EFFECTIVE INTERVENTIONS TO PREVENT EMERGENCE AND DISSEMINATION OF ANTIMICROBIAL RESISTANCE AT THE POPULATION, ANIMAL, AND MICROBIAL LEVELS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: TERMINATED
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1000838
• Grant No.: 2013-68003-21282
• Project No.: OHCVMGRT00030019
• Proposal No.: 2012-04255
• Program Code: A4171
• Project Start Date: Sep 1, 2013
• Project End Date: Aug 31, 2018
• Grant Year: 2013

Project Director
Wittum, T. E.

Recipient Organization
OHIO STATE UNIVERSITY - VET MED
1900 COFFEY ROAD, 127L VMAB
COLUMBUS,OH 43210

Performing Department
Veterinary Preventive Medicine

Non Technical Summary
The emergence and dissemination of antimicrobial-resistant zoonotic pathogens in livestock populations is driven by complex interactions of production systems management, antimicrobial use in individual animals, and the animal's enteric flora. This suggests that effective interventions may be applied at various levels of organization including the production system, the individual animal, and the bacterial flora of food animals. We propose to investigate mitigation strategies to prevent the emergence and dissemination of antimicrobial resistant enteric bacteria and resistance genes of animal and public health concern. We will focus on extended-spectrum cephalosporin and fluoroquinolone resistance because of the critical importance of these antimicrobials in both veterinary and human medicine. Our central hypothesis is that effective interventions to mitigate the dissemination of pathogens resistant to critically important antimicrobial drugs in livestock populations can be identified at the levels of the production system, individual animal, and the bacterial flora present in animals. Our objectives are to 1. Establish the effectiveness of specific animal-level mitigation strategies that can be applied to herds of food animals that impact the emergence, maintenance, and dissemination of antimicrobial resistant pathogens and resistance genes, 2. Estimate the effectiveness of population-level mitigation strategies by measuring the impact of regulatory restrictions on the emergence and dissemination of antimicrobial resistance, 3. Identify potential bacterial flora-level mitigation strategies by describing and understanding the competition of multiple bacterial strains for the same ecological niche in the microbial flora, and 4. Disseminate knowledge of specific antimicrobial resistance mitigation strategies to veterinarians and their clients that produce food animals. We expect to identify effective new strategies for mitigation of antimicrobial resistance in livestock populations which in turn will protect animal health and agricultural productivity while improving food safety and the public health.

Animal Health Component

50%

Research Effort Categories

Basic

(N/A)

Applied

100%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
712	3999	1170	100%

Knowledge Area
712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins;

Subject Of Investigation
3999 - Animal research, general;

Field Of Science
1170 - Epidemiology;

Keywords

antimicrobial resistance

fluoroquinolone

livestock

Goals / Objectives
1. Establish the effectiveness of specific animal-level mitigation strategies that can be applied to herds of food animals that impact the emergence, maintenance, and dissemination of antimicrobial resistant pathogens and resistance genes. 2. Estimate the effectiveness of population-level mitigation strategies by measuring the impact of regulatory restrictions on the emergence and dissemination of antimicrobial resistance. 3. Identify potential bacterial flora-level mitigation strategies by describing and understanding the competition of multiple bacterial strains the same ecological niche in the microbial flora.4.Disseminate knowledge of specific antimicrobial resistance mitigation strategies to veterinarians and their clients that produce food animals.

Project Methods
Our overall approach will be to generate scientifically valid data to evaluate interventions applied at various levels of organization including the animal (herd), the population (regulatory), and the microbial flora (bacteria). We will accomplish our first objective by testing the impact of replacing ceftiofur antimicrobial therapy for metritis in dairy cows with a non-antimicrobial treatment on the presence and quantity of extended-spectrum cephalosporin resistance genes in the enteric commensal flora. In addition, we will test the impact of removing exposure to antimicrobials present in waste milk fed to dairy calves on resistance genes in their enteric flora. We will accomplish our second objective to test population-level regulatory interventions by comparing the evolution of extended-spectrum cephalosporin and fluoroquinolone resistance in Salmonella recovered from finishing swine barns and dairy herds since the relatively recent approval of enrofloxicin for use in these production systems with very restrictive label applications compared to the much less restrictive label for ceftiofur use. We will accomplish our third objective to identify potential microbial-level interventions by describing the competition of multiple bacterial strains for the same ecological niche in the microbial flora in order to identify candidate susceptible strains that may be able to fully displace resistant strains and replace them in their ecological niche. We will also develop and integrated outreach extension program to educate food animal veterinarians and their livestock producer clients regarding appropriate antimicrobial use and effective mitigation strategies to prevent the emergence and dissemination of antimicrobial resistance.

