02483nas a2200205   4500000000100000000000100001008004100002260007000043653002300113653002200136653003000158653001500188100001400203700001700217245018200234300001200416490000800428520182700436022001402263       2012                            d  c11/2012bSchlütersche Verlagsgesellschaft mbH & Co. KGaHannover10amastitis pathogens10amolecular methods10aconventional bacteriology10adairy cows1 aS Spittel1 aM Hoedemaker00aMastitis diagnosis in dairy cows using PathoProofTM real-time polymerase chain reaction assay in comparison with conventional bacterial  culture in a Northern German field study  a494-5020 v1253 aIn the following field study, the commercial PathoProofTM Mastitis PCR Assay, a real-time PCR for identifying eleven mastitis pathogens and the staphylococcal beta-lactamase gene, was compared with conventional bacterial culture. For this purpose, 681 udder quarter samples from 173 clinically healthy cows with vary- ing somatic cell count from four dairy herds in the region of Osnabrück, Lower Saxony, Germany, were collected between July 2010 and February 2011 and sub- jected to PCR and bacterial culture. The frequency of positive pathogen signals was markedly higher with PCR compared with culture (70.6% vs. 32.2%). This was accompanied by a substantial higher percentage of multiple pathogen identi- fications and a lower percentage of single identifications in the PCR compared with bacterial culture. Using bacterial culture as gold standard, moderate to high sensitivities (76.4–100%) and specificities (63.3–48.7%) were calculated for six out of seven pathogens with sufficient detection numbers. For Enterococcus spp., the sensitivity was only 4.1%. When the PCR results of pooled udder quarter samples of the 173 cows were compared with the single udder quarter samples, in 72% of the cases, major pathogen DNA was either not found in both types of samples, or in the case of a positive pool sample, the respective pathogens were foundin at least one udder quarter sample. With both methods, the most frequently detected mastitis pathogens were coryneform bacteria (PCR: Corynebacterium bovis), coagulase-negative staphylococci (CNS) and Staphylococcus (S.) aureus, followed by Arcanobacterium pyogenes/Peptoniphilus indolicus with PCR, and then with both methods, Streptococcus uberis. The staphylococcal beta-lactamase gene was found in 27.7% of the S. aureus and in 37.0% of the CNS identifications.  a0005-9366