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Wyrsch ER, Hoye BJ, Sanderson-Smith M, Gorman J, Maute K, Cummins ML, Jarocki VM, Marenda MS, Dolejska M, Djordjevic SP. The faecal microbiome of the Australian silver gull contains phylogenetically diverse ExPEC, aEPEC and Escherichia coli carrying the transmissible locus of stress tolerance. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170815. [PMID: 38336047 DOI: 10.1016/j.scitotenv.2024.170815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/28/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Wildlife are implicated in the dissemination of antimicrobial resistance, but their roles as hosts for Escherichia coli that pose a threat to human and animal health is limited. Gulls (family Laridae) in particular, are known to carry diverse lineages of multiple-antibiotic resistant E. coli, including extra-intestinal pathogenic E. coli (ExPEC). Whole genome sequencing of 431 E. coli isolates from 69 healthy Australian silver gulls (Chroicocephalus novaehollandiae) sampled during the 2019 breeding season, and without antibiotic selection, was undertaken to assess carriage in an urban wildlife population. Phylogenetic analysis and genotyping resolved 123 sequence types (STs) representing most phylogroups, and identified diverse ExPEC, including an expansive phylogroup B2 cluster comprising 103 isolates (24 %; 31 STs). Analysis of the mobilome identified: i) widespread carriage of the Yersinia High Pathogenicity Island (HPI), a key ExPEC virulence determinant; ii) broad distribution of two novel phage elements, each carrying sitABCD and iii) carriage of the transmissible locus of stress tolerance (tLST), an element linked to sanitation resistance. Of the 169 HPI carrying isolates, 49 (48 %) represented diverse B2 isolates hosting FII-64 ColV-like plasmids that lacked iutABC and sitABC operons typical of ColV plasmids, but carried the serine protease autotransporter gene, sha. Diverse E. coli also carried archetypal ColV plasmids (52 isolates; 12 %). Clusters of closely related E. coli (<50 SNVs) from ST58, ST457 and ST746, sourced from healthy gulls, humans, and companion animals, were frequently identified. In summary, anthropogenically impacted gulls host an expansive E. coli population, including: i) putative ExPEC that carry ColV virulence gene cargo (101 isolates; 23.4 %) and HPI (169 isolates; 39 %); ii) atypical enteropathogenic E. coli (EPEC) (17 isolates; 3.9 %), and iii) E. coli that carry the tLST (20 isolates; 4.6 %). Gulls play an important role in the evolution and transmission of E. coli that impact human health.
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Affiliation(s)
- Ethan R Wyrsch
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
| | - Bethany J Hoye
- School of Earth, Atmospheric and Life Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Martina Sanderson-Smith
- Molecular Horizons Research Institute, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Jody Gorman
- Molecular Horizons Research Institute, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Kimberly Maute
- School of Earth, Atmospheric and Life Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Max L Cummins
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
| | - Veronica M Jarocki
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
| | - Marc S Marenda
- Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, VIC 3030, Australia
| | - Monika Dolejska
- Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Czech Republic; CEITEC VETUNI, University of Veterinary Sciences Brno, Czech Republic; Department of Clinical Microbiology and Immunology, Institute of Laboratory Medicine, The University Hospital Brno, Czech Republic; Department of Microbiology, Faculty of Medicine and University Hospital in Plzen, Charles University, Pilsen, Czech Republic
| | - Steven P Djordjevic
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia.
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Berdejo D, Mortier J, Cambré A, Sobota M, Van Eyken R, Kim TD, Vanoirbeek K, García Gonzalo D, Pagán R, Diard M, Aertsen A. Evolutionary trade-off between heat shock resistance, growth at high temperature, and virulence expression in Salmonella Typhimurium. mBio 2024; 15:e0310523. [PMID: 38349183 PMCID: PMC10936172 DOI: 10.1128/mbio.03105-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/12/2024] [Indexed: 03/14/2024] Open
Abstract
Understanding the evolutionary dynamics of foodborne pathogens throughout our food production chain is of utmost importance. In this study, we reveal that Salmonella Typhimurium can readily and reproducibly acquire vastly increased heat shock resistance upon repeated exposure to heat shock. Counterintuitively, this boost in heat shock resistance was invariantly acquired through loss-of-function mutations in the dnaJ gene, encoding a heat shock protein that acts as a molecular co-chaperone of DnaK and enables its role in protein folding and disaggregation. As a trade-off, however, the acquisition of heat shock resistance inevitably led to attenuated growth at 37°C and higher temperatures. Interestingly, loss of DnaJ also downregulated the activity of the master virulence regulator HilD, thereby lowering the fraction of virulence-expressing cells within the population and attenuating virulence in mice. By connecting heat shock resistance evolution to attenuation of HilD activity, our results confirm the complex interplay between stress resistance and virulence in Salmonella Typhimurium. IMPORTANCE Bacterial pathogens such as Salmonella Typhimurium are equipped with both stress response and virulence features in order to navigate across a variety of complex inhospitable environments that range from food-processing plants up to the gastrointestinal tract of its animal host. In this context, however, it remains obscure whether and how adaptation to one environment would obstruct fitness in another. In this study, we reveal that severe heat stress counterintuitively, but invariantly, led to the selection of S. Typhimurium mutants that are compromised in the activity of the DnaJ heat shock protein. While these mutants obtained massively increased heat resistance, their virulence became greatly attenuated. Our observations, therefore, reveal a delicate balance between optimal tuning of stress response and virulence features in bacterial pathogens.
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Affiliation(s)
- Daniel Berdejo
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Zaragoza, Spain
| | - Julien Mortier
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | - Alexander Cambré
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | | | - Ronald Van Eyken
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | - Tom Dongmin Kim
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | - Kristof Vanoirbeek
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | - Diego García Gonzalo
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Zaragoza, Spain
| | - Rafael Pagán
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Zaragoza, Spain
| | | | - Abram Aertsen
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
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Zhang R, Wang Y. EvgS/EvgA, the unorthodox two-component system regulating bacterial multiple resistance. Appl Environ Microbiol 2023; 89:e0157723. [PMID: 38019025 PMCID: PMC10734491 DOI: 10.1128/aem.01577-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023] Open
Abstract
IMPORTANCE EvgS/EvgA, one of the five unorthodox two-component systems in Escherichia coli, plays an essential role in adjusting bacterial behaviors to adapt to the changing environment. Multiple resistance regulated by EvgS/EvgA endows bacteria to survive in adverse conditions such as acidic pH, multidrug, and heat. In this minireview, we summarize the specific structures and regulation mechanisms of EvgS/EvgA and its multiple resistance. By discussing several unresolved issues and proposing our speculations, this review will be helpful and enlightening for future directions about EvgS/EvgA.
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Affiliation(s)
- Ruizhen Zhang
- MoE Key Laboratory of Evolution and Marine Biodiversity, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Yan Wang
- MoE Key Laboratory of Evolution and Marine Biodiversity, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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4
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Sui X, Yang X, Luo M, Wang H, Liu Q, Sun H, Jin Y, Wu Y, Bai X, Xiong Y. Characteristics of Shiga Toxin-Producing Escherichia coli Circulating in Asymptomatic Food Handlers. Toxins (Basel) 2023; 15:640. [PMID: 37999503 PMCID: PMC10675304 DOI: 10.3390/toxins15110640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/22/2023] [Accepted: 10/31/2023] [Indexed: 11/25/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a foodborne zoonotic pathogen that causes diarrhea, hemorrhagic colitis (HC), and hemolytic uremic syndrome (HUS) worldwide. Since the infection can be asymptomatic, the circulation of STEC in some asymptomatic carriers, especially in healthy-food-related professionals, is not yet well understood. In this study, a total of 3987 anal swab samples from asymptomatic food handlers were collected, and ten swabs recovered STEC strains (0.251%). Of the ten STEC isolates, seven serotypes and eight sequence types (ST) were determined using whole genome sequencing (WGS). Two stx1 subtypes (stx1a and stx1c) and four stx2 subtypes (stx2a, stx2b, stx2d, and stx2e) were detected. Seven different insertion sites were found in fourteen Stx prophages, and the dmsB and yfhL were the newly identified insertion sites. The ten strains showed the variable Stx transcription levels after the mitomycin C induction. The whole-genome phylogeny indicated that the strains from the asymptomatic food handlers were genetically distant from the strains of HUS patients. The STEC isolates circulating in asymptomatic carriers might pose a low potential to cause disease.
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Affiliation(s)
- Xinxia Sui
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Xi Yang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Ming Luo
- Yulin Center for Disease Control and Prevention, Yulin 537000, China
| | - Hua Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Qian Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Hui Sun
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Yujuan Jin
- Longgang Center for Disease Control and Prevention, Shenzhen 518172, China
| | - Yannong Wu
- Yulin Center for Disease Control and Prevention, Yulin 537000, China
| | - Xiangning Bai
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Division of Laboratory Medicine, Oslo University Hospital, 0372 Oslo, Norway
| | - Yanwen Xiong
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
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Machado MAM, Castro VS, da Cunha-Neto A, Vallim DC, Pereira RDCL, Dos Reis JO, de Almeida PV, Galvan D, Conte-Junior CA, Figueiredo EEDS. Heat-resistant and biofilm-forming Escherichia coli in pasteurized milk from Brazil. Braz J Microbiol 2023; 54:1035-1046. [PMID: 36811769 PMCID: PMC10235242 DOI: 10.1007/s42770-023-00920-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
Escherichia coli harboring a transmissible locus of stress tolerance (tLST) and the ability to form biofilms represent a serious risk in dairy production. Thus, we aimed to evaluate the microbiological quality of pasteurized milk from two dairy producers in Mato Grosso, Brazil, with a focus on determining the possible presence of E. coli with heat resistance (60 °C/6 min), biofilm-forming potential phenotypes and genotypes, and antimicrobial susceptibility. For this, fifty pasteurized milk samples from producers named A and B were obtained for 5 weeks to investigate the presence of Enterobacteriaceae members, coliforms, and E. coli. For heat resistance, E. coli isolates were exposed to a water bath at 60 °C for 0 and 6 min. In antibiogram analysis, eight antibiotics belonging to six antimicrobial classes were analyzed. The potential to form biofilms was quantified at 570 nm, and curli expression by Congo Red was analyzed. To determine the genotypic profile, we performed PCR for the tLST and rpoS genes, and pulsed-field gel electrophoresis (PFGE) was used to investigate the clonal profile of the isolates. Thus, producer A presented unsatisfactory microbiological conditions regarding Enterobacteriaceae and coliforms for weeks 4 and 5, while all samples analyzed for producer B were contaminated at above-the-limit levels established by national and international legislation. These unsatisfactory conditions enabled us to isolate 31 E. coli from both producers (7 isolates from producer A and 24 isolates from producer B). In this way, 6 E. coli isolates (5 from producer A and 1 from producer B) were highly heat resistant. However, although only 6 E. coli showed a highly heat-resistant profile, 97% (30/31) of all E. coli were tLST-positive. In contrast, all isolates were sensitive to all antimicrobials tested. In addition, moderate or weak biofilm potential was verified in 51.6% (16/31), and the expression of curli and presence of rpoS was not always related to this biofilm potential. Therefore, the results emphasize the spreading of heat-resistant E. coli with tLST in both producers and indicate the biofilm as a possible source of contamination during milk pasteurization. However, the possibility of E. coli producing biofilm and surviving pasteurization temperatures cannot be ruled out, and this should be investigated.
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Affiliation(s)
- Maxsueli Aparecida Moura Machado
- Graduate Program in Food Science, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Adelino da Cunha-Neto
- Department of Food and Nutrition, Federal University of Mato Grosso - Campus Cuiabá, Fernando Correa da Costa. Avenue, Boa Esperança, Mato Grosso, 78060-900, Brazil
| | | | | | | | | | - Diego Galvan
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carlos Adam Conte-Junior
- Graduate Program in Food Science, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Eduardo Eustáquio de Souza Figueiredo
- Department of Food and Nutrition, Federal University of Mato Grosso - Campus Cuiabá, Fernando Correa da Costa. Avenue, Boa Esperança, Mato Grosso, 78060-900, Brazil.
- Graduate Program in Animal Science, Federal University of Mato Grosso, Mato Grosso, Brazil.
