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Nouws S, Verhaegen B, Denayer S, Crombé F, Piérard D, Bogaerts B, Vanneste K, Marchal K, Roosens NHC, De Keersmaecker SCJ. Transforming Shiga toxin-producing Escherichia coli surveillance through whole genome sequencing in food safety practices. Front Microbiol 2023; 14:1204630. [PMID: 37520372 PMCID: PMC10381951 DOI: 10.3389/fmicb.2023.1204630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 06/22/2023] [Indexed: 08/01/2023] Open
Abstract
Introduction Shiga toxin-producing Escherichia coli (STEC) is a gastrointestinal pathogen causing foodborne outbreaks. Whole Genome Sequencing (WGS) in STEC surveillance holds promise in outbreak prevention and confinement, in broadening STEC epidemiology and in contributing to risk assessment and source attribution. However, despite international recommendations, WGS is often restricted to assist outbreak investigation and is not yet fully implemented in food safety surveillance across all European countries, in contrast to for example in the United States. Methods In this study, WGS was retrospectively applied to isolates collected within the context of Belgian food safety surveillance and combined with data from clinical isolates to evaluate its benefits. A cross-sector WGS-based collection of 754 strains from 1998 to 2020 was analyzed. Results We confirmed that WGS in food safety surveillance allows accurate detection of genomic relationships between human cases and strains isolated from food samples, including those dispersed over time and geographical locations. Identifying these links can reveal new insights into outbreaks and direct epidemiological investigations to facilitate outbreak management. Complete WGS-based isolate characterization enabled expanding epidemiological insights related to circulating serotypes, virulence genes and antimicrobial resistance across different reservoirs. Moreover, associations between virulence genes and severe disease were determined by incorporating human metadata into the data analysis. Gaps in the surveillance system were identified and suggestions for optimization related to sample centralization, harmonizing isolation methods, and expanding sampling strategies were formulated. Discussion This study contributes to developing a representative WGS-based collection of circulating STEC strains and by illustrating its benefits, it aims to incite policymakers to support WGS uptake in food safety surveillance.
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Affiliation(s)
- Stéphanie Nouws
- Transversal Activities in Applied Genomics, Sciensano, Brussels, Belgium
- IDlab, Department of Information Technology, Ghent University—IMEC, Ghent, Belgium
| | - Bavo Verhaegen
- National Reference Laboratory for Shiga Toxin-Producing Escherichia coli (NRL STEC) and for Foodborne Outbreaks (NRL FBO), Foodborne Pathogens, Sciensano, Brussels, Belgium
| | - Sarah Denayer
- National Reference Laboratory for Shiga Toxin-Producing Escherichia coli (NRL STEC) and for Foodborne Outbreaks (NRL FBO), Foodborne Pathogens, Sciensano, Brussels, Belgium
| | - Florence Crombé
- National Reference Centre for Shiga Toxin-Producing Escherichia coli (NRC STEC), Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Denis Piérard
- National Reference Centre for Shiga Toxin-Producing Escherichia coli (NRC STEC), Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Bert Bogaerts
- Transversal Activities in Applied Genomics, Sciensano, Brussels, Belgium
| | - Kevin Vanneste
- Transversal Activities in Applied Genomics, Sciensano, Brussels, Belgium
| | - Kathleen Marchal
- IDlab, Department of Information Technology, Ghent University—IMEC, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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Bumunang EW, Zaheer R, Stanford K, Laing C, Niu D, Guan LL, Chui L, Tarr GAM, McAllister TA. Genomic Analysis of Shiga Toxin-Producing E. coli O157 Cattle and Clinical Isolates from Alberta, Canada. Toxins (Basel) 2022; 14:toxins14090603. [PMID: 36136541 PMCID: PMC9505746 DOI: 10.3390/toxins14090603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/24/2022] [Accepted: 08/24/2022] [Indexed: 12/02/2022] Open
Abstract
