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Methner U.,Institute of Bacterial Infections and Zoonoses at the Friedrich Loeffler Institute | Barrow P.A.,University of Nottingham | Berndt A.,Institute of Molecular Pathogenesis at The Friedrich Loeffler Institute | Rychlik I.,Veterinary Research Institute
Vaccine | Year: 2011

Salmonella Enteritidis mutants with deletions in phoP, fliC or phoPfliC were tested for their virulence and their ability to induce parameters of the innate and adaptive immunity in addition to their potential for serological differentiation between vaccinated, non-vaccinated and infected chickens. The double phoPfliC deletion mutant was sufficiently attenuated but not diminished in its capability to inhibit the caecal colonisation and systemic invasion of homologous Salmonella Enteritidis shortly after administration of the vaccine strain to very young chicks. Immunisation with the attenuated Δ phoPfliC mutant resulted in protective effects which were only slightly and insignificantly lower than after " immunisation" with a Salmonella wild-type strain, indicating the capability to induce an intense adaptive immune response and protection against Salmonella exposure in older chickens. The deletion in fliC enabled the effective the differentiation between immunised and infected chickens using a commercially available ELISA kit. The double phoPfliC deletion mutant of Salmonella Enteritidis might be a potential and promising live Salmonella vaccine candidate with novel characteristics for use in poultry. © 2011 Elsevier Ltd.

Methner U.,Institute of Bacterial Infections and Zoonoses at the Friedrich Loeffler Institute | Barrow P.A.,University of Nottingham | Berndt A.,Institute of Molecular Pathogenesis at The Friedrich Loeffler Institute
Vaccine | Year: 2010

Administration of live Salmonella strains to day-old chicks provides protection against infection within hours by intestinal colonisation-inhibition. However, the extent to which the oral application of live Salmonella wild-type or vaccine strains may induce an early invasion-inhibition effect is unknown. Potentially protective pre-treatment strains of Salmonella Enteritidis and Infantis were examined for their ability (i) to colonise the caeca, to invade the liver, to induce an influx of granulocytes in caecal mucosa and, (ii) for their capacity to inhibit the systemic invasion of homologous and heterologous Salmonella challenge organisms. The highly invasive strain Salmonella Enteritidis induced a strong influx of heterophils in the caecal mucosa followed by a complete invasion-inhibition of both homologous and heterologous Salmonella challenge organisms administered 24 h later. Pre-treatment with a less invasive Salmonella Infantis resulted in a lower influx of granulocytes in the caecal tissue followed by a complete invasion-inhibition of the homologous serovar Infantis but only an incomplete invasion-inhibition of heterologous serovars. This invasion-inhibition effect has not been described previously in chickens and should be considered in the development of novel live Salmonella vaccines to prevent an early invasion of extra-intestinal organs by Salmonella challenge organisms in young chicks. © 2010 Elsevier Ltd.

Methner U.,Institute of Bacterial Infections and Zoonoses at the Friedrich Loeffler Institute | Heller M.,Institute of Bacterial Infections and Zoonoses at the Friedrich Loeffler Institute | Bocklisch H.,Thuringian State Authority for Food Safety and Consumer Protection
European Journal of Wildlife Research | Year: 2010

Salmonella (S.) enterica subspecies enterica serovar Choleraesuis, the swine-adapted serovar is found rarely in Western European countries including Germany. However, the regional laboratory of the federal state Thuringia in Germany examined diseased wild boars routinely also for the occurrence of Salmonella organisms. Between 2006 and 2008, only the serovar S. Choleraesuis was islolated from 24 animals, three strains isolated from domestic pigs were included. In order to detect a possible epidemiological context, the strains of S. Choleraesuis were characterised by macrorestriction and plasmid analysis, repetitive sequence PCR, antimicrobial testing and determining the biochemical profile. A combination of all methods enabled the identification of five epidemiological groups. Two groups were detected in the same territory but three other discriminative groups were predominant in different regions. S. Choleraesuis strains of the different epidemiological groups circulate in wild boar populations in the corresponding regions. However, it could be concluded that both natural barriers like mountains and artificial barriers like arterial roads may cause the separation of wild boar populations and as a result also the respective S. Choleraesuis organisms. The occurrence of the identical epidemiological groups in wild boars and domestic pigs indicates the possible mutual exposure of the pathogen. To avoid risks for human and domestic pig health regular inspection of meat from wildlife by official veterinarians and advice of hunters and persons who prepare and consume wild boar meat should be enhanced. © 2009 Springer-Verlag.

Braun S.D.,Alere Technologies GmbH | Ziegler A.,Alere Technologies GmbH | Methner U.,Institute of Bacterial Infections and Zoonoses at the Friedrich Loeffler Institute | Slickers P.,Alere Technologies GmbH | And 4 more authors.
PLoS ONE | Year: 2012

Salmonellosis caused by Salmonella (S.) belongs to the most prevalent food-borne zoonotic diseases throughout the world. Therefore, serotype identification for all culture-confirmed cases of Salmonella infection is important for epidemiological purposes. As a standard, the traditional culture method (ISO 6579:2002) is used to identify Salmonella. Classical serotyping takes 4-5 days to be completed, it is labor-intensive, expensive and more than 250 non-standardized sera are necessary to characterize more than 2,500 Salmonella serovars currently known. These technical difficulties could be overcome with modern molecular methods. We developed a microarray based serogenotyping assay for the most prevalent Salmonella serovars in Europe and North America. The current assay version could theoretically discriminate 28 O-antigens and 86 H-antigens. Additionally, we included 77 targets analyzing antimicrobial resistance genes. The Salmonella assay was evaluated with a set of 168 reference strains representing 132 serovars previously serotyped by conventional agglutination through various reference centers. 117 of 132 (81%) tested serovars showed an unique microarray pattern. 15 of 132 serovars generated a pattern which was shared by multiple serovars (e.g., S. ser. Enteritidis and S. ser. Nitra). These shared patterns mainly resulted from the high similarity of the genotypes of serogroup A and D1. Using patterns of the known reference strains, a database was build which represents the basis of a new PatternMatch software that can serotype unknown Salmonella isolates automatically. After assay verification, the Salmonella serogenotyping assay was used to identify a field panel of 105 Salmonella isolates. All were identified as Salmonella and 93 of 105 isolates (88.6%) were typed in full concordance with conventional serotyping. This microarray based assay is a powerful tool for serogenotyping. © 2012 Braun et al.

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