Accuracy of qPCR and bacterial culture for the diagnosis of bovine intramammary infections and teat skin colonisation with Streptococcus agalactiae and Staphylococcus aureus using Bayesian analysis

Svennesen, Line; Mahmmod, Yasser S.; Skjølstrup, Nanna K.; Mathiasen, L. R.; Katholm, J.; Pedersen, Karl; Klaas, Ilka Christine; Nielsen, Søren Saxmose

doi:10.1016/j.prevetmed.2018.10.013

Cited by 16 publications

(13 citation statements)

References 32 publications

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“…However, in the ICS test, which is based on an immunoassay, the anti-RP-L7/L12 antibody induces a positive response to killed bacteria. Indeed, these results could easily be inconsistent with the diagnosis results from the bacterial culture method because PCR has a potential for higher sensitivity and specificity due to its ability to detect both live and dead microorganisms (29,32,33). Actually, the present study also demonstrated that qPCR of nuc tended to contain false-positives at same level as ICS test.…”

Section: Discussionmentioning

confidence: 52%

Rapid Staphylococcus aureus Detection From Clinical Mastitis Milk by Colloidal Gold Nanoparticle-Based Immunochromatographic Strips

et al. 2020

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Rapid diagnostic technologies for bovine mastitis caused by Staphylococcus aureus (S. aureus) are urgently needed. In the current study, we generated an anti-ribosomal protein-L7/L12 antibody to detect S. aureus and an anti-ribosomal protein-L7/L12 antibody-coated immune-chromatographic strip (ICS) test. Moreover, we determined the ability of the ICS test to detect S. aureus from milk samples collected from cows with clinical mastitis. The developed ICS reacted to S. aureus in a bacteria load-dependent manner with a detection limit of ∼10 4 CFU/mL. In the evaluation of possible cross-reactivity of the ICS test, six strains of coagulase-negative Staphylococci showed slightly positive reactions, although at a lower level; however, other bacteria were completely negative. Next, we investigated the sensitivity and specificity of the ICS test compared with the bacteriological culture method using milk samples from clinical bovine mastitis. The results of the experiments demonstrated that the ICS test had high sensitivity [100%, 95% confidence interval (CI): 91.3-100%] and specificity (91.9%, CI: 90.5-91.9%) compared with culture tests. In addition, the kappa statistic demonstrated that ICS tests showed substantial agreement (k = 0.77, CI: 0.66-0.87) with culture tests. Positive correlations were observed for the statistical analysis between S. aureus (nuc gene) copy numbers and ICS test scores in mastitic milk infected by S. aureus. Therefore, we assume that this new detection method using ICS may be useful as a highly sensitive S. aureus-screening method for the diagnosis of bovine mastitis. Our findings support the ongoing effort to develop an ICS method for bovine S. aureus-induced mastitis, which can contribute to the rapid diagnosis of this disease.

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Section: Discussionmentioning

confidence: 52%

Rapid Staphylococcus aureus Detection From Clinical Mastitis Milk by Colloidal Gold Nanoparticle-Based Immunochromatographic Strips

et al. 2020

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“…aureus and Strep. agalactiae as recently demonstrated (Nyman et al, ; Svennesen et al, ) especially from polybacterial samples, can therefore be regarded as contaminants. Conversely 38 samples gave no bacterial growth and only one colony type grew from 82 samples, confirming that the sampling method was correctly performed for the majority of the samples.…”

Section: Discussionmentioning

confidence: 87%

Comparison of quantitative PCR and MALDI‐TOF mass spectrometry assays for identification of bacteria in milk samples from cows with subclinical mastitis

