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Potsdam, Germany

Rubbenstroth D.,University of Veterinary Medicine Hannover | Rubbenstroth D.,Albert Ludwigs University of Freiburg | Ryll M.,University of Veterinary Medicine Hannover | Knobloch J.K.-M.,University of Lubeck | And 2 more authors.
Avian Pathology | Year: 2013

Riemerella anatipestifer (RA) is an important avian pathogen with considerable impact on poultry production worldwide. However, the diagnosis of RA infections may be difficult, mainly due to problems with unequivocal differentiation of RA from other Flavobacteriaceae and a lack of standardized methods and reagents. The aim of the present study was therefore to complement the routine diagnostic strategies for RA by design and evaluation of alternative diagnostic tools. We designed and validated a new RA-specific polymerase chain reaction assay, which proved to be a valuable tool for the identification of RA isolates as well as for rapid and sensitive RA detection directly from diagnostic samples. Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry fingerprinting of whole bacterial cells was also demonstrated to identify RA isolates efficiently. Furthermore, this method may also provide opportunities for RA subtyping. In our study, a stable subcluster was formed by the mass spectroscopy profiles of a group of RA isolates originating from turkey flocks in northern Germany, suggesting an epidemiological relationship of these isolates. Serotyping is a further important measure to characterize RA isolates. We tested a set of commercially available anti-RA sera with RA serotype reference strains and field isolates to allow comparison between these sera and reference sera. In summary, this report contributes to the improvement of present microbiological and molecular strategies for the diagnosis of RA infections by providing new tools as well as enhanced knowledge on existing methods. © 2013 Copyright Houghton Trust Ltd. Source


Gomila M.,University of the Balearic Islands | Prince-Manzano C.,University of the Balearic Islands | Svensson-Stadler L.,Gothenburg University | Busquets A.,University of the Balearic Islands | And 5 more authors.
PLoS ONE | Year: 2014

The Achromobacter is a genus in the family Alcaligenaceae, comprising fifteen species isolated from different sources, including clinical samples. The ability to detect and correctly identify Achromobacter species, particularly A. xylosoxidans, and differentiate them from other phenotypically similar and genotypically related Gram-negative, aerobic, non-fermenting species is important for patients with cystic fibrosis (CF), as well as for nosocomial and other opportunistic infections. Traditional phenotypic profile-based analyses have been demonstrated to be inadequate for reliable identifications of isolates of Achromobacter species and genotypic-based assays, relying upon comparative 16S rRNA gene sequence analyses are not able to insure definitive identifications of Achromobacter species, due to the inherently conserved nature of the gene. The uses of alternative methodologies to enable high-resolution differentiation between the species in the genus are needed. A comparative multi-locus sequence analysis (MLSA) of four selected 'house-keeping' genes (atpD, gyrB, recA, and rpoB) assessed the individual gene sequences for their potential in developing a reliable, rapid and cost-effective diagnostic protocol for Achromobacter species identifications. The analysis of the type strains of the species of the genus and 46 strains of Achromobacter species showed congruence between the cluster analyses derived from the individual genes. The MLSA gene sequences exhibited different levels of resolution in delineating the validly published Achromobacter species and elucidated strains that represent new genotypes and probable new species of the genus. Our results also suggested that the recently described A. spritinus is a later heterotypic synonym of A. marplatensis. Strains were analyzed, using whole-cell Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight mass spectrometry (MALDI-TOF MS), as an alternative phenotypic profile-based method with the potential to support the identifications determined by the genotypic DNA sequencebased MLSA. The MALDI-TOF MS data showed good accordance in strain groupings and identifications by the MLSA data. Copyright: © 2014 Gomila et al. Source


Frohling A.,Leibniz Institute for Agricultural Engineering | Erhard M.,Ripac Labor GmbH | Muranyi P.,Fraunhofer Institute for Process Engineering and Packaging | Schluter O.,Leibniz Institute for Agricultural Engineering
Landtechnik | Year: 2015