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6
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Distribution of Extremely Heat-Resistant Escherichia coli in the Beef Production and Processing Continuum. J Food Prot 2023; 86:100031. [PMID: 36916589 DOI: 10.1016/j.jfp.2022.100031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/30/2022] [Accepted: 12/13/2022] [Indexed: 12/31/2022]
Abstract
Understanding the dynamics of stress-resistant Escherichia coli (E. coli) across the meat production and processing continuum is important for tracking sources of such microbes and devising effective modes of control. The Locus of Heat Resistance (LHR) is a ∼14-19 Kb genetic element imparting extreme heat resistance (XHR) in Enterobacteriaceae. It has been hypothesized that thermal and antimicrobial interventions applied during meat processing may select for LHR+E. coli. Thus, our goal was to study the prevalence and molecular biology of LHR+E. coli among lots of beef cattle (n = 3) from production through processing. Two hundred thirty-two generic E. coli isolated from the same animals through seven stages of the beef processing continuum (cattle in feedyards to packaged strip loins) were examined. LHR+E. coli were rare (0.6%; 1 of 180) among the early stages of the beef continuum (feces and hides at feedlot, feces and hides at harvest, and preevisceration carcasses), whereas the prevalence of LHR+E. coli on final carcasses and strip loins was remarkably higher. Half (14 of 28) of the final carcass E. coli possessed the LHR, while 79.2% (19 of 24) of the strip loin E. coli did. Eighty-five percent (29 of 34) of the LHR+E. coli presented with the XHR phenotype. The selection or enrichment of LHR+E. coli from harvest steps to the final products appeared unlikely as the LHR+E. coli isolates were effectively controlled by antimicrobial interventions typically used during beef processing. Further, whole-genome sequencing of the isolates suggested LHR+E. coli are persisting in the chilled processing environment and that horizontal LHR transfer among E. coli isolates may take place.
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Machado MAM, Castro VS, Monteiro MLG, Bernardo YADA, Figueiredo EEDS, Conte‐Junior CA. Effect of
UVC‐LED
and ultrasound alone and combined on heat‐resistant
Escherichia coli
isolated from pasteurised milk. INT J DAIRY TECHNOL 2022. [DOI: 10.1111/1471-0307.12925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Maxsueli Aparecida Moura Machado
- Postgraduate Program in Food Science (PPGCAL) Chemistry Institute, Federal University of Rio de Janeiro (UFRJ) Rio de Janeiro 21941‐909 RJ Brazil
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC) Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria Rio de Janeiro 21941‐598 RJ Brazil
- Department of Biochemistry, Laboratory of Advanced Analysis in Biochemistry and Molecular Biology (LAABBM) Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria Rio de Janeiro 21941‐909 RJ Brazil
| | - Vinicius Silva Castro
- University of Lethbridge, 4401 University Drive Lethbridge Lethbridge Alberta T1K 3M4 Canada
| | - Maria Lúcia Guerra Monteiro
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC) Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria Rio de Janeiro 21941‐598 RJ Brazil
- Department of Biochemistry, Laboratory of Advanced Analysis in Biochemistry and Molecular Biology (LAABBM) Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria Rio de Janeiro 21941‐909 RJ Brazil
- Postgraduate Program in Veterinary Hygiene (PPGHV), Faculty of Veterinary Medicine Fluminense Federal University (UFF) Niterói 24230‐340 RJ Brazil
| | - Yago Alves de Aguiar Bernardo
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC) Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria Rio de Janeiro 21941‐598 RJ Brazil
- Department of Biochemistry, Laboratory of Advanced Analysis in Biochemistry and Molecular Biology (LAABBM) Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria Rio de Janeiro 21941‐909 RJ Brazil
- Postgraduate Program in Veterinary Hygiene (PPGHV), Faculty of Veterinary Medicine Fluminense Federal University (UFF) Niterói 24230‐340 RJ Brazil
| | | | - Carlos Adam Conte‐Junior
- Postgraduate Program in Food Science (PPGCAL) Chemistry Institute, Federal University of Rio de Janeiro (UFRJ) Rio de Janeiro 21941‐909 RJ Brazil
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC) Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria Rio de Janeiro 21941‐598 RJ Brazil
- Department of Biochemistry, Laboratory of Advanced Analysis in Biochemistry and Molecular Biology (LAABBM) Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria Rio de Janeiro 21941‐909 RJ Brazil
- Postgraduate Program in Veterinary Hygiene (PPGHV), Faculty of Veterinary Medicine Fluminense Federal University (UFF) Niterói 24230‐340 RJ Brazil
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8
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Kausrud K, Skjerdal T, Johannessen GS, Ilag HK, Norström M. The Heat Is On: Modeling the Persistence of ESBL-Producing E. coli in Blue Mussels under Meal Preparation. Foods 2022; 12:foods12010014. [PMID: 36613230 PMCID: PMC9818077 DOI: 10.3390/foods12010014] [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: 11/18/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Pathways for exposure and dissemination of antimicrobial-resistant (AMR) bacteria are major public health issues. Filter-feeding shellfish concentrate bacteria from the environment and thus can also harbor extended-spectrum β-lactamase—producing Escherichia coli (ESBL E. coli) as an example of a resistant pathogen of concern. Is the short steaming procedure that blue mussels (Mytilus edulis) undergo before consumption enough for food safety in regard to such resistant pathogens? In this study, we performed experiments to assess the survival of ESBL E. coli in blue mussel. Consequently, a predictive model for the dose of ESBL E. coli that consumers would be exposed to, after preparing blue mussels or similar through the common practice of brief steaming until opening of the shells, was performed. The output of the model is the expected number of colony forming units per gram (cfu/g) of ESBL E. coli in a meal as a function of the duration and the temperature of steaming and the initial contamination. In these experiments, the heat tolerance of the ESBL-producing E. coli strain was indistinguishable from that of non-ESBL E. coli, and the heat treatments often practiced are likely to be insufficient to avoid exposure to viable ESBL E. coli. Steaming time (>3.5−4.0 min) is a better indicator than shell openness to avoid exposure to these ESBL or indicator E. coli strains.
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Affiliation(s)
| | - Taran Skjerdal
- Norwegian Veterinary Institute, 1431 Ås, Norway
- Correspondence:
| | | | - Hanna K. Ilag
- Norwegian Veterinary Institute, 1431 Ås, Norway
- Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway
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9
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Soni A, Bremer P, Brightwell G. A Comprehensive Review of Variability in the Thermal Resistance (D-Values) of Food-Borne Pathogens-A Challenge for Thermal Validation Trials. Foods 2022; 11:foods11244117. [PMID: 36553859 PMCID: PMC9777713 DOI: 10.3390/foods11244117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/13/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
The thermal processing of food relies heavily on determining the right time and temperature regime required to inactivate bacterial contaminants to an acceptable limit. To design a thermal processing regime with an accurate time and temperature combination, the D-values of targeted microorganisms are either referred to or estimated. The D-value is the time required at a given temperature to reduce the bacterial population by 90%. The D-value can vary depending on various factors such as the food matrix, the bacterial strain, and the conditions it has previously been exposed to; the intrinsic properties of the food (moisture, water activity, fat content, and pH); the method used to expose the microorganism to the thermal treatment either at the laboratory or commercial scale; the approach used to estimate the number of survivors; and the statistical model used for the analysis of the data. This review focused on Bacillus cereus, Cronobacter sakazakii, Escherichia coli, Listeria monocytogenes, and Clostridium perfringens owing to their pathogenicity and the availability of publications on their thermal resistance. The literature indicates a significant variation in D-values reported for the same strain, and it is concluded that when designing thermal processing regimes, the impact of multiple factors on the D-values of a specific microorganism needs to be considered. Further, owing to the complexity of the interactions involved, the effectiveness of regimes derived laboratory data must be confirmed within industrial food processing settings.
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Affiliation(s)
- Aswathi Soni
- Food System Integrity, Smart Foods and Bioproducts, AgResearch Ltd., Palmerston North 4414, New Zealand
- Correspondence: ; Tel.: +64-6350-0819
| | - Phil Bremer
- Department of Food Science, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
- New Zealand Food Safety Science and Research Centre, Palmerston North 4474, New Zealand
| | - Gale Brightwell
- Food System Integrity, Smart Foods and Bioproducts, AgResearch Ltd., Palmerston North 4414, New Zealand
- New Zealand Food Safety Science and Research Centre, Palmerston North 4474, New Zealand
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10
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Fang Y, Brückner LL, McMullen LM, Gänzle MG. Transduction of stx2a mediated by phage (Φ11-3088) from Escherichia coli O104:H4 in vitro and in situ during sprouting of mung beans. Int J Food Microbiol 2022; 383:109952. [PMID: 36191491 DOI: 10.1016/j.ijfoodmicro.2022.109952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/19/2022] [Accepted: 09/23/2022] [Indexed: 12/29/2022]
Abstract
Escherichia coli O104:H4 strain 11-3088 encoding Stx2a is epidemiologically related to the foodborne outbreak associated with sprouts in Germany, 2011. Sprouting provides suitable conditions for bacterial growth and may lead to transduction of non-pathogenic strains of E. coli with Stx phages. Although transduction of E. coli by Stx phages in food has been documented, data on the phages from E. coli O104:H4 is limited. This study determined the host range of the bacteriophage Φ11-3088 from E. coli O104:H4 using E. coli O104:H4 ∆stx2::gfp::ampr and demonstrated phage transduction during sprouting. The Φ11-3088∆stx transduced 5/45 strains, including generic E. coli, pap-positive E. coli O103:H2, ETEC, and S. sonnei. The expression level of Φ11-3088∆stx differed among lysogens upon induction. Of the 3 highly induced lysogens, the lytic cycle was induced in E. coli O104:H4∆stx2::gfp::ampr and O103:H2 but not in S. sonnei. E. coli DH5α was the only strain susceptible to lytic infection by Φ11-3088∆stx. To explore the effect of drying and rehydration during seed storage and sprouting on phage induction and transduction, mung beans inoculated with the phage donor E. coli O104:H4∆stx2::gfp::ampr (8 log CFU/g) were dried, rehydrated, and incubated with the phage recipient E. coli DH5α (7 log CFU/g) for 96 h. Sprouted seeds harbored about 3 log CFU/g of putative lysogens that acquired ampicillin resistance. At the end of sprouting, 71 % of putative lysogens encoded gfp, confirming phage transduction. Overall, stx transfer by phages may increase the cell counts of STEC during sprouting by converting generic E. coli to STEC.
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Affiliation(s)
- Yuan Fang
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Luisa Linda Brückner
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Lynn M McMullen
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Michael G Gänzle
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada.
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Carter MQ, Laniohan N, Pham A, Quiñones B. Comparative genomic and phenotypic analyses of the virulence potential in Shiga toxin-producing Escherichia coli O121:H7 and O121:H10. Front Cell Infect Microbiol 2022; 12:1043726. [PMID: 36506028 PMCID: PMC9729726 DOI: 10.3389/fcimb.2022.1043726] [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: 09/13/2022] [Accepted: 11/03/2022] [Indexed: 11/25/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) O121 is among the top six non-O157 serogroups that are most frequently associated with severe disease in humans. While O121:H19 is predominant, other O121 serotypes have been frequently isolated from environmental samples, but their virulence repertoire is poorly characterized. Here, we sequenced the complete genomes of two animal isolates belonging to O121:H7 and O121:H10 and performed comparative genomic analysis with O121:H19 to assess their virulence potential. Both O121:H7 and O121:H10 strains carry a genome comparable in size with the O121:H19 genomes and belong to phylogroup B1. However, both strains appear to have evolved from a different lineage than the O121:H19 strains according to the core genes-based phylogeny and Multi Locus Sequence Typing. A systematic search of over 300 E. coli virulence genes listed in the Virulence Factor DataBase revealed a total of 73 and 71 in O121:H7 and O121:H10 strains, respectively, in comparison with an average of 135 in the O121:H19 strains. This variation in the virulence genes repertoire was mainly attributed to the reduction in the number of genes related to the Type III Secretion System in the O121:H7 and O121:H10 strains. Compared to the O121:H19 strains, the O121:H7 strain carries more adherence and toxin genes while the O121:H10 strain carries more genes related to the Type VI Secretion System. Although both O121:H7 and O121:H10 strains carry the large virulence plasmid pEHEC, they do not harbor all pEHEC virulence genes in O121:H19. Furthermore, unlike the O121:H19 strains, neither the O121:H7 nor O121:H10 strain carried the Locus of Enterocyte Effacement, OI-122, nor the tellurite resistance island. Although an incomplete Locus of Adhesion and Autoaggregation (LAA) was identified in the O121:H7 and O121:H10 strains, a limited number of virulence genes were present. Consistently, both O121:H7 and O121:H10 strains displayed significant reduced cytotoxicity than either the O157:H7 strain EDL933 or the O121:H19 strain RM8352. In fact, the O121:H7 strain RM8082 appeared to cause minimal cytotoxicity to Vero cells. Our study demonstrated distinct evolutionary lineages among the strains of serotypes O121:H19, O121:H10, and O121:H7 and suggested reduced virulence potentials in STEC strains of O121:H10 and O121:H7.
