Author
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Cray, Paula |
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Submitted to: American Association of Swine Veterinarians Annual Meeting
Publication Type: Proceedings Publication Acceptance Date: 3/5/2011 Publication Date: 3/5/2011 Citation: Cray, P.J. 2011. Antibiotics and the R’s – Mechanisms of resistance. American Association of Swine Veterinarians Annual Meeting. March 5-8,2011. Phoenix, Arizona. Interpretive Summary: Technical Abstract: Introduction Illness attributable to foods and food stuff in the United States (U.S.) does not appear to be diminishing.1 Collectively, Scharff reports the total cost of food borne illness in the U.S. at $152 billion a year. 2 While antimicrobial treatment of uncomplicated gastroenteritis in not typically indicated, when it is warranted3, the presence/development of resistance can result in treatment failure. Global concern regarding the development of antimicrobial resistant bacteria has not waned since the introduction of penicillin. In fact, concern over the emergence of new resistance patterns, including the development of multidrug resistance (MDR), continues to rise.4 Surveillance/monitoring programs can allow for detection of emerging/increasing resistance over time. However, the specific design and harmonization of antimicrobial surveillance programs is difficult. Currently, the World Health Organization has convened an Advisory Group on Integrated Surveillance of Antimicrobial Resistance (WHO-AGISAR) to minimize the public health impact of antimicrobial resistance associated with the use of antimicrobials in food animals.5 In particular, the Advisory Group assists WHO on matters relating to integrated (global) surveillance of antimicrobial resistance and containment of food-related antimicrobial resistance. One major goal of AGISAR is to develop harmonized schemes for monitoring antimicrobial resistance in zoonotic and enteric bacteria; appropriate sampling is included. Since 1996 the U.S. has conducted surveillance on food borne and commensal antimicrobial resistance bacteria through the National Antimicrobial Resistance Monitoring System - Enteric Bacteria (NARMS) to prospectively monitor changes in antimicrobial susceptibilities of zoonotic pathogens from human and animal clinical specimens, from healthy farm animals, and from raw product of food-producing animals at slaughter.6,7 Non-typhoid Salmonella was selected as the sentinel organism. The goals and objectives of the monitoring program are to 1) monitor trends in antimicrobial resistance among food borne bacteria from humans, retail meats, and animals, 2) disseminate timely information on antimicrobial resistance to promote interventions that reduce resistance among food borne bacteria, 3) conduct research to better understand the emergence, persistence, and spread of antimicrobial resistance, and 4) assist the FDA in making decisions related to the approval of safe and effective antimicrobial drugs for animals.8 Information from NARMS is released through the publication of annual reports covering the current status of resistance in humans, retail meats, and food animals.8-12 The program underwent a review by the FDA Science Board in 2007 that, while lauding the program’s accomplishments, suggested sampling strategies and in particular animal sampling should be reevaluated and modified. As reviewed by others sampling and provision of contextual information are two major sources of bias which must be addressed within surveillance systems.6-18 For NARMS as a whole, a cost-effective, unbiased and unambiguous process for collecting this information has not been established and a review and analysis of existing sampling strategies is needed within the animal arm of NARMS. Currently, isolates are collected as part of the USDA FSIS HACCP risk-based inspection program.19 Isolates received under this program are biased toward plants with high microbial risk which exceed the guidelines for Salmonella testing. As a result, there tends to be an over representation of isolates originating from these plants and this does not necessarily provide national representation of the resistance problem in food animals. This bias calls for a re-evaluation and re-design of the sampling strategy. Materials and methods Experimental Design on Farm Sampling – Contribution |
