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Wang W, Wei X, Zhu Z, Wu L, Zhu Q, Arbab S, Wang C, Bai Y, Wang Q, Zhang J. Tn3-like structures co-harboring of bla CTX-M-65, bla TEM-1 and bla OXA-10 in the plasmids of two Escherichia coli ST1508 strains originating from dairy cattle in China. BMC Vet Res 2023; 19:279. [PMID: 38110972 PMCID: PMC10729465 DOI: 10.1186/s12917-023-03847-2] [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: 02/16/2023] [Accepted: 12/05/2023] [Indexed: 12/20/2023] Open
Abstract
The purpose of this study was to determine the level of horizontal transmission of the blaCTX-M-65 gene and the role of its associated mobile genetic elements (MGEs) in the bovine-derived Escherichia coli. After PCR identification, two plasmids carrying blaCTX-M-65 were successfully transferred to the recipient E. coli J53 Azr through conjugation assays and subsequently selected for Whole-Genome sequencing (WGS) analysis. The resistance profiles of these two positive strains and their transconjugants were also determined through antimicrobial susceptibility tests. Whole genome data were acquired using both the PacBio sequencing platform and the Illumina data platform. The annotated results were then submitted to the Genbank database for accession number recording. For comparison, the genetic environment of plasmids carrying the resistance gene blaCTX-M-65 was mapped using the Easyfig software. WGS analysis revealed Tn3-like composite transposons bearing blaCTX-M-65, blaTEM-1, and blaOXA-10 in the IncHI2-type plasmids of these two E. coli ST1508 strains. A phylogenetic tree was generated from all 48 assembled E. coli isolates blaCTX-M-65, blaTEM-1, and blaOXA-10 from the NCBI Pathogen Detection database with our two isolates, showing the relationships and the contribution of SNPs to the diversity between genetic samples. This study suggests that the transmissibility of blaCTX-M-65 on Tn3-like composite transposons contributes to an increased risk of its transmission in E. coli derived from dairy cattle.
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Affiliation(s)
- Weiwei Wang
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
| | - Xiaojuan Wei
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
| | - Zhen Zhu
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
- College of Life Science and Food Engineering, Hebei University of Engineering, Handan, Hebei Province, 056038, People's Republic of China
| | - Lingyu Wu
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
| | - Qiqi Zhu
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
- College of Life Science and Food Engineering, Hebei University of Engineering, Handan, Hebei Province, 056038, People's Republic of China
| | - Safia Arbab
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
| | - Chengye Wang
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
- College of Life Science and Food Engineering, Hebei University of Engineering, Handan, Hebei Province, 056038, People's Republic of China
| | - Yubin Bai
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
| | - Qing Wang
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China
- College of Veterinary Medicines, Gansu Agriculture University, Lanzhou, Gansu Province, 730070, People's Republic of China
| | - Jiyu Zhang
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, Gansu Province, 730050, People's Republic of China.
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, Gansu Province, 730050, People's Republic of China.
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Jiangouyan, Qilihe District, Lanzhou, Gansu Province, 730050, People's Republic of China.
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Prevalence and Whole-Genome Sequence-Based Analysis of Shiga Toxin-Producing Escherichia coli Isolates from the Recto-Anal Junction of Slaughter-Age Irish Sheep. Appl Environ Microbiol 2021; 87:e0138421. [PMID: 34644161 DOI: 10.1128/aem.01384-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) organisms are a diverse group of pathogenic bacteria capable of causing serious human illness, and serogroups O157 and O26 are frequently implicated in human disease. Ruminant hosts are the primary STEC reservoir, and small ruminants are important contributors to STEC transmission. This study investigated the prevalence, serotypes, and shedding dynamics of STEC, including the supershedding of serogroups O157 and O26, in Irish sheep. Recto-anal mucosal swab samples (n = 840) were collected over 24 months from two ovine slaughtering facilities. Samples were plated on selective agars and were quantitatively and qualitatively assessed via real-time PCR (RT-PCR) for Shiga toxin prevalence and serogroup. A subset of STEC isolates (n = 199) were selected for whole-genome sequencing and analyzed in silico. In total, 704/840 (83.8%) swab samples were Shiga toxin positive following RT-PCR screening, and 363/704 (51.6%) animals were subsequently culture positive for STEC. Five animals were shedding STEC O157, and three of these were identified as supershedders. No STEC O26 was isolated. Post hoc statistical analysis showed that younger animals are more likely to harbor STEC and that STEC carriage is most prevalent during the summer months. Following sequencing, 178/199 genomes were confirmed as STEC. Thirty-five different serotypes were identified, 15 of which were not yet reported for sheep. Serotype O91:H14 was the most frequently reported. Eight Shiga toxin gene variants were reported, two stx1 and six stx2, and three novel Shiga-toxin subunit combinations were observed. Variant stx1c was the most prevalent, while many strains also harbored stx2b. IMPORTANCE Shiga toxin-producing Escherichia coli (STEC) bacteria are foodborne, zoonotic pathogens of significant public health concern. All STEC organisms harbor stx, a critical virulence determinant, but it is not expressed in most serotypes. Sheep shed the pathogen via fecal excretion and are increasingly recognized as important contributors to the dissemination of STEC. In this study, we have found that there is high prevalence of STEC circulating within sheep and that prevalence is related to animal age and seasonality. Further, sheep harbor a variety of non-O157 STEC, whose prevalence and contribution to human disease have been underinvestigated for many years. A variety of Stx variants were also observed, some of which are of high clinical importance.
