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Tomeh R, Nemati A, Hashemi Tabar G, Tozzoli R, Badouei MA. Antimicrobial resistance, β-lactamase genotypes, and plasmid replicon types of Shiga toxin-producing Escherichia coli isolated from different animal hosts. J Appl Microbiol 2024; 135:lxae059. [PMID: 38467395 DOI: 10.1093/jambio/lxae059] [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: 01/16/2024] [Revised: 02/11/2024] [Accepted: 03/10/2024] [Indexed: 03/13/2024]
Abstract
AIMS The primary objective of this study was to analyze antimicrobial resistance (AMR), with a particular focus on β-lactamase genotypes and plasmid replicon types of Shiga toxin-producing Escherichia coli (STEC) strains originating from various animal hosts. METHODS AND RESULTS A total of 84 STEC strains were isolated from cattle (n = 32), sheep/goats (n = 26), pigeons (n = 20), and wild animals (n = 6) between 2010 and 2018 in various regions of Iran. The Kirby-Bauer susceptibility test and multiple polymerase chain reaction (PCR) panels were employed to elucidate the correlation between AMR and plasmid replicon types in STEC isolates. The predominant replicon types were IncFIC and IncFIB in cattle (46.8%), IncFIC in sheep/goats (46.1%), IncA/C in pigeons (90%), and IncP in wild animals (50%). STEC of serogroups O113, O26, and O111 harbored the IncFIB (100%), IncI1 (80%), and IncFIC + IncA/C (100%) plasmids, respectively. A remarkable AMR association was found between ciprofloxacin (100%), neomycin (68.7%), and tetracycline (61.7%) resistance with IncFIC; amoxicillin + clavulanic acid (88.8%) and tetracycline (61.7%) with IncA/C; ciprofloxacin (100%) with IncFIB; fosfomycin (85.7%) and sulfamethoxazole + trimethoprim (80%) with IncI1. IncI1 appeared in 83.3%, 50%, and 100% of the isolates harboring blaCTX-M, blaTEM, and blaOXA β-lactamase genes, respectively. CONCLUSIONS The emergence of O26/IncI1/blaCTX-M STEC in cattle farms poses a potential risk to public health.
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Affiliation(s)
- Rwida Tomeh
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad 9177948974, Iran
| | - Ali Nemati
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad 9177948974, Iran
| | - Gholamreza Hashemi Tabar
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad 9177948974, Iran
| | - Rosangela Tozzoli
- European Union Reference Laboratory for Escherichia coli, Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Mahdi Askari Badouei
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad 9177948974, Iran
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Fang Y, Tran F, Stanford K, Yang X. Stress Resistance and Virulence Gene Profiles Associated with Phylogeny and Phenotypes of Escherichia coli from Cattle. J Food Prot 2023; 86:100122. [PMID: 37355007 DOI: 10.1016/j.jfp.2023.100122] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/15/2023] [Accepted: 06/19/2023] [Indexed: 06/26/2023]
Abstract
Seven serogroups of E. coli (Top seven E. coli) are frequently implicated in foodborne outbreaks in North America, largely due to their carriage of Shiga toxin genes (stx). This study aimed to profile resistance genes and virulence factors (VF), and their potential association with phylogeny and phenotypes of Top seven E. coli originating from cattle in Canada. 155 Top seven E. coli isolates previously characterized for heat and acid resistance and biofilm-forming ability were whole-genome sequenced and analyzed for phylogeny, VF, and stress resistance genes. The 155 E. coli strains belonged to six phylogroups: A (n = 32), B1 (n = 93), C (n = 3), D (n = 11), E (n = 15), and G (n = 1). Different phylogroups were clearly separated on the core genome tree, with strains of the same serotype closely clustered. The carriage of stx and the transmissible locus of stress tolerance (tLST), the extreme heat resistance marker, was mutually exclusive, in 33 and 15 genomes, respectively. A novel O84:H2 strain carrying stx1a was also identified. In total, 70, 41, and 32 VF, stress resistance genes and antibiotic resistance genes were identified. The stress resistance genes included those for metal (n = 29), biocides/acid (n = 4), and heat (n = 8) resistance. All heat resistance genes and most metal-resistance genes that were differentially distributed among the phylogroups were exclusively in phylogroup A. VF were least and most present in phylogroups A and D, respectively. No specific genes associated with acid resistance or biofilm formation phenotypes were identified. VF were more abundant (P < 0.05) in the non-biofilm-forming population and acid-resistant population.