The increasing demand on safe food with high quality poses a high challenge especially for perishable products. Microbiological sampling along the food processing chain is mainly focused on selected indicator microorganisms and unexpected potential human pathogenic bacteria may remain undetected. The detection of unexpected pathogenic bacteria is of great interest to avoid potential risks for consumers. The change microbial community of perishables exemplarily shown for mung bean sprouts was evaluated using plate count methods and MALDI-TOF MS. The total aerobic viable count of sprouts was 8-9 log CFU/g and among others bacteria from Bacillus cereus group, Yersinia sp., Enterobacter spp., Klebsiella spp., Pantoea spp., and Pseudomonas spp. were identified. © 2015 by the authors. Source


Kondori N.,Gothenburg University | Erhard M.,Ripac Labor GmbH | Welinder-Olsson C.,Gothenburg University | Groenewald M.,Fungal Biodiversity Center | And 2 more authors.
FEMS Microbiology Letters | Year: 2015

Conventional mycological identifications based on the recognition of morphological characteristics can be problematic. A relatively new methodology applicable for the identification of microorganisms is based on the exploitation of taxonspecific mass patterns recorded from abundant cell proteins directly from whole-cell preparations, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This study reports the application of MALDI-TOF MS for the differentiation and identifications of black yeasts, isolated from the respiratory tracts of patients with cystic fibrosis (CF). Initial phenotypic and DNA sequence-based analyses identified these isolates to be Exophiala dermatitidis. The type strains of E. dermatitidis (CBS 207.35T) and other species of Exophiala were included in the MALDI-TOF MS analyses to establish the references for comparing the mass spectra of the clinical isolates of Exophiala. MALDI-TOF MS analyses exhibited extremely close relationships among the clinical isolates and with the spectra generated from the type strain of E. dermatitidis. The relationships observed between the E. dermatitidis strains from the MALDI-TOF MS profiling analyses were supported by DNA sequence-based analyses of the rRNA ITS1 and ITS2 regions. These data demonstrated the applicability of MALDI-TOF MS as a reliable, rapid and cost-effective method for the identification of isolates of E. dermatitidis and other clinically relevant fungi and yeasts that typically are difficult to identify by conventional methods. © FEMS 2014. Source


Jung A.,University of Veterinary Medicine Hannover | Metzner M.,Ripac Labor GmbH | Kohler-Repp D.,Ripac Labor GmbH | Rautenschlein S.,University of Veterinary Medicine Hannover
Avian Pathology | Year: 2013

Enterococcus cecorum (EC) was thus far only known as a pathogen for broilers and broiler breeders. Recently there was evidence of EC field outbreaks in Pekin duck flocks in Germany. In this study we experimentally reproduced an EC infection in Pekin ducks. At 12 days post hatch, groups of Pekin ducks were infected orally, via the thoracic air sac or intravenously with 1.5 × 109 colony-forming units (CFU) of EC per bird or via the air sac with 8.5 × 105 or 8.5 × 107 CFU per bird. Ducks of the intravenously infected group showed 100% mortality after 2 days post infection. The air sac inoculated high-dose group exhibited a mortality rate of 67%. Birds that were infected with 8.5 × 105 and 8.5 × 107 CFU showed 6.7% mortality after 7 days post infection. Dead birds displayed pneumonia, airsacculitis, pericarditis and splenitis and EC was re-isolated from these organs. Surviving birds of all groups apart from the orally infected ducks demonstrated clinical signs such as huddling, reduced mobility and diarrhoea. Furthermore, they showed gross pathological lesions including airsacculitis and splenitis and lower bodyweights than the control group at necropsy on days 7, 14 and 21 post infection. The present study clearly confirms that EC is pathogenic for Pekin ducks after experimental infection via the intravenous route or the respiratory tract. EC therefore has to be considered as an emerging avian pathogen not only in broilers but also in Pekin ducks. © 2013 © 2013 Houghton Trust Ltd. Source

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