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McCarthy SC, Burgess CM, Fanning S, Duffy G. An Overview of Shiga-Toxin Producing Escherichia coli Carriage and Prevalence in the Ovine Meat Production Chain. Foodborne Pathog Dis 2021; 18:147-168. [PMID: 33395551 DOI: 10.1089/fpd.2020.2861] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Shiga-toxin producing Escherichia coli (STEC) are zoonotic foodborne pathogens that are capable of causing serious human illness. Ovine ruminants are recognized as an important source of STEC and a notable contributor to contamination within the food industry. This review examined the prevalence of STEC in the ovine food production chain from farm-to-fork, reporting carriage in sheep herds, during abattoir processing, and in raw and ready-to-eat meats and meat products. Factors affecting the prevalence of STEC, including seasonality and animal age, were also examined. A relative prevalence can be obtained by calculating the mean prevalence observed over multiple surveys, weighted by sample number. A relative mean prevalence was obtained for STEC O157 and all STEC serogroups at multiple points along the ovine production chain by using suitable published surveys. A relative mean prevalence (and range) for STEC O157 was calculated: for feces 4.4% (0.2-28.1%), fleece 7.6% (0.8-12.8%), carcass 2.1% (0.2-9.8%), and raw ovine meat 1.9% (0.2-6.3%). For all STEC independent of serotype, a relative mean prevalence was calculated: for feces 33.3% (0.9-90.0%), carcass 58.7% (2.0-81.6%), and raw ovine meat 15.4% (2.7-35.5%). The prevalence of STEC in ovine fleece was reported in only one earlier survey, which recorded a prevalence of 86.2%. Animal age was reported to affect shedding in many surveys, with younger animals typically reported as having a higher prevalence of the pathogen. The prevalence of STEC decreases significantly along the ovine production chain after the application of postharvest interventions. Ovine products pose a small risk of potential STEC contamination to the food supply chain.
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Affiliation(s)
- Siobhán C McCarthy
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin, Ireland.,UCD-Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
| | - Catherine M Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin, Ireland
| | - Séamus Fanning
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
| | - Geraldine Duffy
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin, Ireland
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G M Gonzalez A, M F Cerqueira A. Shiga toxin-producing Escherichia coli in the animal reservoir and food in Brazil. J Appl Microbiol 2019; 128:1568-1582. [PMID: 31650661 DOI: 10.1111/jam.14500] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/18/2019] [Accepted: 10/22/2019] [Indexed: 12/11/2022]
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathotype associated with human gastrointestinal disease that may progress to severe complications. Ruminants, especially cattle, are the main reservoirs of STEC contaminating the environment and foods of animal or vegetable origin. Besides Shiga toxin, other virulence factors are involved in STEC virulence. O157:H7 remains the most frequent serotype associated with disease. In Brazil, the prevalence of STEC reaches values as high as 90% in cattle and 20% in meat products which may impact the Brazilian food export trade. However, only few reports are related to human disease. The stx1 gene prevails in cattle, whereas the stx2 gene is more frequent in food. Several STEC serotypes have been isolated from cattle and food in Brazil, including the O157:H7, O111:NT, NT:H19 as well as O26 and O103 serogroups. O113: H21 STEC strains are frequent in ruminants and foods but with no report in human disease. The virulence profile of Brazilian STEC strains from cattle and food suggests a pathogenic potential to humans, although some differences with clinical strains have been detected. Further studies, employing recent and more discriminative techniques are in need to better clarify their virulence potential.
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Affiliation(s)
- Alice G M Gonzalez
- Departamento de Bromatologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Aloysio M F Cerqueira
- Departamento de Microbiologia e Parasitologia, Universidade Federal Fluminense, Niterói, Brazil
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Castro VS, Figueiredo EEDS, Stanford K, McAllister T, Conte-Junior CA. Shiga-Toxin Producing Escherichia Coli in Brazil: A Systematic Review. Microorganisms 2019; 7:E137. [PMID: 31100803 PMCID: PMC6560443 DOI: 10.3390/microorganisms7050137] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/01/2019] [Accepted: 05/04/2019] [Indexed: 02/07/2023] Open
Abstract
Shiga-toxin producing E. coli (STEC) can cause serious illnesses, including hemorrhagic colitis and hemolytic uremic syndrome. This is the first systematic review of STEC in Brazil, and will report the main serogroups detected in animals, food products and foodborne diseases. Data were obtained from online databases accessed in January 2019. Papers were selected from each database using the Mesh term entries. Although no human disease outbreaks in Brazil related to STEC has been reported, the presence of several serogroups such as O157 and O111 has been verified in animals, food, and humans. Moreover, other serogroups monitored by international federal agencies and involved in outbreak cases worldwide were detected, and other unusual strains were involved in some isolated individual cases of foodborne disease, such as serotype O118:H16 and serogroup O165. The epidemiological data presented herein indicates the presence of several pathogenic serogroups, including O157:H7, O26, O103, and O111, which have been linked to disease outbreaks worldwide. As available data are concentrated in the Sao Paulo state and almost completely lacking in outlying regions, epidemiological monitoring in Brazil for STEC needs to be expanded and food safety standards for this pathogen should be aligned to that of the food safety standards of international bodies.