Shiga toxin (stx) is the principal virulence factor of the foodborne pathogen, Shiga toxin-producing Escherichia coli (STEC) O157:H7 and is associated with various lambdoid bacterio (phages). A comparative genomic analysis was performed on STEC O157 isolates from cattle (n = 125) and clinical (n = 127) samples to characterize virulence genes, stx-phage insertion sites and antimicrobial resistance genes that may segregate strains circulating in the same geographic region. In silico analyses revealed that O157 isolates harboured the toxin subtypes stx1a and stx2a. Most cattle (76.0%) and clinical (76.4%) isolates carried the virulence gene combination of stx1, stx2, eae and hlyA. Characterization of stx1 and stx2-carrying phages in assembled contigs revealed that they were associated with mlrA and wrbA insertion sites, respectively. In cattle isolates, mlrA and wrbA insertion sites were occupied more often (77% and 79% isolates respectively) than in clinical isolates (38% and 1.6% isolates, respectively). Profiling of antimicrobial resistance genes (ARGs) in the assembled contigs revealed that 8.8% of cattle (11/125) and 8.7% of clinical (11/127) isolates harboured ARGs. Eight antimicrobial resistance genes cassettes (ARCs) were identified in 14 isolates (cattle, n = 8 and clinical, n = 6) with streptomycin (aadA1, aadA2, ant(3’’)-Ia and aph(3’’)-Ib) being the most prevalent gene in ARCs. The profound disparity between the cattle and clinical strains in occupancy of the wrbA locus suggests that this trait may serve to differentiate cattle from human clinical STEC O157:H7. These findings are important for stx screening and stx-phage insertion site genotyping as well as monitoring ARGs in isolates from cattle and clinical samples.
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Affiliation(s)
- Emmanuel W. Bumunang
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Rahat Zaheer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB T1J 4B1, Canada
| | - Kim Stanford
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 1M4, Canada
| | - Chad Laing
- National Centre for Animal Disease Canadian Food Inspection Agency, Lethbridge, AB T1J 0P3, Canada
| | - Dongyan Niu
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Le Luo Guan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P9, Canada
| | - Linda Chui
- Alberta Precisions Laboratory, Alberta Public Health, Edmonton, AB T6G 2J2, Canada
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2B7, Canada
| | - Gillian A. M. Tarr
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Tim A. McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB T1J 4B1, Canada
- Correspondence:
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Phage Cocktail Targeting STEC O157:H7 Has Comparable Efficacy and Superior Recovery Compared with Enrofloxacin in an Enteric Murine Model. Microbiol Spectr 2022; 10:e0023222. [PMID: 35536028 PMCID: PMC9241756 DOI: 10.1128/spectrum.00232-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
O157:H7 is the most important Shiga toxin-producing Escherichia coli (STEC) serotype in relation to public health. Given that antibiotics may contribute to the exacerbation of STEC-related disease and an increased frequency of antibiotic-resistant strains, bacteriophage (phage) therapy is considered a promising alternative. However, phage therapy targeting enteric pathogens is still underdeveloped with many confounding effects from the microbiota. Here we comprehensively compared the therapeutic efficacy of a phage cocktail with the antibiotic enrofloxacin in a mouse model of STEC O157:H7 EDL933 infection. Enrofloxacin treatment provided 100% survival and the phage cocktail treatment provided 90% survival. However, in terms of mouse recovery, the phage cocktail outperformed enrofloxacin in all measured outcomes. Compared with enrofloxacin treatment, phage treatment led to a faster elimination of enteric pathogens, decreased expression levels of inflammatory markers, increased weight gain, maintenance of a stable relative organ weight, and improved homeostasis of the gut microbiota. These results provide support for the potential of phage therapy to combat enteric pathogens and suggest that phage treatment leads to enhanced recovery of infected mice compared with antibiotics. IMPORTANCE With the increasing severity of antibiotic resistance and other adverse consequences, animal experiments and clinical trials investigating the use of phages for the control and prevention of enteric bacterial infections are growing. However, the effects of phages and antibiotics on organisms when treating intestinal infections have not been precisely studied. Here, we comprehensively compared the therapeutic efficacy of a phage cocktail to the antibiotic enrofloxacin in a mouse model of STEC O157:H7 EDL933 infection. We found that, despite a slightly lower protection rate, phage treatment contributed to a faster recovery of infected mice compared with enrofloxacin. These results highlight the potential benefits of phage therapy to combat enteric infections.