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Kim H, Moon S, Ham S, Lee K, Römling U, Lee C. Cytoplasmic molecular chaperones in Pseudomonas species. J Microbiol 2022; 60:1049-1060. [PMID: 36318358 DOI: 10.1007/s12275-022-2425-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/20/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Pseudomonas is widespread in various environmental and host niches. To promote rejuvenation, cellular protein homeostasis must be finely tuned in response to diverse stresses, such as extremely high and low temperatures, oxidative stress, and desiccation, which can result in protein homeostasis imbalance. Molecular chaperones function as key components that aid protein folding and prevent protein denaturation. Pseudomonas, an ecologically important bacterial genus, includes human and plant pathogens as well as growth-promoting symbionts and species useful for bioremediation. In this review, we focus on protein quality control systems, particularly molecular chaperones, in ecologically diverse species of Pseudomonas, including the opportunistic human pathogen Pseudomonas aeruginosa, the plant pathogen Pseudomonas syringae, the soil species Pseudomonas putida, and the psychrophilic Pseudomonas antarctica.
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Affiliation(s)
- Hyunhee Kim
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Seongjoon Moon
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Soojeong Ham
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Kihyun Lee
- CJ Bioscience, Seoul, 04527, Republic of Korea
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 171 77, Sweden
| | - Changhan Lee
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea.
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Whole-Genome Sequencing Analyses of Heat-Resistant Escherichia coli Isolated from Brazilian Beef. Microbiol Resour Announc 2022; 11:e0037122. [PMID: 35861524 PMCID: PMC9387239 DOI: 10.1128/mra.00371-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Four Escherichia coli isolates with moderate or high heat resistance were sequenced. Through sequencing, truncated transmissible locus of stress tolerance (tLST) variants tLST1 and tLSTa were identified in the three isolates. The most identified tLST genes (clpK and hsp) are responsible for the homeostasis module.
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Yu D, Ryu K, Zhi S, Otto SJG, Neumann NF. Naturalized Escherichia coli in Wastewater and the Co-evolution of Bacterial Resistance to Water Treatment and Antibiotics. Front Microbiol 2022; 13:810312. [PMID: 35707173 PMCID: PMC9189398 DOI: 10.3389/fmicb.2022.810312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/09/2022] [Indexed: 12/30/2022] Open
Abstract
Antibiotic resistance represents one of the most pressing concerns facing public health today. While the current antibiotic resistance crisis has been driven primarily by the anthropogenic overuse of antibiotics in human and animal health, recent efforts have revealed several important environmental dimensions underlying this public health issue. Antibiotic resistant (AR) microbes, AR genes, and antibiotics have all been found widespread in natural environments, reflecting the ancient origins of this phenomenon. In addition, modern societal advancements in sanitation engineering (i.e., sewage treatment) have also contributed to the dissemination of resistance, and concerningly, may also be promoting the evolution of resistance to water treatment. This is reflected in the recent characterization of naturalized wastewater strains of Escherichia coli-strains that appear to be adapted to live in wastewater (and meat packing plants). These strains carry a plethora of stress-resistance genes against common treatment processes, such as chlorination, heat, UV light, and advanced oxidation, mechanisms which potentially facilitate their survival during sewage treatment. These strains also carry an abundance of common antibiotic resistance genes, and evidence suggests that resistance to some antibiotics is linked to resistance to treatment (e.g., tetracycline resistance and chlorine resistance). As such, these naturalized E. coli populations may be co-evolving resistance against both antibiotics and water treatment. Recently, extraintestinal pathogenic strains of E. coli (ExPEC) have also been shown to exhibit phenotypic resistance to water treatment, seemingly associated with the presence of various shared genetic elements with naturalized wastewater E. coli. Consequently, some pathogenic microbes may also be evolving resistance to the two most important public health interventions for controlling infectious disease in modern society-antibiotic therapy and water treatment.
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Affiliation(s)
- Daniel Yu
- School of Public Health, University of Alberta, Edmonton, AB, Canada
- Antimicrobial Resistance – One Health Consortium, Calgary, AB, Canada
| | - Kanghee Ryu
- School of Public Health, University of Alberta, Edmonton, AB, Canada
- Antimicrobial Resistance – One Health Consortium, Calgary, AB, Canada
| | - Shuai Zhi
- School of Medicine, Ningbo University, Ningbo, China
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo, China
| | - Simon J. G. Otto
- School of Public Health, University of Alberta, Edmonton, AB, Canada
- Antimicrobial Resistance – One Health Consortium, Calgary, AB, Canada
- Human-Environment-Animal Transdisciplinary Antimicrobial Resistance Research Group, School of Public Health, University of Alberta, Edmonton, AB, Canada
- Healthy Environments, Centre for Health Communities, School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Norman F. Neumann
- School of Public Health, University of Alberta, Edmonton, AB, Canada
- Antimicrobial Resistance – One Health Consortium, Calgary, AB, Canada
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Comparative Genomics Applied to Systematically Assess Pathogenicity Potential in Shiga Toxin-Producing Escherichia coli O145:H28. Microorganisms 2022; 10:microorganisms10050866. [PMID: 35630311 PMCID: PMC9144400 DOI: 10.3390/microorganisms10050866] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 01/27/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) O145:H28 can cause severe disease in humans and is a predominant serotype in STEC O145 environmental isolates. Here, comparative genomics was applied to a set of clinical and environmental strains to systematically evaluate the pathogenicity potential in environmental strains. While the core genes-based tree separated all O145:H28 strains from the non O145:H28 reference strains, it failed to segregate environmental strains from the clinical. In contrast, the accessory genes-based tree placed all clinical strains in the same clade regardless of their genotypes or serotypes, apart from the environmental strains. Loss-of-function mutations were common in the virulence genes examined, with a high frequency in genes related to adherence, autotransporters, and the type three secretion system. Distinct differences in pathogenicity islands LEE, OI-122, and OI-57, the acid fitness island, and the tellurite resistance island were detected between the O145:H28 and reference strains. A great amount of genetic variation was detected in O145:H28, which was mainly attributed to deletions, insertions, and gene acquisition at several chromosomal “hot spots”. Our study demonstrated a distinct virulence gene repertoire among the STEC O145:H28 strains originating from the same geographical region and revealed unforeseen contributions of loss-of-function mutations to virulence evolution and genetic diversification in STEC.
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Genetic Characteristics of the Transmissible Locus of Stress Tolerance (tLST) and tLST Harboring Escherichia coli as Revealed by Large-Scale Genomic Analysis. Appl Environ Microbiol 2022; 88:e0218521. [PMID: 35285715 DOI: 10.1128/aem.02185-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The transmissible locus of stress tolerance (tLST) confers resistance to multiple stresses in E. coli. Utilizing 18,959 E. coli genomes available in the NCBI database, we investigated the prevalence, phylogenetic distribution, and configuration patterns of tLST, and correlations between tLST, and virulence and antimicrobial resistance (AMR) genes in E. coli. Four tLST variants were found in 2.7% of E. coli, with the most prevalent (77.1%) variant being tLST1 followed by tLST2 (8.3%), tLST3b (8.3%) and tLST3a (6.3%). The majority (93%) of those tLST were in E. coli belonging to phylogroup A in which the prevalence was 10.4%. tLST was also found in phylogroup B1 (0.5%) and C (0.5%) but not found in B2 or D-G. An additional 1% of the 18,959 E. coli genomes harbored tLST fragments to various extent. Phylogenetic analysis revealed both intra- and interspecies transmission of both chromosomal and plasmid-borne tLST, with E. coli showing a preference of chromosomal over plasmid-borne tLST. The presence of tLST and virulence genes in E. coli was overall negatively correlated, but tLST was found in all genomes of a subgroup of enterotoxigenic E. coli (ST2332). Of note, no Shiga toxin-producing E. coli (n = 3,492) harbored tLST. The prevalence of tLST and AMR genes showed different temporal trends over the period 1985 to 2019. However, a substantial fraction of tLST positive E. coli harbor AMR genes, posing a threat to public health. In conclusion, this study improves our understanding of the genetic characteristics of tLST and E. coli harboring tLST. IMPORTANCE This study, through a large-scale genomic analysis, demonstrated that the genomic island tLST related to multiple stress resistance (such as extreme heat resistance and oxidative stress tolerance) in E. coli is differentially present in subgroups of E. coli and is strongly associated with certain phylogenetic background of the host strain. The study also shows the transmission mechanisms of tLST in E. coli and other bacterial species. The overall negative association of tLST, and virulence genes and antimicrobial (AMR) genes suggest the selective pressures for the acquisition and transmission of these traits likely differ. Even so, the high prevalence of tLST in the enterotoxigenic E. coli clone ST2332 and co-occurrence of tLST and AMR genes in E. coli are concerning. Thus, the findings better our understanding of tLST evolution and provide information for risk assessment of tLST harboring bacteria.
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Xu ZS, Yang X, Gänzle MG. Resistance of biofilm- and pellicle-embedded strains of Escherichia coli encoding the transmissible locus of stress tolerance (tLST) to oxidative sanitation chemicals. Int J Food Microbiol 2021; 359:109425. [PMID: 34607035 DOI: 10.1016/j.ijfoodmicro.2021.109425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/13/2021] [Accepted: 09/23/2021] [Indexed: 12/11/2022]
Abstract
Biofilm formation in food processing plants reduces the efficacy of sanitation. The presence of transmissible locus of stress tolerance (tLST) also enhances resistance of planktonic cells of Escherichia coli to sanitation chemicals but the role of tLST in resistance of biofilm-embedded cells remains unclear. This study investigated the link of tLST to biofilm formation and its contribution to resistance of biofilm-embedded E. coli to sanitation. Biofilms were formed as single-strain and as dual-strain biofilms in association with E. coli, Aeromonas australensis or Carnobacterium maltaromaticum. Biofilms on stainless steel were compared to floating biofilms formed at the air-liquid interface (pellicles). The resistance of biofilm-embedded tLST positive strains of E. coli to chlorine, hydrogen peroxide, and peroxyacetic acid was higher than the resistance of tLST negative strains. Higher biofilm density as measured by crystal violet staining was observed in tLST-positive strains of E. coli when compared to tLST negative strains. Biofilm density positively correlated to resistance to disinfectants. The use of confocal laser scanning microscopy detected more compact structure of pellicles compared to solid surface-attached biofilms, resulting in higher chlorine resistance despite the absence of tLST in strains of E. coli. Collectively, the findings of this study elucidated the impact of tLST in strains of E. coli on biofilm formation and sanitizer resistance. These findings may inform the development of improved sanitization protocols for food facilities.
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Affiliation(s)
- Zhaohui S Xu
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, AB, Canada
| | - Xianqin Yang
- Agriculture and Agri-Food Canada, Lacombe Research and Development Centre, 6000 C and E Trail, Lacombe T4L 1W1, AB, Canada
| | - Michael G Gänzle
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, AB, Canada.
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Biofilm-Forming Capacity of Escherichia coli Isolated from Cattle and Beef Packing Plants: Relation to Virulence Attributes, Stage of Processing, Antimicrobial Interventions, and Heat Tolerance. Appl Environ Microbiol 2021; 87:e0112621. [PMID: 34550756 DOI: 10.1128/aem.01126-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite the importance of biofilm formation in the contamination of meat by pathogenic Escherichia coli at slaughter plants, drivers for biofilm remain unclear. To identify selection pressures for biofilm, we evaluated 745 isolates from cattle and 700 generic E. coli isolates from two beef slaughter plants for motility, the expression of curli and cellulose, and biofilm-forming potential. Cattle isolates were also screened for serogroup, stx1, stx2, eae, and rpoS. Generic E. coli isolates were compared by source (hide of carcass, hide-off carcass, and processing equipment) before and after the implementation of antimicrobial hurdles. The proportion of E. coli isolates capable of forming biofilms was lowest (7.1%; P < 0.05) for cattle isolates and highest (87.3%; P < 0.05) from equipment. Only one enterohemorrhagic E. coli (EHEC) isolate was an extremely strong biofilm former, in contrast to 73.4% of E. coli isolates from equipment. Isolates from equipment after sanitation had a greater biofilm-forming capacity (P < 0.001) than those before sanitation. Most cattle isolates were motile and expressed curli, although these traits along with the expression of cellulose and the detection of rpoS were not necessary for biofilm formation. In contrast, isolates capable of forming biofilms on equipment were almost exclusively motile and able to express curli. The results of the present study indicate that cattle rarely carry EHEC capable of making strong biofilms in slaughter plants. However, if biofilm-forming EHEC contaminates equipment, current sanitation procedures may not eliminate the most robust biofilm-forming strains. Accordingly, new and effective antibiofilm hurdles for meat-processing equipment are required to reduce future instances of foodborne disease. IMPORTANCE As the majority of enterohemorrhagic E. coli (EHEC) isolates are not capable of forming biofilms, sources were undetermined for biofilm-forming EHEC isolated from "high-event periods" in beef slaughter plants. This study demonstrated that sanitation procedures used on beef-processing equipment may inadvertently lead to the survival of robust biofilm-forming strains of E. coli. Cattle only rarely carry EHEC capable of forming strong biofilms (1/745 isolates evaluated), but isolates with greater biofilm-forming capacity were more likely (P < 0.001) to survive equipment sanitation. In contrast, chilling carcasses for 3 days at 0°C reduced (P < 0.05) the proportion of biofilm-forming E. coli. Consequently, an additional antibiofilm hurdle for meat-processing equipment, perhaps involving cold exposure, is necessary to further reduce the risk of foodborne disease.
