Research Accomplishment Reports 2011

An Integrated Approach to Control of Bovine Rrespiratory Diseases (NC107)

Erol, E.
Livestock Disease Diagnostic Center (Veterinary Diagnostic Laboratory)

 

Non-Technical Summary

The purpose of antibiotic susceptibility testing is to predict the success of antibiotic therapy in live animals being treated by practicing veterinarians. Choosing the best antibiotic for therapy is extremely important, especially when treating respiratory diseases. The quality of antimicrobial susceptibility testing by our microbiology laboratory is crucial to assure susceptibility to drugs of choice for particular bacterial infection, or to detect drug resistance in individual bacterial isolates. Currently, our laboratory measures the growth response of isolated organisms to antibiotics by using disk diffusion method (Kirby-Bauer method), which only provides a qualitative result. In addition, disk diffusion is labor intensive and lacks sensitivity for certain antibiotics because of the specific physiochemical properties of the molecules. In addition, some slow-growing bacteria and fungi, which may cause diseases in livestock, can not be accurately tested by disk diffusion method. With this project, we would like to identify, purchase and implement an automated system that reports not only qualitative but also quantitative antibiotic susceptibility results by calculating Minimal Inhibitory Concentrations (MIC). The automated method is reproducible and allows for the development of custom antibiotic panels. It will also allow our laboratory to test all bacteria and fungi, thereby enhancing service to our clients. Finally, computerized reports will be generated by using an automated panel reader, enabling us to keep our clients aware of the best antibiotics to use in treating animals. Before switching from the Disk Diffusion method to the automated susceptibility system, standard known (quality control) organisms (Pasteurella multocida, Mannheimia haemolytica, Escherichia coli, Stapyhlococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumonia) will be tested in both systems based on Clinical and Laboratory Standards Institute (CLSI) criteria for one week. After that, the isolates from clinical samples will be compared by both methods. The automated system will not be implemented until comparable results are obtained. This project will result in greatly improved service to the Kentucky livestock industry with respect to the treatment of bovine respiratory bacterial infections.

2011 Project Description

Utilization of automated micro-dilution methods has greatly improved our laboratory's ability to serve our clients. We have now an updated list of antimicrobials and our reports include not only qualitative but also quantitative antibiotic susceptibility results (i.e. pharmacokinetic/pharmacodynamic surrogate parameters can be correctly calculated using MIC values).

We are able to perform susceptibilites for some slow growing bacteria, yeast and anaerobes as well, further enhancing our test offerings to clients.

Finally, computerized statistical reports are being generated by using an automated panel reader.

This data will help us to develop best practice guidelines of antibiotic susceptibility in clinical isolates including bovine respiratory bacteria (and other isolates) for use by veterinarians, producers, and researchers who submit samples for diagnosis.

2011 Impact

The purpose of antibiotic susceptibility testing is to predict the success of antibiotic therapy in animals being treated by practicing veterinarians. Choosing the best antibiotic for therapy is extremely important, especially when treating respiratory diseases.

By purchasing this equipment (Automated broth-Micro dilution method-TREK, the quality of our antimicrobial susceptibility method has significantly improved following Clinical and Laboratory Standards Institute (CLSI) criteria. This method is reproducible and allows our laboratory to test all bacteria and fungi, thereby enhancing service to our clients. Finally, computerized reports can be generated by using an automated panel reader, enabling us to keep our clients aware of the best antibiotics to use in treating animals. We believe this equipment results in greatly improved service to the Kentucky livestock industry with respect to the treatment of bovine respiratory bacterial infections.

2011 Publications

Carter CN, Vanzant E, Odoi A, Smith J, Dwyer R, Riley J, Stepusin R: Supercomputer-Based Animal Health Risk Forecasting, Proceed 147th American Veterinary Medical Association, July, 2011