References of "Szalo, Ioan Mihai"
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See detailPneumonia with Aeromonas sobria in a Carpet Python
Gandar, Frederic ULg; Szalo, Ioan Mihai ULg; Marlier, Didier ULg

Conference (2011, August 11)

Aeromonas sobria was isolated and identified upon post-mortem examination from the respiratory tract and the blood of a carpet python (Morelia spilota variegata). The snake was referred to the Faculty of ... [more ▼]

Aeromonas sobria was isolated and identified upon post-mortem examination from the respiratory tract and the blood of a carpet python (Morelia spilota variegata). The snake was referred to the Faculty of Veterinary Medicine of Liège for necropsy, just the day after it suddenly died without previous clinical sign. Lung and liver biopsies were performed and fixed in neutral buffered 10% formalin and paraffin embedded. Blood samples were collected via cardiocentesis, and air sac abscesses were cultured. Bacterial strains were identified as Aeromonas sobria by 16S rDNA sequencing. Based on histological and bacterial examinations, the death of this snake was attributed to a septicemia, following an acute primary, or secondary exudative pneumonia. Aeromonas sp. is established as a potential pathogen in reptiles. Among this genus, Aeromonas hydrophila is the most frequently isolated. A. sobria has been reported as a primary pathogen in farmed perch (Perca fluviatilis) and humans. Conversely, few data are available concerning the pathogenicity of A. sobria in reptiles. Other non-bacterial agents (virus, fungus, endoparasites) or predisposing factors (such as obesity) can also be responsible for respiratory tract disease in snakes . Unfortunately, in the current case, virological investigations were not performed. [less ▲]

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See detailSalmonella Typhimurium oral challenge model in mature broilers: Bacteriological, immunological, and growth performance aspects.
Marcq, Christopher ULg; Cox, Edwin; Szalo, Ioan Mihai ULg et al

in Poultry Science (2011), 90(1), 59-67

In this study, Salmonella enterica serovar Typhimurium challenge models were tested to identify the best conditions under which to perform the experimental infection of 3-wk-old broilers. Such a model ... [more ▼]

In this study, Salmonella enterica serovar Typhimurium challenge models were tested to identify the best conditions under which to perform the experimental infection of 3-wk-old broilers. Such a model would be useful to study the efficiency of therapeutic treatments that could take place at the end of the grow-out period. Salmonella-free chicks were obtained from a breeder flock vaccinated with Salmonella. Intestinal maternal immunity was monitored by ELISA analyses at 2, 9, and 16 d of age. Data indicated that protection of maternal origin was not maintained over time and was drastically reduced at 9 d of age (P < 0.01). At 21 d of age, chickens were orally inoculated with Salmonella Typhimurium. The effects of the oral challenge dose (0, 3 x 10(3), 3 x 10(6), and 3 x 10(9) cfu/bird) and vancomycin pretreatment (no administration or 25 mg/bird) on intestinal immune responses, growth performance, and Salmonella colonization of chickens were investigated. After infection, the mucosal immune response was rapid, with increased (P < 0.01) anti-Salmonella Typhimurium IgA titers measured at 8 d postinfection in intestinal contents. A linear relationship (P < 0.05) existed between specific IgA levels in intestinal and cecal contents and the challenge dose inoculated. None of the challenge protocols caused mortality or clinical symptoms after infection. Nevertheless, the experimental infection induced a significant deterioration of growth performance. The pretreatment with 25 mg of vancomycin at 3 h before Salmonella inoculation was able to establish stable infection rates among the population of 3-wk-old infected chickens. Nevertheless, Salmonella shedding was not stable over the rearing period, and the bacteria seemed to be naturally eliminated from most birds at 22 d postinfection. This natural clearance of the gut, which was related, at least in part, to the intestinal immune response, should limit the usability of the created mature challenge model within 1 to 2 wk after inoculation. [less ▲]

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See detailInitial adherence of EPEC, EHEC and VTEC to host cells.
Bardiau, Marjorie ULg; Szalo, Ioan Mihai ULg; Mainil, Jacques ULg

in Veterinary Research (2010), 41(5), 57

Initial adherence to host cells is the first step of the infection of enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains ... [more ▼]

