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Comparison of an on-farm point-of-care diagnostic with conventional culture in analysing bovine mastitis samples

Published online by Cambridge University Press:  30 April 2019

Geoff Jones ,
Olaf Bork ,
Scott A Ferguson  and
Andrew Bates
Geoff Jones*
Affiliation:
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
Olaf Bork
Affiliation:
Mastaplex Ltd, Dunedin, New Zealand
Scott A Ferguson
Affiliation:
Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
Andrew Bates
Affiliation:
Vetlife Ltd, Temuka, New Zealand
*
Author for correspondence: Geoff Jones, Email: [email protected]
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Abstract

The performance of a new point-of-care diagnostic (Mastatest), an on-farm test designed to identify bacteria and provide antibiotic sensitivity testing information from milk samples, was compared with standard microbiological culture methods. A total of 292 milk samples from clinical mastitis cases in dairy cows on New Zealand dairy farms were examined, and latent class analysis was used to estimate the performance characteristics of both tests. Two hundred and fifty-six samples (87.7%) demonstrated bacterial infection in standard culture, and 269 (92.1%) using the point-of-care diagnostic. The most common bacterial species detected was Streptococcus uberis, found in 195 samples (66.8%) using standard culture and 190 samples (65.1%) using the point-of-care diagnostic. Latent class analysis found no significant differences in test characteristics between the point-of-care diagnostic and standard culture. The estimated sensitivity and specificity of the point-of-care diagnostic against all targets combined were 94.6 and 72.1% respectively; the corresponding estimates for standard culture were 90.5 and 73.9%. Comparison of antibiotic susceptibility testing using the point-of-care diagnostic and the reference method showed similar trends and, in some cases, identical MIC50 and MIC90 values, with at most one antibiotic dilution difference.

Keywords

Bovine mastitislatent class analysispoint-of-care diagnosticsensitivityspecificity
Type
Research Article
Information
Journal of Dairy Research , Volume 86 , Issue 2 , May 2019 , pp. 222 - 225
Copyright
Copyright © Hannah Dairy Research Foundation 2019 

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