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Affiliation(s)
- Yuan Fang
- Agriculture and Agri-Food Canada Lacombe Research and Development Centre, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada
| | - Frances Tran
- Agriculture and Agri-Food Canada Lacombe Research and Development Centre, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada
| | - Kim Stanford
- University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Xianqin Yang
- Agriculture and Agri-Food Canada Lacombe Research and Development Centre, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada.
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Prevalence and Virulent Gene Profiles of Sorbitol Non-Fermenting Shiga Toxin-Producing Escherichia coli Isolated from Goats in Southern Thailand. Trop Med Infect Dis 2022; 7:tropicalmed7110357. [DOI: 10.3390/tropicalmed7110357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/31/2022] [Accepted: 10/31/2022] [Indexed: 11/09/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is the pathogenic E. coli causing disease in humans via the consumption or handling of animal food products. The high prevalence of these organisms in ruminants has been widely reported. Among STECs, O157 is one of the most lethal serotypes causing serious disease in humans. The present study investigated the prevalence of sorbitol non-fermenting STECs in goats reared in the lower region of southern Thailand and described the virulent factors carried by those isolates. Sorbitol non-fermenting (SNF)-STECs were found in 57 out of 646 goats (8.82%; 95% CI 6.75% to 11.28%). Molecular identification revealed that 0.77% of SNF-STEC isolates were the O157 serotype. Shiga toxin genes (stx1 and stx2) and other virulent genes (i.e., eaeA, ehxA, and saa) were detected by molecular techniques. The presence of stx1 (75.44%) was significantly higher than that of stx2 (22.81%), whereas 1.75% of the total isolates carried both stx1 and stx2. Most of the isolates carried ehxA for 75.44%, followed by saa (42.11%) and eaeA (12.28%). In addition, 21.05% of STEC isolates did not carry any eaeA, ehxA, or saa. The first investigation on SNF-STECs in goat was conducted in the lower region of southern Thailand. The present study revealed that goats could be one of the potential carriers of SNF-STECs in the observing area.
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Galarce N, Sánchez F, Escobar B, Lapierre L, Cornejo J, Alegría-Morán R, Neira V, Martínez V, Johnson T, Fuentes-Castillo D, Sano E, Lincopan N. Genomic Epidemiology of Shiga Toxin-Producing Escherichia coli Isolated from the Livestock-Food-Human Interface in South America. Animals (Basel) 2021; 11:ani11071845. [PMID: 34206206 PMCID: PMC8300192 DOI: 10.3390/ani11071845] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/20/2022] Open
Abstract
Simple Summary Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens that cause food-borne diseases in humans, where cattle and derived products play a key role as reservoirs and vehicles. We analyzed the genomic data of STEC strains circulating at the livestock-food-human interface in South America, extracting clinically and epidemiologically relevant information (serotypes, virulome, resistance genes, sequence types, and phylogenomics). This study included 130 STEC genomes obtained from cattle (n = 51), beef (n = 48), and human (n = 31) samples. The successful expansion of O157:H7 (ST11) and non-O157 (ST16, ST21, ST223, ST443, ST677, ST679, ST2388) clones is highlighted, suggesting common activities, such as multilateral trade and travel. Circulating STEC strains analyzed exhibit high genomic diversity and harbor several genetic determinants associated with severe illness in humans, highlighting the need to establish official surveillance of this pathogen that should be focused on detecting molecular determinants of virulence and clonal relatedness, in the whole beef production chain. Abstract Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens responsible for causing food-borne diseases in humans. While South America has the highest incidence of human STEC infections, information about the genomic characteristics of the circulating strains is scarce. The aim of this study was to analyze genomic data of STEC strains isolated in South America from cattle, beef, and humans; predicting the antibiotic resistome, serotypes, sequence types (STs), clonal complexes (CCs) and phylogenomic backgrounds. A total of 130 whole genome sequences of STEC strains were analyzed, where 39.2% were isolated from cattle, 36.9% from beef, and 23.8% from humans. The ST11 was the most predicted (20.8%) and included O-:H7 (10.8%) and O157:H7 (10%) serotypes. The successful expansion of non-O157 clones such as ST16/CC29-O111:H8 and ST21/CC29-O26:H11 is highlighted, suggesting multilateral trade and travel. Virulome analyses showed that the predominant stx subtype was stx2a (54.6%); most strains carried ehaA (96.2%), iha (91.5%) and lpfA (77.7%) genes. We present genomic data that can be used to support the surveillance of STEC strains circulating at the livestock-food-human interface in South America, in order to control the spread of critical clones “from farm to table”.