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Affiliation(s)
- Vinicius Silva Castro
- Institute of Chemistry, Universidade Federal do Rio de Janeiro, 21941-909 Rio de Janeiro, Brazil.
- Agronomy and Animal Science College, Universidade Federal de Mato Grosso, 78060-900 Cuiabá-Mato Grosso, Brazil.
- Nutrition College, Universidade Federal de Mato Grosso, 78060-900 Cuiabá-Mato Grosso, Brazil.
- Department of Food Technology, Faculdade de Veterinária, Universidade Federal Fluminense, 24230-340 Rio de Janeiro, Brazil.
| | - Eduardo Eustáquio de Souza Figueiredo
- Agronomy and Animal Science College, Universidade Federal de Mato Grosso, 78060-900 Cuiabá-Mato Grosso, Brazil.
- Nutrition College, Universidade Federal de Mato Grosso, 78060-900 Cuiabá-Mato Grosso, Brazil.
- Alberta Agriculture and Forestry, #100-5401 1st Ave. S, Lethbridge, AB T1J 4V6, Canada.
| | - Kim Stanford
- Alberta Agriculture and Forestry, #100-5401 1st Ave. S, Lethbridge, AB T1J 4V6, Canada.
| | - Tim McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, 5403 1st Avenue South, Lethbridge, AB T1J 4B1, Canada.
| | - Carlos Adam Conte-Junior
- Institute of Chemistry, Universidade Federal do Rio de Janeiro, 21941-909 Rio de Janeiro, Brazil.
- Department of Food Technology, Faculdade de Veterinária, Universidade Federal Fluminense, 24230-340 Rio de Janeiro, Brazil.
- National Institute of Health Quality Control, Fundação Oswaldo Cruz, Rio de Janeiro, 21040-900 Rio de Janeiro, Brazil.
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Ferhat L, Chahed A, Hamrouche S, Korichi-Ouar M, Hamdi TM. Research and molecular characteristic of Shiga toxin-producing Escherichia coli isolated from sheep carcasses. Lett Appl Microbiol 2019; 68:546-552. [PMID: 30801745 DOI: 10.1111/lam.13142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 12/16/2022]
Abstract
Domestic ruminants are regarded as the major reservoir of Shiga toxin-producing Escherichia coli (STEC) closely related to human infection. A total of 363 ovine carcasses were swabbed in an Algiers city slaughterhouse for research on STEC. First of all, screening of the STECs was carried out by a multiplex PCR searching for the genes coding for the virulence factors stx1 , stx2 and eae. This step was followed by STEC isolation and serotyping. The presence of stx+ /stx+ eae+ genes was shown in 116 sheep carcasses (31·95%). From the 116 positive samples, 20 bacterial strains (17·24%) were isolated. Nineteen strains belonged to the species E. coli (STEC), and 1 belonged to Citrobacter braakii (eae+ stx1 + ). During this study, the presence of potentially pathogenic STEC for humans on the surface of sheep carcasses was confirmed. Corrective measures should be considered at the slaughterhouse level to avoid outbreaks of STEC in Algeria. SIGNIFICANCE AND IMPACT OF THE STUDY: PCR screening revealed the significant presence of the genetic markers of Shiga toxin-producing Escherichia coli (STEC) (stx+ /stx+ eae+ ) on the surfaces of sheep carcasses. Citrobacter braakii (stx1 + eae+ ) was isolated for the first time in this study. The risk of foodborne diseases due to STEC must be taken into account in Algeria. To prevent the emergence of epidemic outbreaks among children and older by people, preventive measures should be taken.
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Affiliation(s)
- L Ferhat
- Laboratory of Food Hygiene and Quality Insurance System, High National Veterinary School of Algiers, Algiers, Algeria
| | - A Chahed
- High National Veterinary School of Algiers, Algiers, Algeria
| | - S Hamrouche
- Laboratory of Enterobacteria and Other Related Bacteria, Pasteur Institute, Dely Ibrahim, Algeria
| | - M Korichi-Ouar
- Laboratory of Enterobacteria and Other Related Bacteria, Pasteur Institute, Dely Ibrahim, Algeria
| | - T-M Hamdi
- Laboratory of Food Hygiene and Quality Insurance System, High National Veterinary School of Algiers, Algiers, Algeria
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Rigobelo EEC, Karapetkov N, Maestá SA, Avila FA, McIntosh D. Use of probiotics to reduce faecal shedding of Shiga toxin-producing Escherichia coli in sheep. Benef Microbes 2015; 6:53-60. [PMID: 25380795 DOI: 10.3920/bm2013.0094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Shiga toxin-producing Escherichia coli (STEC) are zoonotic, foodborne pathogens of humans. Ruminants, including sheep, are the primary reservoirs of STEC and there is a need to develop intervention strategies to reduce the entry of STEC into the food chain. The initiation of the majority of bacterial, enteric infections involves colonisation of the gut mucosal surface by the pathogen. However, probiotic bacteria can serve to decrease the severity of infection via a number of mechanisms including competition for receptors and nutrients, and/or the synthesis of organic acids and bacteriocins that create an environment unfavourable for pathogen development. The aim of the current study was to determine whether the administration of a probiotic mixture to sheep experimentally infected with a non-O157 STEC strain, carrying stx1, stx2 and eae genes, was able to decrease faecal shedding of the pathogen. The probiotic mixture contained Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus bulgaricus, Lactobacillus lactis, Streptococcus thermophilus and Enterococcus faecium. The numbers of non-O157 STEC in faecal samples collected from sheep receiving daily doses of the probiotic mixture were significantly lower at the 3rd, 5th and 6th week post-inoculation when compared to the levels recorded in untreated animals. It was concluded that administration of the probiotic mixture reduced faecal shedding of non-O157 STEC in sheep, and holds potential as a pre-harvest intervention method to reduce transmission to humans.
