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Pokharel P, Dhakal S, Dozois CM. The Diversity of Escherichia coli Pathotypes and Vaccination Strategies against This Versatile Bacterial Pathogen. Microorganisms 2023; 11:344. [PMID: 36838308 PMCID: PMC9965155 DOI: 10.3390/microorganisms11020344] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/03/2023] Open
Abstract
Escherichia coli (E. coli) is a gram-negative bacillus and resident of the normal intestinal microbiota. However, some E. coli strains can cause diseases in humans, other mammals and birds ranging from intestinal infections, for example, diarrhea and dysentery, to extraintestinal infections, such as urinary tract infections, respiratory tract infections, meningitis, and sepsis. In terms of morbidity and mortality, pathogenic E. coli has a great impact on public health, with an economic cost of several billion dollars annually worldwide. Antibiotics are not usually used as first-line treatment for diarrheal illness caused by E. coli and in the case of bloody diarrhea, antibiotics are avoided due to the increased risk of hemolytic uremic syndrome. On the other hand, extraintestinal infections are treated with various antibiotics depending on the site of infection and susceptibility testing. Several alarming papers concerning the rising antibiotic resistance rates in E. coli strains have been published. The silent pandemic of multidrug-resistant bacteria including pathogenic E. coli that have become more difficult to treat favored prophylactic approaches such as E. coli vaccines. This review provides an overview of the pathogenesis of different pathotypes of E. coli, the virulence factors involved and updates on the major aspects of vaccine development against different E. coli pathotypes.
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Affiliation(s)
- Pravil Pokharel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Sabin Dhakal
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Charles M. Dozois
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
- Pasteur Network, Laval, QC H7V 1B7, Canada
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Lin CS, Huang CH, Adi VSK, Huang CW, Cheng YI, Chen JH, Liu YC. A statistical approach to identify prevalent virulence factors responsible for post-weaning diarrhoeic piglets. VET MED-CZECH 2022; 67:430-439. [PMID: 38846158 PMCID: PMC11154881 DOI: 10.17221/84/2021-vetmed] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 04/12/2022] [Indexed: 06/09/2024] Open
Abstract
A statistical approach was carried out to identify the prevalent virulence factors responsible for post-weaning diarrhoea (PWD). Healthy piglets' faecal samples and diarrhoeic piglets' rectal swab specimens were secured. Twenty-six (26) and 100 independent enterotoxigenic Escherichia coli (ETEC) strains were subsequently isolated. These strains were assessed utilising polymerase chain reaction to identify the encoding genes of six virulence factors: heat-labile enterotoxin (LT; encoded by eltAB), heat-stable enterotoxin A (STa; encoded by estA), heat-stable enterotoxin B (STb; encoded by estB), enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1; encoded by astA), Shiga toxin 2e (Stx2e; encoded by stx2e), and F18 fimbriae (encoded by fedA). The LT and ST secretions were investigated using enzyme-linked immunosorbent assays. From direct observation, no stx2e was evident in the 126 strains. Among the 26 strains retrieved from the healthy piglets, none harboured fedA or secreted LT; 23% (6/26) secreted ST, and 50% (13/26) carried astA. A statistical regression was applied on the 100 E. coli strains retrieved from the diarrhoeic piglets, where fedA was set as the dependent variable and the enterotoxin secretions were set as the independent variables. The results exhibit that the LT secretion was the only significant factor (P < 0.000 1) correlated to fedA in the diarrhoeic piglets; thus, it is concluded that the prevalent virulence factors for PWD were the ECET strain with F18 fimbriae adhesion and LT secretion, but not astA or stx2e.