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Genetic Determinants of Stress Resistance in Desiccated Salmonella enterica. Appl Environ Microbiol 2021; 87:e0168321. [PMID: 34586905 DOI: 10.1128/aem.01683-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enteric pathogens, including Salmonella, are capable of long-term survival after desiccation and resist heat treatments that are lethal to hydrated cells. The mechanisms of dry-heat resistance differ from those of wet-heat resistance. To elucidate the mechanisms of dry-heat resistance in Salmonella, screening of the dry-heat resistance of 108 Salmonella strains, representing 39 serotypes, identified the 22 most resistant and the 8 most sensitive strains for comparative genome analysis. A total of 289 genes of the accessory genome were differently distributed between resistant and sensitive strains. Among these genes, 28 proteins with a putative relationship to stress resistance were selected for to quantify relative gene expression before and after desiccation and expression by solid-state cultures on agar plates relative to cultures growing in liquid culture media. Of these 28 genes, 15 genes were upregulated (P < 0.05) after desiccation or by solid-state cultures on agar plates. These 15 genes were cloned into the low-copy-number vector pRK767 under the control of the lacZ promoter. The expression of 6 of these 15 genes increased (P < 0.05) resistance to dry heat and to treatment with pressure of 500 MPa. Our finding extends the knowledge of mechanisms of stress resistance in desiccated Salmonella to improve control of this bacterium in dry food. IMPORTANCE This study directly targeted an increasing threat to food safety and developed knowledge and targeted strategies that can be used by the food industry to help reduce the risk of foodborne illness in their dry products and thereby reduce the overall burden of foodborne illness. Genomic and physiological analyses have elucidated mechanisms of bacterial resistance to many food preservation technologies, including heat, pressure, disinfection chemicals, and UV light; however, information on bacterial mechanisms of resistance to dry heat is scarce. Mechanisms of tolerance to desiccation likely also contribute to resistance to dry heat, but this assumption has not been verified experimentally. It remains unclear how mechanisms of resistance to wet heat relate to dry-heat resistance. Thus, this study will fill a knowledge gap to improve the safety of dry foods.
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Genomic and Phenotypic Analysis of Heat and Sanitizer Resistance in Escherichia coli from Beef in Relation to the Locus of Heat Resistance. Appl Environ Microbiol 2021; 87:e0157421. [PMID: 34550750 DOI: 10.1128/aem.01574-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The locus of heat resistance (LHR) can confer heat resistance to Escherichia coli to various extents. This study investigated the phylogenetic relationships and the genomic and phenotypic characteristics of E. coli with or without LHR recovered from beef by direct plating or from enrichment broth at 42°C. LHR-positive E. coli isolates (n = 24) were subjected to whole-genome sequencing by short and long reads. LHR-negative isolates (n = 18) from equivalent sources as LHR-positive isolates were short-read sequenced. All isolates were assessed for decimal reduction time at 60°C (D60°C) and susceptibility to the sanitizers E-SAN and Perox-E. Selected isolates were evaluated for growth at 42°C. The LHR-positive and -negative isolates were well separated on the core genome tree, with 22/24 positive isolates clustering into three clades. Isolates within clade 1 and 2, despite their different D60°C values, were clonal, as determined by subtyping (multilocus sequence typing [MLST], core genome MLST, and serotyping). Isolates within each clade are of one serotype. The LHR-negative isolates were genetically diverse. The LHR-positive isolates had a larger (P < 0.001) median genome size by 0.3 Mbp (5.0 versus 4.7 Mbp) and overrepresentation of genes related to plasmid maintenance, stress response, and cryptic prophages but underrepresentation of genes involved in epithelial attachment and virulence. All LHR-positive isolates harbored a chromosomal copy of LHR, and all clade 2 isolates had an additional partial copy of LHR on conjugative plasmids. The growth rates at 42°C were 0.71 ± 0.02 and 0.65 ± 0.02 log(OD) h-1 for LHR-positive and -negative isolates, respectively. No meaningful difference in sanitizer susceptibility was noted between LHR-positive and -negative isolates. IMPORTANCE Resistant bacteria are serious food safety and public health concerns. Heat resistance conferred by the LHR varies largely among different strains of E. coli. The findings in this study show that genomic background and composition of LHR, in addition to the presence of LHR, play an important role in the degree of heat resistance in E. coli and that strains with certain genetic backgrounds are more likely to acquire and maintain the LHR. Also, caution should be exercised when recovering E. coli at elevated temperatures, as the presence of LHR may confer growth advantages to some strains. Interestingly, the LHR-harboring strains seem to have evolved further from their primary animal host to adapt to their secondary habitat, as reflected by fewer genes involved in virulence and epithelial attachment. The phylogenetic relationships among the isolates point toward multiple mechanisms for acquisition of LHR by E. coli, likely prior to its being deposited on meat.
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21
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Effects of high-pressure carbon dioxide on microbial quality and germination of cereal grains and beans. J Supercrit Fluids 2021. [DOI: 10.1016/j.supflu.2021.105272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ecology and Function of the Transmissible Locus of Stress Tolerance in Escherichia coli and Plant-Associated Enterobacteriaceae. mSystems 2021; 6:e0037821. [PMID: 34402641 PMCID: PMC8407380 DOI: 10.1128/msystems.00378-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transmissible locus of stress tolerance (tLST) is a genomic island which confers resistance to heat and chlorine. In this study, we determined that the tLST is frequent in genomes of those Enterobacteriaceae that occur in association with plants as well as the intestines of humans and animals and are relevant as nosocomial pathogens, e.g., Klebsiella and Cronobacter species. The tLST is more frequent in environmental and clinical isolates of Klebsiella pneumoniae than in animal isolates, and heat and chlorine resistance of tLST-positive strains of K. pneumoniae matched the resistance of tLST-positive strains of Escherichia coli. The function of 13 tLST genes was determined by assessing the heat and chlorine resistance of E. coli MG1655 mutants. The deletion of sHsp20, clpKGI, sHspGI, pscA, pscB, and hdeDGI reduced both heat and chlorine resistance; deletion of kefB reduced only chlorine resistance. Genes coding for heat shock proteins sHsp20, clpKGI, and sHspGI decreased the oxidation of cytoplasmic proteins, while kefB decreased the oxidation of membrane lipids. The fitness cost of the tLST for E. coli MG1655 was assessed by pairwise competition experiments with isogenic tLST-positive or tLST-negative strains. The tLST imposes a fitness cost that is compensated for by frequent and lethal challenges with chlorine. All core genes need to be present to maintain the ecological advantage relative to the fitness cost. Taken together, core tLST genes are necessary to provide protection for E. coli against heat and chlorine stress, and the selective pressure for the tLST maintains core genes. IMPORTANCE The transmissible locus of stress tolerance (tLST) is a genomic island comprising 10 core genes that occurs in diverse Enterobacteriaceae and confers resistance to heat and chlorine. Experimentation described in the manuscript describes the physiological function of the core genes by characterization of the resistance of 13 single-knockout (KO) mutants and by characterization of protein and membrane oxidation in these strains after chlorine challenge. Results identify tLST resistance as a genomic island that is specific for those Enterobacteriaceae that occur in plant-associated habitats as well in the intestines of vertebrates. In addition, the ecological function of the genomic island was characterized by large-scale genomic analysis and competition experiments of wild-type and mutant strains. Results suggest that tLST-mediated resistance to chlorine may contribute to the persistence of nosocomial pathogens in hospitals.
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Kamal SM, Simpson DJ, Wang Z, Gänzle M, Römling U. Horizontal Transmission of Stress Resistance Genes Shape the Ecology of Beta- and Gamma-Proteobacteria. Front Microbiol 2021; 12:696522. [PMID: 34295324 PMCID: PMC8290217 DOI: 10.3389/fmicb.2021.696522] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/07/2021] [Indexed: 01/25/2023] Open
Abstract
The transmissible locus of stress tolerance (tLST) is found mainly in beta- and gamma-Proteobacteria and confers tolerance to elevated temperature, pressure, and chlorine. This genomic island, previously referred to as transmissible locus of protein quality control or locus of heat resistance likely originates from an environmental bacterium thriving in extreme habitats, but has been widely transmitted by lateral gene transfer. Although highly conserved, the gene content on the island is subject to evolution and gene products such as small heat shock proteins are present in several functionally distinct sequence variants. A number of these genes are xenologs of core genome genes with the gene products to widen the substrate spectrum and to be highly (complementary) expressed thus their functionality to become dominant over core genome genes. In this review, we will present current knowledge of the function of core tLST genes and discuss current knowledge on selection and counter-selection processes that favor maintenance of the tLST island, with frequent acquisition of gene products involved in cyclic di-GMP signaling, in different habitats from the environment to animals and plants, processed animal and plant products, man-made environments, and subsequently humans.
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Affiliation(s)
- Shady Mansour Kamal
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - David J Simpson
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Zhiying Wang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Michael Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
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Zhang P, Essendoubi S, Keenliside J, Reuter T, Stanford K, King R, Lu P, Yang X. Genomic analysis of Shiga toxin-producing Escherichia coli O157:H7 from cattle and pork-production related environments. NPJ Sci Food 2021; 5:15. [PMID: 34210979 PMCID: PMC8249597 DOI: 10.1038/s41538-021-00097-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/06/2021] [Indexed: 02/04/2023] Open
Abstract
Three E. coli O157:H7 outbreaks have been attributed to contaminated pork in Alberta, Canada, recently. This study investigates the phylogenetic relatedness of E. coli O157:H7 from pigs, cattle, and pork-production environments for source attribution. Limited strain diversity was observed using five conventional subtyping methods, with most or all strains being in one subgroup. Whole-genome single nucleotide polymorphism analysis confirmed the recent ancestry of the isolates from all three sources. Most environmental isolates clustered closer with pig isolates than cattle isolates. Also, a direct link was observed between 2018-outbreak environmental isolates and isolates collected from a pig farm in 2018. The majority of pig isolates harbor only one Shiga toxin gene, stx2a, while 70% (35/50) of the cattle isolates have both stx1a and stx2a. The results show some E. coli O157:H7 strains could establish persistence on pig farms and as such, pigs can be a significant source of the organism.
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Affiliation(s)
- Peipei Zhang
- grid.55614.330000 0001 1302 4958Agriculture and Agri-Food Canada, Lacombe, Alberta Canada
| | | | | | - Tim Reuter
- Alberta Agriculture and Forestry, Lethbridge, Alberta Canada ,grid.47609.3c0000 0000 9471 0214University of Lethbridge, Lethbridge, Alberta Canada
| | - Kim Stanford
- Alberta Agriculture and Forestry, Lethbridge, Alberta Canada ,grid.47609.3c0000 0000 9471 0214University of Lethbridge, Lethbridge, Alberta Canada
| | - Robin King
- Alberta Agriculture and Forestry, Edmonton, Alberta Canada
| | - Patricia Lu
- Alberta Agriculture and Forestry, Edmonton, Alberta Canada
| | - Xianqin Yang
- grid.55614.330000 0001 1302 4958Agriculture and Agri-Food Canada, Lacombe, Alberta Canada
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Katikaridis P, Bohl V, Mogk A. Resisting the Heat: Bacterial Disaggregases Rescue Cells From Devastating Protein Aggregation. Front Mol Biosci 2021; 8:681439. [PMID: 34017857 PMCID: PMC8129007 DOI: 10.3389/fmolb.2021.681439] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/12/2021] [Indexed: 11/23/2022] Open
Abstract
Bacteria as unicellular organisms are most directly exposed to changes in environmental growth conditions like temperature increase. Severe heat stress causes massive protein misfolding and aggregation resulting in loss of essential proteins. To ensure survival and rapid growth resume during recovery periods bacteria are equipped with cellular disaggregases, which solubilize and reactivate aggregated proteins. These disaggregases are members of the Hsp100/AAA+ protein family, utilizing the energy derived from ATP hydrolysis to extract misfolded proteins from aggregates via a threading activity. Here, we describe the two best characterized bacterial Hsp100/AAA+ disaggregases, ClpB and ClpG, and compare their mechanisms and regulatory modes. The widespread ClpB disaggregase requires cooperation with an Hsp70 partner chaperone, which targets ClpB to protein aggregates. Furthermore, Hsp70 activates ClpB by shifting positions of regulatory ClpB M-domains from a repressed to a derepressed state. ClpB activity remains tightly controlled during the disaggregation process and high ClpB activity states are likely restricted to initial substrate engagement. The recently identified ClpG (ClpK) disaggregase functions autonomously and its activity is primarily controlled by substrate interaction. ClpG provides enhanced heat resistance to selected bacteria including pathogens by acting as a more powerful disaggregase. This disaggregase expansion reflects an adaption of bacteria to extreme temperatures experienced during thermal based sterilization procedures applied in food industry and medicine. Genes encoding for ClpG are transmissible by horizontal transfer, allowing for rapid spreading of extreme bacterial heat resistance and posing a threat to modern food production.