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Blais BW, Tapp K, Dixon M, Carrillo CD. Genomically Informed Strain-Specific Recovery of Shiga Toxin-Producing Escherichia coli during Foodborne Illness Outbreak Investigations. J Food Prot 2019; 82:39-44. [PMID: 30586325 DOI: 10.4315/0362-028x.jfp-18-340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Next-generation sequencing plays an important role in the characterization of clinical bacterial isolates for source attribution purposes during investigations of foodborne illness outbreaks. Once an illness cluster and a suspect food vehicle have been identified, food testing is initiated for confirmation and to determine the scope of a contamination event so that the implicated lots may be removed from the marketplace. For biochemically diverse families of pathogens such as Shiga toxin-producing Escherichia coli (STEC), the ability to detect specific strains may be hampered by the lack of a universal selective enrichment approach for their recovery against high levels of background microbiota. The availability of whole genome sequence data for a given outbreak STEC strain prior to commencement of food testing may provide food microbiologists an opportunity to customize selective enrichment techniques favoring the recovery of the outbreak strain. Here we demonstrate the advantages of using the publicly available ResFinder tool in the analysis of STEC model strains belonging to serotypes O111 and O157 to determine antimicrobial resistance traits that can be used in formulating strain-specific enrichment media to enhance recovery of these strains from microbiologically complex food samples. The improved recovery from ground beef of model STEC strains with various antimicrobial resistance profiles was demonstrated using three classes of antibiotics as selective agents, suggesting the universal applicability of this new approach in supporting foodborne illness investigations.
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Affiliation(s)
- Burton W Blais
- Research and Development Section, Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, Ontario, Canada K1A 0C6
| | - Kyle Tapp
- Research and Development Section, Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, Ontario, Canada K1A 0C6
| | - Martine Dixon
- Research and Development Section, Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, Ontario, Canada K1A 0C6
| | - Catherine D Carrillo
- Research and Development Section, Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, Ontario, Canada K1A 0C6
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Mir RA, Kudva IT. Antibiotic‐resistant Shiga toxin‐producing
Escherichia coli
: An overview of prevalence and intervention strategies. Zoonoses Public Health 2018; 66:1-13. [DOI: 10.1111/zph.12533] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 10/08/2018] [Indexed: 12/22/2022]
Affiliation(s)
- Raies A. Mir
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service U.S. Department of Agriculture Ames Iowa
- Oak Ridge Institute for Science and Education (ORISE) ARS Research Participation Program Oak Ridge Tennessee
| | - Indira T. Kudva
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service U.S. Department of Agriculture Ames Iowa
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Um MM, Brugère H, Kérourédan M, Oswald E, Bibbal D. Antimicrobial Resistance Profiles of Enterohemorrhagic and Enteropathogenic Escherichia coli of Serotypes O157:H7, O26:H11, O103:H2, O111:H8, O145:H28 Compared to Escherichia coli Isolated from the Same Adult Cattle. Microb Drug Resist 2018; 24:852-859. [PMID: 29723122 DOI: 10.1089/mdr.2017.0106] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The aim of this study was to compare the antimicrobial resistance profiles of top five enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) to E. coli isolated from the fecal flora of the same adult cattle. Previous prevalence studies had led to the isolation by immunomagnetic separation (IMS) of 39 EHEC and 80 EPEC. Seven EHEC were resistant (17.9%), and six were multidrug resistant (MDR) (15.4%). None of the top five EHEC was resistant to azithromycin. Nine EPEC O26:H11 (11.3%) were resistant. They were all resistant to tetracycline, and four were MDR (5.0%). An E. coli strain was isolated from the feces (without preselection by IMS) of 97 bovine carriers of top 5 strains. All these strains were susceptible to antibiotics. Comparative analyses did not reveal any differences between the cytotoxic activities of resistant EHEC and their susceptible counterparts or in the production of attachment and effacement lesions. These results highlighted the higher percentage of resistance of EHEC and EPEC strains compared to other E. coli. They also showed that resistance traits did not have any impact on the expression of virulence phenotypes in EHEC strains.