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Affiliation(s)
- Chuan-Shun Lin
- Animal Technology Research Center, Agricultural Technology Research Institute, Taiwan, R.O.C
| | - Chiao-Hsia Huang
- Institute of Molecular Biology, National Chung Hsing University, Taiwan, R.O.C
| | | | - Chien-Wen Huang
- Department of Medical Laboratory Science and Biotechnology, Asia University, Taiwan, R.O.C
| | - Yen-I Cheng
- Institute of Molecular Biology, National Chung Hsing University, Taiwan, R.O.C
| | - Jiann-Hwa Chen
- Institute of Molecular Biology, National Chung Hsing University, Taiwan, R.O.C
| | - Yung-Chuan Liu
- Department of Chemical Engineering, National Chung Hsing University, Taiwan, R.O.C
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Qi M, Cao Z, Shang P, Zhang H, Hussain R, Mehmood K, Chang Z, Wu Q, Dong H. Comparative analysis of fecal microbiota composition diversity in Tibetan piglets suffering from diarrheagenic Escherichia coli (DEC). Microb Pathog 2021; 158:105106. [PMID: 34311015 DOI: 10.1016/j.micpath.2021.105106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/29/2021] [Accepted: 07/20/2021] [Indexed: 02/06/2023]
Abstract
This study was ascertained to investigate the adverse effects of pathogenic E. coli on gut microbiota of Tibetan piglets with history of yellow and white dysentery. For this purpose, a total of 18 fecal samples were collected from infected and healthy Tibetan piglets for 16S rRNA gene amplification and sequencing of V3-V4 region. Results showed that Firmicutes, Bacteroidia Fusobacteriota, Proteobacteria and Actinobacteriota were the predominant bacteria in Tibetan piglets at the level of phylum classification. Results on classification at family level showed that Lactobacillus, Bacteroidota, Fusobacteriota and Enterobacteriaceae were the dominant bacteria. Results on classification of bacteria at phylum level compared with normal piglets indicated that Bacteroidota, Actinobacteriota, Euryarchaota and Spirochaetota in fecal microbial community in Tibetan piglets showing yellow dysenteric and diarrhea group were significantly decreased (P ≤ 0.05). Compared with the feces of healthy Tibetan piglets, the abundance of Escherichia-Shigella, Lactobacillus and Enterococcus increased significantly in feces of Tibetan piglets having yellow dysentery and white dysentery. Moreover, results exhibited that the Proteobacteria and Fusobacteriota were significantly increased (P ≤ 0.05) suggesting dominant microbial community. Results revealed that E. coli induced different pathological alterations in intestine including damage to intestinal epithelial cells, infiltration of inflammatory cells, presence of red blood cells in spaces of tissues, hemorrhages and necrosis of intestinal villi in piglets with history of yellow dysentery. This study for the first time reported the composition, characteristics, and differences of the fecal microflora diversity of Tibetan piglets with yellow and white dysentery in Qinghai-Tibet Plateau, which can provide a suitable support for effective control of diarrhoeal disease in these animals.
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Affiliation(s)
- Ming Qi
- Animal Science College, Tibet Agriculture & Animal Husbandry University, Linzhi, China
| | - Zhipeng Cao
- Animal Science College, Tibet Agriculture & Animal Husbandry University, Linzhi, China
| | - Peng Shang
- Animal Science College, Tibet Agriculture & Animal Husbandry University, Linzhi, China
| | - Hui Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Riaz Hussain
- Department of Pathology, Faculty of Veterinary and Animal Sciences, The Islamia University of Bahawalpur, 63100, Pakistan
| | - Khalid Mehmood
- Department of Clinical Medicine and Surgery, Faculty of Veterinary and Animal Sciences, The Islamia University of Bahawalpur, 63100, Pakistan
| | - Zhenyu Chang
- Animal Science College, Tibet Agriculture & Animal Husbandry University, Linzhi, China
| | - Qingxia Wu
- Animal Science College, Tibet Agriculture & Animal Husbandry University, Linzhi, China
| | - Hailong Dong
- Animal Science College, Tibet Agriculture & Animal Husbandry University, Linzhi, China.