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Affiliation(s)
- E E C Rigobelo
- UNESP, Cmte João Ribeiro de Barros, km 651 17900-000 Dracena, SP, Brazil
| | - N Karapetkov
- Lactina Ltd., 101 Sofia str., 1320 Bankya, Bulgaria
| | - S A Maestá
- UNESP, Cmte João Ribeiro de Barros, km 651 17900-000 Dracena, SP, Brazil
| | - F A Avila
- UNESP Jaboticabal, Rodovia Prof. Paulo Donato Castellane, 14884-900 Jaboticabal, SP, Brazil
| | - D McIntosh
- Departamento de Parasitologia Animal, Instituto de Veterinaria, Universidade Federal Rural do Rio de Janeiro (UFRRJ), BR-465 km 7, 23890-000 Seropédica, RJ, Brazil
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Marin J, Maluta R, Borges C, Beraldo L, Maesta S, Lemos M, Ruiz U, Ávila F, Rigobelo E. Fate of non O157 Shigatoxigenic Escherichia coli in ovine manure composting. ARQ BRAS MED VET ZOO 2014. [DOI: 10.1590/1678-6001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Livestock manure may contain pathogenic microorganisms which pose a risk to the health of animal or humans if the manure is not adequately treated or disposed of. To determine the fate of Shiga toxigenic Escherichia coli (STEC) non O157 in composted manure from naturally colonized sheep, fresh manure was obtained from animals carrying bacterial cells with stx1/ stx2 genes. Two composting systems were used, aerated and non-aerated, and the experiments were done in Dracena city, São Paulo State. Every week, for seven weeks, one manure sample from six different points in both systems was collected and cultured to determine the presence of E. coli, the presence of the virulence genes in the cells, and also the susceptibility to 10 antimicrobial drugs. The temperature was verified at each sampling. STEC non-O157 survived for 49 days in both composting systems. E. coli non-STEC showing a high degree of antibiotic resistance was recovered all long the composting period. No relationship was established between the presence of virulence genes and antibiotic resistance. The presence of virulence genes and multiple antibiotic resistances in E. coli implicates a potential risk for these genes spread in the human food chain, which is a reason for concern.
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Amézquita-López BA, Quiñones B, Cooley MB, León-Félix J, Castro-del Campo N, Mandrell RE, Jiménez M, Chaidez C. Genotypic analyses of shiga toxin-producing Escherichia coli O157 and non-O157 recovered from feces of domestic animals on rural farms in Mexico. PLoS One 2012; 7:e51565. [PMID: 23251577 PMCID: PMC3519732 DOI: 10.1371/journal.pone.0051565] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 11/02/2012] [Indexed: 11/18/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) are zoonotic enteric pathogens associated with human gastroenteritis worldwide. Cattle and small ruminants are important animal reservoirs of STEC. The present study investigated animal reservoirs for STEC in small rural farms in the Culiacan Valley, an important agricultural region located in Northwest Mexico. A total of 240 fecal samples from domestic animals were collected from five sampling sites in the Culiacan Valley and were subjected to an enrichment protocol followed by either direct plating or immunomagnetic separation before plating on selective media. Serotype O157:H7 isolates with the virulence genes stx2, eae, and ehxA were identified in 40% (26/65) of the recovered isolates from cattle, sheep and chicken feces. Pulse-field gel electrophoresis (PFGE) analysis grouped most O157:H7 isolates into two clusters with 98.6% homology. The use of multiple-locus variable-number tandem repeat analysis (MLVA) differentiated isolates that were indistinguishable by PFGE. Analysis of the allelic diversity of MLVA loci suggested that the O157:H7 isolates from this region were highly related. In contrast to O157:H7 isolates, a greater genotypic diversity was observed in the non-O157 isolates, resulting in 23 PFGE types and 14 MLVA types. The relevant non-O157 serotypes O8:H19, O75:H8, O111:H8 and O146:H21 represented 35.4% (23/65) of the recovered isolates. In particular, 18.5% (12/65) of all the isolates were serotype O75:H8, which was the most variable serotype by both PFGE and MLVA. The non-O157 isolates were predominantly recovered from sheep and were identified to harbor either one or two stx genes. Most non-O157 isolates were ehxA-positive (86.5%, 32/37) but only 10.8% (4/37) harbored eae. These findings indicate that zoonotic STEC with genotypes associated with human illness are present in animals on small farms within rural communities in the Culiacan Valley and emphasize the need for the development of control measures to decrease risks associated with zoonotic STEC.