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Affiliation(s)
- Nicolás Galarce
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile; (F.S.); (B.E.); (L.L.); (J.C.); (R.A.-M.); (V.N.)
- Correspondence:
| | - Fernando Sánchez
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile; (F.S.); (B.E.); (L.L.); (J.C.); (R.A.-M.); (V.N.)
- Programa de Doctorado en Ciencias Silvoagropecuarias y Veterinarias, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile
| | - Beatriz Escobar
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile; (F.S.); (B.E.); (L.L.); (J.C.); (R.A.-M.); (V.N.)
| | - Lisette Lapierre
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile; (F.S.); (B.E.); (L.L.); (J.C.); (R.A.-M.); (V.N.)
| | - Javiera Cornejo
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile; (F.S.); (B.E.); (L.L.); (J.C.); (R.A.-M.); (V.N.)
| | - Raúl Alegría-Morán
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile; (F.S.); (B.E.); (L.L.); (J.C.); (R.A.-M.); (V.N.)
- Facultad de Ciencias Agropecuarias y Ambientales, Universidad Pedro de Valdivia, Santiago 8370007, Chile
| | - Víctor Neira
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile; (F.S.); (B.E.); (L.L.); (J.C.); (R.A.-M.); (V.N.)
| | - Víctor Martínez
- Departamento de Fomento de la Producción Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8820808, Chile;
| | - Timothy Johnson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA;
| | - Danny Fuentes-Castillo
- Departamento de Patología, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo 05508-270, Brazil;
| | - Elder Sano
- Departamento de Microbiología, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-900, Brazil; (E.S.); (N.L.)
| | - Nilton Lincopan
- Departamento de Microbiología, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-900, Brazil; (E.S.); (N.L.)
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Molecular Characterization of the Enterohemolysin Gene ( ehxA) in Clinical Shiga Toxin-Producing Escherichia coli Isolates. Toxins (Basel) 2021; 13:toxins13010071. [PMID: 33477906 PMCID: PMC7833379 DOI: 10.3390/toxins13010071] [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: 12/15/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 12/04/2022] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) is an important foodborne pathogen with the ability to cause bloody diarrhea (BD) and hemolytic uremic syndrome (HUS). Little is known about enterohemolysin-encoded by ehxA. Here we investigated the prevalence and diversity of ehxA in 239 STEC isolates from human clinical samples. In total, 199 out of 239 isolates (83.26%) were ehxA positive, and ehxA was significantly overrepresented in isolates carrying stx2a + stx2c (p < 0.001) and eae (p < 0.001). The presence of ehxA was significantly associated with BD and serotype O157:H7. Five ehxA subtypes were identified, among which, ehxA subtypes B, C, and F were overrepresented in eae-positive isolates. All O157:H7 isolates carried ehxA subtype B, which was related to BD and HUS. Three ehxA groups were observed in the phylogenetic analysis, namely, group Ⅰ (ehxA subtype A), group Ⅱ (ehxA subtype B, C, and F), and group Ⅲ (ehxA subtype D). Most BD- and HUS-associated isolates were clustered into ehxA group Ⅱ, while ehxA group Ⅰ was associated with non-bloody stool and individuals ≥10 years of age. The presence of ehxA + eae and ehxA + eae + stx2 was significantly associated with HUS and O157:H7 isolates. In summary, this study showed a high prevalence and the considerable genetic diversity of ehxA among clinical STEC isolates. The ehxA genotypes (subtype B and phylogenetic group Ⅱ) could be used as risk predictors, as they were associated with severe clinical symptoms, such as BD and HUS. Furthermore, ehxA, together with stx and eae, can be used as a risk predictor for HUS in STEC infections.