et al. 2019

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Aims: The objective of this study was to compare qualitatively and quantitatively the results of identification of the bacteria present in milk samples from cows with subclinical mastitis using multiplex qPCR assay and matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS â ) after bacteriological growth. Methods and Results: A total of 182 samples were aseptically collected from 119 cows with high somatic cell counts (>2Á10 5 SCC per ml) on 11 farms in Belgium in 2014. The mutiplex qPCR assay was carried out on 350 µl of milk with the PathoProof â Complete-16kit. Ten microlitre of milk was streaked on Columbia blood agar and three selective agar plates. Growing colonies were identified by MALDI-TOF MS. Of the 182 samples, 90 gave positive results with either or both tests for one or two bacterial species/genera. Total qualitative agreement of the bacteria identified was observed in 41 mono-or bi-bacterial samples (46%) and partial agreement in 19 bi-bacterial samples at both or either tests (21%). The results of both tests on those mono-and bibacterial samples were not significantly different (McNemar test; P = 0Á395) with a fair agreement (Cohen's kappa test; k = 0Á375; P = 0Á055). Moreover, quantitative correlation between the qPCR intensity and the numbers of growing colonies was observed in half of the 60 samples with qualitative matching results. Conclusions: Both methods give identical qualitative and quantitative results with approximately a half and a quarter of the mono-and bi-bacterial samples respectively. Several reasons can explain the differences. The multiplex qPCR assay only targets the most important mammary gland pathogens and can detect DNA of bacteria both alive and dead. Conversely, bacteria only grow when alive and the MALDI-TOF MS databases do not include all bovine milkassociated bacterial species yet. Significance and Impact of the Study: This study further highlights the limitations and complementarity of the genetic and phenotypic tests for the identification of bacteria present in milk samples.

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“…aureus em infecções intramamárias sejam conflitantes e o envolvimento da pele do teto na epidemiologia deste agente é estudada (Mahmmod, et al, 2018;Svennesen, et al, 2018), evidenciando possíveis focos de infecção externas à glândula mamária. Resultados de pesquisas indicam que tetos com pele colonizada por S. aureus apresentam 4,5 vezes mais riscos de infecções intramamárias do que teto isentos de colonização (Costa, et al, 2014).…”

Section: Resultsunclassified

“…Estafilococos coagulase negativo foi o grupo identificado em maior frequência tanto nos submetidos ao tratamento com novo produto (13,54%), quanto ao tratamento com produtos convencionais (10,94%), semelhante a outros estudos (Mahmmod, et al, 2018;Svennesen, et al, 2018).…”

Section: Resultsunclassified

Óleo essencial de Lippia origanoides (Verbenaceae) na higienização de tetos de vacas leiteiras

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Mourão

Mourthé

et al. 2021

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O presente estudo teve como objetivo avaliar a eficácia de um novo produto elaborado a base de óleo essencial de alecrim pimenta sob a redução da contagem de microrganismos presentes na pele de tetos de vacas leiteiras. Para o teste in vivo, avaliou-se a eficácia do novo produto sob a antissepsia de negativos para mastite clínica (192 tetos), em comparação ao tratamento que continha produtos comerciais (192 tetos), durante um período de 42 dias. Os tetos foram diariamente acompanhados clinicamente, havendo semanalmente avaliação da microbiota presente na pele dos mesmos quanto à redução na contagem de Staphylococcus aureus, Estafilococos coagulase negativo (ECN), Echerichia coli e aeróbios mesófilos. Os dois produtos mantiveram a integridade dos tetos, sendo observado ausência de mastite clínica durante o período experimental. Não observou-se diferença significativa na ocorrência de mastite subclínica e de microrganismos nos tetos dos dois grupos em estudo pelo teste de Fisher em nível de significância de 5%. Ao comparar a redução Log da contagem em UFC.mL-1 dos microrganismos para o grupo tratado com produto convencional e com produto experimental para aeróbios mesófilos, E. coli, S. aureus e Estafilococos coagulase negativa, obtidos com o processo de higienização dos tetos foi observada diferença estatística(p>0,05), na contagem de microrganismos, evidenciando que ambos apresentaram efeito semelhante ao controle de microrganismos presentes na pele dos tetos. Sendo assim, o novo produto contendo óleo essencial de alecrim pimenta apresentou eficácia semelhante ao produto convencional clorexidine e iodo para antissepsia dos tetos de vacas leiteiras sem promover reações locais na pele, podendo este vir a ser utilizado como produto alternativo no manejo de ordenha.

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Accuracy of qPCR and bacterial culture for the diagnosis of bovine intramammary infections and teat skin colonisation with Streptococcus agalactiae and Staphylococcus aureus using Bayesian analysis

Cited by 16 publications

References 32 publications

Rapid Staphylococcus aureus Detection From Clinical Mastitis Milk by Colloidal Gold Nanoparticle-Based Immunochromatographic Strips

Rapid Staphylococcus aureus Detection From Clinical Mastitis Milk by Colloidal Gold Nanoparticle-Based Immunochromatographic Strips

Comparison of quantitative PCR and MALDI‐TOF mass spectrometry assays for identification of bacteria in milk samples from cows with subclinical mastitis

Óleo essencial de Lippia origanoides (Verbenaceae) na higienização de tetos de vacas leiteiras

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