4.7 Article

Prevalence of non-aureus staphylococci species causing intramammary infections in Canadian dairy herds

期刊

JOURNAL OF DAIRY SCIENCE
卷 100, 期 7, 页码 5592-5612

出版社

ELSEVIER SCIENCE INC
DOI: 10.3168/jds.2016-12478

关键词

dairy; mastitis; intramammary infection; coagulase-negative staphylococci; prevalence

资金

  1. Natural Sciences and Engineering Research Council of Canada (NSERC) Industrial Research Chair in Infectious Diseases of Dairy Cattle
  2. Dairy Farmers of Canada and Agriculture and Agri-Food Canada through the Dairy Research Cluster 2 Program
  3. NSERC-CREATE in milk quality scholarship
  4. Natural Sciences and Engineering Research Council of Canada (Ottawa, ON, Canada)
  5. Alberta Milk (Edmonton, AB, Canada)
  6. Dairy Farmers of New Brunswick (Sussex, NB, Canada)
  7. Dairy Farmers of Nova Scotia (Lower Truro, NS, Canada)
  8. Dairy Farmers of Ontario (Mississauga, ON, Canada)
  9. Dairy Farmers of Prince Edward Island (Charlottetown, PE, Canada)
  10. Novalait Inc. (Quebec City, QC, Canada)
  11. Dairy Farmers of Canada (Ottawa, ON, Canada)
  12. Canadian Dairy Network (Guelph, ON, Canada)
  13. Agriculture and Agri-Food Canada (Ottawa, ON, Canada)
  14. Public Health Agency of Canada (Ottawa, ON, Canada)
  15. Technology PEI Inc. (Charlottetown, PE, Canada)
  16. Universite de Montreal (Montreal, QC, Canada)
  17. University of Prince Edward Island (Charlottetown, PE, Canada) through the Canadian Bovine Mastitis
  18. Milk Quality Research Network

向作者/读者索取更多资源

Non-aureus staphylococci (NAS), the microorganisms most frequently isolated from bovine milk worldwide, are a heterogeneous group of numerous species. To establish their importance as a group, the distribution of individual species needs to be determined. In the present study, NAS intramammary infection (IMI) was defined as a milk sample containing >1,000 cfu/ mL in pure or mixed culture that was obtained from a cohort of cows assembled by the Canadian Bovine Mastitis Research Network. Overall, 6,213 (6.3%) of 98,233 quarter-milk samples from 5,149 cows and 20,305 udder quarters were associated with an NAS IMI. Of the 6,213 phenotypically identified NAS isolates, 5,509 (89%) were stored by the Canadian Bovine Mastitis Research Network Mastitis Pathogen Collection and characterized using partial sequencing of the rpoB housekeeping gene, confirming 5,434 isolates as NAS. Prevalence of each NAS species IMI was estimated using Bayesian models, with presence of a specific NAS species as the outcome. Overall quarter-level NAS IMI prevalence was 26%. The most prevalent species causing IMI were Staphylococcus chromogenes (13%), Staphylococcus simulans (4%), Staphylococcus haemolyticus (3%), Staphylococcus xylosus (2%), and Staphylococcus epidermidis (1%). The prevalence of NAS IMI as a group was highest in first-parity heifers and was evenly distributed throughout cows in parities >2. The IMI prevalence of some species such as S. chromogenes, S. simulans, and S. epidermidis differed among parities. Overall prevalence of NAS IMI was 35% at calving, decreased over the next 10 d, and then gradually increased until the end of lactation. The prevalence of S. chromogenes, Staphylococcus gallinarum, Staphylococcus cohnii, and Staphylococcus capitis was highest at calving, whereas the prevalence of S. chromogenes, S. haemolyticus, S. xylosus, and S. cohnii increased during lactation. Although the overall prevalence of NAS IMI was similar across barn types, the prevalence of S. simulans, S. xylosus, S. cohnii, Staphylococcus saprophyticus, S. capitis, and Staphylococcus arlettae IMI was higher in tiestall barns; the prevalence of S. epidermidis IMI was lowest; and the prevalence of S. chromogenes and Staphylococcus sciuri IMI was highest in bedded pack barns. Staphylococcus simulans, S. epidermidis, S. xylosus, and S. cohnii IMI were more prevalent in herds with intermediate to high bulk milk somatic cell count (BMSCC) and S. haemolyticus IMI was more prevalent in herds with high BMSCC, whereas other common NAS species IMI were equally prevalent in all 3 BMSCC categories. Distribution of NAS species IMI differed among the 4 regions of Canada. In conclusion, distribution differed considerably among NAS species IMI; therefore, accurate identification (species level) is essential for studying NAS epidemiology.

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