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Jajarmi M, Askari Badouei M, Ghanbarpour R, Karmostaji A, Alizade H. Antimicrobial resistance patterns and phylogenetic analysis of Shiga toxin-producing Escherichia coli strains from goats using both Clermont phylogenetic schemes. BULGARIAN JOURNAL OF VETERINARY MEDICINE 2021. [DOI: 10.15547/bjvm.2019-0055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Foodborne transmission of Shiga toxin-producing Escherichia coli (STEC) poses a threat to public health. The Clermont typing schemes (previous and revised) have been used widely to phylotype E. coli. The present study was conducted to compare the relationship of the Clermont phylogenet-ic schemes in STEC strains isolated from goats and antibiotic resistance patterns in the southeast of Iran. Overall 52 strains carrying the stx gene were used for subsequent analysis. All strains were determined by analysing the genomic DNA with a PCR-based method using the two Clermont et al. (2000, 2013) schemes. Extended spectrum beta-lactamase (ESBL) producing strains were con-firmed by the double disk-diffusion method. STEC strains were also tested for susceptibility to 20 antimicrobials agents. In the original Clermont method, the prevalent phylogroups were B1 (69.2%) and A (28.8%). The significant phylogenetic groups of strains according to the revised Clermont method were B1 (82.7%), A (13.5%) and unknown (3.8%). However, STEC strains underwent changes as noted from A to B1 (17.3%), B1 to unknown (3.8%), B1 to A (1.9%) and D to B1 (1.9%) groupings. Of the 52 stx-positive strains, two ESBL producing strains were detected. Susceptibility data showed that the most frequent resistance phenotype was related to cefazolin (90.4%), streptomycin (88.5%), ampicillin (86.5%) and oxytetracycline (82.7%) respectively. Alt-hough the overall frequency of the reassigned phylotypes was not significant, most changes oc-curred within the A phylotype. Therefore, implementation of the new method on isolates belong-ing to the A phylotype in the old method seems to be necessary to obtain accurate results.
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Genetic diversity of the intimin gene (eae) in non-O157 Shiga toxin-producing Escherichia coli strains in China. Sci Rep 2020; 10:3275. [PMID: 32094410 PMCID: PMC7040016 DOI: 10.1038/s41598-020-60225-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 02/05/2020] [Indexed: 12/24/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen. The increasing incidence of non-O157 STEC has posed a great risk to public health. Besides the Shiga toxin (Stx), the adherence factor, intimin, coded by eae gene plays a critical role in STEC pathogenesis. In this study, we investigated the prevalence and polymorphisms of eae gene in non-O157 STEC strains isolated from different sources in China. Among 735 non-O157 STEC strains, eae was present in 70 (9.5%) strains. Eighteen different eae genotypes were identified in 62 eae-positive STEC strains with the nucleotide identities ranging from 86.01% to 99.97%. Among which, seven genotypes were newly identified in this study. The eighteen eae genotypes can be categorized into five eae subtypes, namely β1, γ1, ε1, ζ3 and θ. Associations between eae subtypes/genotypes and serotypes as well as origins of strains were observed in this study. Strains belonging to serotypes O26:H11, O103:H2, O111:H8 are associated with particular eae subtypes, i.e., β1, ε1, θ, respectively. Most strains from diarrheal patients (7/9, 77.8%) carried eae-β1 subtype, while most isolates from cattle (23/26, 88.5%) carried eae-ζ3 subtype. This study demonstrated a genetic diversity of eae gene in non-O157 STEC strains from different sources in China.