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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: 6] [Impact Index Per Article: 2.0] [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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Essendoubi S, Yang X, King R, Keenliside J, Bahamon J, Diegel J, Lu P, Cassis R, Gensler G, Stashko N, Rolheiser D. Prevalence and Characterization of Escherichia coli O157:H7 on Pork Carcasses and in Swine Colon Contents from Provincially Licensed Abattoirs in Alberta, Canada. J Food Prot 2020; 83:1909-1917. [PMID: 32584991 DOI: 10.4315/jfp-20-146] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 06/23/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT The objective of this study was to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in colon contents and on carcasses from pigs slaughtered at provincially licensed abattoirs (PLAs) in Alberta, Canada. In 2017, carcass sponge samples and colon content samples were collected from 504 healthy market hogs at 39 PLAs and analyzed for E. coli O157:H7. Carcass samples were also analyzed for E. coli and aerobic colony count (ACC). Nine (1.8%) of 504 carcass samples were confirmed positive for E. coli O157:H7. Seven (1.4%) of 504 colon content samples were confirmed positive for E. coli O157:H7. These positives were found in 5 (12.8%) of 39 PLAs from hogs originating from eight farms. The E. coli O157:H7 isolates recovered from the positive samples (n = 1 isolate per sample) were clonal, as determined by pulsed-field gel electrophoresis. Six E. coli O157:H7 isolates obtained over 8 months from one PLA that only processed hogs and sourced hogs from one farm had indistinguishable pulsed-field gel electrophoresis patterns. All 16 E. coli O157:H7 isolates harbored eae and ehxA and were of stx2a subtype, suggesting that swine can carry E. coli O157:H7 of importance to human health. All carcass sponge swabs (100%) were positive for ACC. E. coli was present in 72% of carcass swabs. Carcasses from PLAs slaughtering both beef and hogs had a numerically higher ACC mean value but not statistically different compared with the carcasses from PLAs slaughtering only swine (2,799 and 610 CFU/cm2, respectively). E. coli showed a similar trend with a mean value of 0.88 CFU/cm2 in PLAs slaughtering both species and 0.26 CFU/cm2 in PLAs slaughtering only swine (P ≤ 0.05). This study provides evidence that healthy market hogs from different producers and farms in Alberta can carry E. coli O157:H7, and some strains of the organism may be able to establish persistence on some swine farms. HIGHLIGHTS
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Affiliation(s)
- Saida Essendoubi
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
| | - Xianqin Yang
- Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, Alberta, Canada T4L 1W1
| | - Robin King
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
| | - Julia Keenliside
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
| | - Javier Bahamon
- Alberta Pork, 4828 89 Street N.W., Edmonton, Alberta, Canada, T6E 5K1
| | - Jennifer Diegel
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
| | - Patricia Lu
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
| | - Rashed Cassis
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
| | - Gary Gensler
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
| | - Natisha Stashko
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
| | - Deana Rolheiser
- Alberta Agriculture and Forestry, J. G. O'Donoghue Building, 7000 113 Street, Edmonton, Alberta, Canada T6H 5T6
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de Carvalho MPN, Fernandes MR, Sellera FP, Lopes R, Monte DF, Hippólito AG, Milanelo L, Raso TF, Lincopan N. International clones of extended-spectrum β-lactamase (CTX-M)-producing Escherichia coli in peri-urban wild animals, Brazil. Transbound Emerg Dis 2020; 67:1804-1815. [PMID: 32239649 PMCID: PMC7540485 DOI: 10.1111/tbed.13558] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/29/2020] [Accepted: 03/23/2020] [Indexed: 12/22/2022]
Abstract
CTX-M-type extended-spectrum β-lactamase (ESBL)-producing Escherichia coli clones have been increasingly reported worldwide. In this regard, although discussions of transmission routes of these bacteria are in evidence, molecular data are lacking to elucidate the epidemiological impacts of ESBL producers in wild animals. In this study, we have screened 90 wild animals living in a surrounding area of São Paulo, the largest metropolitan city in South America, to monitor the presence of multidrug-resistant (MDR) Gram-negative bacteria. Using a genomic approach, we have analysed eight ceftriaxone-resistant E. coli. Resistome analyses revealed that all E. coli strains carried blaCTX-M -type genes, prevalent in human infections, besides other clinically relevant resistance genes to aminoglycosides, β-lactams, phenicols, tetracyclines, sulphonamides, trimethoprim, fosfomycin and quinolones. Additionally, E. coli strains belonged to international sequence types (STs) ST38, ST58, ST212, ST744, ST1158 and ST1251, and carried several virulence-associated genes. Our findings suggest spread and adaptation of international clones of CTX-M-producing E. coli beyond urban settings, including wildlife from shared environments.
