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.

München, Techn. University, Diss., 2003.

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

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.

Leipzig, Universiẗat, Diss., 2003.

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

Yersinia enterocolitica subsp. palearctica Serobiotyp O:3/4 ist verantwortlich für 80-90 % aller Yersiniosen beim Menschen in Deutschland und Europa. Y. enterocolitica Infektionen zeigen vielfältige Krankheitsbilder wie Gastroenteritis, Lymphadenitis und verschiedene Spätkomplikationen wie reaktive Arthritis. Das wichtigste Tierreservoir stellt das Hausschwein dar. Rohes Schweinefleisch in Metzgereien in Deutschland und anderen Regionen in Nord-Ost Europa ist häufig mit Yersinien kontaminiert (Bayern: 25 %). Da sich Serobiotyp O:3/4-Stämme geografisch und phylogenetisch deutlich von dem bisher sequenzierten Serobiotyp O:8/1B Stamm 8081 unterscheiden, wurde eine komplette Genomsequenzierung des europäischen Serobiotyp O:3/4 DSMZ Referenzstammes Y11 (aus Patientenstuhl isoliert) durchgeführt. Um einen genaueren Einblick in die Y. enterocolitica subsp. palearctica Gruppe zu erhalten, wurden zusätzlich zwei weitere Serobiotyp O:3/4 Isolate (Stamm Y8265, Patientenisolat, und Stamm Y5307, mit reaktiver Arthritis assoziiertes Patientenisolat), sowie ein eng verwandtes Y. enterocolitica subsp. palearctica Serobiotyp O:5,27/3 Isolat, Stamm Y527P, und zwei Biotyp 1A Isolate (ein Isolat nosokomialer Herkunft (Serogruppe O:5) und ein Umwelt-Isolat (O:36)) unvollständig sequenziert. Die nicht mausvirulenten Stämme wurden mit dem mausvirulenten Y. enterocolitica subsp. enterocolitica Serobiotyp O:8/1B Stamm 8081 verglichen, um genetische Besonderheiten von Stamm Y11 und der Y. enterocolitica subsp. palearctica Gruppe zu identifizieren. Besonderer Fokus lag hierbei auf dem pathogenen Potential von Stamm Y11, um neue potentielle Virulenz Faktoren und Fitnessfaktoren zu identifizieren, darunter vor allem solche, die eine Rolle bei der Wirtsspezifität von Serobiotyp O:3/4 spielen könnten. Y. enterocolitica subsp. palearctica Serobiotyp O:3/4 Stämmen fehlen einige der Charakteristika der mausvirulenten Gruppe Y. enterocolitica subsp. enterocolitica, beispielsweise die Yersiniabactin kodierende‚ High-Pathogenicity Island (HPI), das Yts1 Typ 2 Sekretionssystem und das Ysa Typ 3 Sekretionssystem. Die Serobiotyp O:3/4-Stämme haben ein anderes Repertoir von Virulenz Faktoren erworben, darunter Gene bzw. genomische Inseln für das Ysp Typ 3 Sekretionssystem, Rtx-ähnliches putatives Toxin, Insektizid-Toxine und ein funktionelles PTS System für die Aufnahme von N-acetyl-galactosamin, dem aga-Operon. Nach dem Transfer des aga-Operons in Y. enterocolitica subsp. enterocolitica O:8/1B konnte Wachstum auf N-acetyl-galactosamin festgestellt werden. Neben diesen Genen können möglicherweise auch zwei Prophagen (PhiYep-2 und PhiYep-3) und eine asn tRNA assoziierte genomische Insel (GIYep-01) zur Pathoadaptation von Y. enterocolitica subsp. palearctica Serobiotyp O:3/4 beitragen. Der PhiYep-3 Prophage und die GIYep-01 Insel weisen Rekombinationsaktivität auf, und PhiYep-3 wurde nicht in allen untersuchten Serobiotyp O:3/4 Stämmen gefunden. Y. enterocolitica subsp. palearctica Serobiotyp O:5,27/3 Stamm Y527P ist genetisch eng verwandt zu allen Serobiotyp O:3/4 Isolaten, wohingegen die Biotyp 1A Isolate ein mehr Mosaik-artiges Genom aufweisen und potentielle Virulenzgene sowohl mit Serobiotyp O:8/1B als auch O:3/4 gemeinsam haben, was einen gemeinsamen Vorfahren impliziert. Neben dem pYV Virulenz-Plasmid fehlen den Biotyp 1A Isolaten klassische Virulenzmarker wie das Ail Adhesin, das YstA Enterotoxin und das Virulenz-assoziierte Protein C (VapC). Interessanterweise gibt es keine beträchtlichen Unterschiede zwischen den bekannten Virulenzfaktoren des nosokomialen Isolats und dem Umweltisolat der Biotyp 1A-Gruppe, abgesehen von einem verkürzten Rtx Toxin-ähnlichem Genkluster und Überresten eines P2-ähnlichen Phagen im Krankenhausisolat der Serogruppe O:5. / Yersinia enterocolitica subsp. palearctica serobiotype O:3/4 comprises about 80-90 % of all human patient isolates in Germany and Europe and is responsible for sporadic cases worldwide. Even though this serobiotype is low pathogenic, Y. enterocolitica subsp. palearctica serobiotype O:3/4 is involved in gastroenteritis, lymphadenitis and various extraintestinal sequelae as reactive arthritis. The main animal reservoir of this serobiotype are pigs, causing a high rate of O:3/4 contaminations of raw pork in butcher shops in Germany (e.g. Bavaria 25 %) and countries in north-east Europe. As Y. enterocolitica O:3/4 is geographically and phylogenetically distinct from the so far sequenced mouse-virulent O:8/1B strain, complete genome sequencing has been performed for the European serobiotype O:3/4 DSMZ reference strain Y11, which has been isolated from a patient stool. To gain greater insight into the Y. enterocolitica subspecies palearctica group, also draft genome sequences of two other human O:3/4 isolates (strains Y8265, patient isolate, and Y5307, patient isolate associated with reactive arthritis), a closely related Y. enterocolitica palearctica serobiotype O:5,27/3 (strain Y527P), and two biotype 1A strains (a nosocomial strain of serogroup O:5 and an environmental serogroup O:36 isolate) have been performed. Those strains were compared to the high-pathogenic Y. enterocolitica subsp. enterocolitica serobiotype O:8/1B strain 8081 to address the peculiarities of the strain Y11 and the Y. enterocolitica subspecies palearctica group. The main focus was to unravel the pathogenic potential of strain Y11 and thus to identify novel putative virulence genes and fitness factors, especially those that may constitute host specificity of serobiotype O:3/4. Y. enterocolitica subspecies palearctica serobiotype O:3/4 strains lack most of the mouse-virulence-associated determinants of Y. enterocolitica subsp. enterocolitica serotype O:8, for example the HPI, Yts1 type 2 and Ysa type three secretion systems. In comparison, serobiotype O:3/4 strains obviously acquired a different set of genes and genomic islands for virulence and fitness such as the Ysp type three secretion system, an RtxA-like putative toxin, insecticidal toxins and a functional PTS system for N-acetyl-galactosamine uptake, named aga-operon. The aga-operon is able to support the growth of the Y. enterocolitica subsp. enterocolitica O:8/1B on N-acetyl-galactosamine after transformation with the aga operon. Besides these genes, also two prophages, PhiYep-2 and PhiYep-3, and a asn tRNA-associated GIYep-01 genomic island might influence the Y. enterocolitica subsp. palearctica serobiotype O:3/4 pathoadaptation. The PhiYep-3 prophage and the GIYep-01 island show recombination activity and PhiYep-3 was not found in all O:3/4 strains of a small strain collection tested. Y. enterocolitica subsp. palearctica serobiotype O:5,27/3 strain Y527P was found to be closely related to all serobiotype O:3/4 strains, whereas the biotype 1A isolates have more mosaic-segmented genomes and share putative virulence genes both with serobiotypes O:8/1B and O:3/4, which implies their common descent. Besides the pYV virulence plasmid, biotype 1A strains lack classical virulence markers as the Ail adhesin, the YstA enterotoxin, and the virulence-associated protein C. Interestingly, there are no notable differences between the known virulence factors present in nosocomial and environmental strains, except the presence of a truncated Rtx toxin-like gene cluster and remnants of a P2-like prophage in the hospital serogroup O:5 isolate.

