Browsing by Author "Liljebjelke, Karen"

Now showing 1 - 8 of 8
  • Thumbnail Image
    ItemOpen Access
    Antimicrobial Resistant Escherichia coli in Alberta's Rural Well Water
    (2017) Meyer, Kelsey; Checkley, Sylvia; DeVinney, Rebekah; Liljebjelke, Karen
    The consumption of rural well water (RWW) contaminated with antimicrobial resistant (AMR) Escherichia coli has been linked to human carriage of resistance. Our objective was to determine whether AMR and extended spectrum beta lactamase (ESBL) producing E.coli are present in Alberta’s RWW. Resistant isolates were detected with an agar screen on (up to) 20 isolates from each sample, and AMR was measured with NARMS Sensititre(TM) panels. Disk diffusion assays detected ESBL-producing E.coli, and spatial clusters of AMR E.coli were assessed using ArcGIS (version 10.4.1) and SaTScan(TM) (version 9.4.4). Among 1129 samples, 22% contained AMR E.coli including four ESBL-producers. Resistance to three or more classes of antimicrobials was observed in 48% of AMR E.coli isolates, and a significant cluster of AMR E.coli was detected between Calgary and Lethbridge (p<0.05). Our results suggest AMR and ESBL-producing E.coli are present in Alberta’s rural well water, posing a risk to human and animal health.
  • Thumbnail Image
    ItemOpen Access
    Characterization and Comparison of Antimicrobial Resistance Phenotypes and Genotypes in Enterococcus spp. Isolated from Cattle Feces, Poultry Feces, and Beef and Poultry Retail Meats in Alberta, Canada, Related to Surveillance
    (2020-12-15) Rogers, Lindsay A; Checkley, Sylvia L.; Cork, Susan C.; McAllister, Tim A.; Zaheer, Rahat; Liljebjelke, Karen
    Enterococcus spp. are ubiquitous in the gastrointestinal tracts of animals and the environment and are important nosocomial pathogens. The use of antimicrobials in food producing animals along with the ability of enterococci to acquire antimicrobial resistance leads to concern about the contamination of retail meat products with antimicrobial resistant Enterococcus spp. from food production animals. The concern is that the antimicrobial resistant enterococci from retail meats may transfer to the human population and cause disease. In addition, increased resistant enterococci and genes in the environment may increase overall risk their transfer to humans. The objective of this thesis was to contribute to the surveillance of Enterococcus spp. from food animal production through a scoping review and the characterization of enterococcal isolates from surveillance in Alberta, Canada using whole genome sequencing. The scoping review followed PRISMA and JBI guidelines and included 57 articles, of which 87.7% identified E. faecium and the majority included isolates from human clinical or commensal samples. Significant findings from the articles included the increasing prevalence of vancomycin-resistant enterococci in hospitals and the importance of surveillance for enterococci in humans, animals, and the environment. E. faecium (n=107) and E. faecalis (n=132) were isolated from research and surveillance samples previously collected from beef cattle feces, broiler poultry feces, and beef and poultry retail meats in Alberta, Canada. Antimicrobial susceptibility and whole genome sequencing with comparative genomics were performed on the isolates. The odds of multiclass resistance in E. faecium was about 3 times that of E. faecalis after adjusting for sample source and clustering (OR 3.09; 95% CI: 1.48, 6.48). In contrast, a higher number of virulence genes were found in E. faecalis as compared to E. faecium. Generally antimicrobial resistance genotype showed good sensitivity and specificity for use as a presumptive predictor of the corresponding phenotype. Comparative genomic analyses showed distinct clustering within sample source for E. faecium, but not for E. faecalis. Overall, this work supports the usefulness of whole genome sequencing for surveillance of Enterococcus spp. and further characterizes a population of E. faecium and E. faecalis isolates from surveillance programs in Alberta, Canada.