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Affiliation(s)
| | - Miriam R. Fernandes
- Department of Clinical and Toxicological AnalysisSchool of Pharmaceutical SciencesUniversity of Sao PauloSao PauloBrazil
| | - Fábio P. Sellera
- Department of Internal MedicineSchool of Veterinary Medicine and Animal ScienceUniversity of São PauloSão PauloBrazil
| | - Ralf Lopes
- Department of MicrobiologyInstituto de Ciências BiomédicasUniversidade de São PauloSão PauloBrazil
| | - Daniel F. Monte
- Department of Food and Experimental NutritionFaculty of Pharmaceutical SciencesFood Research CenterUniversity of São PauloSão PauloBrazil
| | - Alícia G. Hippólito
- Department of Veterinary Surgery and AnesthesiologySchool of Veterinary Medicine and Animal ScienceUniversidade Estadual Paulista (UNESP)BotucatuBrazil
| | - Liliane Milanelo
- Reception Center for WildlifeEcological Park TietêSão PauloBrazil
| | - Tânia F. Raso
- Department of PathologySchool of Veterinary Medicine and Animal ScienceUniversity of São PauloSão PauloBrazil
| | - Nilton Lincopan
- Department of Clinical and Toxicological AnalysisSchool of Pharmaceutical SciencesUniversity of Sao PauloSao PauloBrazil
- Department of MicrobiologyInstituto de Ciências BiomédicasUniversidade de São PauloSão PauloBrazil
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Nimnoi P, Pongsilp N. Distribution and expression of virulence genes in potentially pathogenic bacteria isolated from seafood in Thailand. CYTA - JOURNAL OF FOOD 2020. [DOI: 10.1080/19476337.2020.1842502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Pongrawee Nimnoi
- Department of Microbiology, Faculty of Liberal Arts and Science, Kasetsart University, Nakhon Pathom, Thailand
| | - Neelawan Pongsilp
- Department of Microbiology, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
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Won G, Kim TH, Lee JH. A novel Salmonella strain inactivated by a regulated autolysis system and expressing the B subunit of Shiga toxin 2e efficiently elicits immune responses and confers protection against virulent Stx2e-producing Escherichia coli. BMC Vet Res 2017; 13:40. [PMID: 28143511 PMCID: PMC5286835 DOI: 10.1186/s12917-017-0962-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 01/26/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Salmonella Typhimurium (S. Typhimurium) inactivated by a regulated autolysis system was genetically engineered to express the homo-pentameric B subunit of Shiga toxin 2e (Stx2eB) on its surface. To prepare a strain able to yield autolyzed Salmonella bearing Stx2eB, the plasmid pJHL184 harboring stx 2eB gene was transformed into the attenuated S. Typhimurium strain, JOL1454. Stx2eB subcloned into the antigen delivery cassette of the plasmid was expressed as fusion protein with the outer membrane protein RESULTS: The expression of Stx2eB fused to the signal peptide in JOL1454 was validated by immunoblot analysis. To determine the immunogenicity of JOL1454, female BALB/c mice were intramuscularly injected with 1 × 108 CFU of the inactivated cells at weeks 0 and 2. Significantly elevated levels of IgG and IgA specific to Stx2eB was observed at weeks 4 and 6 post-immunization (PI) (P <0.05). Proportion of CD3+CD4+ T lymphocyte subpopulation was also significantly augmented in in vivo stimulated splenocytes relative to that in the control group. The increased titers of IgG1 and IgG2a, and of immunomodulatory cytokines indicated that the immunization elicited Th1 and Th2 immune responses. Further, immunomodulatory cytokine genes (IL-6, IL-17A, IL21 and JOL1454) efficiently upregulated in naïve porcine peripheral blood mononuclear cells (PBMCs) pulsed with JOL1454. At week 6 PI, following the challenge with a virulent Stx2e-producing Escherichia coli in the mice, all immunized mice survived whereas approximately 30% of the mice in the control group died. CONCLUSIONS JOL1454 provided superior immunogenicity and effective protection against challenge with a sublethal dose, which demonstrates its potential as a candidate vaccine against edema disease.