Progress 09/01/13 to 08/31/18

Outputs
Target Audience:Our target constituients were US veterinarians, livestock producers, food processors and distributors, and food retailers, as well as related policy-makers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Through this project, we trained one veterinarian to completion of a PhD program in veterinary epidemiology and antimicrobial resistance. We also trained one postdoctoctoral scientist an molecular epidemiology of antimicrobial resistance in livestock populations. How have the results been disseminated to communities of interest?Wehave dissemiated our results to the scientific community through the publication of peer-reviewed scientific manuscripts and by presenting our results at appropriate national and international scientific meetings. We have disseminated our results to veterinarians through continuing education instruction and through individual consultations. We have disseminated our results to livestock producers through Extension publications and producer meetings. We have disseminated our results to future veterinarians in classes within our professional DVM curriculum. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Our results have contributed to a better understanding of the role of enteric reservoir bacteria in the emergence and dissemination of antimicrobial resistant pathogens in livestock populations. Commensal bacteria in the enteric flora can harbor rare but clinically relevant resistance genotypes. When the flora are exposed to appropriate antimicrobial selection pressure these rare strains proliferate and disseminate to other animals in close contact within a population. This can produce a high frequency of colonization with clinically relevant resistance genes within farms. These genes can then be further amplified when therapeutic antimicrobials are applied prophylactically to entire populations of animal on farms. This appears to increase the probability that clinically relevant antimicrobial resistance genes will contaminate fresh retail meat products and ultimately colonize the enteric flora of consumers. This risk may be mitigated by utilizing targeted antimicrobial therapy of sick animals rather than the mass prophylactic therapy of both healthy and sick animals under disease control labels. Our results have also established the importance of the environment in the maintenance and dissemination of antimicrobial resistant bacteria. Animal environments are frequently contaminated with clinically relevant antimicrobial resistant enteric bacteria and serves as a reservoir for the colonization of animals or for zoonotic transmission. Environmental contamination with antimicrobial resistant bacteria is most common when antibiotics are frequently applied to animals in the environment. Contamination of animal environments can be reduced by using targeted antimicrobial therapy of sick animals rather than mass prophylactic antimicrobial therapy of both health and sick animals in livestock populations. In addition, cleanliness of the animal environment can play a role in the dissemination of resistant enteric bacteria and colonization of the enteric flora. It is also clear from our results that antimicrobial resistance disseminates at the level of the mobile genetic element, and not just at the level of the microorganism. Antimicrobial selection pressure applied to animals favors the resistant bacterial strains, but also facilitates the mobilization of mobile genetic elements including plasmids and gene cassettes. These mobile genetic elements can spread in an epidemic manner similar to, but independent of specific bacterial strains. The mass application of therapeutic antimicrobial drugs prophylactically in livestock populations has facilitated the dissemination of these mobile genetic elements in animals and through zoonotic foodborne transmission to consumers where they pose a public health threat. We have widely disseminated our research results to the scientific community in scientific publications and at appropriate scientific meetings. In addition, we have trained and continue to train veterinarians and livestock producers in antimicrobial use, resistance, and stewardship. This training includes future veterinarians as we have incorporated these topics into our professional DVM curriculum so that future veterinarians will be better trained to make antibiotic treatment decisions regarding their livestock patients.

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Adams RJ, Kim SS, Mollenkopf DF, Mathys DA, Schuenemann GM, Daniels JB, Wittum TE. Antimicrobial?resistant Enterobacteriaceae recovered from companion animal and livestock environments. Zoonoses and public health. 2018 Aug;65(5):519-27.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Mathys DA, Mathys BA, Mollenkopf DF, Daniels JB, Wittum TE. Enterobacteriaceae harboring AmpC (bla CMY) and ESBL (bla CTX-M) in migratory and nonmigratory wild songbird populations on Ohio dairies. Vector-Borne and Zoonotic Diseases. 2017 Apr 1;17(4):254-9.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Mathys DA, Mollenkopf DF, Van Balen JC, Wittum TE. ?-Lactam and Fluoroquinolone-Resistant Enterobacteriaceae Recovered from the Environment of Human and Veterinary Tertiary Care Hospitals. Vector-Borne and Zoonotic Diseases. 2018 Nov 1;18(11):620-3.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Landers TF, Mollenkopf DF, Faubel RL, Dent A, Pancholi P, Daniels JB, Wittum TE. Extended?Spectrum ??lactam Resistance in the Enteric Flora of Patients at a Tertiary Care Medical Centre. Zoonoses and public health. 2017 Mar;64(2):161-4.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Mathys DA, Mollenkopf DF, Feicht SM, Adams RJ, Albers AL, Stuever DM, Grooters SV, Ballash GA, Daniels JB, Wittum TE. Carbapenemase-producing Enterobacteriaceae and Aeromonas spp. present in wastewater treatment plant effluent and nearby surface waters in the US. PloS one. 2019;14(6).
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Mollenkopf DF, De Wolf B, Feicht SM, Cenera JK, King CA, van Balen JC, Wittum TE. Salmonella spp. and extended-spectrum cephalosporin-resistant Escherichia coli frequently contaminate broiler chicken transport cages of an organic production company. Foodborne Pathogens and Disease. 2018 Sep 1;15(9):583-8.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Mollenkopf DF, Mathys DA, Dargatz DA, Erdman MM, Habing GG, Daniels JB, Wittum TE. Genotypic and epidemiologic characterization of extended-spectrum cephalosporin resistant Salmonella enterica from US beef feedlots. Preventive veterinary medicine. 2017 Oct 1;146:143-9.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Mathys DA, Mollenkopf DF, Nolting J, Bowman AS, Daniels JB, Wittum TE. Extended-spectrum cephalosporin-resistant enterobacteriaceae in enteric microflora of wild ducks. Journal of wildlife diseases. 2017 Jul;53(3):690-4.