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Affiliation(s)
- Maryse Michèle Um
- 1 IRSD, Université de Toulouse , INSERM, INRA, ENVT, UPS, Toulouse, France
| | - Hubert Brugère
- 1 IRSD, Université de Toulouse , INSERM, INRA, ENVT, UPS, Toulouse, France
| | - Monique Kérourédan
- 1 IRSD, Université de Toulouse , INSERM, INRA, ENVT, UPS, Toulouse, France
| | - Eric Oswald
- 1 IRSD, Université de Toulouse , INSERM, INRA, ENVT, UPS, Toulouse, France .,2 CHU de Toulouse, Hôpital Purpan , Toulouse, France
| | - Delphine Bibbal
- 1 IRSD, Université de Toulouse , INSERM, INRA, ENVT, UPS, Toulouse, France
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An R, Alshalchi S, Breimhurst P, Munoz-Aguayo J, Flores-Figueroa C, Vidovic S. Strong influence of livestock environments on the emergence and dissemination of distinct multidrug-resistant phenotypes among the population of non-typhoidal Salmonella. PLoS One 2017; 12:e0179005. [PMID: 28591163 PMCID: PMC5462443 DOI: 10.1371/journal.pone.0179005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 05/22/2017] [Indexed: 11/18/2022] Open
Abstract
The problem of emergence and dissemination of multidrug resistance, especially among Gram-negative bacteria, has reached alarming levels. This increases the need to develop surveillance methods that more effectively and accurately provide information about the emergence and spread of multidrug-resistant organisms. In this study, using a well-defined population of non-typhoidal Salmonella (NTS) isolates associated with avian, bovine and porcine hosts, we found that the livestock environments had a specific (P < 0.005) and profound (P < 0.005) effect on the evolution of multidrug-resistant phenotypes among population of NTS isolates. The MDR pattern containing penicillins, tetracyclines and macrolides and the evolving counterparts (i.e., penicillins, tetracyclines and macrolides + other antibiotic classes) were significantly (P < 0.005) associated with NTS isolates of porcine origin. Similarly, MDR patterns containing folate pathway inhibitors, macrolides and aminocyclitol or containing penicillins, cephalosporins, tetracyclines, phenicols and macrolides were significantly associated with avian (P < 0.005) and bovine (P < 0.005) NTS isolates, respectively. Furthermore, STRUCTURE, an evolutionary analysis, clearly showed that the host origin (i.e., livestock environment), and not the genetic background of different NTS serovars, was the most determinative factor for acquisition and spread of MDR phenotypes. In addition, we described a novel non-synonymous mutation, located outside of the QRDR at position 864 of GyrA, that was likely associated with fluoroquinolone resistance.
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Affiliation(s)
- Ran An
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, United States of America
| | - Sahar Alshalchi
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, United States of America
| | - Peter Breimhurst
- College of Biological Sciences, University of Minnesota, Minneapolis, United States of America
| | - Jeannette Munoz-Aguayo
- Mid-Central Research and Outreach Center, University of Minnesota, Willmar, United States of America
| | - Christian Flores-Figueroa
- Mid-Central Research and Outreach Center, University of Minnesota, Willmar, United States of America
| | - Sinisa Vidovic
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, United States of America
- * E-mail:
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8
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Day M, Doumith M, Jenkins C, Dallman TJ, Hopkins KL, Elson R, Godbole G, Woodford N. Antimicrobial resistance in Shiga toxin-producing Escherichia coli serogroups O157 and O26 isolated from human cases of diarrhoeal disease in England, 2015. J Antimicrob Chemother 2016; 72:145-152. [PMID: 27678285 DOI: 10.1093/jac/dkw371] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/05/2016] [Accepted: 08/05/2016] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES Shiga toxin-producing Escherichia coli (STEC) are zoonotic and transmission to humans occurs via contaminated food or contact with infected animals. In this study, WGS data were used to predict antimicrobial resistance (AMR) in STEC from symptomatic human cases to assess the extent of transmission of antibiotic-resistant E. coli from animals to humans. METHODS WGS data from 430 isolates of STEC were mapped to genes known to be associated with phenotypic AMR. Susceptibility testing was performed by a breakpoint method on all viable isolates exhibiting resistance to at least one antimicrobial. RESULTS 327/396 (82.6%) of STEC O157 and 22/34 (64.7%) of STEC O26 lacked identifiable resistance genes and were predicted to be fully susceptible to 11 diverse classes of antimicrobials. For the remaining 81 isolates, 74 were phenotypically tested and there was concordance between WGS-predicted resistance and expression of phenotypic resistance. The most common resistance profile was ampicillin, streptomycin, trimethoprim/sulphonamide and tetracycline occurring in 25 (5.8%) isolates. Resistance to other antimicrobials, including resistance to chloramphenicol (2.1%), resistance to azithromycin (0.2%) and reduced susceptibility to ciprofloxacin (2.6%), was less frequent. Three isolates were identified as ESBL producers. CONCLUSIONS β-Lactams, trimethoprim/sulphonamides and tetracyclines account for the majority of therapeutic antimicrobials sold for veterinary use and this may be a risk factor for the presence of AMR in domestically acquired human clinical isolates of STEC. Isolates that were resistant to ampicillin, streptomycin, sulphonamide, tetracycline and azithromycin and had reduced susceptibility to ciprofloxacin were associated with cases who reported recent travel abroad.