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Affiliation(s)
- Panagiotis Katikaridis
- Center for Molecular Biology of the Heidelberg University and German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Valentin Bohl
- Center for Molecular Biology of the Heidelberg University and German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Axel Mogk
- Center for Molecular Biology of the Heidelberg University and German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
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26
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Bacterial cyclic diguanylate signaling networks sense temperature. Nat Commun 2021; 12:1986. [PMID: 33790266 PMCID: PMC8012707 DOI: 10.1038/s41467-021-22176-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/17/2021] [Indexed: 02/01/2023] Open
Abstract
Many bacteria use the second messenger cyclic diguanylate (c-di-GMP) to control motility, biofilm production and virulence. Here, we identify a thermosensory diguanylate cyclase (TdcA) that modulates temperature-dependent motility, biofilm development and virulence in the opportunistic pathogen Pseudomonas aeruginosa. TdcA synthesizes c-di-GMP with catalytic rates that increase more than a hundred-fold over a ten-degree Celsius change. Analyses using protein chimeras indicate that heat-sensing is mediated by a thermosensitive Per-Arnt-SIM (PAS) domain. TdcA homologs are widespread in sequence databases, and a distantly related, heterologously expressed homolog from the Betaproteobacteria order Gallionellales also displayed thermosensitive diguanylate cyclase activity. We propose, therefore, that thermotransduction is a conserved function of c-di-GMP signaling networks, and that thermosensitive catalysis of a second messenger constitutes a mechanism for thermal sensing in bacteria.
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Yu D, Banting G, Neumann NF. A review of the taxonomy, genetics, and biology of the genus Escherichia and the type species Escherichia coli. Can J Microbiol 2021; 67:553-571. [PMID: 33789061 DOI: 10.1139/cjm-2020-0508] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Historically, bacteriologists have relied heavily on biochemical and structural phenotypes for bacterial taxonomic classification. However, advances in comparative genomics have led to greater insights into the remarkable genetic diversity within the microbial world, and even within well-accepted species such as Escherichia coli. The extraordinary genetic diversity in E. coli recapitulates the evolutionary radiation of this species in exploiting a wide range of niches (i.e., ecotypes), including the gastrointestinal system of diverse vertebrate hosts as well as non-host natural environments (soil, natural waters, wastewater), which drives the adaptation, natural selection, and evolution of intragenotypic conspecific specialism as a strategy for survival. Over the last few years, there has been increasing evidence that many E. coli strains are very host (or niche)-specific. While biochemical and phylogenetic evidence support the classification of E. coli as a distinct species, the vast genomic (diverse pan-genome and intragenotypic variability), phenotypic (e.g., metabolic pathways), and ecotypic (host-/niche-specificity) diversity, comparable to the diversity observed in known species complexes, suggest that E. coli is better represented as a complex. Herein we review the taxonomic classification of the genus Escherichia and discuss how phenotype, genotype, and ecotype recapitulate our understanding of the biology of this remarkable bacterium.
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Affiliation(s)
- Daniel Yu
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
| | - Graham Banting
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
| | - Norman F Neumann
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
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Zhu T, Wang Z, McMullen LM, Raivio T, Simpson DJ, Gänzle MG. Contribution of the Locus of Heat Resistance to Growth and Survival of Escherichia coli at Alkaline pH and at Alkaline pH in the Presence of Chlorine. Microorganisms 2021; 9:701. [PMID: 33800639 PMCID: PMC8067161 DOI: 10.3390/microorganisms9040701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/15/2022] Open
Abstract
The locus of heat resistance (LHR) confers resistance to extreme heat, chlorine and oxidative stress in Escherichia coli. This study aimed to determine the function of the LHR in maintaining bacterial cell envelope homeostasis, the regulation of the genes comprising the LHR and the contribution of the LHR to alkaline pH response. The presence of the LHR did not affect the activity of the Cpx two-component regulatory system in E. coli, which was measured to quantify cell envelope stress. The LHR did not alter E. coli MG1655 growth rate in the range of pH 6.9 to 9.2. However, RT-qPCR results indicated that the expression of the LHR was elevated at pH 8.0 when CpxR was absent. The LHR did not improve survival of E. coli MG1655 at extreme alkaline pH (pH = 11.0 to 11.2) but improved survival at pH 11.0 in the presence of chlorine. Therefore, we conclude that the LHR confers resistance to extreme alkaline pH in the presence of oxidizing agents. Resistance to alkaline pH is regulated by an endogenous mechanism, including the Cpx envelope stress response, whereas the LHR confers resistance to extreme alkaline pH only in the presence of additional stress such as chlorine.
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Affiliation(s)
- Tongbo Zhu
- Department of Agricultural, Food and Nutritional Science, 4-10 Ag/For Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (T.Z.); (Z.W.); (L.M.M.); (D.J.S.)
| | - Zhiying Wang
- Department of Agricultural, Food and Nutritional Science, 4-10 Ag/For Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (T.Z.); (Z.W.); (L.M.M.); (D.J.S.)
| | - Lynn M. McMullen
- Department of Agricultural, Food and Nutritional Science, 4-10 Ag/For Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (T.Z.); (Z.W.); (L.M.M.); (D.J.S.)
| | - Tracy Raivio
- Department of Biological Science, University of Alberta, Edmonton, AB T6G 2E9, Canada;
| | - David J. Simpson
- Department of Agricultural, Food and Nutritional Science, 4-10 Ag/For Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (T.Z.); (Z.W.); (L.M.M.); (D.J.S.)
| | - Michael G. Gänzle
- Department of Agricultural, Food and Nutritional Science, 4-10 Ag/For Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (T.Z.); (Z.W.); (L.M.M.); (D.J.S.)
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Yan R, Pinto G, Taylor-Roseman R, Cogan K, D'Alesandre G, Kovac J. Evaluation of the Thermal Inactivation of a Salmonella Serotype Oranienburg Strain During Cocoa Roasting at Conditions Relevant to the Fine Chocolate Industry. Front Microbiol 2021; 12:576337. [PMID: 33763036 PMCID: PMC7982832 DOI: 10.3389/fmicb.2021.576337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 02/04/2021] [Indexed: 12/31/2022] Open
Abstract
Cocoa roasting produces and enhances distinct flavor of chocolate and acts as a critical control point for inactivation of foodborne pathogens in chocolate production. In this study, the inactivation kinetics of Salmonella enterica subsp. enterica serotype Oranienburg strain was assessed on whole cocoa beans using roasting protocols relevant to the fine chocolate industry. Beans were inoculated with 107-108 log10 CFU/bean of Salmonella Oranienburg and roasted at 100-150°C for 2-100 min. A greater than 5 log10 reduction of S. Oranienburg was experimentally achieved after 10-min roasting at 150°C. Data were fitted using log-linear and Weibull models. The log-linear models indicated that the roasting times (D) needed to achieve a decimal reduction of Salmonella at 100, 110, 115, 120, 130, and 140°C were 33.34, 18.57, 12.92, 10.50, 4.20, and 1.90 min, respectively. A Weibull model indicated a decrease in the Salmonella inactivation rate over time (β < 1). Statistical analysis indicated that the Weibull model fitted the data better compared to a log-linear model. These data demonstrate the efficacy of cocoa roasting in inactivation of Salmonella and may be used to guide food safety decision-making.
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Affiliation(s)
- Runan Yan
- Department of Food Science, The Pennsylvania State University, University Park, PA, United States
| | - Gabriella Pinto
- Department of Food Science, The Pennsylvania State University, University Park, PA, United States
| | | | - Karen Cogan
- Dandelion Chocolate Inc., San Francisco, CA, United States
| | | | - Jasna Kovac
- Department of Food Science, The Pennsylvania State University, University Park, PA, United States
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Rosario AILS, Castro VS, Santos LF, Lisboa RC, Vallim DC, Silva MCA, Figueiredo EES, Conte-Junior CA, Costa MP. Shiga toxin-producing Escherichia coli isolated from pasteurized dairy products from Bahia, Brazil. J Dairy Sci 2021; 104:6535-6547. [PMID: 33741165 DOI: 10.3168/jds.2020-19511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 01/28/2021] [Indexed: 11/19/2022]
Abstract
The presence of pathogenic Shiga toxin-producing Escherichia coli (STEC) in dairy products represents a public health concern because of its ability to produce the toxins Stx1 and Stx2, which cause intestinal diseases. Monitoring the stages of milk production and checking dairy products for contamination are crucial steps to ensure dairy safety. This study aimed to report the occurrence of thermotolerant coliforms, E. coli, and STEC strains in pasteurized dairy products and to evaluate the antibiotic resistance profiles, serotypes, and characterizations of the STEC isolates by pulsed-field gel electrophoresis. We obtained a total of 138 pasteurized dairy products from 15 processing plants in Bahia, Brazil, to examine coliforms, E. coli, and STEC strains. We found that 43% of samples (59/138) contained thermotolerant coliforms, and 30% (42/138) did not comply with Brazilian regulations. Overall, 6% (9/138) were positive for E. coli and 4% (5/138) were positive for STEC. We recovered 9 STEC isolates from pasteurized cream (2/9), Minas Padrão cheese (2/9), Minas Frescal cheese (4/9), and ricotta (1/9). All isolates were stx2-positive, and 2 were eae-positive. All isolates were negative for the "big 6" STEC serogroups, belonging instead to serotypes ONT:HNT, ONT:H12, O148:H-, OR:H40, OR:HNT, and O148:HNT. Pulsed-field gel electrophoresis revealed 100% genetic similarity among 3 isolates from 2 different samples produced in the same production facility, which may suggest cross-contamination. As well, we found isolates that were 98% similar but in samples produced in different production facilities, suggesting a mutual source of contamination or a circulating strain. Two STEC strains exhibited resistance to streptomycin. Although the isolates presented a low resistance profile and no strain belonged to the "big 6" pathogenic group, the circulation of stx2-positive STEC strains in ready-to-eat products highlights the importance of epidemiological surveillance inside the Brazilian dairy chain.
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Affiliation(s)
- Anisio I L S Rosario
- Graduate Program in Food Science (PGAli), Faculty of Pharmacy, Federal University of Bahia (UFBA), Salvador, BA, 40170-115, Brazil; Laboratório de Inspeção e Tecnologia de Leite e Derivados (LAITLACTEOS), Federal University of Bahia (UFBA), Salvador, BA, 40170-110, Brazil; Center for Food Analysis (NAL), Technological Development Support, Laboratory (LADETEC), Federal University of Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro, RJ, 21941-598, Brazil
| | - Vinicius S Castro
- Center for Food Analysis (NAL), Technological Development Support, Laboratory (LADETEC), Federal University of Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro, RJ, 21941-598, Brazil; Graduate Program in Food Science (PPGCAL), Institute of Chemistry (IQ), Federal University of Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro, RJ, 21941-909, Brazil
| | - Luis F Santos
- Núcleo de Doenças Entéricas e Infecções por Patógenos Especiais, Adolfo Lutz Institute, São Paulo, SP, 01246-902, Brazil
| | - Rodrigo C Lisboa
- Laboratório de Zoonoses Bacterianas, Oswaldo Cruz Institute, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, 21040-900, Brazil
| | - Deyse C Vallim
- Laboratório de Zoonoses Bacterianas, Oswaldo Cruz Institute, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, 21040-900, Brazil
| | - Maurício C A Silva
- Laboratório de Inspeção e Tecnologia de Carnes e Derivados (LABCARNE), Federal University of Bahia (UFBA), Salvador, BA, 40170-110, Brazil
| | - Eduardo E S Figueiredo
- Laboratório de Microbiologia Molecular de Alimentos, Federal University of Mato Grosso (UFMT), Cuiabá, MT, 78060-900, Brazil
| | - Carlos A Conte-Junior
- Center for Food Analysis (NAL), Technological Development Support, Laboratory (LADETEC), Federal University of Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro, RJ, 21941-598, Brazil; Graduate Program in Food Science (PPGCAL), Institute of Chemistry (IQ), Federal University of Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro, RJ, 21941-909, Brazil; Laboratory of Advanced Analysis in Biochemistry and Molecular Biology (LAABBM), Department of Biochemistry, Federal University of Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro, RJ, 21941-909, Brazil; Graduate Program in Veterinary Hygiene (PPGHV), Faculty of Veterinary Medicine, Fluminense Federal University (UFF), Vital Brazil Filho, Niterói, RJ, 24230-340, Brazil; Graduate Program in Sanitary Surveillance (PPGVS), National Institute of Health Quality Control (INCQS), Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, 21040-900, Brazil; Graduate Program in Chemistry (PGQu), Institute of Chemistry (IQ), Federal University of Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro, RJ, 21941-909, Brazil
| | - Marion P Costa
- Graduate Program in Food Science (PGAli), Faculty of Pharmacy, Federal University of Bahia (UFBA), Salvador, BA, 40170-115, Brazil; Laboratório de Inspeção e Tecnologia de Leite e Derivados (LAITLACTEOS), Federal University of Bahia (UFBA), Salvador, BA, 40170-110, Brazil.
