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Antimicrobial resistance and possible transmission of Escherichia coli between companion animals and related-personnels
반려동물과 관련∙종사자에서 분리된 항생제 내성 대장균의 상관성 분석

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dc.contributor.advisor박용호-
dc.contributor.author정연수-
dc.date.accessioned2017-10-27T17:00:32Z-
dc.date.available2017-10-27T17:00:32Z-
dc.date.issued2017-08-
dc.identifier.other000000145647-
dc.identifier.urihttps://hdl.handle.net/10371/137010-
dc.description학위논문 (박사)-- 서울대학교 대학원 수의과대학 수의학과, 2017. 8. 박용호.-
dc.description.abstractLivestocks today are not that much more valuable than they were long ago, we treat our companion animals as if they were far more valuable. In addition, we have seen a huge switch in animal medicine, from a focus on livestocks to a focus on companion animals such as horses, dogs and cats. In the Korean companion animal industry, the market size associated with companion animals is rapidly increasing and estimated to be $5.4 billion by 2020. In addition, more and more Korean people have recognized the importance of horse industry according to the increasing trend of horse-riding. However, limited information is available regarding horse-associated antimicrobial resistant (AR) bacteria in Korea.
As first study, we evaluated the frequency and characterize the pattern of AR Escherichia coli (E. coli) from healthy horse-associated samples. Thirty of the E. coli isolates (21%) showed antimicrobial resistance to at least one antimicrobial agent, and four of the AR E. coli (13.3%) were defined as multi-drug resistance. Pulsed-field gel electrophoretic analysis showed the cross-transmissions between horses or horses and environments were detected in two facilities. Although cross-transmission of AR E. coli in horses and their environments was generally low, our study suggests a risk of transmission of AR bacteria between horses and humans.
Quinolone (Q) and fluoroquinolone (FQ) are broad-spectrum synthetic antimicrobials used to treat bacterial infections in humans and animals. Since they are very potent antimicrobial agents against Gram-negative bacteria including E. coli, these agents have been widely used to treat a range of infections in companion animals. Consequently, (F)Q resistance has markedly increased worldwide, posing a significant threat to the health of animals and humans. In the second study, we investigated the prevalence and the mechanisms of FQ/Q resistance in E. coli isolates from companion animals, owners, and non-owners. A total of 27 nalidixic acid (NA)-resistant isolates were identified. Of these, 10 isolates showed ciprofloxacin (CIP) resistance. Efflux pump activity was detected in 18 isolates (66.7%), but this was not correlated with the increased minimum inhibitory concentration (MIC). Target gene mutations in Q resistance-determining regions (QRDRs) were the main cause of (F)Q resistance in E. coli. The number of point mutations in QRDRs was strongly correlated with increased MIC (R = 0.878 for NA and 0.954 for CIP). Interestingly, (F)Q resistance mechanisms observed in isolates from companion animals were the same as those in humans. Therefore, a prudent use of (F)Q in veterinary medicine is warranted to prevent the dissemination of (F)Q-resistant bacteria from animals to humans.
Companion animals such as horses and dogs are considered as one of the reservoirs of AR bacteria that can be cross-transmitted to humans. The inherent risk of any use of antimicrobials to select for AR bacteria poses a relevant risk for public health by spreading of antimicrobial resistance from animals to humans via direct or indirect contacts. However, limited information is available on the possibility of AR bacteria originating from companion animals being transmitted secondarily from owners to non-owners sharing the same space. To address this issue, in the third place, we investigated clonal relatedness among AR E. coli isolated from dog owners and non-owners in the same college classroom or household. Of 31 E. coli, 20 isolates (64.5%) were resistant to at least one antimicrobial, and 16 isolates (51.6%) were determined as multi-drug resistant E. coli. Pulsed-field gel electrophoretic analysis identified three different E. coli clonal sets among isolates, indicating that cross-transmission of AR E. coli can easily occur between owners and non-owners. The findings emphasize a potential risk of spread of AR bacteria originating from companion animals within human communities, once they are transferred to humans.
Antimicrobial resistance is an urgent global problem. There are increasing concerns about the emergence of multi-drug resistant bacteria in humans, animals and environments. The antimicrobial resistance is a complex phenomenon driven by many factors such as the interaction of humans, animals and environmental sources for antimicrobial resistance. Our study also showed that they could be not only reservoirs but also transmitters of antimicrobial-resistant bacteria. Therefore, the aims of combating antimicrobial-resistant bacteria and preserving the efficacy of the currently available antimicrobials in human and veterinary medicine as well as in ecological systems should be addressed in an interdisciplinary effort within a One Health approaches.