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Affiliation(s)
- Martin Day
- Bacteriology Reference Department, Reference Microbiology Services, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Michel Doumith
- Bacteriology Reference Department, Reference Microbiology Services, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Claire Jenkins
- Bacteriology Reference Department, Reference Microbiology Services, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Timothy J Dallman
- Bacteriology Reference Department, Reference Microbiology Services, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Katie L Hopkins
- Bacteriology Reference Department, Reference Microbiology Services, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Richard Elson
- Gastrointestinal and Emerging Zoonotic Infections Department, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Gauri Godbole
- Bacteriology Reference Department, Reference Microbiology Services, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Neil Woodford
- Bacteriology Reference Department, Reference Microbiology Services, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
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Utility of Whole-Genome Sequencing of Escherichia coli O157 for Outbreak Detection and Epidemiological Surveillance. J Clin Microbiol 2015; 53:3565-73. [PMID: 26354815 PMCID: PMC4609728 DOI: 10.1128/jcm.01066-15] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/30/2015] [Indexed: 12/30/2022] Open
Abstract
Detailed laboratory characterization of Escherichia coli O157 is essential to inform epidemiological investigations. This study assessed the utility of whole-genome sequencing (WGS) for outbreak detection and epidemiological surveillance of E. coli O157, and the data were used to identify discernible associations between genotypes and clinical outcomes. One hundred five E. coli O157 strains isolated over a 5-year period from human fecal samples in Lothian, Scotland, were sequenced with the Ion Torrent Personal Genome Machine. A total of 8,721 variable sites in the core genome were identified among the 105 isolates; 47% of the single nucleotide polymorphisms (SNPs) were attributable to six “atypical” E. coli O157 strains and included recombinant regions. Phylogenetic analyses showed that WGS correlated well with the epidemiological data. Epidemiological links existed between cases whose isolates differed by three or fewer SNPs. WGS also correlated well with multilocus variable-number tandem repeat analysis (MLVA) typing data, with only three discordant results observed, all among isolates from cases not known to be epidemiologically related. WGS produced a better-supported, higher-resolution phylogeny than MLVA, confirming that the method is more suitable for epidemiological surveillance of E. coli O157. A combination of insilico analyses (VirulenceFinder, ResFinder, and local BLAST searches) were used to determine stx subtypes, multilocus sequence types (15 loci), and the presence of virulence and acquired antimicrobial resistance genes. There was a high level of correlation between the WGS data and our routine typing methods, although some discordant results were observed, mostly related to the limitation of short sequence read assembly. The data were used to identify sublineages and clades of E. coli O157, and when they were correlated with the clinical outcome data, they showed that one clade, Ic3, was significantly associated with severe disease. Together, the results show that WGS data can provide higher resolution of the relationships between E. coli O157 isolates than that provided by MLVA. The method has the potential to streamline the laboratory workflow and provide detailed information for the clinical management of patients and public health interventions.