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Affiliation(s)
- Gayeon Won
- College of Veterinary Medicine, Chonbuk National University, Iksan campus, Gobong-ro 79, Iksan, 54596, Republic of Korea
| | - Tae Hoon Kim
- College of Veterinary Medicine, Chonbuk National University, Iksan campus, Gobong-ro 79, Iksan, 54596, Republic of Korea
| | - John Hwa Lee
- College of Veterinary Medicine, Chonbuk National University, Iksan campus, Gobong-ro 79, Iksan, 54596, Republic of Korea.
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Stratakos AC, Linton M, Millington S, Grant IR. A loop-mediated isothermal amplification method for rapid direct detection and differentiation of nonpathogenic and verocytotoxigenic Escherichia coli in beef and bovine faeces. J Appl Microbiol 2017; 122:817-828. [PMID: 27992094 DOI: 10.1111/jam.13381] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/07/2016] [Accepted: 12/13/2016] [Indexed: 11/29/2022]
Abstract
AIM To develop a multiplex loop-mediated isothermal amplification (LAMP) assay capable of quantifying Escherichia coli and differentiating verocytotoxigenic E. coli (VTEC). METHODS AND RESULTS Primer sets were selected to amplify the phoA gene (all E. coli strains) and stx1 and/or stx2 genes (VTEC strains only). LAMP calibration curves demonstrated good quantification capability compared with conventional culture. The limits of detection 50% (LOD50 ) of the multiplex LAMP assay were 2·8 (95% CI 2·4-3·3), 3·2 (95% CI 2·5-3·9) and 2·8-3·2 (95% CI 2·1-3·5) log CFU per g for the phoA, stx1 and stx2 genes, respectively. When validated by testing retail beef and bovine faeces samples, good correlation between E. coli counts indicated by the LAMP assay and culture was observed; however, false-negative LAMP assay results were obtained for 12·5-14·7% of samples. CONCLUSIONS A rapid, multiplex LAMP assay for direct quantification of E. coli and specific detection of VTEC in beef and faeces was successfully developed. Further optimisation of the assay would be needed to improve detection sensitivity. SIGNIFICANCE AND IMPACT OF THE STUDY The multiplex LAMP assay represents a rapid alternative to culture for monitoring E. coli levels on beef for hygiene monitoring purposes, and, potentially, a method for detection of VTEC in beef and faeces.