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Affiliation(s)
| | - Beatriz Quiñones
- U.S. Department of Agriculture/Agricultural Research Service, Produce Safety and Microbiology Research Unit, Western Regional Research Center, Albany, California, United States of America
- * E-mail: (BQ); (CC)
| | - Michael B. Cooley
- U.S. Department of Agriculture/Agricultural Research Service, Produce Safety and Microbiology Research Unit, Western Regional Research Center, Albany, California, United States of America
| | - Josefina León-Félix
- Centro de Investigación en Alimentación y Desarrollo, Culiacán, Sinaloa, México
| | | | - Robert E. Mandrell
- U.S. Department of Agriculture/Agricultural Research Service, Produce Safety and Microbiology Research Unit, Western Regional Research Center, Albany, California, United States of America
| | - Maribel Jiménez
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Sinaloa, Culiacán, Sinaloa, México
| | - Cristóbal Chaidez
- Centro de Investigación en Alimentación y Desarrollo, Culiacán, Sinaloa, México
- * E-mail: (BQ); (CC)
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Ayala CDO, Ramos Moreno AC, Martinez MB, Burgos YK, Pestana de Castro AF, Bando SY. Determination of flagellar types by PCR-RFLP analysis of enteropathogenic Escherichia coli (EPEC) and Shiga toxin-producing E. coli (STEC) strains isolated from animals in São Paulo, Brazil. Res Vet Sci 2010; 92:18-23. [PMID: 21094508 DOI: 10.1016/j.rvsc.2010.10.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 10/14/2010] [Accepted: 10/25/2010] [Indexed: 10/18/2022]
Abstract
This study evaluated the polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) analysis of fliC for typing flagella antigen (H) of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) strains isolated from different animals. The molecular typing of the H type was efficient in the determination of 93 (85%) strains. Two nonmotile (H-) E. coli strains showed a PCR-RFLP electrophoretic profile that did not match known H type patterns. The fliC nucleotide sequence of strains B2N and 4a revealed a nucleotide substitution at the restriction site and a nucleotide insertion that generated a stop codon, respectively. The results of this study showed that PCR-RFLP analysis of fliC is faster, less laborious and as efficient for the determination of H type E. coli isolated from animals, compared to serotyping and that it is useful in determining H type in nonmotile strains and strains expressing non-reactive H antigens. Moreover, the fliC sequence of strain B2N suggests that we could have found a new flagellin antigen type.
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Moura RA, Sircili MP, Leomil L, Matté MH, Trabulsi LR, Elias WP, Irino K, Pestana de Castro AF. Clonal relationship among atypical enteropathogenic Escherichia coli strains isolated from different animal species and humans. Appl Environ Microbiol 2009; 75:7399-408. [PMID: 19801470 PMCID: PMC2786407 DOI: 10.1128/aem.00636-09] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Forty-nine typical and atypical enteropathogenic Escherichia coli (EPEC) strains belonging to different serotypes and isolated from humans, pets (cats and dogs), farm animals (bovines, sheep, and rabbits), and wild animals (monkeys) were investigated for virulence markers and clonal similarity by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The virulence markers analyzed revealed that atypical EPEC strains isolated from animals have the potential to cause diarrhea in humans. A close clonal relationship between human and animal isolates was found by MLST and PFGE. These results indicate that these animals act as atypical EPEC reservoirs and may represent sources of infection for humans. Since humans also act as a reservoir of atypical EPEC strains, the cycle of mutual infection of atypical EPEC between animals and humans, mainly pets and their owners, cannot be ruled out since the transmission dynamics between the reservoirs are not yet clearly understood.
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Affiliation(s)
- Rodrigo A. Moura
- Laboratory of Human and Veterinary Bacteriology, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil, Laboratory of Bacteriology, Butantan Institute, São Paulo, SP, Brazil, Laboratory of Public Health, Public Health School, University of São Paulo, São Paulo, SP, Brazil, Adolfo Lutz Institute, São Paulo, SP, Brazil
| | - Marcelo P. Sircili
- Laboratory of Human and Veterinary Bacteriology, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil, Laboratory of Bacteriology, Butantan Institute, São Paulo, SP, Brazil, Laboratory of Public Health, Public Health School, University of São Paulo, São Paulo, SP, Brazil, Adolfo Lutz Institute, São Paulo, SP, Brazil
| | - Luciana Leomil
- Laboratory of Human and Veterinary Bacteriology, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil, Laboratory of Bacteriology, Butantan Institute, São Paulo, SP, Brazil, Laboratory of Public Health, Public Health School, University of São Paulo, São Paulo, SP, Brazil, Adolfo Lutz Institute, São Paulo, SP, Brazil
| | - Maria Helena Matté
- Laboratory of Human and Veterinary Bacteriology, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil, Laboratory of Bacteriology, Butantan Institute, São Paulo, SP, Brazil, Laboratory of Public Health, Public Health School, University of São Paulo, São Paulo, SP, Brazil, Adolfo Lutz Institute, São Paulo, SP, Brazil
| | - Luiz R. Trabulsi
- Laboratory of Human and Veterinary Bacteriology, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil, Laboratory of Bacteriology, Butantan Institute, São Paulo, SP, Brazil, Laboratory of Public Health, Public Health School, University of São Paulo, São Paulo, SP, Brazil, Adolfo Lutz Institute, São Paulo, SP, Brazil
| | - Waldir P. Elias
- Laboratory of Human and Veterinary Bacteriology, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil, Laboratory of Bacteriology, Butantan Institute, São Paulo, SP, Brazil, Laboratory of Public Health, Public Health School, University of São Paulo, São Paulo, SP, Brazil, Adolfo Lutz Institute, São Paulo, SP, Brazil
| | - Kinue Irino
