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Dissemination, Maintenance and Amplification Reservoirs of β-lactamase producing Enterobacteriaceae in Livestock, Human, Companion Animal, Wildlife, and Environmental Populations

mathys, Dimitria

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Comparative and Veterinary Medicine.
Carbapenem-resistant Enterobacteriaceae (CREs), extended-spectrum β-lactamases (ESBL) and AmpC harboring bacteria are a major public health risk because they are resistant to our most important lifesaving antibiotics. Reservoirs of CRE and ESBL lead to the maintenance, amplification, and dissemination of these resistant bacteria. These genes amplify and emerge in populations with a high population density and frequent antimicrobial use, in particular cephalosporin use. These types of populations include human hospitals and intensively managed animal agriculture facilities. These bacteria harboring antimicrobial resistance genes, such as CRE and ESBL can be maintained in populations such as wastewater treatment facilities and in healthy human and animal (both companion and livestock) populations. Finally, CRE and ESBL harboring bacteria can be disseminated via wildlife, environmental waterways, and food products into new populations. Wild birds in and around Ohio dairies were sampled and found to harbor ESBL harboring bacteria within their gastrointestinal tract sampled via a direct cloacal or immediate fecal sample and on their external bodies. Three dairy locations were sampled in Ohio, 623 individual birds were sampled and banded to prevent re-sampling. There were no difference in prevalence between migratory birds and resident songbirds. Among all birds, 3% harbored blaCMY and 5.1% harbored blaCTX-M either in their cloacal swab or their external swab. Birds sampled immediately adjacent to the dairy barns had a higher prevalence then those birds sampled 600 feet away. Wild ducks were additionally sampled from on or around Lake Erie in Ohio, 772 wild ducks were caught, a cloacal swab was obtained and then were banded and released. Of all ducks sampled 5.7% harbored blaCMY and 0.3% harbored blaCTX-M. These data indicate that wild birds can indeed serve a role in disseminating antimicrobial resistance genes of probably livestock origin to other livestock facilities or into natural habitats. Additionally, many of these birds travel a great distance during migration and the potential to disseminate large distances and across international boundaries is possible. Surface water upstream and downstream of wastewater treatment plants (WWTPs) were found to harbor carbapenemase-producing bacteria (CPB). Upstream water samples were collected from 50 sites across the United States and 8% of them were positive for CPB. Additionally, 18% of the downstream water samples and were statistically higher than the upstream samples. This shows that water can indeed move or disseminate antimicrobial resistant bacteria of extreme clinical significance from a maintenance reservoir to other populations. The healthy canine population can potentially serve as a maintenance reservoir for CREs, ESBL, and AmpC harboring bacteria. Healthy dogs submitting fecal samples for routine parasite screening were screened. Of this healthy dog population 14% harbored blaCMY and 4.0% harbored blaCTX-M. The potential is there among our healthy dog population to maintain these antimicrobial resistant genes for animal populations but additionally for the human population who live in close proximity to their canine pets. Additionally, antimicrobial resistant bacteria can be maintained in wastewater treatment plants or facilities (WWTP). Effluent water samples were screened from 50 WWTPs throughout the United States. Metropolitan and rural facilities were sampled and 20% of the effluent samples harbored carbapenemase-producing bacteria (CPB) of clinical importance. Metropolitan WWTPs were more likely to harbor these bacteria compared to rural WWTPs. Given that these WWTPs primarily clean water of human waste products it indicates that the general human population harbors CPB of clinical importance. Emergence reservoirs tend to be in population dense environments with frequent antimicrobial use. Human and veterinary hospitals were sampled by looking at different environmental surfaces to investigate if clinically important antimicrobial resistant bacteria are able to be recovered from common surfaces. A total of 31 contact surfaces were sampled at each of five visits to two human hospitals. In addition, 34 surfaces were sampled at each of three visits to a veterinary hospital serving both farm animal and companion animal patients. Isolates expressing the blaCMY phenotype were recovered from 0.6%, 100%, and 18.2% of human hospitals, veterinary farm animal, and veterinary companion animal hospital surfaces, respectively. Isolates expressing the blaCTX-M phenotype were recovered from 0.6%, 55%, and 16.7% of human hospitals, farm animal, and companion animal veterinary hospital surfaces, respectively. Carbapenemase-producing Enterobacteriaceae (CPE) were detected from 1.3% of human hospital surfaces, but none were recovered from the veterinary hospital. Indicating that even outside patients direct contact surfaces are occasionally contaminated leading to potential dissemination. Additionally, we found that intensively managed dairies in Ohio were often harboring ESBL harboring bacteria within the feces of the majority of cows.
Thomas Wittum (Advisor)
Mary Jo Burkhard (Committee Member)
Jason Stull (Committee Member)
164 p.

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Citations

  • mathys, D. (2019). Dissemination, Maintenance and Amplification Reservoirs of β-lactamase producing Enterobacteriaceae in Livestock, Human, Companion Animal, Wildlife, and Environmental Populations [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574336795072146

    APA Style (7th edition)

  • mathys, Dimitria. Dissemination, Maintenance and Amplification Reservoirs of β-lactamase producing Enterobacteriaceae in Livestock, Human, Companion Animal, Wildlife, and Environmental Populations. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1574336795072146.

    MLA Style (8th edition)

  • mathys, Dimitria. "Dissemination, Maintenance and Amplification Reservoirs of β-lactamase producing Enterobacteriaceae in Livestock, Human, Companion Animal, Wildlife, and Environmental Populations." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574336795072146

    Chicago Manual of Style (17th edition)