Made available in DSpace on 2014-06-11T19:30:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-14Bitstream added on 2014-06-13T20:00:43Z : No. of bitstreams: 1 tumitan_arp_dr_arafcf.pdf: 486259 bytes, checksum: e8184ac2899ff2bbb1e4a6c4b9f77604 (MD5) / Universidade Estadual Paulista (UNESP) / O objetivo deste estudo foi verificar a influência da infecção por Y. enterocolitica na modulação de macrófagos M1 e M2 em camundongos suscetíveis (BALB/c) e resistentes (C57BL/6). Camundongos de ambas as linhagens foram infectados com Y. enterocolitica O:8 WA 2707. Células do lavado peritoneal e células esplênicas foram retiradas no 1º, 3º e 5º dia pós-infecção. Em cultura de macrófagos foi verificada a atividade das enzimas iNOS e arginase, medidas por seus produtos NO/citrulina e ornitina, respectivamente, e a produção de TGFb-1. Em cultura de linfócitos foram verificadas as respostas Th1 e Th2, avaliadas pela produção das citocinas IFN-g e IL-4. No 1º e 3º dia após infecção com Y. enterocolitica, os macrófagos de camundongos C57BL/6 aumentaram a produção de NO/citrulina e não produziram TGFb-1; enquanto que os macrófagos de BALB/c aumentaram a produção de ornitina e de TGFb-1. Os linfócitos de C57BL/6 aumentaram a produção de IFN-g e não produziram IL-4, enquanto que os BALB/c apresentaram um aumento mais discreto nos níveis de IFN-g e produziram IL-4 no 5º dia pós-infecção. / The objective of this study was to verify the modulation of Y. enterocolitica infection in M1 and M2 macrophage modulation in susceptible (BALB/c) and resistant (C57BL/6) mice. Both strains of mice were infected with Y. enterocolitica O:8 WA 2707. Peritoneal macrophages and spleen cells were obtained on days 1, 3 and 5 post-infection. We verified the iNOS and the arginase activities in macrophage cultures, measured by their NO/citruline and ornithine products, respectively. The TGF b-1 production was also measured in supernatants of macrophage cultures. The Th1 and Th2 responses were evaluated in supernatants of lymphocyte cultures, by IFNg and IL-4 production. In the 1st and 3rd day after infection with Y. enterocolitica, macrophages from C57BL/6 mice increased their NO/citruline production and they didn't produce TGF b-1 ; while macrophages from BALB/c mice increased their ornithine and TGF b-1 production. The lymphocytes from C57BL/6 mice increased their IFNg production and didn't produce IL-4, while BALB/c showed a discreet increase in the IFNg levels and produced IL-4 in the 5th day post-infection.