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ZnO nanoparticles impose a panmetabolic toxic effect along with strong necrosis, inducing activation of the envelope stress response in Salmonella enterica serovar Enteritidis. Antimicrob Agents Chemother 2015; 59:3317-28. [PMID: 25801570 DOI: 10.1128/aac.00363-15] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/17/2015] [Indexed: 11/20/2022] Open
Abstract
In this study, we tested the antimicrobial activity of three metal nanoparticles (NPs), ZnO, MgO, and CaO NPs, against Salmonella enterica serovar Enteritidis in liquid medium and on solid surfaces. Out of the three tested metal NPs, ZnO NPs exhibited the most significant antimicrobial effect both in liquid medium and when embedded on solid surfaces. Therefore, we focused on revealing the mechanisms of surface-associated ZnO biocidal activity. Using the global proteome approach, we report that a great majority (79%) of the altered proteins in biofilms formed by Salmonella enterica serovar Enteritidis were downregulated, whereas a much smaller fraction (21%) of proteins were upregulated. Intriguingly, all downregulated proteins were enzymes involved in a wide range of the central metabolic pathways, including translation; amino acid biosynthetic pathways; nucleobase, nucleoside, and nucleotide biosynthetic processes; ATP synthesis-coupled proton transport; the pentose phosphate shunt; and carboxylic acid metabolic processes, indicating that ZnO NPs exert a panmetabolic toxic effect on this prokaryotic organism. In addition to their panmetabolic toxicity, ZnO NPs induced profound changes in cell envelope morphology, imposing additional necrotic effects and triggering the envelope stress response of Salmonella serovar Enteritidis. The envelope stress response effect activated periplasmic chaperones and proteases, transenvelope complexes, and regulators, thereby facilitating protection of this prokaryotic organism against ZnO NPs.
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Characterization of Shiga toxin-producing Escherichia coli isolated from ground beef collected in different socioeconomic strata markets in Buenos Aires, Argentina. BIOMED RESEARCH INTERNATIONAL 2014; 2014:795104. [PMID: 25006586 PMCID: PMC4070525 DOI: 10.1155/2014/795104] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 05/06/2014] [Indexed: 11/24/2022]
Abstract
Consumption of raw/undercooked ground beef is the most common route of transmission of Shiga toxin-producing E. coli (STEC). The aim of the study was to determine the STEC contamination level of the ground beef samples collected in 36 markets of different socioeconomic strata in Buenos Aires, Argentina, and the characterization of the isolated strains. Ninety-one out of 252 (36.1%) samples were stx+. Fifty-seven STEC strains were recovered. Eleven STEC strains belonged to O157 serogroup, and 46 to non-O157 serogroups. Virulence markers of the 57 STEC were stx1, 5.3% (3/57); stx2, 86.0% (49/57); stx1/stx2, 8.8% (5/57); ehxA, 61.4% (35/57); eae, 26.3% (15/57); saa, 24.6% (14/57). Shiga toxin subtypes were stx2, 31.5% (17/54); stx2c-vhb, 24.1% (13/54); stx2c-vha, 20.4% (11/54); stx2/stx2c-vha, 14.8% (8/54); stx2/stx2c-vhb, 5.6% (3/54); stx2c-vha/vhb, 3.7% (2/54). Serotypes O178:H19 and O157:H7 were prevalent. Contamination rate of STEC in all strata was high, and the highest O157 contamination was observed at low strata at several sampling rounds. Persistence of STEC was not detected. Sixteen strains (28.1%) were resistant to ampicillin, streptomycin, amikacin, or tetracycline. The STEC contamination level of ground beef could vary according to the sociocultural characteristics of the population.
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12
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Vidovic S, Korber DR. Escherichia coli O157: Insights into the adaptive stress physiology and the influence of stressors on epidemiology and ecology of this human pathogen. Crit Rev Microbiol 2014; 42:83-93. [PMID: 24601836 DOI: 10.3109/1040841x.2014.889654] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Escherichia coli O157, a foodborne pathogen of major concern for public health, has been associated with numerous outbreaks of haemorrhagic colitis and hemolytic uremic syndrome worldwide. Human infection with E. coli O157 has been primarily associated with the food-chain transmission route. This transmission route commonly elicits a multi-faceted adaptive stress response of E. coli O157 for an extended period of time prior to human infection. Several recent research articles have indicated that E. coli O157:H7 has evolved unique survival characteristics which can affect the epidemiology and ecology of this zoonotic pathogen. This review article summarizes the recent knowledge of the molecular responses of E. coli O157 to the most common stressors found within the human food chain, and further emphasizes the influence of these stressors on the epidemiology and ecology of E. coli O157.
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Affiliation(s)
- Sinisa Vidovic
- a Department of Food and Bioproducts Sciences , University of Saskatchewan , Saskatchewan , Canada
| | - Darren R Korber
- a Department of Food and Bioproducts Sciences , University of Saskatchewan , Saskatchewan , Canada
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