2008 Annual Report
1a.Objectives (from AD-416)
Assess the epidemiology of animal Salmonella, E. coli, Enterococci, Campylobacter and other bacteria to determine the frequency, phenotypic and genotypic characteristics and trends of resistance present in the bacterial populations studied in addition to defining areas best suited for interventions.
1b.Approach (from AD-416)
Antimicrobial susceptibility testing will be conducted on approximately 125,000 Salmonella, Campylobacter spp., Enterococci, and E. coli isolates and other bacterial isolates which may be added to the program. Isolates will originate from multiple animal species and the environment obtained from in-house studies, from the National Veterinary Services Laboratories, from FSIS sponsored projects, from sentinel sites, from APHIS sponsored projects, and from collaborators. A Sensititre Semi-Automated Sensititre System will be used for testing. Associated research will consist of in vivo and in vitro approaches to determine if pathogenesis is attributed to an increase in resistance. Alternative approaches to use of antimicrobials will also be explored; risk factors likely to be affected by interventions will be identified and resistance mechanisms will be characterized at the molecular level.
This project is related to objective 1 of this in-house project: To use antibiotic resistance data obtained from the Collaboration on Animal Health and Food Safety Epidemiology (CAHFSE) and the National Antimicrobial Resistance Monitoring System - Enteric Bacteria (NARMS) programs and poultry studies to identify sources, reservoirs and amplifiers of resistant food borne and commensal bacteria, as well as the path of dissemination of these resistant bacteria in food producing animals and poultry. Results may be used for risk assessment and in developing mitigation strategies.
For 2008, over 4,000 Salmonella, 1,500 Enterococci, and 1,000 Campylobacter isolates were speciated/serotyped and all Salmonella, Enterococci, and Campylobacter isolates, plus 1,500 generic E. coli isolates, were tested for susceptibility to a custom-made panel of antimicrobials which are important in veterinary and human medicine. An annual National Antimicrobial Resistance Monitoring System (NARMS) report was generated and posted to the website (http://www.ars.usda.gov/Main/docs.htm?docid=6750). In addition the executive report for 2004, which combines data from all three arms of NARMS, was posted to the web.
We have continued to expand our pulsed-field gel electrophoresis (PFGE) testing of Salmonella and Campylobacter isolates as part of USDA VetNet. USDA VetNet was established in collaboration with Center for Disease Control (CDC) to compare PFGE patterns of Salmonella and Campylobacter isolates of animal origin collected as a part of the animal arm of NARMS with PFGE patterns of isolates collected from humans (as part of FoodNet and the human arm of NARMS). Integration with PulseNet has occurred. Additionally, ARS has collaborated with FSIS to develop web based analytics for use in analyzing NARMS and VetNet data. Results from these programs will facilitate the identification of resistance in humans and animals as it arises, provide descriptive data on the extent and temporal trends of antimicrobial susceptibility, provide timely information to veterinarians and physicians, prolong the lifespan of approved drugs by promoting the prudent and judicious use of antimicrobials, and identify research areas requiring more detailed investigation.