- Laboratory of Human and Veterinary Bacteriology, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil, Laboratory of Bacteriology, Butantan Institute, São Paulo, SP, Brazil, Laboratory of Public Health, Public Health School, University of São Paulo, São Paulo, SP, Brazil, Adolfo Lutz Institute, São Paulo, SP, Brazil
| | - Antonio F. Pestana de Castro
- Laboratory of Human and Veterinary Bacteriology, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil, Laboratory of Bacteriology, Butantan Institute, São Paulo, SP, Brazil, Laboratory of Public Health, Public Health School, University of São Paulo, São Paulo, SP, Brazil, Adolfo Lutz Institute, São Paulo, SP, Brazil
- Corresponding author. Mailing address: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Avenida Prof. Lineu Prestes 1374, 05508-900 São Paulo, SP, Brazil. Phone: 5511 3091-7298. Fax: 5511 3091-7354. E-mail:
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12
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Vettorato MP, de Castro AFP, Cergole-Novella MC, Camargo FLL, Irino K, Guth BEC. Shiga toxin-producing Escherichia coli and atypical enteropathogenic Escherichia coli strains isolated from healthy sheep of different populations in São Paulo, Brazil. Lett Appl Microbiol 2009; 49:53-9. [PMID: 19413771 DOI: 10.1111/j.1472-765x.2009.02617.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Sheep are important carriers of Shiga toxin-producing Escherichia coli (STEC) in several countries. However, there are a few reports about ovine STEC in American continent. METHODS AND RESULTS About 86 E. coli strains previously isolated from 172 healthy sheep from different farms were studied. PCR was used for detection of stx(1), stx(2), eae, ehxA and saa genes and for the identification of intimin subtypes. Restriction fragment length polymorphism (RFLP)-PCR was performed to investigate the variants of stx(1) and stx(2), and the flagellar antigen (fliC) genes in nonmotile isolates. Five isolates were eae(+) and stx(-), and belonged to serotypes O128:H2/beta-intimin (2), O145:H2/gamma, O153:H7/beta and O178:H7/epsilon. Eighty-one STEC isolates were recovered, and the stx genotypes identified were stx(1c)stx(2d-O118) (46.9%), stx(1c) (27.2%), stx(2d-O118) (23.4%), and stx(1c)stx(2dOX3a) (2.5%). Pulsed-field gel electrophoresis (PFGE) revealed 27 profiles among 53 STEC and atypical enteropathogenic Escherichia coli (EPEC) isolates. CONCLUSIONS This study demonstrated that healthy sheep in São Paulo, Brazil, can be carriers of potential human pathogenic STEC and atypical EPEC. SIGNIFICANCE AND IMPACT OF THE STUDY As some of the STEC serotypes presently found have been involved with haemolytic uraemic syndrome (HUS) in other countries, the important role of sheep as sources of STEC infection in our settings should not be disregarded.
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Affiliation(s)
- M P Vettorato
- Departamento de Microbiologia, Instituto de Ciências Biomédicas-II, Universidade de São Paulo, SP, Brazil
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Mendes-Ledesma MRB, Rocha LB, Bueris V, Krause G, Beutin L, Franzolin MR, Trabulsi LR, Elias WP, Piazza RMF. Production and characterization of rabbit polyclonal sera against Shiga toxins Stx1 and Stx2 for detection of Shiga toxin-producing Escherichia coli. Microbiol Immunol 2008; 52:484-91. [PMID: 18822082 DOI: 10.1111/j.1348-0421.2008.00068.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
STEC has emerged as an important group of enteric pathogens worldwide. In this study, rabbit polyclonal Stx1 and Stx2 antisera were raised and employed in the standardization of immunoassays for STEC detection. Using their respective antisera, the limit of detection of the toxin was 35.0 pg for Stx1 and 5.4 pg for Stx2. By immunoblotting, these antisera recognized both toxin subunits. Cross-reactivity was observed in the A subunit, but only Stx2 antiserum was able to neutralize the cytotoxicity of both toxins in the Vero cell assay. Six stx-harboring E. coli isolates were analyzed for their virulence traits. They belonged to different serotypes, including the O48:H7, described for the first time in Brazil. Only three strains harbored eae, and the e-hly gene and hemolytic activity was detected in five strains. Three isolates showed new stx2 variants (stx(2v-ha) and stx(2vb-hb)). The ELISA assay detected all six isolates, including one VCA-negative isolate, while the immunodot assay failed to detect one isolate, which was VCA-positive. In contrast, the colony-immunoblot assay detected only one VCA-positive isolate. Our results demonstrate that among the immunoassays developed in this study, the immunodot, and particularly the ELISA, appear as perspective for STEC detection in developing countries.
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Affiliation(s)
- Meire R B Mendes-Ledesma
- Bacteriology Laboratory, Butantan Institute, Avenida Vital Brazil, 1500, São Paulo, SP, 05503-900, Brazil
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14
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Liu Y, DebRoy C, Fratamico P. Sequencing and analysis of the Escherichia coli serogroup O117, O126, and O146 O-antigen gene clusters and development of PCR assays targeting serogroup O117-, O126-, and O146-specific DNA sequences. Mol Cell Probes 2007; 21:295-302. [PMID: 17452091 DOI: 10.1016/j.mcp.2007.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 02/27/2007] [Accepted: 03/08/2007] [Indexed: 11/22/2022]
Abstract
The O-antigen gene clusters of Escherichia coli serogroups O117, O126, and O146 were sequenced, and 11, 10, and 11 open reading frames (ORFs) were identified, respectively. Genes required for O-antigen sugar biosynthesis, sugar transfer, and sugar processing were identified. Multiplex polymerase chain reaction (PCR) assays were developed targeting the wzx and wzy genes present in the O-antigen gene cluster of these serogroups. The assays were highly serogroup specific when tested against strains belonging to serogroups that were isolated from food, humans, animals, and environmental sources, as well as against representative strains belonging to ca. 165 different E. coli O serogroups and a number of non-E. coli bacteria. Thus, the results demonstrate that the wzx and wzy gene sequences were specific to E. coli O117, O126, and O146 and can be used as diagnostic markers for rapid identification and detection of these serogroups.
