A Clostridioides difficile surveillance study of Canadian retail meat samples from 2016-2018: a possible source of human clinical infections?
| dc.contributor.author | Tan, Derek | |
| dc.contributor.examiningcommittee | Zhanel, George (Medical Microbiology and Infectious Diseases) | en_US |
| dc.contributor.examiningcommittee | Mulvey, Michael (Medical Microbiology and Infectious Diseases) | en_US |
| dc.contributor.examiningcommittee | Bay, Denice (Medical Microbiology and Infectious Diseases) | en_US |
| dc.contributor.supervisor | Golding, George | |
| dc.date.accessioned | 2023-01-04T23:26:57Z | |
| dc.date.available | 2023-01-04T23:26:57Z | |
| dc.date.copyright | 2023-01-04 | |
| dc.date.issued | 2022-11 | |
| dc.date.submitted | 2023-01-02T07:04:34Z | en_US |
| dc.date.submitted | 2023-01-04T21:25:46Z | en_US |
| dc.degree.discipline | Medical Microbiology and Infectious Diseases | en_US |
| dc.degree.level | Master of Science (M.Sc.) | en_US |
| dc.description.abstract | Introduction: C. difficile spores are dispersed throughout the environment and can asymptomatically colonize and/or infect animals. Previous studies have shown that C. difficile spores can be isolated from commercially available beef, veal, pork, vegetables, and seafood. However, a definitive link has yet to have been made between food contamination and hospitalized cases. This study aims to isolate C. difficile from retail meat samples and compare them to human isolates. Methods: Frozen retail pork, beef, and veal samples were obtained from the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) program and FoodNet Canada. These samples were analyzed for C. difficile contamination by direct plating on selective media and by inoculation in enrichment broth. Suspected C. difficile colonies were confirmed by polymerase chain reaction (PCR). Toxigenic C. difficile isolates were molecularly characterized by ribotyping and pulsed-field gel electrophoresis (PFGE). Antibiotic susceptibility was determined by ETEST® strips. Whole genome sequencing (WGS) was performed on all C. difficile isolates from retail meats and from select human cases. Results: Overall, toxigenic C. difficile was isolated from 10 of 644 retail meat samples (1.6%). All 10 isolates were A/B toxin positive. Additionally, 2 isolates were found to harbor binary toxin. All retail meat isolates were susceptible to vancomycin, metronidazole, tigecycline, rifampin, and clindamycin, excluding 1 NAP1 isolate that was resistant to moxifloxacin. Molecular typing revealed strain types commonly found in human clinical isolates (e.g. NAP1 (RT027), NAP4 (RTNS195), and NAP11 (RT106)). The closest related human clinical isolate to the C. difficile isolates from retail meats differed by 8-34 SNVs when analyzed at the highest resolution (84.54%-95.02% core genome). Conclusion: A low percentage of retail meats (1.6%) were contaminated by C. difficile. All ribotypes and NAP types of C. difficile isolates from retail meats have been previously identified in human cases. Through WGS, half of the C. difficile isolates from retail meats were determined to be closely related to a C. difficile isolate from a human case (≤10 SNVs), while the other half were genetically distinct (>10 SNVs), suggesting that retail meats may be a vector of dissemination for C. difficile in the community. | en_US |
| dc.description.note | February 2023 | en_US |
| dc.identifier.uri | http://hdl.handle.net/1993/37050 | |
| dc.language.iso | eng | en_US |
| dc.rights | open access | en_US |
| dc.subject | C. difficile | en_US |
| dc.subject | Retail Meats | en_US |
| dc.subject | CDI | en_US |
| dc.subject | Clostridioides difficile | en_US |
| dc.subject | Spores | en_US |
| dc.title | A Clostridioides difficile surveillance study of Canadian retail meat samples from 2016-2018: a possible source of human clinical infections? | en_US |
| dc.type | master thesis | en_US |
| local.subject.manitoba | no | en_US |
| project.funder.name | Public Health Agency Of Canada | en_US |