Thesis (MAppSc)--University of South Australia, 1996

A semi-quantitative indirect immunofluorescence assay was developed which distinguishes two types of patients from whom yersiniae are recovered: those who produce a strong yersiniae specific coproantibody secretory IgA (SIgA) response and those who do not. This SIgA response appeared to be yersiniae specific as faecal supernatant controls from patients whose stools where shown to yield negative or positive cultures for Salmonella, Campylobacter, or Clostridia were SIgA negative. Organisms isolated from patients with high SIgA titers had a higher incidence of virulence associated characteristics although SIgA response was not associated with most other commonly recognized assays of virulence. A strong association was shown to exist between SIgA titre and mouse virulence, the gold standard of bacterial virulence. Clinical examination of patients culture positive with yersiniae documented a strong association between acute enteric illness and high SIgA titre. This association was not dependant on the cultured yersiniae species. No single in vitro virulence associated assay was found to be a reliable predictor of animal virulence. The virulence of nine Y.frederiksenii and one Y.kristensenii, previously thought to be non-pathogenic in man, was also documented. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Procedures were developed to evaluate thermal injury to three strains of Yersinia enterocolitica (serotype 0:3, 0:8 and 0:17). Serotype 0:17 (atypical strain) was more sensitive to bile salts (BS) #3 and to sublethal heat treatment than the typical strains, 0:3 and 0:8. When the 0:3, 0:8 and 0:17 serotypes were thermally stressed in 0.1 M PO₄ buffer, pH=7.0, at 47C for 70, 60 and 12 min, respectively, greater than 99% of the total viable cell population was injured. Injury was determined by the ability of cells to form colonies on Brain heart infusion (BHI) agar, but not on Trypticase soy agar (TSA) plus 0.6% BS #3 for serotypes 0:3 and 0:8 and TSA plus 0.16% BS #3 for 0:17. Heat injury of serotype 0:17 cells for 15 min in 0.1 M PO₄ buffer caused an approximate 1000-fold reduction in cell numbers on selective media as compared to cells heated in PI, BHI broth and 10% nonfat dry milk (NFDM). The extended lag and resuscitation period on BHI broth was 2.5 times greater for 0:17 cells injured in 0.1 M PO₄ than for cells injured in BHI or PI menstruums. The rate and extent of repair of Y. enterocolitica 0:17 cells in three recovery media were directly related to the heating menstruum used for injury. The use of metabolic inhibitors demonstrated that ribonucleic acid (RNA) synthesis was required for repair, whereas deoxyribonucleic (DNA), cell wall and protein synthesis were not necessary for recovery of 0:17 cells injured in 0.1 M PO₄ buffer, BHI or PI menstruums. Inhibition of respiration by 2,4-dinitrophenol slowed repair only for 0:17 cells injured in 0.1 M PO₄ buffer, but not cells injured in PI or BHI menstruums.

Thesis (Ph. D., Microbiology, Molecular Biology and Biochemistry)--University of Idaho, May 2009. / Major professor: Gustavo Arrizabalaga. Includes bibliographical references. Also available online (PDF file) by subscription or by purchasing the individual file.

München, Techn. University, Diss., 2003.

Isolates of Yersinia ruckeri were obtained from Europe, North America, Australia and South Africa. The biochemical and serological characteristics of the isolates were investigated. Biochemically the isolates were extremely uniform although motile, Tween positive isolates could be differentiated from non-motile, Tween negative isolates; these were designated biotypes 1 and 2 respectively. With the exception of two isolates, biotype 2 isolates were confined to the U. K. Five 0-serotypes were recognised and an O-serotyping scheme is proposed; the relation of this scheme to previously described schemes is discussed. The geographic distribution of the different serotypes is also discussed. The lipopolysaccharide (LPS) and outer membrane protein (OMP) profiles of isolates were analysed by SDS-PAGE and Western-blotting using both rabbit and rainbow trout antisera. The relation of LPS-type to 0- serotype, as well as variation within LPS-types, is discussed. Based on interstrain variation in the molecular weight of a heat-modifiable protein and of peptidoglycan-associated (porin) proteins, an OMP-typing scheme was developed. Three major OMP-types comprised 95% of the isolates studied. Variation in biotype, serotype and OMP-type was used as an epizootiological tool, and six serotype 01 clonal groups were recognised which differed in their geographic distribution. The production of iron-regulated OMPs and siderophores was investigated. Four iron-regulated OMPs were produced in all of the isolates examined; siderophores appeared not to be produced by any of the isolates. Production of iron-regulated OMPs was not an important virulence determinant and appears to be a chromosomally-mediated factor. Resistance to the bactericidal effects of normal rainbow trout serum and virulence were also investigated. Serum-resistance was associated principally with two serotype 01 clonal groups and virulence was associated with the same two clonal groups. Other serotype 01 clonal groups and other serotypes were iii generally serum-sensitive and avirulent. Thus, serum-resistance is an important virulence determinant in this organism. The role of outer membrane components in serum-resistance and virulence is discussed.

Thesis (Ph. D.).--University of Texas Graduate School of Biomedical Sciences at San Antonio, 2007. / Vita. Includes bibliographical references.

Thèses (M.Sc.)--Université de Sherbrooke (Canada), 2000. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Tübingen, Univ., Diss., 2005.

München, Univ., Diss., 2004. / Computerdatei im Fernzugriff.