Addressing this urgent threat requires the multifaceted strategies. Elements include strengthened surveillance of antimicrobial usage
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dc.description.abstractimproved antimicrobial stewardship in humans and animals-
dc.description.abstractapproaches to incentivize new antimicrobials development-
dc.description.abstractincreased research on mechanisms of resistance-
dc.description.abstracta prudent use of antimicrobials by veterinarians as well as clinicians.-
dc.description.tableofcontentsLiterature Review 1
I. The genus Escherichia coli 2
II. Use of antimicrobials in animals 5
III-1. Mechanisms of antimicrobial resistance in bacteria 9
III-2. Mechanisms of quinolone resistance 12
1. Mutations in DNA gyrase and topoisomerase IV 13
2. The presence of PMQR genes 15
3. Efflux pump activity 16
IV. The emergence of antimicrobial resistance in animals 18
General Introduction 23
Chapter I. Isolation and characterization of antimicrobial-resistant E. coli from national horse racetracks and private horse-riding courses in Korea 27
I. Introduction 28
II. Materials and methods 29
1. Sampling 30
2. Isolation and identification of E. coli 30
3. Antimicrobial resistance profiling of E. coli isolates 31
4. Detection of antimicrobial resistance and integrase genes 32
5. Determination of O and H serotypes 33
6. Molecular fingerprinting 33
III. Results 34
1. E. coli isolation from the horse-associated samples 34
2. Phenotypic characterization of antimicrobial resistance of E. coli isolates 35
3. Detection of the antimicrobial resistance and integrase genes in AR E. coli isolates 35
4. Serotyping of E. coli isolates 36
5. Genotyping of AR E. coli by PFGE 36
IV. Discussion 37
Chapter II. Mechanisms of quinolone resistance in Escherichia coli isolated from companion animals, owners, and non-owners 50
I. Introduction 51
II. Materials and methods 52
1. Sampling 52
2. Isolation of NA-resistant E. coli from swab samples 53
3. Antimicrobial resistance profiling of NA-resistant E. coli isolates 53
4. Determination of minimum inhibitory concentrations (MICs) of NA and CIP 54
5. Detection of PMQR genes and mutations in QRDRs 55
6. Organic solvent tolerance (OST) assay 55
7. Evaluation of the effect of each (F)Q resistance mechanism on MICs of NA and CIP 56
III. Results 56
1. Isolation of NA or CIP resistant E. coli from companion animals and humans 56
2. Susceptibility of NA-resistant E. coli isolates to other antimicrobials 57
3. Determination of MICs 57
4. Analysis of mutations in QRDRs and detection of PMQR genes 58
5. Measurement of efflux pump activity 59
6. Relative contribution of each (F)Q resistance mechanism to increases in MIC 59
IV. Discussion 60
Chapter III. Probable secondary transmission of antimicrobial-resistant Escherichia coli between people living with and without companion animals 70
I. Introduction 71
II. Materials and methods 72
1. Sampling 72
2. E. coli isolation and identification 73
3. Antimicrobial susceptibility test 73
4. Detection of integrase genes in E. coli isolates 74
5. Molecular fingerprinting 74
III. Results 75
1. Isolation of E. coli from swab samples 75
2. Antibiogram of 31 E. coli isolates 75
3. Detection of integrase genes in E. coli isolates 76
4. Genetic relatedness of E. coli isolates from owners and non-owners 76
IV. Discussion 77
References 85
General Conclusion 118
국문초록 120
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dc.formatapplication/pdf-
dc.format.extent1784970 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectAntimicrobial resistance-
dc.subjectEscherichia coli-
dc.subjectone health-
dc.subjecthorses-
dc.subjectcompanion animal-owners-
dc.subjectnon-owners-
dc.subjectfluoroquinolone-
dc.subject.ddc636.089-
dc.titleAntimicrobial resistance and possible transmission of Escherichia coli between companion animals and related-personnels-
dc.title.alternative반려동물과 관련∙종사자에서 분리된 항생제 내성 대장균의 상관성 분석-
dc.typeThesis-
dc.contributor.AlternativeAuthorCHUNG YEON SOO-
dc.description.degreeDoctor-
dc.contributor.affiliation수의과대학 수의학과-
dc.date.awarded2017-08-
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College of Veterinary Medicine (수의과대학)Dept. of Veterinary Medicine (수의학과)Theses (Ph.D. / Sc.D._수의학과)
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