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Affiliation(s)
- Yanhong Liu
- Eastern Regional Research Center, US Department of Agriculture, Agricultural Research Service, Wyndmoor, PA 19038, USA
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15
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de Souza RL, Nishimura LS, Guth BEC. Uncommon Shiga toxin-producing Escherichia coli serotype O165:HNM as cause of hemolytic uremic syndrome in São Paulo, Brazil. Diagn Microbiol Infect Dis 2007; 59:223-5. [PMID: 17662558 DOI: 10.1016/j.diagmicrobio.2007.04.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 04/23/2007] [Accepted: 04/29/2007] [Indexed: 10/23/2022]
Abstract
Current knowledge of the circulating enterohemorrhagic Escherichia coli (EHEC) strains as agents of severe infections has a significant impact on the improvement of diagnostic procedures and control strategies. This report describes a case of hemolytic uremic syndrome related to an uncommon EHEC O165:HNM serotype. As far as we know, this serotype has not been previously associated with human infections, nor has it been isolated from the animal reservoir in São Paulo, Brazil.
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Affiliation(s)
- Renato L de Souza
- Departamento de Medicina, Universidade Federal de São Paulo-Escola Paulista de Medicina, São Paulo, SP, Brazil
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16
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Oliveira MG, Brito JRF, Carvalho RR, Guth BEC, Gomes TAT, Vieira MAM, Kato MAMF, Ramos II, Vaz TMI, Irino K. Water buffaloes (Bubalus bubalis) identified as an important reservoir of Shiga toxin-producing Escherichia coli in Brazil. Appl Environ Microbiol 2007; 73:5945-8. [PMID: 17644639 PMCID: PMC2074925 DOI: 10.1128/aem.00929-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The presence of Shiga toxin-producing Escherichia coli (STEC) in water buffaloes is reported for the first time in South America. The prevalence of STEC ranged from 0 to 64% depending on the farm. STEC isolates exhibiting the genetic profiles stx(1)stx(2)ehxA iha saa and stx(2)ehxA iha saa predominated. Of the 20 distinct serotypes identified, more than 50% corresponded to serotypes associated with human diseases.
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Bettelheim KA. The non-O157 shiga-toxigenic (verocytotoxigenic) Escherichia coli; under-rated pathogens. Crit Rev Microbiol 2007; 33:67-87. [PMID: 17453930 DOI: 10.1080/10408410601172172] [Citation(s) in RCA: 197] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Following a brief review of the ecology of Escherichia coli in general, the role of Shiga-Toxigenic (Verocytotoxigenic) E. coli (STEC) as pathogens is addressed. While STEC belonging to the serogroup O157 have been extensively studied and shown to be involved in many cases and outbreaks of human disease, the importance of STEC belonging to other serogroups has not been recognized as much. This review addresses the problems associated with these pathogens, demonstrating that increasing the awareness of them is a major part of the problem. This review then demonstrates how widespread isolations especially from food animals and human disease have been, discussing in particular STEC belonging to serogroups O8, O26, O103, O111, O113 and O128. The animal host-specificity of these STEC is also reviewed. In conclusion some methods of improving isolation of these pathogens is addressed.
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Rey J, Sánchez S, Blanco JE, Hermoso de Mendoza J, Hermoso de Mendoza M, García A, Gil C, Tejero N, Rubio R, Alonso JM. Prevalence, serotypes and virulence genes of Shiga toxin-producing Escherichia coli isolated from ovine and caprine milk and other dairy products in Spain. Int J Food Microbiol 2006; 107:212-7. [PMID: 16260057 DOI: 10.1016/j.ijfoodmicro.2005.08.025] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Revised: 07/13/2005] [Accepted: 08/17/2005] [Indexed: 10/25/2022]
Abstract
The aim of this study was to determinate the prevalence, serotypes and virulence genes of Shiga toxin-producing Escherichia coli (STEC) strains isolated from different dairy products (DP) in Spain with the purpose of determining whether DP represent a potential source of STEC pathogenic for humans. A total of 502 DP were examined from 64 different ovine and caprine flocks and 6 dairy plants in Extremadura (Western Spain). Samples were collected monthly between March 2003 and June 2004 and included 360 unpasteurised milk obtained from the bulk tank, 103 fresh cheese curds and 39 cheeses. Samples obtained were examined for STEC using genotypic (PCR) methods. STEC strains were detected from 39 (10.8%) bulk tank, 4 (3.9%) fresh cheese curds and 2 (5%) cheese, whereas O157:H7 serotype were isolated from one (0.3%) bulk tank. A total of 9 STEC strains (O27:H18, O45:H38, O76:H19, O91:H28, O157:H7, ONT:H7, ONT:H9 and ONT:H21) were identified in this study. One of them, the serotype O27:H18, has not been reported previously as STEC. PCR showed that 3 strains carried stx1 genes, 5 possessed stx2 genes and 1 both stx1 and stx2. Whereas all STEC caprine isolates showed ehxA genes, only O157:H7 serotype showed eae virulence genes. The strain O157:H7 isolated possessed intimin type gamma1 and belonged to phage type 31. This study confirms that dairy product is an important reservoir of STEC pathogenic for humans.
