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Schabauer L.,University of Veterinary Medicine Vienna | Wenning M.,TU Munich | Huber I.,Bavarian Health and Food Safety Authority LGL | Ehling-Schulz M.,University of Veterinary Medicine Vienna
BMC Veterinary Research | Year: 2014

Background: The routine diagnosis of Streptococcus spp. and other mastitis associated gram-positive, catalase-negative cocci is still based upon biochemical tests and serological methods, which frequently provide ambiguous identification results. We therefore aimed to establish an accurate identification system for differential diagnosis of mastitis associated Streptococcus spp. and related species using biophysical techniques such as Fourier-transform infrared (FTIR) spectroscopy and MALDI - TOF/MS.Results: Based on a panel of 210 isolates from cases of bovine mastitis, an unsupervised FTIR spectral reference library was established and an artificial neural network (ANN) - assisted identification system was developed. All bacterial isolates were previously identified by species-specific PCR and/or 16S rRNA gene sequence analysis. An overall identification rate of 100% at species level for 173 strains unknown to the ANN and the library was achieved by combining ANN and the spectral database, thus demonstrating the suitability of our FTIR identification system for routine diagnosis. In addition, we investigated the potential of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of mastitis associated Streptococcus spp. and related bacteria. Using the Microflex LT System, MALDI Biotyper software™ (V3.3) we achieved an accuracy rate of 95.2%. A blind study, including 21 clinical samples from dairy cows, revealed a 100% correct species identification rate for FTIR and 90.5% for MALDI-TOF MS, indicating that these techniques are valuable tools for diagnosis.Conclusions: This study clearly demonstrates that FTIR spectroscopy as well as MALDI-TOF MS can significantly improve and facilitate the identification and differentiation of mastitis associated Streptococcus spp. and related species. Although the FTIR identification system turned out being slightly superior to MALDI-TOF MS in terms of identification on species level, both methods offer interesting alternatives to conventional methods currently used in mastitis diagnosis as both of them provide high accuracy at low operating costs once the instrument is acquired. © 2014 Schabauer et al.; licensee BioMed Central Ltd. Source


Broeders S.,Scientific Institute of Public Health WIV ISP | Huber I.,Bavarian Health and Food Safety Authority LGL | Grohmann L.,Federal Office of Consumer Protection and Food Safety BVL | Berben G.,Walloon Agricultural Research Center | And 5 more authors.
Trends in Food Science and Technology | Year: 2014

As for many areas of molecular testing, detection of Genetically Modified Organisms (GMO) relies on the real-time Polymerase Chain Reaction (qPCR) technology. Due to the increasing number of GMO, a screening approach using qualitative screening methods has become an integrated part of GMO detection. However, specific guidelines for the validation of these methods are lacking. Here, a pragmatic approach to conduct in-house and inter-laboratory validation studies for GMO screening methods, is proposed. Such guidelines could be adapted to other areas where qualitative qPCR methods are used for molecular testing allowing to implement easily a more reliable screening phase where necessary. © 2014 Elsevier Ltd. Source


Huang J.-H.,ETH Zurich | Ilgen G.,University of Bayreuth | Fecher P.,Bavarian Health and Food Safety Authority LGL
Journal of Analytical Atomic Spectrometry | Year: 2010

Extraction using 0.28 M nitric acid at 95 °C for 90 min recovers not only arsenic quantitatively from rice grains independent of types but also preserves arsenic speciation completely. It is simple, economic, effective and reliable and is especially suitable for routine analysis of large amounts of samples. © The Royal Society of Chemistry 2010. Source


Huang J.-H.,ETH Zurich | Fecher P.,Bavarian Health and Food Safety Authority LGL | Ilgen G.,University of Bayreuth | Hu K.-N.,U.S. National Institute of Diabetes and Digestive and Kidney Diseases | Yang J.,University of Sichuan
Food Chemistry | Year: 2012

Arsenite and arsenate speciation was performed in 121 commercially purchased samples of 12 rice types to understand their relative relevance in rice grain. General effectiveness of a recently developed extraction protocol based on 0.28 M nitric acid at 95 °C was verified by checking the recovery of total grain arsenic and by comparing arsenic speciation in NIST-CRM-1568a, NMIJ-CRM-7503a and IMEP-107 with certificated and literature values. The arsenic speciation highlights the predominance of arsenite in 115 and dimethylarsinic acid in six samples and common minor components including arsenate, monomethylarsonic acid and two unknown arsenical species. Our data also indicate potential influences of other trace elements on As speciation in rice grain. Averagely, arsenite accounts for 90% of inorganic grain arsenic regardless of geographic origin, rice type, grain size, cultural practice and polish treatment. The high arsenite predominance indicates an elevated toxic effect of arsenic in rice than is perceived to date. © 2011 Elsevier Ltd. All rights reserved. Source


Froschle B.,Bavarian State Research Center for Agriculture LfL | Messelhausser U.,Bavarian Health and Food Safety Authority LGL | Holler C.,Bavarian Health and Food Safety Authority LGL | Lebuhn M.,Bavarian State Research Center for Agriculture LfL
Journal of Applied Microbiology | Year: 2015

Aims: This study aimed to assess the sanitary situation in agricultural biogas plants (BP) regarding pathogenic Clostridium spp. Methods and Results: The incidence of Clostridium botulinum, Clostridium difficile, Clostridium novyi, Clostridium haemolyticum, Clostridium septicum and Clostridium chauvoei was investigated in 154 plant and animal substrates, digester sludges and digestates from full-scale BP using a method combining microbial enrichment with Real-Time PCR. The investigated clostridia were absent in the samples, except for Cl. novyi that was barely present (3·9%) and Cl. difficile that was more frequently detected (44·8%). Clostridium botulinum exposed to lab-scale digesters in sentinel chambers was reduced with D-values of 34·6 ± 11·2 days at 38°C and 1·0 ± 0·2 days at 55°C. Conclusions: These findings indicate minor relevance of clostridial pathogens in BP and an improved sanitary quality of the digestion product compared to untreated substrates concerning Cl. botulinum. However, the frequent detection of Cl. difficile opens questions on the durability of this organism in manure digestion lines. Significance and Impact of the Study: This is the first study providing data on the reduction of Cl. botulinum during biogas processes that scientifically invalidate contrary claims by some media in the public. Furthermore, the results improve the fragmentary knowledge on the prevalence of several clostridial pathogens in agricultural biogas production. © 2015 The Society for Applied Microbiology. Source

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