  • Thumbnail Image
    ItemOpen Access
    Characterization of Antimicrobial and Metal Resistance in Contemporary and Historical clinical isolates of Histophilus somni from Feedlot cattle in Alberta
    (2016) Bhatt, Krishna; Liljebjelke, Karen; Windeyer, Claire; Timsit, Edouard; Storey, Douglas
    This study was conducted to determine antimicrobial and metal resistance, associated resistant genes, and mobile genetic elements in contemporary (2012-2016, n=63) and historical (1980’s, n=31) clinical isolates of Histophilus somni from feedlot cattle in Alberta. A significant increase in antimicrobial resistance was observed in the contemporary isolates compared to the historical (P<0.001). Sixty-two percent of the contemporary isolates exhibited multidrug resistance (resistance to 3 drug classes). Sixty-eight percent and 52% of the contemporary isolates showed tolerance to copper and zinc concentrations above one millimolar, respectively. Multicopper oxidase and cation efflux pump genes associated with copper and zinc tolerance and tet(H) gene associated with oxytetracycline resistance were identified. We identified integrative conjugative element carrying antimicrobial, copper, and zinc resistance genes, which indicates the possibility of co-selection of antimicrobial resistance due to copper and zinc selection pressure, and the dissemination of resistance by horizontal gene transfer.
  • Thumbnail Image
    ItemOpen Access
    Cytosine-guanosine deoxynucleotides (CpG DNA)-mediated Antiviral Response Against Avian Influenza Virus Infection
    (2016) Mohamed Abdul Cader, Mohamed Sarjoon; Abdul-Careem, Faizal; Schaetzl, Hermann; Fonseca, Kevin; Liljebjelke, Karen
    Cytosine-guanosine deoxynucleotides (CpG DNA) can be used for the stimulation of toll-like receptor (TLR)21 signaling pathway in avian species, that ultimately leads to upregulation of gene transcription for pro-inflammatory molecules including nitric oxide (NO) and recruitment of innate immune cells. These innate immune mediators, play various roles in the innate immune system against viruses that infect mammals and avian species. The objective of the study was to determine the antiviral effect of NO, produced in response to in ovo delivery of CpG DNA, against H4N6 low pathogenic avian influenza virus (LPAIV) infection in the avian respiratory system. First, we observed that when CpG DNA is delivered at embryo day (ED)18 in ovo and subsequently challenged with H4N6 LPAIV at ED19 pre-hatch and day 1 post-hatch, CpG DNA reduces H4N6 LPAIV replication in the respiratory tract. Second, we observed that CpG DNA-mediated H4N6 LPAIV inhibition was attributable to NO production. Third, we observed that the antiviral response elicited by in ovo CpG DNA delivery is also associated with macrophage recruitment in the lungs. Finally, we showed that NO originated from macrophages is capable of eliciting antiviral response against H4N6 LPAIV infection in a dose-dependent manner. Altogether, CpG DNA-mediated antiviral response against H4N6 LPAIV infection is attributable to increased macrophage numbers in the lungs and elevated NO production originated from macrophages. The study provides insights into the mechanisms of CpG DNA-mediated antiviral response, particularly against H4N6 LPAIV infection in avian species.