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Locus of Heat Resistance (LHR) in Meat-Borne Escherichia coli: Screening and Genetic Characterization. Appl Environ Microbiol 2021; 87:AEM.02343-20. [PMID: 33483306 DOI: 10.1128/aem.02343-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/12/2021] [Indexed: 11/20/2022] Open
Abstract
Microbial resistance to processing treatments poses a food safety concern, as treatment tolerant pathogens can emerge. Occasional foodborne outbreaks caused by pathogenic Escherichia coli have led to human and economic losses. Therefore, this study screened for the extreme heat resistance (XHR) phenotype as well as one known genetic marker, the locus of heat resistance (LHR), in 4,123 E. coli isolates from diverse meat animals at different processing stages. The prevalences of XHR and LHR among the meat-borne E. coli were found to be 10.3% and 11.4%, respectively, with 19% agreement between the two. Finished meat products showed the highest LHR prevalence (24.3%) compared to other processing stages (0 to 0.6%). None of the LHR+ E. coli in this study would be considered pathogens based on screening for virulence genes. Four high-quality genomes were generated by whole-genome sequencing of representative LHR+ isolates. Nine horizontally acquired LHRs were identified and characterized, four plasmid-borne and five chromosomal. Nine newly identified LHRs belong to ClpK1 LHR or ClpK2 LHR variants sharing 61 to 68% nucleotide sequence identity, while one LHR appears to be a hybrid. Our observations suggest positive correlation between the number of LHR regions present in isolates and the extent of heat resistance. The isolate exhibiting the highest degree of heat resistance possessed four LHRs belonging to three different variant groups. Maintenance of as many as four LHRs in a single genome emphasizes the benefits of the LHR in bacterial physiology and stress response.IMPORTANCE Currently, a "multiple-hurdle" approach based on a combination of different antimicrobial interventions, including heat, is being utilized during meat processing to control the burden of spoilage and pathogenic bacteria. Our recent study (M. Guragain, G. E. Smith, D. A. King, and J. M. Bosilevac, J Food Prot 83:1438-1443, 2020, https://doi.org/10.4315/JFP-20-103) suggests that U.S. beef cattle harbor Escherichia coli that possess the locus of heat resistance (LHR). LHR seemingly contributes to the global stress tolerance in bacteria and hence poses a food safety concern. Therefore, it is important to understand the distribution of the LHRs among meat-borne bacteria identified at different stages of different meat processing systems. Complete genome sequencing and comparative analysis of selected heat-resistant bacteria provide a clearer understanding of stress and heat resistance mechanisms. Further, sequencing data may offer a platform to gain further insights into the genetic background that provides optimal bacterial tolerance against heat and other processing treatments.
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Lee C, Klockgether J, Fischer S, Trcek J, Tümmler B, Römling U. Why? - Successful Pseudomonas aeruginosa clones with a focus on clone C. FEMS Microbiol Rev 2021; 44:740-762. [PMID: 32990729 PMCID: PMC7685784 DOI: 10.1093/femsre/fuaa029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/12/2020] [Indexed: 12/20/2022] Open
Abstract
The environmental species Pseudomonas aeruginosa thrives in a variety of habitats. Within the epidemic population structure of P. aeruginosa, occassionally highly successful clones that are equally capable to succeed in the environment and the human host arise. Framed by a highly conserved core genome, individual members of successful clones are characterized by a high variability in their accessory genome. The abundance of successful clones might be funded in specific features of the core genome or, although not mutually exclusive, in the variability of the accessory genome. In clone C, one of the most predominant clones, the plasmid pKLC102 and the PACGI-1 genomic island are two ubiquitous accessory genetic elements. The conserved transmissible locus of protein quality control (TLPQC) at the border of PACGI-1 is a unique horizontally transferred compository element, which codes predominantly for stress-related cargo gene products such as involved in protein homeostasis. As a hallmark, most TLPQC xenologues possess a core genome equivalent. With elevated temperature tolerance as a characteristic of clone C strains, the unique P. aeruginosa and clone C specific disaggregase ClpG is a major contributor to tolerance. As other successful clones, such as PA14, do not encode the TLPQC locus, ubiquitous denominators of success, if existing, need to be identified.
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Affiliation(s)
- Changhan Lee
- Department of Microbiology, Tumor and Cell Biology, Biomedicum C8, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Jens Klockgether
- Clinic for Paediatric Pneumology, Allergology and Neonatology, Clinical Research Group 'Pseudomonas Genomics', Hannover Medical School, D-30625 Hannover, Germany
| | - Sebastian Fischer
- Clinic for Paediatric Pneumology, Allergology and Neonatology, Clinical Research Group 'Pseudomonas Genomics', Hannover Medical School, D-30625 Hannover, Germany
| | - Janja Trcek
- Faculty of Natural Sciences and Mathematics, Department of Biology, University of Maribor, Maribor, 2000, Slovenia
| | - Burkhard Tümmler
- Clinic for Paediatric Pneumology, Allergology and Neonatology, Clinical Research Group 'Pseudomonas Genomics', Hannover Medical School, D-30625 Hannover, Germany
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Biomedicum C8, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Katikaridis P, Römling U, Mogk A. Basic mechanism of the autonomous ClpG disaggregase. J Biol Chem 2021; 296:100460. [PMID: 33639171 PMCID: PMC8024975 DOI: 10.1016/j.jbc.2021.100460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/05/2021] [Accepted: 02/23/2021] [Indexed: 01/19/2023] Open
Abstract
Bacterial survival during lethal heat stress relies on the cellular ability to reactivate aggregated proteins. This activity is typically executed by the canonical 70-kDa heat shock protein (Hsp70)–ClpB bichaperone disaggregase, which is most widespread in bacteria. The ClpB disaggregase is a member of the ATPase associated with diverse cellular activities protein family and exhibits an ATP-driven threading activity. Substrate binding and stimulation of ATP hydrolysis depends on the Hsp70 partner, which initiates the disaggregation reaction. Recently elevated heat resistance in gamma-proteobacterial species was shown to be mediated by the ATPase associated with diverse cellular activities protein ClpG as an alternative disaggregase. Pseudomonas aeruginosa ClpG functions autonomously and does not cooperate with Hsp70 for substrate binding, enhanced ATPase activity, and disaggregation. With the underlying molecular basis largely unknown, the fundamental differences in ClpG- and ClpB-dependent disaggregation are reflected by the presence of sequence alterations and additional ClpG-specific domains. By analyzing the effects of mutants lacking ClpG-specific domains and harboring mutations in conserved motifs implicated in ATP hydrolysis and substrate threading, we show that the N-terminal, ClpG-specific N1 domain generally mediates protein aggregate binding as the molecular basis of autonomous disaggregation activity. Peptide substrate binding strongly stimulates ClpG ATPase activity by overriding repression by the N-terminal N1 and N2 domains. High ATPase activity requires two functional nucleotide binding domains and drives substrate threading which ultimately extracts polypeptides from the aggregate. ClpG ATPase and disaggregation activity is thereby directly controlled by substrate availability.
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Affiliation(s)
- Panagiotis Katikaridis
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; German Cancer Research Center (DKFZ), A250 Chaperones and Proteases, Heidelberg, Germany
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Axel Mogk
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; German Cancer Research Center (DKFZ), A250 Chaperones and Proteases, Heidelberg, Germany.
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Ma A, Neumann N, Chui L. Phenotypic and Genetic Determination of Biofilm Formation in Heat Resistant Escherichia coli Possessing the Locus of Heat Resistance. Microorganisms 2021; 9:microorganisms9020403. [PMID: 33672009 PMCID: PMC7919257 DOI: 10.3390/microorganisms9020403] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 02/03/2023] Open
Abstract
Despite the effectiveness of thermal inactivation processes, Escherichiacoli biofilms continue to be a persistent source of contamination in food processing environments. E. coli strains possessing the locus of heat resistance are a novel food safety threat and raises the question of whether these strains can also form biofilms. The objectives of this study were to determine biofilm formation in heat resistant E. coli isolates from clinical and environmental origins using an in-house, two-component apparatus and to characterize biofilm formation-associated genes in the isolates using whole genome sequencing. Optimal conditions for biofilm formation in each of the heat resistant isolates were determined by manipulating inoculum size, nutrient concentration, and temperature conditions. Biofilm formation in the heat resistant isolates was detected at temperatures of 24 °C and 37 °C but not at 4 °C. Furthermore, biofilm formation was observed in all environmental isolates but only one clinical isolate despite shared profiles in biofilm formation-associated genes encoded by the isolates from both sources. The circulation of heat resistant E. coli isolates with multi-stress tolerance capabilities in environments related to food processing signify that such strains may be a serious food safety and public health risk.
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Affiliation(s)
- Angela Ma
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2R3, Canada;
| | - Norman Neumann
- School of Public Health, University of Alberta, Edmonton, AB T6G 2R3, Canada;
| | - Linda Chui
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2R3, Canada;
- Alberta Precision Laboratories—Provincial Laboratory for Public Health, Edmonton, AB T6G 2J2, Canada
- Correspondence: ; Tel.: +1-780-407-8951
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Abstract
Conjugative plasmids can mediate the spread and maintenance of diverse traits and functions in microbial communities. This role depends on the plasmid's ability to persist in a population. However, for a community consisting of multiple populations transferring multiple plasmids, the conditions underlying plasmid persistence are poorly understood. Here, we describe a plasmid-centric framework that makes it computationally feasible to analyze gene flow in complex communities. Using this framework, we derive the 'persistence potential': a general, heuristic metric that predicts the persistence and abundance of any plasmids. We validate the metric with engineered microbial consortia transferring mobilizable plasmids and with quantitative data available in the literature. We believe that our framework and the resulting metric will facilitate a quantitative understanding of natural microbial communities and the engineering of microbial consortia.
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Affiliation(s)
- Teng Wang
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Lingchong You
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
- Center for Genomic and Computational Biology, Duke University, Durham, NC, 27708, USA.
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27708, USA.
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36
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Luoyizha W, Wu X, Zhang M, Guo X, Li H, Liao X. Compared analysis of microbial diversity in donkey milk from Xinjiang and Shandong of China through High-throughput sequencing. Food Res Int 2020; 137:109684. [PMID: 33233260 DOI: 10.1016/j.foodres.2020.109684] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/18/2020] [Accepted: 09/06/2020] [Indexed: 12/26/2022]
Abstract
Donkey milk has received increasing attention from consumers and dairy industry because of its nutritional value, health benefits, and proximity to human milk. Microbial diversity in donkey milk has a great impact on its quality and safety, however, microbiota in donkey milk from the major donkey-breeding regions of China have not been well documented. In this study, bacterial communities in donkey milk from Yopurga County in Western China (XJ), and Dong'e County in Eastern China (SD) were determined using high-throughput sequencing. Major phyla identified in the two donkey milk groups consistently included Acinetobacter, Proteobacteria, Firmicutes, and Bacteroidetes but with very different abundance for each phylum. Prevelence of genera was found to be diverse between the two groups, with Macrococcus and Acinetobacter dominating in the XJ samples while Streptococcus, Pseudoclavibacter, and Pseudomonas being the most abundant ones in the XJ samples. Alpha diversity analysis showed that there was significant difference in richness between the two sample groups but no difference in bacterial community diversity or coverage. The presence of possible harmful bacteria and lactic acid bacteria in donkey milk in this study provides the microbial profiles of pathogens and spoilage bacteria that need to be controlled and proposes possible utilization of beneficial microbial resources for the future.
