Bayesian estimation of qPCR and bacterial culture accuracy for detection of bovine coagulase‐negative staphylococci from milk and teat apex at different test cut‐off points

Aim:To primarily estimate the sensitivity (Se) and specificity (Sp) of thecommercially available Mastit4 quantitative PCR (qPCR) assay and bacterialculture (BC) for diagnosis of intramammary infections (IMI) and teat apexcolonization (TAC) with coagulase-negative staphylococci (CNS) at differentcut-offs for qPCR cycle threshold values using Bayesian latent class analysis. Asecondary objective was to evaluate two cut-offs of BC for diagnosis of IMIand TAC with CNS.Methods and Results:We randomly selected 13–20 cows with subclinicalmastitis from eight dairy herds. Teat skin samples and aseptically collectedforemilk samples were collected from the right hindquarters (n=149) for BCand qPCR analysis. The Se of qPCR was always higher than BCSein diagnosis ofIMI, however; the Sp of BC was higher than qPCRSp.BCSeand BCSpshowed nosubstantial difference between the tested BC cut-offs. In contrast to IMI,estimates of BC and qPCR in diagnosing TAC were different. BCSewas higherthan qPCRSeat all tested cut-offs, however; qPCRSpwas higher than BCSp.Conclusion:The overall performance of qPCR is higher than BC in thediagnosis of IMI; however, the performance of BC is better than qPCR indiagnosis of TAC. The qPCR and BC are valid diagnostics for bovine IMI withCNS. However, for TAC, both techniques require further investigation toreduce the uncertainty of the true status of the quarter and teat skin.Significance and Impact of the Study:We reported, for the first time, thediagnostic performance of new mastitis technology (Mastit4 PCR) and culturefor detection of CNS in milk and nonmilk samples in dairy herds withautomatic milking systems. Our findings will improve the interpretation of thetest results of culture and qPCR assay and subsequently, will strengthen thecontrol of IMI with CNS in dairy cows.info:eu-repo/semantics/acceptedVersio

Streptococcus agalactiae Serotype IV in Humans and Cattle, Northern Europe

Streptococcus agalactiae is an emerging pathogen of nonpregnant human adults worldwide and a reemerging pathogen of dairy cattle in parts of Europe. To learn more about interspecies transmission of this bacterium, we compared contemporaneously collected isolates from humans and cattle in Finland and Sweden. Multilocus sequence typing identified 5 sequence types (STs) (ST1, 8, 12, 23, and 196) shared across the 2 host species, suggesting possible interspecies transmission. More than 54% of the isolates belonged to those STs. Molecular serotyping and pilus island typing of those isolates did not differentiate between populations isolated from different host species. Isolates from humans and cattle differed in lactose fermentation, which is encoded on the accessory genome and represents an adaptation to the bovine mammary gland. Serotype IV-ST196 isolates were obtained from multiple dairy herds in both countries. Cattle may constitute a previously unknown reservoir of this strain.Peer reviewe

Prevalence of contagious and environmental mastitis-causing bacteria in bulk tank milk and its relationships with milking practices of dairy cattle herds in São Miguel Island (Azores)

This study aimed to assess the degree of contamination of bulk tank milk (BTM) by Staphylococcus spp. and coliform bacteria and to identify major milking practices that help perpetuate them in dairy cattle herds in São Miguel Island. In July 2014, BTM was sampled and a survey concerning local milking practices was conducted on 100 herds. Semi quantitative multiplex polymerase chain reaction detected coagulase-negative staphylococci, Escherichia coli, Staphylococcus aureus, and other coliform bacteria (Klebsiella oxytoca, Klebsiella pneumoniae, andSerratia marcescens) in 100, 75, 59, and 35 % of BTM, respectively. According to multivariable univariate models, on herds not using hot water for cleaning the milking machine and teat liners, there was at least 3.4 more odds (P<0.01) to have S. aureus or coliform bacteria contamination in BTM. The likelihoodoffinding S.aureus inBTMwas higher(P<0.001)on herds without high hygiene during milking, when milking mastitic cows at the end, on abrupt cessation of milking at dry-off, and official milk control implementation. The glove use also favored (odds ratio (OR) 5.8; P<0.01)thedetection ofcoliformbacteriainBTM.Poormilkingpracticesidentified in this study should be avoided in order to decrease S. aureus and coliform bacteria contamination of BTM. Other factors associated with milk quality in São Miguel Island also should be further investigated

Genomic analysis of European bovine Staphylococcus aureus from clinical versus subclinical mastitis

