Abstract
1. Objectives: The objectives of this study were to: (i) describe the mastitis pathogens isolated from bovine milk samples submitted to four veterinary diagnostic laboratories in Australia between 2015 and 2019, (ii) determine the isolation pattern, and (iii) summarise the antimicrobial susceptibility data
available for the most common mastitis causing pathogens.
2. Materials and methods: A retrospective cross-sectional study was conducted using samples (N=21,701) submitted between January 2015 and December 2019. A descriptive analysis was performed summarising mastitis causing pathogens by year, season, and dairy region. Logistic regression models were developed to explore the effects of season, dairy region and year on a sample being culture positive for individual pathogens. One-way random effect models were employed to assess the correlation of pathogen occurrence and postcode of dairy farms by estimating the intra-class correlation (ICC). In addition, the results of antimicrobial susceptibility testing of the main mastitis-causing bacterial pathogens were summarised.
3. Results: Of the 21,701 submitted samples, 50.7% (n=11,006) had growth for at least one significant pathogen; mixed/contaminated growth was reported for 22.6% (n=4,913) and no growth for 26.6% (n=5,782) samples. The most requently isolated mastitis-causing pathogens included Streptococcus uberis (41.2%, 95% Confidence Interval (CI): 40.3-42.0), Staphylococcus aureus (23.5%, 95% CI: 22.8-24.3), Escherichia coli (8.0%, 95% CI: 7.5-8.5), treptococcus dysgalactiae (6.6%, 95% CI: 6.1-7.0) and Corynebacterium bovis (5.7%, 95% CI: 5.3-6.1). No significant effects of season, dairy region and year on a sample being culture positive for individual pathogens was observed. We identified significant clustering of a sample being positive for Staphylococcus aureus
(ICC=0.42, 95% CI: 0.32-0.51, p<0.001 and Streptococcus uberis (ICC=0.88, 95% CI: 0.86-0.91, p<0.001). The major mastitis-causing pathogens demonstrated high antimicrobial susceptibility for a range of antimicrobials.
4. Conclusion: Our results can be used to streamline and improve mastitis management and treatment decisions by dairy stakeholders.
available for the most common mastitis causing pathogens.
2. Materials and methods: A retrospective cross-sectional study was conducted using samples (N=21,701) submitted between January 2015 and December 2019. A descriptive analysis was performed summarising mastitis causing pathogens by year, season, and dairy region. Logistic regression models were developed to explore the effects of season, dairy region and year on a sample being culture positive for individual pathogens. One-way random effect models were employed to assess the correlation of pathogen occurrence and postcode of dairy farms by estimating the intra-class correlation (ICC). In addition, the results of antimicrobial susceptibility testing of the main mastitis-causing bacterial pathogens were summarised.
3. Results: Of the 21,701 submitted samples, 50.7% (n=11,006) had growth for at least one significant pathogen; mixed/contaminated growth was reported for 22.6% (n=4,913) and no growth for 26.6% (n=5,782) samples. The most requently isolated mastitis-causing pathogens included Streptococcus uberis (41.2%, 95% Confidence Interval (CI): 40.3-42.0), Staphylococcus aureus (23.5%, 95% CI: 22.8-24.3), Escherichia coli (8.0%, 95% CI: 7.5-8.5), treptococcus dysgalactiae (6.6%, 95% CI: 6.1-7.0) and Corynebacterium bovis (5.7%, 95% CI: 5.3-6.1). No significant effects of season, dairy region and year on a sample being culture positive for individual pathogens was observed. We identified significant clustering of a sample being positive for Staphylococcus aureus
(ICC=0.42, 95% CI: 0.32-0.51, p<0.001 and Streptococcus uberis (ICC=0.88, 95% CI: 0.86-0.91, p<0.001). The major mastitis-causing pathogens demonstrated high antimicrobial susceptibility for a range of antimicrobials.
4. Conclusion: Our results can be used to streamline and improve mastitis management and treatment decisions by dairy stakeholders.
| Original language | English |
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| Pages | 742 |
| Number of pages | 1 |
| Publication status | Published - 07 Aug 2022 |
| Event | 16th International Symposium of Veterinary Epidemiology and Economics 2022: ISVEE 16 - The Halifax Convention Centre, Halifax, Canada Duration: 07 Aug 2022 → 12 Aug 2022 https://venuewest.eventsair.com/isvee2022/ https://venuewest-my.sharepoint.com/personal/congress_venuewest_com/_layouts/15/onedrive.aspx?id=%2Fpersonal%2Fcongress%5Fvenuewest%5Fcom%2FDocuments%2FPublic%2FISVEE%202022%2FISVEE%2D2022%2DProceedings%2Epdf&parent=%2Fpersonal%2Fcongress%5Fvenuewest%5Fcom%2FDocuments%2FPublic%2FISVEE%202022&ga=1 (Proceedings) https://www.sciquest.org.nz/browse/publications/view/109 (Proceedings page) |
Conference
| Conference | 16th International Symposium of Veterinary Epidemiology and Economics 2022 |
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| Abbreviated title | Connecting animals, people, and their shared environments |
| Country/Territory | Canada |
| City | Halifax |
| Period | 07/08/22 → 12/08/22 |
| Other | ISVEE is a global forum for those interested in veterinary epidemiology and economics, and related disciplines in the health and social sciences, that provides an opportunity for scientists, health policymakers and other professionals, to exchange information and discuss solutions to help advance health for people, animals, and ecosystems. The 2022 edition will provide insights into various approaches to addressing animal disease spread, including the One Health perspective as well as different modelling approaches to support the control of transboundary diseases such as peste des petits ruminants (PPR) and foot and mouth disease (FMD). |
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