  • Thumbnail Image
    ItemOpen Access
    Distribution of Staphylococcus non-aureus isolated from bovine milk in Canadian herds
    (2016) Condas, Larissa; Barkema, Herman; De Buck, Jeroen; Liljebjelke, Karen; Kastelic, John; Middleton, John; De Vliegher, Sarne; Armstrong, Glen
    The Staphylococci non-aureus (SNA) species are among the most prevalent isolated from bovine milk. However, the role of each species within the SNA group still needs to be fully understood. Knowing which SNA species are most common in bovine intramammary infections (IMI), as well as their epidemiology, is essential to the improvement of udder health on dairy farms worldwide. This thesis is comprised of two studies on the epidemiology of SNA species in bovine milk, and used molecular methods to identify of isolates obtained from the Canadian Bovine Mastitis and Milk Quality Research Network. The first study focused on the prevalence of SNA species on Canadian dairy farms and potential associations of SNA positive mammary quarters with bulk milk somatic cell count (BMSCC), barn type, parity, month of lactation and quarter location. Overall SNA represented 9% of the isolates from culture positive mammary quarters and the most common species were S. chromogenes, S. simulans, S. xylosus, S. haemolyticus, and S. epidermidis. Province and barn type were associated with SNA species distribution; Albertan bedded-packs were mostly affected by S. chromogenes, Maritimes free-stall herds by S. epidermidis, and Ontario and Quebec tie-stalls by S. xylosus. Staphylococcus arlettae, S. cohnii, and S. gallinarum were isolated from quarters of herds with high BMSCC. Fresh heifers and cows in later lactation were most frequently infected by S. chromogenes. The second study focused on the distribution of the same species in SNA positive-quarters according to udder inflammation status, classified according to low and high SCC and clinical mastitis. Average somatic cell count (SCC) for the SNA as a group was 70,000 cells/mL, driven mostly by S. chromogenes, S. haemolyticus, S. xylosus and S. epidermidis. Species-specific prevalence of SNA-positive quarters was higher in high (≥ 200,000 cells/mL) than in low SCC (< 200,000 cells/mL) samples for the 11 most frequently isolated SNA species. Staphylococcus sciuri was more frequently isolated from clinical mastitis samples. Considering SNA as a group will misrepresent the role of individual species on farms. Ultimately, adopting molecular identification of SNA species along with future research in species-specific risk factors are necessary to fully elucidate the importance of of the different SNA species on udder health and possible species-specific interventions.
  • Thumbnail Image
    ItemOpen Access
    Environmental Reservoir of Antimicrobial Resistance in Poultry Production Facilities and Processing Plants in Alberta
    (2015-07-09) Thapa, Paras; Liljebjelke, Karen
    This study was conducted to determine the role of environmental bacteria in maintaining antimicrobial resistance genes in poultry barns and poultry processing plants in Alberta. Aerobic, non-fastidious, fast growing bacteria were isolated from environmental samples. Approximately half of the bacteria were gram-negative and half were gram-positive. Resistance to clinically important antibiotics such as third generation cephalosporins was observed in 20-35% of the gram-negative isolates. Sixty percent of all bacteria assayed were considered multi-drug resistant, having resistance to antibiotics in three or more drug classes. Ten of 14 E. coli isolates were resistant to 1st, 2nd and 3rd generation cephalosporins, three of which harboured the blaCMY-2 gene, which encodes a plasmid borne AmpC cephalosporinase enzyme. Bacterial species expressing a variety of resistance phenotypes were tested for their ability to form a biofilm in vitro and for their ability to withstand exposure to commonly used disinfectants while residing in biofilm. In conclusion, multi-drug resistant environmental bacteria present in poultry barns and processing facilities can serve as reservoir of antimicrobial resistant genes, which could potentially be transferred to pathogenic bacteria.