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Affiliation(s)
- A Ch Stratakos
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - M Linton
- Food Microbiology Branch, Agriculture, Food and Environmental Science Division, Agri-Food and Biosciences Institute for Northern Ireland, Belfast, UK
| | | | - I R Grant
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
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10
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The dnd operon for DNA phosphorothioation modification system in Escherichia coli is located in diverse genomic islands. BMC Genomics 2015; 16:199. [PMID: 25879448 PMCID: PMC4373003 DOI: 10.1186/s12864-015-1421-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 02/28/2015] [Indexed: 11/29/2022] Open
Abstract
Background Strains of Escherichia coli that are non-typeable by pulsed-field gel electrophoresis (PFGE) due to in-gel degradation can influence their molecular epidemiological data. The DNA degradation phenotype (Dnd+) is mediated by the dnd operon that encode enzymes catalyzing the phosphorothioation of DNA, rendering the modified DNA susceptible to oxidative cleavage during a PFGE run. In this study, a PCR assay was developed to detect the presence of the dnd operon in Dnd+E. coli strains and to improve their typeability. Investigations into the genetic environments of the dnd operon in various E. coli strains led to the discovery that the dnd operon is harboured in various diverse genomic islands. Results The dndBCDE genes (dnd operon) were detected in all Dnd+E. coli strains by PCR. The addition of thiourea improved the typeability of Dnd+E. coli strains to 100% using PFGE and the Dnd+ phenotype can be observed in both clonal and genetically diverse E. coli strains. Genomic analysis of 101 dnd operons from genome sequences of Enterobacteriaceae revealed that the dnd operons of the same bacterial species were generally clustered together in the phylogenetic tree. Further analysis of dnd operons of 52 E. coli genomes together with their respective immediate genetic environments revealed a total of 7 types of genetic organizations, all of which were found to be associated with genomic islands designated dnd-encoding GIs. The dnd-encoding GIs displayed mosaic structure and the genomic context of the 7 islands (with 1 representative genome from each type of genetic organization) were also highly variable, suggesting multiple recombination events. This is also the first report where two dnd operons were found within a strain although the biological implication is unknown. Surprisingly, dnd operons were frequently found in pathogenic E. coli although their link with virulence has not been explored. Conclusion Genomic islands likely play an important role in facilitating the horizontal gene transfer of the dnd operons in E. coli with 7 different types of islands discovered so far. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1421-8) contains supplementary material, which is available to authorized users.
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11
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In situ prebiotics for weaning piglets: in vitro production and fermentation of potato galacto-rhamnogalacturonan. Appl Environ Microbiol 2014; 81:1668-78. [PMID: 25527557 DOI: 10.1128/aem.03582-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Postweaning diarrhea (PWD) in pigs is a leading cause of economic loss in pork production worldwide. The current practice of using antibiotics and zinc to treat PWD is unsustainable due to the potential of antibiotic resistance and ecological disturbance, and novel methods are required. In this study, an in vitro model was used to test the possibility of producing prebiotic fiber in situ in the gastrointestinal (GI) tract of the piglet and the prebiotic activity of the resulting fiber in the terminal ileum. Soluble fiber was successfully produced from potato pulp, an industrial waste product, with the minimal enzyme dose in a simulated upper GI tract model extracting 26.9% of the initial dry matter. The fiber was rich in galactose and galacturonic acid and was fermented at 2.5, 5, or 10 g/liter in a glucose-free medium inoculated with the gut contents of piglet terminal ileum. Fermentations of 5 g/liter inulin or 5 g/liter of a purified potato fiber were used as controls. The fibers showed high fermentability, evident by a dose-dependent drop in pH and an increase in the organic acid content, with lactate in particular being increased. Deep sequencing showed a significant increase in the numbers of Lactobacillus and Veillonella organisms and an insignificant increase in the numbers of Clostridium organisms as well as a decrease in the numbers of Streptococcus organisms. Multivariate analysis showed clustering of the treatment groups, with the group treated with purified potato fiber being clearly separated from the other groups, as the microbiota composition was 60% Lactobacillus and almost free of Clostridium. For animal studies, a dosage corresponding to the 5-g/liter treatment is suggested.
