Progress 10/01/00 to 09/30/04
Outputs
This project explored the use of animal health and treatment records in monitoring and evaluating the relationship between animal health events and antibiotic treatment practices. Accomplishments were made in two areas. First, we evaluated the use of commercially available micro-computer based on-farm records management systems for recording, monitoring and evaluating animal health and antibiotic use events. Results in this area confirm that adequate and easy to use micro-computer based systems are commercially available, and these systems can be adapted or customized for use in recording animal health and antibiotic treatment events on individual dairy farms. Second we developed methods to characterize and quantify antimicrobial sensitivity of mastitis pathogens isolated from dairy farms. Resistance phenotypes of Staphylococcus aureus and Escherichia coli isolates collected from dairy farms that regularly use antibiotics for treatment of mastitis have been compared to
farms that severely restrict antibiotic use. The majority of mastitis isolates from all dairy farms are identified as a sensitive phenotype, consistent with previous reports. However, Staphylococcus aureus isolates from organic dairy farms, (farms with restricted antibiotic use), have significantly higher levels of sensitivity for beta-lactam, macrolide, and tetracycline antibiotics. Results indicate that antibiotic use practices may influence antimicrobial resistance patterns on dairy farms. Taken in combination, results of our work in these two areas suggest that individual farm level data on disease and antimicrobial use may be recorded in commercially available dairy farm management software systems, and that this data may be used to further evaluate the potential association between animal disease rates, the level of antimicrobial use, and the extent of antimicrobial resistance observed on dairy farms.
Impacts
This project provides information to assess the risk of development of antibiotic resistance resulting from use of antibiotics on dairy farms. In addition this project explored methods to record and monitor animal health events and antibiotic use practices on dairy farms using commercially available farm management software programs.
Publications
- Tikofsky, L.L., Barlow, J.W., Santisteban, C., and Schukken, Y.H. 2003. A comparison of antimicrobial susceptibility patterns for Staphylococcus aureus in organic and conventional dairy herds. Microbial Drug Resistance 9:s39-s45.
- Nugent, C., Murdough, P., Barlow, J. 2001. Establishing and comparing profiles of antimicrobial resistance in Staphylococcus aureus isolates from selected organic and conventional dairy farms in Vermont. J. Dairy Sci. 84(s 1): 334.
- Barlow, J. , Resnick, R., Dooley, C., and Huot, A. 2000. Effect of bovine leukemia virus infection on prevalence and incidence of clinical and subclinical mastitis in a dairy herd. Conference of Research Workers in Animal Diseases, Proceedings of the 81st Annual Meeting, 33P.
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Progress 01/01/03 to 12/31/03
Outputs
Progress has been made in the development and application of methods to characterize antimicrobial sensitivity of mastitis pathogens isolated from dairy farms. Resistance phenotypes of Staphylococcus aureus isolates collected from dairy farms that regularly use antibiotics have been compared to farms that severely restrict antibiotic use. The majority of mastitis isolates from all dairy farms are identified as a sensitive phenotype, consistent with previous reports. However, Staphylococcus aureus isolates from organic dairy farms, (farms with restricted antibiotic use), have significantly higher levels of sensitivity for beta-lactam, macrolide, and tetracycline antibiotics. Genetic markers of antibiotic resistance are being developed in order to further describe the molecular epidemiology of antimicrobial resistance for mastitis pathogens. The ability to conduct prospective studies that investigate the association between antibiotic use practices for mastitis control
and antimicrobial resistance patterns among mastitis pathogens on dairy farms is being explored.
Impacts
This project will provide information to assess the risk of development of antibiotic resistance resulting from use of antibiotics on dairy farms.
Publications
- Tikofsky, L.L., Barlow, J.W., Santisteban, C., and Schukken, Y.H. 2003. A comparison of antimicrobial susceptibility patterns for Staphylococcus aureus in organic and conventional dairy herds. Microbial Drug Resistance. 9:s39-s45.
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Progress 01/01/02 to 12/31/02
Outputs
Progress has been made in the development of methods to characterize antimicrobial sensitivity phenotypes of pathogens isolated from dairy farms. Resistance profiles of Staphylococcus aureus isolates collected from dairy farms that regularly use antibiotics have been compared to farms that severely restrict antibiotic use. The majority of isolates are identified as sensitive, consistent with previous reports that have examined isolates from similar sources. However, farms that used antibiotic treatments had significantly fewer susceptible isolates for the drugs penicllin, sulfamethazole, and tetracycline. Increased resistance to antibiotics that are commonly used on dairy farms can be observed, and individual farm practices may affect resistance patterns of pathogens isolated at the herd level. Possible associations between level and type of antibiotic use on dairy farms and the sensitivity phenotypes of pathogens isolated on those farms are being explored. Methods
for recording animal health and treatment events using commercially available micro-computer software programs are being implemented. The ability to conduct prospective studies that investigate the association between antibiotic use practices and antimicrobial resistance patterns on farms is being explored.
Impacts
This project will provide information to assess the risk of development of antibiotic resistance resulting from use of antibiotics on dairy farms.
Publications
- No publications reported this period
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Progress 01/01/01 to 12/31/01
Outputs
Progress has been made in the development of methods to characterize antimicrobial sensitivity phenotypes of pathogens isolated from dairy farms. Resistance profiles of Staphylococcus aureus isolates collected from dairy farms that regularly use antibiotics have been compared to farms that severely restrict antibiotic use. The majority of isolates are identified as sensitive, consistent with previous reports that have examined isolates from similar sources. However, farms that used antibiotic treatments had significantly fewer susceptible isolates for the drugs penicllin, sulfamethazole, and tetracycline. Increased resistance to antibiotics that are commonly used on dairy farms can be observed, and individual farm practices may affect resistance patterns of pathogens isolated at the herd level. Possible associations between level and type of antibiotic use on dairy farms and the sensitivity phenotypes of pathogens isolated on those farms are being explored. Methods
for recording animal health and treatment events using commercially available micro-computer software programs are being implemented. The ability to conduct prospective studies that investigate the association between antibiotic use practices and antimicrobial resistance patterns on farms is being explored.
Impacts
This project will provide information to assess the risk of development of antibiotic resistance resulting from use of antibiotics on dairy farms.
Publications
- Nugent, C., P. Murdough, W. Panky, and J. Barlow. (2001). Establishing and comparing profiles of antimicrobial resistance in Staphylococcus aureus isolates from selected organic and conventional dairy farms in Vermont. J. Dairy Sci. 84 (supplement 1): 334.
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