Location:
Project Number: 6040-32000-010-006-I
Project Type: Interagency Reimbursable Agreement
Start Date: Jan 22, 2017
End Date: Jul 1, 2019
Objective:
Conducted collaborative research with United States Department of
Agriculture, Animal Health and Plant Health Inspection Service (APHIS)National Animal Health Monitoring System (NAHMS) to determine the prevalence and antimicrobial resistance patterns of foodborne pathogens and commensals from fecal samples from cow-calf operations in the United States. Determine prevalence of pathogens and antimicrobial resistance of Salmonella, Escherichia coli (E. coli) and Enterococcus isolated from United States Cow Calf operations. Compare isolates obtained from fecal pats of cows and calves present on the same operation.
Approach:
Over the course of the three month study, Salmonella, E. coli and enterococci will be isolated from beef cow and calf fecal pats according to methods used in the Bacterial Epidemiology and Antimicrobial Resistance (BEAR) laboratory for years. Briefly beef pats will be subjected to an initial overnight enrichment in buffered peptone water, screened using the BAX® Salmonella real-time polymerase chain reaction (PCR). Presumptive positive
cultures will be transferred to selective broths in parallel, incubated and plated to selective agars. Strains will be sent to collaborators for analysis and isolates will be retained for further analyses. E. coli and Enterococcus spp. will be cultured using direct plating of sample mix onto selective agars and identification will be confirmed by biochemical testing and/or PCR using standard methods. Isolates will be sent to Animal
Health and Plant Health Inspection Service (APHIS) collaborators for typing and samples will be cryopreserved for further characterization studies. Susceptibility testing will be performed on all pathogen isolates in duplicate using broth
microdilution on custom made 96-well panels (Sensititre). Each panel contains up to 15 antimicrobials and is used by the National Antimicrobial Resistance Monitoring System (NARMS) program thereby facilitating data comparison between sample types. Categorization
of isolates as susceptible, intermediate, or resistant will be based on European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off values (ECOFFs).