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12
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Loop-mediated isothermal amplification assay for detection of generic and verocytotoxin-producing Escherichia coli among indigenous individuals in Malaysia. ScientificWorldJournal 2014; 2014:457839. [PMID: 24967435 PMCID: PMC4055146 DOI: 10.1155/2014/457839] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 05/06/2014] [Indexed: 01/08/2023] Open
Abstract
We have successfully developed a Loop-mediated isothermal amplification (LAMP) assay that could specifically detect generic Escherichia coli (E. coli). This assay was tested on 85 bacterial strains and successfully identified 54 E. coli strains (average threshold time, Tt = 21.26). The sensitivity of this assay was evaluated on serial dilutions of bacterial cultures and spiked faeces. The assay could detect 102 CFU/mL for bacterial culture with Tt = 33.30 while the detection limit for spiked faeces was 103 CFU/mL (Tt = 31.12). We have also detected 46 generic E. coli from 50 faecal samples obtained from indigenous individuals with 16% of the positive samples being verocytotoxin-producing E. coli (VTEC) positive. VT1/VT2 allele was present in one faecal sample while the ratio of VT1 to VT2 was 6 : 1. Overall, our study had demonstrated high risk of VTEC infection among the indigenous community and most of the asymptomatic infection occurred among those aged below 15 years. The role of asymptomatic human carriers as a source of dissemination should not be underestimated. Large scale screening of the VTEC infection among indigenous populations and the potential contamination sources will be possible and easy with the aid of this newly developed rapid and simple LAMP assay.
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Meng Q, Bai X, Zhao A, Lan R, Du H, Wang T, Shi C, Yuan X, Bai X, Ji S, Jin D, Yu B, Wang Y, Sun H, Liu K, Xu J, Xiong Y. Characterization of Shiga toxin-producing Escherichia coli isolated from healthy pigs in China. BMC Microbiol 2014; 14:5. [PMID: 24393167 PMCID: PMC3893481 DOI: 10.1186/1471-2180-14-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 01/02/2014] [Indexed: 01/21/2023] Open
Abstract
Background Shiga toxin-producing Escherichia coli (STEC) is recognized as an important human diarrheal pathogen. Swine plays an important role as a carrier of this pathogen. In this study we determined the prevalence and characteristics of STEC from healthy swine collected between May 2011 and August 2012 from 3 cities/provinces in China. Results A total of 1003 samples, including 326 fecal, 351 small intestinal contents and 326 colon contents samples, was analyzed. Two hundred and fifty five samples were stx-positive by PCR and 93 STEC isolates were recovered from 62 stx-positive samples. Twelve O serogroups and 19 O:H serotypes including 6 serotypes (O100:H20/[H20], O143:H38/[H38], O87:H10, O172:H30/[H30], O159:H16, O9:H30/[H30]) rarely found in swine and ruminants were identified. All 93 STEC isolates harbored stx2 only, all of which were stx2e subtype including 1 isolate being a new variant of stx2e. 53.76%, 15.05% and 2.15% STEC isolates carried astA, hlyA and ehxA respectively. Four STEC isolates harbored the high-pathogenicity island. Of the 15 adherence-associated genes tested, 13 (eae, efa1, iha, lpfAO113, lpfAO157/OI-154, lpfAO157/OI-141, toxB, saa, F4, F5, F6, F17 or F41) were all absent while 2 (paa and F18) were present in 7 and 4 STEC isolates respectively. The majority of the isolates were resistant to tetracycline (79.57%), nalidixic acid (78.49%), trimethoprim-sulfamethoxazole (73.12%) and kanamycin (55.91%). The STEC isolates were divided into 63 pulsed-field gel electrophoresis patterns and 21 sequence types (STs). Isolates of the same STs generally showed the same or similar drug resistance patterns. A higher proportion of STEC isolates from Chongqing showed multidrug resistance with one ST (ST3628) resistant to 14 antimicrobials. Conclusions Our results indicate that swine is a significant reservoir of STEC strains in China. Based on comparison by serotypes and sequence types with human strains and presence of virulence genes, the swine STEC may have a low potential to cause human disease.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Yanwen Xiong
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China.
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