Progress 09/01/15 to 08/31/16

Outputs
Target Audience:Other scientists and researchers working in related areas of antimicrobial resistance. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The impact of this work is to identify effective interventions to mitigate the dissemination of pathogens resistant to critically important antimicrobial drugs in livestock populations can be identified and applied at the level of the individual animal, at the population level, or through manipulation of the bacterial flora present in food animals. Objective 1. Establish the effectiveness of specific animal-level mitigation strategies that can be applied to herds of food animals that impact the emergence, maintenance, and dissemination of antimicrobial resistant pathogens and resistance genes. Weare continuing toconduct multiple field research projects as originally proposed for this objective. Objective 2. Estimate the effectiveness of population-level mitigation strategies by measuring the impact of regulatory restrictions on the emergence and dissemination of antimicrobial resistance. We have screened a large number of stored isolates as required for this project. We will continue to make appropriate progress toward completion of this objective during the upcoming project period. Objective 3. Identify potential bacterial flora-level mitigation strategies by describing and understanding the competition of multiple bacterial strains the same ecological niche in the microbial flora. We are continuing the process of screening bacteria to create libraries of known isolates. We are developing new techniques including site-directed mutagenesis to create susceptible strains of bacteria taht can outcompete resistant wild strains for the same ecological niche. Objective 4. Disseminate knowledge of specific antimicrobial resistance mitigation strategies to veterinarians and their clients that produce food animals. We have continued to develop and disseminate Veterinary Extension programming focused on antimicrobial resistance in the state of Ohio. We have placed special emphasis on VFD education this year.

Publications

Progress 09/01/14 to 08/31/15

Outputs
Target Audience:Other scientists working in related areas of antimicrobial resistance. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The impact of this work is to identify effective interventions to mitigate the dissemination of pathogens resistant to critically important antimicrobial drugs in livestock populations can be identified and applied at the level of the individual animal, at the population level, or through manipulation of the bacterial flora present in food animals. Objective 1. Establish the effectiveness of specific animal-level mitigation strategies that can be applied to herds of food animals that impact the emergence, maintenance, and dissemination of antimicrobial resistant pathogens and resistance genes. Weare in teh process of conducting multiplefield research projectsas originally proposed for this objective. We anticipate data available to report for the next annual report. Objective 2. Estimate the effectiveness of population-level mitigation strategies by measuring the impact of regulatory restrictions on the emergence and dissemination of antimicrobial resistance. We havescreeneda large number of stored isolates as required for this project. We will continue to make appropriate progress toward completion of this objective during the upcoming project period. Objective 3. Identify potential bacterial flora-level mitigation strategies by describing and understanding the competition of multiple bacterial strains the same ecological niche in the microbial flora. Weare continuingthe process of screening bacteria to create libraries of known isolates.We are developing and testing model systems for competition experiments. Objective 4. Disseminate knowledge of specific antimicrobial resistance mitigation strategies to veterinarians and their clients that produce food animals. We ahve continued to develop and disseminate Veterinary Extension programming focused on antimicrobial resistancein the state of Ohio.

Publications

Progress 09/01/13 to 08/31/14

Outputs
Target Audience:Scientists working in related areas of antimicrobial resistance. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We will continue to make progress toward accomplishing the stated objectives of our project following the approach described in our original proposal.

Impacts
What was accomplished under these goals? The impact of this work is to identifyeffective interventions to mitigate the dissemination of pathogens resistant to critically important antimicrobial drugs in livestock populations can be identified and applied at the level of the individual animal though disease treatment and management, at the population level through regulation, or through manipulation of the bacterial flora present in food animals. Objective 1. Establish the effectiveness of specific animal-level mitigation strategies that can be applied to herds of food animals that impact the emergence, maintenance, and dissemination of antimicrobial resistant pathogens and resistance genes. We have begun the sampling and preparations for the field research projects that we proposed for this objective. Targeted data collection and testing of interventions will commence in the near future. Objective 2. Estimate the effectiveness of population-level mitigation strategies by measuring the impact of regulatory restrictions on the emergence and dissemination of antimicrobial resistance. We ahve begun the screening of the large numbers of stored isolates required for this project.We will continue to make appropriate progess toward completion of this objective during the upcoming project period. Objective 3. Identify potential bacterial flora-level mitigation strategies by describing and understanding the competition of multiple bacterial strains the same ecological niche in the microbial flora. We have begun the process of screening bacteria to create libraries of known isolates. We are working with possible collaborators in the Department of Food Science to develop a rapid serotype screening tool utilizing infrared to quicklyu create large isolate libraries. Objective 4.Disseminate knowledge of specific antimicrobial resistance mitigation strategies to veterinarians and their clients that produce food animals. Veterianary Extension programming focused on antimicrobial resistance is being developed and disseminated in Ohio.

Publications