Abstract: Intramammary infections (IMI) with Staphylococcus aureus are a common cause of bovine mastitis and can result in both clinical (CM) or subclinical mastitis (SCM). Although bacterial isolates of S. aureus differ in their virulence potential it is largely unclear which bacterial virulence factors are responsible for increased clinical severity. We performed a genome wide association study and used a generalized linear mixed model to investigate the correlation between gene carriage, lineage and clinical outcome of IMI in a collection of S. aureus isolates from cattle with CM (n = 125) and SCM (n = 151) from 11 European countries. An additional aim was to describe the genetic variation of bovine S. aureus in Europa. The dominant lineages in our collection were clonal complex (CC) 151 (81/276, 29.3%), CC97 (54/276, 19.6%), CC479 (32/276, 11.6%) and CC398 (19/276, 6.9%). Virulence and antimicrobial resistance (AMR) gene carriage was highly associated with CC. Among a selection of nine virulence and AMR genes, CC151, CC479 and CC133 carried more virulence genes than other CCs, and CC398 was associated with AMR gene carriage. Whereas CC151, CC97 were widespread in Europe, CC479, CC398 and CC8 were only found in specific countries. Compared to CC151, CC479 was associated with CM rather than SCM (OR 3.62; 95% CI 1.38–9.50) and the other CCs were not. Multiple genes were associated with CM, but due to the clustering within CC of carriage of these genes, it was not possible to differentiate between the effect of gene carriage and CC on clinical outcome of IMI. Nevertheless, this study demonstrates that characterization of S. aureus CC and virulence genes helps to predict the likelihood of the occurrence of CM following S. aureus IMI and highlights the potential benefit of diagnostics tools to identify S. aureus CC during bovine mastitis

TDMA-Medienzugriffsverfahren im Rueckkanal passiver optischer ATM-Zugangsnetze

Our modern information society is built on the availability and exchange of information as an integral part of both economic and private life. For example, the amount of traffic carried per year by the world-wide Internet is growing both due to the increasing popularity of private and business usage of the Internet and also due to the increasing number and size of documents available in the World Wide Web (WWW). The information and services offered via the WWW -from scientific research reports to culture and travel information, telephone directory services, dictionaries, train time tables and even online shopping -make this medium very attractive also for private use. The availability of powerful computers, the integration of 'classic' data services for file and document exchange (ftp and e-mail) into easy-to-use WWW browsers also facilitate the growth of world-wide date networks. Today, residential broadband network access is mostly realized via copper pairs (telephone network with analog or digital subscriber lines), coaxial cables (TV cable networks), radio technology (terrestrial or satellite) or even the power supply infrastructure (powerline communication, PLC). Several studies [20 41, 47, 50, 69, 70, 87, 136, 154] claim that in the future, passive optical networks (PON) will gain importance in broadband access. One example for a project building an ATM PON demonstrator wars the BAF (Broadband Access Facilities) project funded by the European Union [26]. In such ATM PON networks special attention needs to be paid to the upstream media access control if the network is required to offer certain quality of service guarantees such as low delay variation on the one hand and statistical multiplexing of the traffic from different subscribers on the other hand. In this thesis, the mechanisms for upstream media access control to be used in passive ATM access networks are classified, studied and compared with respect to their performance, particularly concentrating on delay variation issues. (orig.)Available from TIB Hannover: RA 2233(74) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Bayesian estimation of qPCR and bacterial culture accuracy for detection of bovine coagulase-negative staphylococci from milk and teat apex at different test cut-off points

Aim:To primarily estimate the sensitivity (Se) and specificity (Sp) of thecommercially available Mastit4 quantitative PCR (qPCR) assay and bacterialculture (BC) for diagnosis of intramammary infections (IMI) and teat apexcolonization (TAC) with coagulase-negative staphylococci (CNS) at differentcut-offs for qPCR cycle threshold values using Bayesian latent class analysis. Asecondary objective was to evaluate two cut-offs of BC for diagnosis of IMIand TAC with CNS.Methods and Results:We randomly selected 13–20 cows with subclinicalmastitis from eight dairy herds. Teat skin samples and aseptically collectedforemilk samples were collected from the right hindquarters (n=149) for BCand qPCR analysis. The Se of qPCR was always higher than BCSein diagnosis ofIMI, however; the Sp of BC was higher than qPCRSp.BCSeand BCSpshowed nosubstantial difference between the tested BC cut-offs. In contrast to IMI,estimates of BC and qPCR in diagnosing TAC were different. BCSewas higherthan qPCRSeat all tested cut-offs, however; qPCRSpwas higher than BCSp.Conclusion:The overall performance of qPCR is higher than BC in thediagnosis of IMI; however, the performance of BC is better than qPCR indiagnosis of TAC. The qPCR and BC are valid diagnostics for bovine IMI withCNS. However, for TAC, both techniques require further investigation toreduce the uncertainty of the true status of the quarter and teat skin.Significance and Impact of the Study:We reported, for the first time, thediagnostic performance of new mastitis technology (Mastit4 PCR) and culturefor detection of CNS in milk and nonmilk samples in dairy herds withautomatic milking systems. Our findings will improve the interpretation of thetest results of culture and qPCR assay and subsequently, will strengthen thecontrol of IMI with CNS in dairy cows.info:eu-repo/semantics/acceptedVersio