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Affiliation(s)
- Wahafu Luoyizha
- College of Food Science and Nutrition Engineering, China Agricultural University, Beijing 100083, PR China; College of Life Science and Technology, Xinjiang University, Xinjiang 830046, PR China
| | - Xiaomeng Wu
- College of Food Science and Nutrition Engineering, China Agricultural University, Beijing 100083, PR China
| | - Ming Zhang
- Xinjiang Yukunlun Natural Food Engineering Co. Ltd., Xinjiang 8444400, PR China
| | - Xingfeng Guo
- College of Agronomy, Liaocheng University, Shandong 252000, PR China
| | - Hui Li
- Institute of Quality Standard and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
| | - Xiaojun Liao
- College of Food Science and Nutrition Engineering, China Agricultural University, Beijing 100083, PR China
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37
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He L, Simpson DJ, Gänzle MG. Detection of enterohaemorrhagic Escherichia coli in food by droplet digital PCR to detect simultaneous virulence factors in a single genome. Food Microbiol 2020; 90:103466. [DOI: 10.1016/j.fm.2020.103466] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/22/2019] [Accepted: 01/12/2020] [Indexed: 02/06/2023]
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38
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Li H, Sun X, Liao X, Gänzle M. Control of pathogenic and spoilage bacteria in meat and meat products by high pressure: Challenges and future perspectives. Compr Rev Food Sci Food Saf 2020; 19:3476-3500. [PMID: 33337070 DOI: 10.1111/1541-4337.12617] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/10/2020] [Accepted: 07/19/2020] [Indexed: 01/18/2023]
Abstract
High-pressure processing is among the most widely used nonthermal intervention to reduce pathogenic and spoilage bacteria in meat and meat products. However, resistance of pathogenic bacteria strains in meats at the current maximum commercial equipment of 600 MPa questions the ability of inactivation by its application in meats. Pathogens including Escherichia coli, Listeria, and Salmonelle, and spoilage microbiota including lactic acid bacteria dominate in raw meat, ready-to-eat, and packaged meat products. Improved understanding on the mechanisms of the pressure resistance is needed for optimizing the conditions of pressure treatment to effectively decontaminate harmful bacteria. Effective control of the pressure-resistant pathogens and spoilage organisms in meats can be realized by the combination of high pressure with application of mild temperature and/or other hurdles including antimicrobial agents and/or competitive microbiota. This review summarized applications, mechanisms, and challenges of high pressure on meats from the perspective of microbiology, which are important for improving the understanding and optimizing the conditions of pressure treatment in the future.
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Affiliation(s)
- Hui Li
- Institute of Quality Standard and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaohong Sun
- College of Food and Biological Engineering, Qiqihar University, Qiqihar, Heilongjiang, China
| | - Xiaojun Liao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Michael Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
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39
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Guragain M, Smith GE, King DA, Bosilevac JM. Prevalence of Extreme Heat-Resistant Gram-Negative Bacteria Carried by U.S. Cattle at Harvest. J Food Prot 2020; 83:1438-1443. [PMID: 32299091 DOI: 10.4315/jfp-20-103] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/15/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Prevalence of heat-resistant bacteria in beef poses a potential problem as thermal interventions are routinely used in beef processing to control contamination. Despite extreme heat-resistant (XHR) Escherichia coli having been isolated from a ground beef processing plant, there has not been a study to assess the prevalence of XHR E. coli among types of cattle. Therefore, this study used a screening assay for XHR gram-negative bacteria and its molecular determinant, the locus of heat resistance (LHR), on feces collected from U.S. cattle. Fecal samples were collected from fed (n = 538), cull dairy (n = 425), and cull beef (n = 475) cattle at nine regional beef processing plants located across the United States. Among the 1,438 cattle sampled from northern (n = 288), southern (n = 288), eastern (n = 287), western (n = 287), and central (n = 288) regions of the United States, 91 (6.3%) cattle showed presence of XHR bacteria, as evident by growth in MacConkey broth following heat treatment of 80°C for 15 min, in their feces. Heat-resistant bacteria (n = 140) were isolated from the 91 fecal samples. Prevalence of XHR bacteria was highest (11%) in cattle from the northern region. Ninety percent of the XHR isolates were identified as E. coli. Multiplex PCR of all 1,438 fecal samples showed that the LHR was absent in 40.7% of samples and intact in 18.7% of samples. Despite the higher prevalence of intact LHR from PCR analysis, only 11 samples (0.8%) were confirmed to contain bacteria with an intact LHR. The LHR was absent in 91% of XHR bacteria, and only 7.9% of XHR bacteria had intact LHR, suggesting a novel mechanism of heat resistance. By developing and using the screening assays, we established the prevalence of XHR bacteria (6.3%) and LHR+ bacteria (0.8%) in U.S. beef cattle. HIGHLIGHTS
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Affiliation(s)
- Manita Guragain
- U.S. Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, P.O. Box 166, State Spur D, Clay Center, Nebraska 68933, USA.,ORCID: https://orcid.org/0000-0002-5266-1746 [M.G.]
| | - Gregory E Smith
- U.S. Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, P.O. Box 166, State Spur D, Clay Center, Nebraska 68933, USA
| | - David A King
- U.S. Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, P.O. Box 166, State Spur D, Clay Center, Nebraska 68933, USA
| | - Joseph M Bosilevac
- U.S. Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, P.O. Box 166, State Spur D, Clay Center, Nebraska 68933, USA.,ORCID: https://orcid.org/0000-0002-0258-6581 [J.M.B.]
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40
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Are Antimicrobial Interventions Associated with Heat-Resistant Escherichia coli on Meat? Appl Environ Microbiol 2020; 86:AEM.00512-20. [PMID: 32303544 DOI: 10.1128/aem.00512-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 04/14/2020] [Indexed: 01/01/2023] Open
Abstract
Decontamination practices, which often involve thermal treatments, are routinely performed in beef packing plants and have generally improved the safety of meat in North America. We investigated whether Escherichia coli in the beef production chain is becoming more heat resistant due to those treatments. Cattle isolates (n = 750) included seven serogroups (O157, O103, O111, O121, O145, O26, and O45) which were collected between 2002 and 2017. Beef plant isolates (n = 700) from carcasses, fabrication equipment, and beef products were included. Heat resistance was determined in Luria-Bertani broth at 60°C and by PCR screening for the locus of heat resistance (LHR). The decimal reduction for E. coli at 60°C (D 60ºC values) ranged from 0 to 7.54 min, with 97.2% of the values being <2 min. The prevalence of E. coli with D 60ºC values of >2 min was not significantly different (P > 0.05) among cattle and meat plant isolates. E. coli from equipment before sanitation (median, 1.03 min) was more heat resistant than that after sanitation (median, 0.9 min). No significant difference in D 60ºC values was observed among E. coli isolates from different years, from carcasses before and after antimicrobial interventions, or from before and during carcass chilling. Of all isolates, 1.97% harbored LHR, and the LHR-positive isolates had greater median D 60ºC values than the LHR-negative isolates (3.25 versus 0.96 min). No increase in heat resistance in E. coli was observed along the beef production chain or with time.IMPORTANCE The implementation of multiple hurdles in the beef production chain has resulted in substantial improvement in the microbial safety of beef in Canada. In this study, we characterized a large number of Escherichia coli isolates (n = 1,450) from various sources/stages of beef processing to determine whether the commonly used antimicrobial interventions would give rise to heat-resistant E. coli on meat, which in turn may require alternatives to the current control of pathogens and/or modifications to the current cooking recommendations for meat. The findings show that the degree and rate of heat resistance in E. coli did not increase along the production chain or with time. This furthers our understanding of man-made ecological niches that are required for the development of heat resistance in E. coli.
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41
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Parvin MS, Talukder S, Ali MY, Chowdhury EH, Rahman MT, Islam MT. Antimicrobial Resistance Pattern of Escherichia coli Isolated from Frozen Chicken Meat in Bangladesh. Pathogens 2020; 9:pathogens9060420. [PMID: 32481680 PMCID: PMC7350304 DOI: 10.3390/pathogens9060420] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/23/2020] [Accepted: 05/25/2020] [Indexed: 01/15/2023] Open
Abstract
Escherichia coli is known as one of the most important foodborne pathogens in humans, and contaminated chicken meat is an important source of foodborne infection with this bacterium. The occurrence of extended-spectrum β-lactamase (ESBL)-producing E. coli (ESBL-Ec), in particular, in chicken meat is considered a global health problem. This study aimed to determine the magnitude of E. coli, with special emphasis on ESBL-Ec, along with their phenotypic antimicrobial resistance pattern in frozen chicken meat. The study also focused on the determination of ESBL-encoding genes in E. coli. A total of 113 frozen chicken meat samples were purchased from 40 outlets of nine branded supershops in five megacities in Bangladesh. Isolation and identification of E. coli were done based on cultural and biochemical properties, as well as PCR assay. The resistance pattern was determined by the disc diffusion method. ESBL-encoding genes were determined by multiplex PCR. The results showed that 76.1% of samples were positive for E. coli, of which 86% were ESBL producers. All the isolates were multidrug-resistant (MDR). Resistance to 9-11 and 12-13 antimicrobial classes was observed in 38.4% and 17.4% isolates, respectively, while only 11.6% were resistant to 3-5 classes. Possible extensive drug resistance (pXDR) was found in 2.3% of isolates. High single resistance was observed for oxytetracycline (93%) and amoxicillin (91.9%), followed by ampicillin (89.5%), trimethoprim-sulfamethoxazole, and pefloxacin (88.4%), and tetracycline (84.9%). Most importantly, 89.6% of isolates were resistant to carbapenems. All the isolates were positive for the blaTEM gene. However, the blaSHV and blaCTX-M-2 genes were identified in two ESBL-non producer isolates. None of the isolates carried the blaCTX-M-1 gene. This study provided evidence of the existence of MDR and pXDR ESBL-Ec in frozen chicken meat in Bangladesh, which may pose a risk to human health if the meat is not properly cooked or pickled raw only. This emphasizes the importance of the implementation of good slaughtering and processing practices by the processors.
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Affiliation(s)
- Mst. Sonia Parvin
- Population Medicine and AMR Laboratory, Department of Medicine, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.S.P.); (S.T.); (M.Y.A.)
| | - Sudipta Talukder
- Population Medicine and AMR Laboratory, Department of Medicine, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.S.P.); (S.T.); (M.Y.A.)
| | - Md. Yamin Ali
- Population Medicine and AMR Laboratory, Department of Medicine, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.S.P.); (S.T.); (M.Y.A.)
| | - Emdadul Haque Chowdhury
- Department of Pathology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh;
| | - Md. Tanvir Rahman
- Department of Microbiology and Hygiene, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh;
| | - Md. Taohidul Islam
- Population Medicine and AMR Laboratory, Department of Medicine, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.S.P.); (S.T.); (M.Y.A.)
- Correspondence: ; Tel.: +880-916-7401
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42
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Zhao R, Chen J, Wang Y, Li Y, Kong X, Han Y. Proteolytic activity of Vibrio harveyi YeaZ is related with resuscitation on the viable but non-culturable state. Lett Appl Microbiol 2020; 71:126-133. [PMID: 32349168 DOI: 10.1111/lam.13304] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/27/2020] [Accepted: 04/21/2020] [Indexed: 02/06/2023]
Abstract
The YeaZ protein of Vibrio harveyi was expressed in Escherichia coli and purified. The purified recombinant protein YeaZ exhibited the protease activity. The proteolytic activities with azocasein as substrate were 39 130 U mg-1 . The mutation of the amino acid in active sites such as Asp88 , Ser185 and Trp169 was performed. The enzyme activities of the purified mutant proteins with Asp88 -Ala, Ser185 -Leu and Trp169 -Glu were decreased to 24·28, 35·27 and 41·66%, respectively. The mutant protein with two amino acid residues (Asp88 -Ala/Ser185 -Leu) lost the protease activity completely. Addition of the purified recombinant YeaZ increased resuscitation of the viable but non-culturable state (VBNC) cells to culturable state, and the culturable cell count increased from 1·35 × 102 to 3·10 × 106 CFU per ml. While addition of the mutant YeaZ without protease activities did not show obvious promoting effect on resuscitation of VBNC cells. Moreover, the purified YeaZ also showed lower muralytic activity, and the activities of proteins with single amino acids mutation (Thr71 and Asp112 ) were reduced from 7·05 to 4·75 and 2·50 U mg-1 , the resuscitation-promoting effect on VBNC cells was not affected by these mutant proteins. These results implied that resuscitation-promoting effect of YeaZ on VBNC cell was partly related to its protease activities, but not with the muralytic activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Vibrio harveyi is a major pathogen of marine animals. The bacterium could enter into a viable but non-culturable state (VBNC) state when exposed to harsh conditions, and retains its pathogenicity after resuscitation. In this work, we analysed the enzyme activities of a resuscitation-promoting factor YeaZ and the relationship of protease activities with its promoting effect on the resuscitation of VBNC cells. The results partly revealed the promoting mechanism of the YeaZ on the bacterial resuscitation from VBNC state. The protein could be used as a new drug target and vaccine candidate.