Initial adherence to host cells is the first step of the infection of enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains. The importance of this step in the infection resides in the fact that (1) adherence is the first contact between bacteria and intestinal cells without which the other steps cannot occur and (2) adherence is the basis of host specificity for a lot of pathogens. This review describes the initial adhesins of the EPEC, EHEC and VTEC strains. During the last few years, several new adhesins and putative colonisation factors have been described, especially in EHEC strains. Only a few adhesins (BfpA, AF/R1, AF/R2, Ral, F18 adhesins) appear to be host and pathotype specific. The others are found in more than one species and/or pathotype (EPEC, EHEC, VTEC). Initial adherence of EPEC, EHEC and VTEC strains to host cells is probably mediated by multiple mechanisms. [less ▲]

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See detailIS EPIZOOTIC RABBIT ENTEROPATHY (ERE) A BACTERIAL DISEASE?
Huybens, Nathalie ULg; Houeix, Julien ULg; Szalo, Ioan Mihai ULg et al

in Proceeding of the 9th World Rabbit Congress (2008, June 12)

The etiology of epizootic rabbit enteropathy (ERE) is still unknown despite ten years of continuous research. A putative bacterial etiology is at the basis of current research. The fractionation of the ... [more ▼]

The etiology of epizootic rabbit enteropathy (ERE) is still unknown despite ten years of continuous research. A putative bacterial etiology is at the basis of current research. The fractionation of the reference inoculum (TEC4) is a major step to find the potential bacterial agent(s). In this study, TEC4 was fractionated with two techniques: centrifugation on discontinuous sucrose gradient then cell adhesion. Two selected fractions were inoculated to SPF rabbits and analyzed with classical bacteriological techniques. ERE was reproduced with both fractions. The 16S rDNA gene was amplified in all fractions and in three negative controls and subsequently analyzed with Restriction Fragment Length Polymorphism (RFLP) and Denaturating Gradient Gel Electrophoresis (DGGE). A difference in bacterial DNA composition was found between virulent and non-virulent fractions which reinforce the potential role of bacteria in the etiology of ERE. [less ▲]

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See detailFractionation of the reference inoculum of epizootic rabbit enteropathy in discontinuous sucrose gradient identifies aetiological agents in high density fractions
Szalo, Ioan Mihai ULg; Lassence, Cédric ULg; Licois, Dominique et al

in Veterinary Journal (2007), 173(3), 652-657

Epizootic rabbit enteropathy (ERE) is a major cause of economic loss in intensive rabbit production. Since its first recognition in 1997, much work has been done to determine the pathogenic mechanisms of ... [more ▼]

Epizootic rabbit enteropathy (ERE) is a major cause of economic loss in intensive rabbit production. Since its first recognition in 1997, much work has been done to determine the pathogenic mechanisms of the disease and to identify the aetiological agent(s). Unfortunately, the quest for aetiology has only met with limited success despite the ability to reproduce the syndrome by inoculation of intestinal contents from field cases. These intestinal inocula contain a huge number of microorganisms which could all be involved in the aetiology of ERE. To decrease the number of putative agents, the French reference inoculum TEC3 was fractionated on a discontinuous sucrose gradient so that seven fractions (supernatant, 10%, 20%, 30%, 40%, 50% and pellet) were obtained. Specific-pathogen-free rabbits were inoculated with three out of these seven fractions (supernatant, 30%, and pellet). The objectives were: (1) to characterise the seven fractions by bacteriological examination; (2) to verify whether the aetiological agent was present in the fractions by inoculation of rabbits; (3) to assign the aetiological agent of ERE to a morphological group of pathogens; (4) to identify a fraction which could replace the reference inoculum TEC3 in applications such as cell cultures or egg inoculation. The results strongly suggest that ERE is a bacterial disease and does not have a viral or parasitic aetiology. (C) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailLe lipopolysaccharide d’Escherichia coli : structure, biosynthèse et rôles
Szalo, Ioan Mihai ULg; Taminiau, Bernard ULg; Mainil, Jacques ULg

in Annales de Médecine Vétérinaire (2006), 150(2), 108-124

The lipopolysaccharide (LPS) is a major component of the surface of the Gram negative bacteria. The LPS is composed of three separately synthesized entities: the lipid A, the core oligosaccharide and the ... [more ▼]

