed resolution or implementation problems. To overcome these limitations, different DNA sequence based techniques were evaluated. Consequently, the final goal of this study was to improve H. parasuis typing and examine the association of groups of strains with disease outcome. In the first chapter of this work, a partial sequence from the heat shock protein 60 KDa (hsp60) gene was assessed as epidemiological marker in a single locus sequence typing (SLST). We compared enterobacterial repetitive intergenic consensus (ERIC)-PCR patterns, partial sequences of hsp60 and 16S rRNA genes from 103 strains of H. parasuis and other related species. In the second chapter of this work, we developed a multilocus sequence typing (MLST) system using partial sequences of the house-keeping genes mdh, 6pgd, atpD, g3pd, frdB, infB and rpoB. Eleven reference strains and 120 field strains were included in this latter study. Our results showed that hsp60 is a reliable marker for epidemiological studies in H. parasuis, and the analysis of its sequence is a better approach than fingerprinting methods. Surprisingly, the 16S rRNA gene showed enough variability to be used, not only for species identification, but also for typing. Furthermore, the analysis of the hsp60 and 16S rRNA sequences revealed the presence of a separated lineage of disease-associated strains. Both SLST and MLST studies indicated the occurrence of lateral gene transfer among H. parasuis and Actinobacillus strains invalidati