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Affiliation(s)
- R Zhao
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, China
| | - J Chen
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, China
| | - Y Wang
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, China
| | - Y Li
- Chongqing Key Laboratory of Environmental Materials and Remediation Technologies, Chongqing University of Arts and Sciences, Chongqing, China
| | - X Kong
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, China
| | - Y Han
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, China
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43
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Schultze DM, Couto R, Temelli F, McMullen LM, Gänzle M. Lethality of high-pressure carbon dioxide on Shiga toxin-producing Escherichia coli, Salmonella and surrogate organisms on beef jerky. Int J Food Microbiol 2020; 321:108550. [DOI: 10.1016/j.ijfoodmicro.2020.108550] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/09/2020] [Accepted: 02/05/2020] [Indexed: 11/28/2022]
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44
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Yang X, Tran F, Klassen MD. Heat resistance in
Escherichia coli
and its implications on ground beef cooking recommendations in Canada. J Food Saf 2020. [DOI: 10.1111/jfs.12769] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Xianqin Yang
- Agriculture and Agri‐Food Canada Lacombe Research and Development Centre Lacombe Alberta Canada
| | - Frances Tran
- Agriculture and Agri‐Food Canada Lacombe Research and Development Centre Lacombe Alberta Canada
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45
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Li H, Mercer R, Behr J, Heinzlmeir S, McMullen LM, Vogel RF, Gänzle MG. Heat and Pressure Resistance in Escherichia coli Relates to Protein Folding and Aggregation. Front Microbiol 2020; 11:111. [PMID: 32117137 PMCID: PMC7010813 DOI: 10.3389/fmicb.2020.00111] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 01/17/2020] [Indexed: 01/16/2023] Open
Abstract
The locus of heat resistance (LHR) confers extreme heat resistance in Escherichia coli. This study explored the role of the LHR in heat and pressure resistance of E. coli, as well as its relationship with protein folding and aggregation in vivo. The role of LHR was investigated in E. coli MG1655 and the pressure resistant E. coli LMM1010 expressing an ibpA-yfp fusion protein to visualize inclusion bodies by fluorescence microscopy. The expression of proteins by the LHR was determined by proteomic analysis; inclusion bodies of untreated and treated cells were also analyzed by proteomics, and by fluorescent microscopy. In total, 11 proteins of LHR were expressed: sHSP20, ClpKGI, sHSP, YdfX1 and YdfX2, HdeD, KefB, Trx, PsiE, DegP, and a hypothetical protein. The proteomic analysis of inclusion bodies revealed a differential abundance of proteins related to oxidative stress in strains carrying the LHR. The LHR reduced the presence of inclusion bodies after heat or pressure treatment, indicating that proteins expressed by the LHR prevent protein aggregation, or disaggregate proteins. This phenotype of the LHR was also conferred by expression of a fragment containing only sHSP20, ClpKGI, and sHSP. The LHR and the fragment encoding only sHSP20, ClpKGI, and sHSP also enhanced pressure resistance in E. coli MG1655 but had no effect on pressure resistance of E. coli LMM1010. In conclusion, the LHR confers pressure resistance to some strains of E. coli, and reduces protein aggregation. Pressure and heat resistance are also dependent on additional LHR-encoded functions.
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Affiliation(s)
- Hui Li
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.,Institute of Quality Standard and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-food Quality and Safety, Ministry of Agriculture, Beijing, China
| | - Ryan Mercer
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Jürgen Behr
- Bavarian Center for Biomolecular Mass Spectrometry, Technical University of Munich, Freising, Germany.,Leibniz-Institute for Food Systems Biology, Technical University of Munich, Freising, Germany
| | - Stephanie Heinzlmeir
- Bavarian Center for Biomolecular Mass Spectrometry, Technical University of Munich, Freising, Germany
| | - Lynn M McMullen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Rudi F Vogel
- Technical University of Munich - Lehrstuhl fär Technische Mikrobiologie, Freising, Germany
| | - Michael G Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.,College of Bioengineering and Food Science, Hubei University of Technology, Wuhan, China
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46
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The Locus of Heat Resistance Confers Resistance to Chlorine and Other Oxidizing Chemicals in Escherichia coli. Appl Environ Microbiol 2020; 86:AEM.02123-19. [PMID: 31811037 DOI: 10.1128/aem.02123-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 11/28/2019] [Indexed: 12/20/2022] Open
Abstract
Some chlorine-resistant Escherichia coli isolates harbor the locus of heat resistance (LHR), a genomic island conferring heat resistance. In this study, the protective effect of the LHR for cells challenged by chlorine and oxidative stress was quantified. Cloning of the LHR protected against NaClO (32 mM; 5 min), H2O2 (120 mM; 5 min), and peroxyacetic acid (105 mg/liter; 5 min) but not against 5.8 mM KIO4, 10 mM acrolein, or 75 mg/liter allyl isothiocyanate. The lethality of oxidizing treatments for LHR-negative strains of E. coli was about 2 log10 CFU/ml higher than that for LHR-positive strains of E. coli The oxidation of cytoplasmic proteins and membrane lipids was quantified with the fusion probe roGFP2-Orp1 and the fluorescent probe BODIPY581/591, respectively. The fragment of the LHR coding for heat shock proteins protected cytoplasmic proteins but not membrane lipids against oxidation. The middle fragment of the LHR protected against the oxidation of membrane lipids but not of cytoplasmic proteins. The addition of H2O2, NaClO, and peroxyacetic acid also induced green fluorescent protein (GFP) expression in the oxidation-sensitive reporter strain E. coli O104:H4 Δstx 2::gfp::amp Cloning of pLHR reduced phage induction in E. coli O104:H4 Δstx 2::gfp::amp after treatment with oxidizing chemicals. Screening of 160 strains of Shiga toxin-producing E. coli (STEC) revealed that none of them harbors the LHR, additionally suggesting that the LHR and Stx prophages are mutually exclusive. Taking our findings together, the contribution of the LHR to resistance to chlorine and oxidative stress is based on the protection of multiple cellular targets by different proteins encoded by the genetic island.IMPORTANCE Chlorine treatments are used in water and wastewater sanitation; the resistance of Escherichia coli to chlorine is thus of concern to public health. We show that a genetic island termed the locus of heat resistance (LHR) protects E. coli not only against heat but also against chlorine and other oxidizing chemicals, adding to our knowledge of the tools used by E. coli to resist stress. Specific detection of the oxidation of different cellular targets in combination with the cloning of fragments of the LHR provided insight into mechanisms of protection and demonstrated that different fragments of the LHR protect different cellular targets. In E. coli, the presence of the LHR virtually always excluded other virulence factors. It is tempting to speculate that the LHR is maintained by strains of E. coli with an environmental lifestyle but is excluded by pathogenic strains that adapted to interact with vertebrate hosts.
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47
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Antunes P, Novais C, Peixe L. Food-to-Humans Bacterial Transmission. Microbiol Spectr 2020; 8:10.1128/microbiolspec.mtbp-0019-2016. [PMID: 31950894 PMCID: PMC10810214 DOI: 10.1128/microbiolspec.mtbp-0019-2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Indexed: 12/17/2022] Open
Abstract
Microorganisms vehiculated by food might benefit health, cause minimal change within the equilibrium of the host microbial community or be associated with foodborne diseases. In this chapter we will focus on human pathogenic bacteria for which food is conclusively demonstrated as their transmission mode to human. We will describe the impact of foodborne diseases in public health, the reservoirs of foodborne pathogens (the environment, human and animals), the main bacterial pathogens and food vehicles causing human diseases, and the drivers for the transmission of foodborne diseases related to the food-chain, host or bacteria features. The implication of food-chain (foodborne pathogens and commensals) in the transmission of resistance to antibiotics relevant to the treatment of human infections is also evidenced. The multiplicity and interplay of drivers related to intensification, diversification and globalization of food production, consumer health status, preferences, lifestyles or behaviors, and bacteria adaptation to different challenges (stress tolerance and antimicrobial resistance) from farm to human, make the prevention of bacteria-food-human transmission a modern and continuous challenge. A global One Health approach is mandatory to better understand and minimize the transmission pathways of human pathogens, including multidrug-resistant pathogens and commensals, through food-chain.
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Affiliation(s)
- Patrícia Antunes
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal
| | - Carla Novais
- Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Luísa Peixe
- Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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48
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Prasad A, Gänzle M, Roopesh MS. Inactivation of Escherichia Coli and Salmonella Using 365 and 395 nm High Intensity Pulsed Light Emitting Diodes. Foods 2019; 8:foods8120679. [PMID: 31847186 PMCID: PMC6963940 DOI: 10.3390/foods8120679] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/10/2019] [Accepted: 12/10/2019] [Indexed: 11/21/2022] Open
Abstract
High intensity pulsed light emitting diode (LED) treatment is a novel approach to inactivate foodborne pathogens. The objective of this study was to evaluate the antibacterial potential of high intensity 365 (UV-A) and 395 nm (NUV-Vis) LED treatments against Escherichia coli and Salmonella enterica at high and low water activity (aw) conditions, and to understand the influence of different process parameters on their antibacterial efficacy. Bacteria at high (in phosphate buffer saline, PBS) and low aw (aw = 0.75) conditions were treated with both the LEDs with specific doses at a fixed distance from the LEDs. The 365 nm LED showed more effectiveness in reducing the dried bacteria compared to 395 nm LED. The dry E. coli showed more resistance to LED treatments compared to Salmonella. The 365 and 395 nm LED treatments with ~658 J/cm2 dose resulted in reductions of 0.79 and 1.76 log CFU/g of Salmonella, respectively, on 0.75 aw pet foods. The LED treatments increased the surface temperature, resulting in water loss in the treated samples. This study showed that the dose, duration of light exposure, bacterial strain, and aw played a major role in the antibacterial efficacy of the 365 and 395 nm LEDs.
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Affiliation(s)
- Amritha Prasad
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2R3, Canada; (A.P.); (M.G.)
| | - Michael Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2R3, Canada; (A.P.); (M.G.)
- College of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430086, China
| | - M. S. Roopesh
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2R3, Canada; (A.P.); (M.G.)
- Correspondence: ; Tel.: +1-780-492-8413
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49
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Characterization of Escherichia coli possessing the locus of heat resistance isolated from human cases of acute gastroenteritis. Food Microbiol 2019; 88:103400. [PMID: 31997757 DOI: 10.1016/j.fm.2019.103400] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 11/26/2019] [Accepted: 12/07/2019] [Indexed: 01/17/2023]
Abstract
The purpose of this study was to identify Escherichia coli isolates obtained from patients experiencing acute gastroenteritis that possess the locus of heat resistance (LHR) and characterize their heat resistance upon exposure to temperatures of 60 °C and 71 °C. From a collection of 613 clinical E. coli strains, 3 heat resistant E. coli isolates were identified. Two of the 3 isolates were stx1 positive; no isolates possessed stx2 as determined by qPCR. D60-values of heat resistant isolates all exceeded 10.20 min with one isolate's D60-values ranging from 20.46 to 72.47 min. The presence of 4% additional NaCl significantly increased D60-values of 2 clinical isolates. Cell reductions of heat resistant isolates in ground beef patties grilled to 60 °C and 71 °C remained above 2.8 and 4.9 log CFU/mL, respectively, compared to reductions of 6.1 log CFU/mL and greater in heat sensitive E. coli. Constitutive expression of novel Clp protease ClpK, encoded on open reading frame 3 of the LHR, was identified in all heat resistant isolates by SDS-PAGE and peptide mass fingerprinting. This data is the first to report heat resistant E. coli possessing the LHR involved in clinical infection, highlighting the potential threat of heat resistant enteric pathogens on food safety.
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50
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Katikaridis P, Meins L, Kamal SM, Römling U, Mogk A. ClpG Provides Increased Heat Resistance by Acting as Superior Disaggregase. Biomolecules 2019; 9:biom9120815. [PMID: 31810333 PMCID: PMC6995612 DOI: 10.3390/biom9120815] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/21/2022] Open
Abstract
Elevation of temperature within and above the physiological limit causes the unfolding and aggregation of cellular proteins, which can ultimately lead to cell death. Bacteria are therefore equipped with Hsp100 disaggregation machines that revert the aggregation process and reactivate proteins otherwise lost by aggregation. In Gram-negative bacteria, two disaggregation systems have been described: the widespread ClpB disaggregase, which requires cooperation with an Hsp70 chaperone, and the standalone ClpG disaggregase. ClpG co-exists with ClpB in selected bacteria and provides superior heat resistance. Here, we compared the activities of both disaggregases towards diverse model substrates aggregated in vitro and in vivo at different temperatures. We show that ClpG exhibits robust activity towards all disordered aggregates, whereas ClpB acts poorly on the protein aggregates formed at very high temperatures. Extreme temperatures are expected not only to cause extended protein unfolding, but also to result in an accelerated formation of protein aggregates with potentially altered chemical and physical parameters, including increased stability. We show that ClpG exerts higher threading forces as compared to ClpB, likely enabling ClpG to process “tight” aggregates formed during severe heat stress. This defines ClpG as a more powerful disaggregase and mechanistically explains how ClpG provides increased heat resistance.
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Affiliation(s)
- Panagiotis Katikaridis
- Center for Molecular Biology of the University of Heidelberg (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; (P.K.); (L.M.)
| | - Lena Meins
- Center for Molecular Biology of the University of Heidelberg (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; (P.K.); (L.M.)
| | - Shady Mansour Kamal
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, 17177 Stockholm, Sweden; (S.M.K.); (U.R.)
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, 17177 Stockholm, Sweden; (S.M.K.); (U.R.)
| | - Axel Mogk
- Center for Molecular Biology of the University of Heidelberg (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; (P.K.); (L.M.)
- Correspondence: ; Tel.: +49-6221-546-863
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