The lipopolysaccharide (LPS) is a major component of the surface of the Gram negative bacteria. The LPS is composed of three separately synthesized entities: the lipid A, the core oligosaccharide and the O antigen, that will be linked together after their respective synthesis. The lipid A, embedded inside the outer membrane, is the proximal part of the LPS and the core is the medial part, whereas the O antigen represents the distal part free in the external environment. Amongst the Enterobacteriaceae family, the lipid A is structurally highly conserved and the variation in the structure of the core oligosaccharide is limited whereas the O antigen is the hypervariable region. Diverse biological activities have been associated with LPS, amongst which the endotoxinic activity carried by the lipid A, and the strain immunogenic specificity carried by the O antigen. In this review manuscript we summarize the state of knowledge on the structures and biosynthesis of the different components of the LPS of Escherichia coli and on their respective roles in the virulence of pathogenic bacteria. [less ▲]

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See detail2F3 Monoclonal Antibody Recognizes the O26 O-Antigen Moiety of the Lipopolysaccharide of Enterohemorrhagic Escherichia coli Strain 4276
Szalo, Ioan Mihai ULg; Taminiau, Bernard ULg; Goffaux, Frédéric et al

in Clinical and Diagnostic Laboratory Immunology (2004), 11(3), 532-537

Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) organisms are groups of pathogenic strains whose infections are characterized by a typical lesion of enterocyte attachment and ... [more ▼]

Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) organisms are groups of pathogenic strains whose infections are characterized by a typical lesion of enterocyte attachment and effacement. They are involved in enteric diseases both in humans and in animals, and EHEC strains can be responsible for hemolytic uremic syndrome in humans. Previously, it was shown that the 2F3 monoclonal antibody (MAb) is specific for the O26 EHEC and EPEC strains (P. Kerr, H. Ball, B. China, J. Mainil, D. Finlay, D. Pollock, I. Wilson, and D. Mackie, Clin. Diagn. Lab. Immunol. 6:610–614, 1999). As these groups of bacteria play an important role in pathology, the aim of this paper was to characterize the antigen recognized by the 2F3 MAb and its genetic determinant. A genomic locus containing the entire O-antigen gene cluster and half of the colanic acid gene cluster from an O26 EHEC strain was shown to be sufficient for the production of the antigen recognized by the 2F3 MAb in an E. coli DH5 strain. By transposon mutagenesis performed on the recombinant plasmid, all 2F3 enzyme-linked immunosorbent assay-negative mutants had their transposons inserted into the O-antigen gene cluster. The O-antigen gene cluster was also cloned from an O26 EHEC strain into the E. coli DH5 strain, which then produced a positive result with the 2F3 MAb. Further analysis of the type of lipopolysaccharides (smooth or rough) produced by the clones and mutants and of the O antigen of the 2F3-positive clones confirmed that the epitope recognized by the 2F3 MAb is located on the O antigen in the O26 EHEC and EPEC strains and that its genetic determinant is located inside the O-antigen gene cluster. [less ▲]

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See detailPresence in bovine enteropathogenic (EPEC) and enterohaemorrhagic (EHEC) Escherichia coli of genes encoding for putative adhesins of human EHEC strains
Szalo, Ioan Mihai ULg; Goffaux, Frédéric; Pirson, Vinciane et al

in Research in Microbiology (2002), 153(10), 653-658

Enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC) infections are characterised by the formation of attaching and effacing lesions on intestinal epithelial cells. The first step of ... [more ▼]

Enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC) infections are characterised by the formation of attaching and effacing lesions on intestinal epithelial cells. The first step of EPEC and EHEC pathogenesis involves the initial adherence of the bacterium to the intestinal epithelium. A collection of bovine EPEC and EHEC strains belonging to different serogroups was tested by colony blot hybridization with gene probes for putative adhesins (BFPA, LPFA, IHA, LIFA) of human EPEC and EHEC, and also for fimbrial and afimbrial adhesins (AFA8, F17, Cs31A) of bovine necrotoxigenic E. coli (NTEC). In the bovine EPEC and EHEC strains tested, sequences homologous to lifA, ihA, and lpfA genes were detected, sometimes in association with particular serogroups. Bovine O26 EPEC also possessed a sequence homologous to a gene of the clp operon, coding for the CS31A adhesin, associated with bovine NTEC. Overall results showed that different genes encoding for putative adhesins of human EHEC strains are present in bovine EPEC and EHEC strains, but not one of them is present in all strains. [less ▲]

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