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Fan R, Shao K, Yang X, Bai X, Fu S, Sun H, Xu Y, Wang H, Li Q, Hu B, Zhang J, Xiong Y. High prevalence of non-O157 Shiga toxin-producing Escherichia coli in beef cattle detected by combining four selective agars. BMC Microbiol 2019; 19:213. [PMID: 31488047 PMCID: PMC6728992 DOI: 10.1186/s12866-019-1582-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 08/27/2019] [Indexed: 12/11/2022] Open
Abstract
Background Shiga toxin-producing Escherichia coli (STEC) are emerging foodborne pathogens that are public health concern. Cattle have been identified as the major STEC reservoir. In the present study, we investigated the prevalence and characteristics of STEC strains in beef cattle from a commercial farm in Sichuan province, China. Results Among 120 beef cattle fecal samples, stx genes were positive in 90% of samples, as assessed using TaqMan real-time PCR, and 87 (72.5%) samples were confirmed to yield at least one STEC isolate by culture using four selective agars, MacConkey, CHROMagar™ ECC, modified Rainbow® Agar O157, and CHROMagar™ STEC, from which 31, 32, 91, and 73 STEC strains were recovered, respectively. A total of 126 STEC isolates were selected and further characterized. Seventeen different O:H serotypes were identified, all of which belonged to the non-O157 serotypes. One stx1 subtype (stx1a) and three stx2 subtypes (stx2a, stx2c, and stx2d) were present among these isolates. The intimin encoding gene eae, and other adherence-associated genes (iha, saa, and paa) were present in 37, 125, 74, and 30 STEC isolates, respectively. Twenty-three isolates carried the virulence gene subA, and only one harbored both cnf1 and cnf2 genes. Three plasmid-origin virulence genes (ehxA, espP, and katP) were present in 111, 111, and 7 isolates, respectively. The 126 STEC isolates were divided into 49 pulsed-field gel electrophoresis (PFGE) patterns. Conclusions Our study showed that the joint use of the selective MacConkey and modified Rainbow® Agar O157 agars increased the recovery frequency of non-O157 STEC strains in animal feces, which could be applied to other samples and in regular STEC surveillance. Moreover, the results revealed high genetic diversity of non-O157 STEC strains in beef cattle, some of which might have the potential to cause human diseases. Electronic supplementary material The online version of this article (10.1186/s12866-019-1582-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ruyue Fan
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Kun Shao
- Shandong Center for Disease Control and Prevention, Jinan, Shandong Province, China
| | - Xi Yang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Xiangning Bai
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Shanshan Fu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Hui Sun
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Yanmei Xu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Hong Wang
- Zigong Center for Disease Control and Prevention, Zigong, Sichuan Province, China
| | - Qun Li
- Zigong Center for Disease Control and Prevention, Zigong, Sichuan Province, China
| | - Bin Hu
- Shandong Center for Disease Control and Prevention, Jinan, Shandong Province, China
| | - Ji Zhang
- mEpiLab, New Zealand Food Safety Science & Research Center, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand
| | - Yanwen Xiong
- State Key Laboratory of 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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Genetics, Toxicity, and Distribution of Enterohemorrhagic Escherichia coli Hemolysin. Toxins (Basel) 2019; 11:toxins11090502. [PMID: 31470552 PMCID: PMC6784236 DOI: 10.3390/toxins11090502] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 11/26/2022] Open
Abstract
The ability to produce enterohemolysin is regarded as a potential virulence factor for enterohemorrhagic Escherichia coli (EHEC) and is frequently associated with severe human diseases such as hemorrhagic colitis (HC) and the hemolytic uremic syndrome (HUS). The responsible toxin, which has also been termed EHEC-hemolysin (EHEC-Hly, syn. Ehx), belongs to the Repeats in Toxin (RTX)-family of pore-forming cytolysins and is characterized by the formation of incomplete turbid lysis zones on blood agar plates containing defibrinated sheep erythrocytes. Besides the expression of Shiga toxins (Stx) and the locus of enterocyte effacement (LEE), EHEC-Hly is a commonly used marker for the detection of potential pathogenic E. coli strains, although its exact role in pathogenesis is not completely understood. Based on the current knowledge of EHEC-Hly, this review describes the influence of various regulator proteins, explains the different mechanisms leading to damage of target cells, discusses the diagnostic role, and gives an insight of the prevalence and genetic evolution of the toxin.
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