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Affiliation(s)
- J Rey
- Unidad de Patología Infecciosa y Epidemiología, Facultad de Veterinaria, Universidad de Extremadura, Avda. de la Universidad s/n, 10071 Cáceres, Spain.
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Irino K, Kato MAMF, Vaz TMI, Ramos II, Souza MAC, Cruz AS, Gomes TAT, Vieira MAM, Guth BEC. Serotypes and virulence markers of Shiga toxin-producing Escherichia coli (STEC) isolated from dairy cattle in São Paulo State, Brazil. Vet Microbiol 2005; 105:29-36. [PMID: 15607081 DOI: 10.1016/j.vetmic.2004.08.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Revised: 08/17/2004] [Accepted: 08/24/2004] [Indexed: 11/22/2022]
Abstract
In order to determine the occurrence, serotypes and virulence markers of Shiga toxin-producing Escherichia coli (STEC) strains, 153 fecal samples of cattle randomly selected from six dairy farms in Sao Paulo State, Brazil, were examined for Shiga toxin (Stx) production by the Vero cell assay. Feces were directly streaked onto MacConkey Sorbitol Agar and incubated at 37 degrees C overnight. Sorbitol-negative colonies (maximum 20) and up to 10 sorbitol-positive colonies from each plate were subcultured onto presumptive diagnostic medium IAL. Sorbitol-negative isolates were screened with O157 antiserum for identification of O157:H7 E. coli. Isolates presenting cytotoxic activity were submitted to colony hybridization assays with specific DNA probes for stx1, stx2, eae, Ehly and astA genes. The isolation rate of STEC ranged from 3.8 to 84.6% depending on the farm analysed. STEC was identified in 25.5% of the animals, and most of them (64.1%) carried a single STEC serotype. A total of 202 STEC isolates were recovered from the animals, and except for the 2 O157:H7 isolates all the others expressed cytotoxic activity. The great majority of the STEC isolates carried both stx1 and stx2 genes (114/202, 56.4%) or stx2 (82/202, 40.6%); and whereas the Ehly sequence occurred in most of them (88%) eae was only observed in O157:H7 and O111:HNM isolates. Serotypes O113:H21, O178:H19 and O79:H14 were the most frequent STEC serotypes identified and widely distributed among animals from different farms, while others such as O77:H18, O88:H25 and O98:H17 occurred only in particular farms. This is the first report on the occurrence of STEC in dairy cattle in Sao Paulo State, and the results point to substantial differences in rate of isolation, serotypes and genetic profile of STEC that has been previously described among beef cattle in our community. Moreover, to our knowledge O79:H14 and O98:H17 represent new STEC serotypes, while O178:H19 has only been recently reported in Spain.
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Affiliation(s)
- K Irino
- Instituto Adolfo Lutz, Av. Dr. Arnaldo, 351 Cerqueira César, CEP 01246-902, São Paulo, Brazil.
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Guo H, Feng L, Tao J, Zhang C, Wang L. Identification of Escherichia coli O172 O-antigen gene cluster and development of a serogroup-specific PCR assay. J Appl Microbiol 2004; 97:181-90. [PMID: 15186455 DOI: 10.1111/j.1365-2672.2004.02305.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To characterize the locus for O-antigen biosynthesis from Escherichia coli O172 type strain and to develop a rapid, specific and sensitive PCR-based method for identification and detection of E. coli O172. METHODS AND RESULTS DNA of O-antigen gene cluster of E. coli O172 was amplified by long-range PCR method using primers based on housekeeping genes galF and gnd Shot gun bank was constructed and high quality sequencing was performed. The putative genes for synthesis of UDP-FucNAc, O-unit flippase, O-antigen polymerase and glycosyltransferases were assigned by the homology search. The evolutionary relationship between O-antigen gene clusters of E. coli O172 and E. coli O26 is shown by sequence comparison. Genes specific to E. coli O172 strains were identified by PCR assays using primers based on genes for O-unit flippase, O-antigen polymerase and glycosyltransferases. The specificity of PCR assays was tested using all E. coli and Shigella O-antigen type strains, as well as 24 clinical E. coli isolates. The sensitivity of PCR assays was determined, and the detection limits were 1 pg microl(-1) chromosomal DNA, 0.2 CFU g(-1) pork and 0.2 CFU ml(-1) water. The total time required from beginning to end of the procedure was within 16 h. CONCLUSION The O-antigen gene cluster of E. coli O172 was identified and PCR assays based on O-antigen specific genes showed high specificity and sensitivity. SIGNIFICANCE AND IMPACT OF THE STUDY An O-antigen gene cluster was identified by sequencing. The specific genes were determined for E. coli O172. The sensitivity of O-antigen specific PCR assay was tested. Although Shiga toxin-producing O172 strains were not yet isolated from clinical specimens, they may emerge as pathogens.
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Affiliation(s)
- H Guo
- TEDA School of Biological Sciences and Biotechnology, Tianjin State Laboratory of Microbial Functional Genomics, Nankai University, TEDA, Tianjin, China
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