  • Thumbnail Image
    ItemOpen Access
    Examination of the horizontal gene transfer dynamics of an integrative conjugative element encoding multi-drug resistance in Histophilus somni
    (2021-01-15) Farghaly, Mai Mohammed; Liljebjelke, Karen; Hynes, Michael; van der Meer, Frank
    Integrative and conjugative elements (ICEs) are autonomous-transferred mobile genetic elements that play a significant role in disseminating antimicrobials between bacteria via horizontal gene transfer (HGT). One recently identified ICE in a clinical isolate of H. somni named ICEHs02 is 72,914 base pairs in length and harbours seven AMR genes which confer resistance to tetracycline (tetR-tet(H)), florfenicol (floR), sulfonamide (sul2), aminoglycoside (APH(3'')-Ib), (APH(6)-Id), and (APH(3')-Ia), and copper (mco). This study investigated the host range of ICEHs02, assessed the effect of antimicrobial stressors on transfer frequency of ICEHs02, and examined effects of ICE acquisition on the host. In vitro conjugation assays were conducted to examine the frequency of transfer of ICEHs02 into other bacteria. PCR and sequence analysis confirmed the presence of ICEHs02 and its circular intermediate in recipient strains. The susceptibility of ICEHs02-carrying recipients was conducted using broth microdilution. The effect of tetracycline and ciprofloxacin on transfer frequency and excision rates was investigated using mating assays and qPCR. Growth curves and competition experiments were conducted to assess the fitness cost of ICEHs02 on the host. ICEHs02 was observed to transfer into H. somni and Pasteurella multocida. PCR assays confirmed the presence of the circular intermediate, ICE-associated core genes and accessory genes in recipient strains. Susceptibility testing confirmed the function of ICEHs02-associated AMR genes in recipient strains. Tetracycline and ciprofloxacin induction significantly increased the transfer rates of ICEHs02. The copy numbers of the circular intermediate of ICEHs02 per chromosome exhibited significant increases of ~ 37-fold after tetracycline exposure, and ~ 4-fold after ciprofloxacin treatment. The acquisition of ICEHs02 reduced the relative fitness of H. somni TG by 28% (w = 0.72 ± 0.04) and P. multocida TG relative fitness was decreased by 15% (w = 0.85 ± 0.01). In conclusion, this study provided information on the host range of the multi-drug resistant ICEHs02, gave insight into the regulatory role of antibiotics on the HGT of ICEs and emphasized the importance of ICEs in the dissemination of AMR between bacteria.
  • Thumbnail Image
    ItemOpen Access
    Identifying Research Gaps for the Role of the Environment in Transmission of Antimicrobial-Resistant Escherichia coli in Cow-Calf Operations in North America: A Scoping Review Protocol
    (2021-06-30) Mangat, Priyanka; Le, Stephanie; Ganshorn, Heather; Checkley, Sylvia; Liljebjelke, Karen
    Escherichia coli (E.coli) is a gram negative rod-shaped bacteria which is found in the intestines of people, animals and in the environment. E.coli is also found in food and untreated water. Antimicrobial use in animal production against bacteria such as E. coli is essential for maintaining animal health. However, increased antimicrobial use poses the risk of contributing to the problem of antimicrobial resistance. Antimicrobial resistance occurs when microorganisms selectively develop mechanisms to protect themselves from the effects of antimicrobial compounds. Antimicrobial resistance is a One Health concern as it impacts animal, human and ecosystem health. In North America, the term cow-calf production refers to cattle raised exclusively or largely on pasture, having a grass- or hay-based diet, and which may consume a low amount of concentrate diet, producing an annual crop of calves. The calves are intended for beef production and are usually backgrounded on pasture or backgrounding lots and then finished with a high concentrate diet in feedlots. Although this literature review is not restricted to North America, information retrieved will be discussed in relation to cow-calf operations in North America. For the purpose of this scoping review, the term “environment” will refer to environmental features such as: manure, wildlife, soil, insects, and water sources. By including these search terms, the scoping review will identify environmental reservoirs that have been shown to impact the transmission of antimicrobial-resistant E. coli in cow-calf operations. Our aim is to conduct a scoping review of the evidence regarding the role of the environment in the transmission and maintenance of antimicrobial-resistant E. coli within cow-calf operations. This study will identify gaps in knowledge regarding the reservoirs and transmission of antimicrobial-resistant E. coli in cow-calf operations (2). Because the mechanisms of maintenance and transmission of antimicrobial resistance in the environment are obscure, this scoping review will aid in determining the quantity and nature of information that presently exists in this field, and aid in identifying directions for future research (3). The review will be conducted between July 1, 2021 and August 31, 2021.