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Optimized sample treatment, combined with real-time PCR, for same-day detection of E. coli O157 in ground beef and leafy greens. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.106790] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Frequency, characterization and genotypic analysis of Shiga toxin-producing Escherichia coli in beef slaughterhouses of Argentina. Rev Argent Microbiol 2018; 51:32-38. [PMID: 29937134 DOI: 10.1016/j.ram.2018.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/14/2017] [Accepted: 03/12/2018] [Indexed: 11/23/2022] Open
Abstract
The objectives of this study were: (1) to estimate STEC frequency in hide and carcass samples taken from beef slaughterhouses supplying the domestic market in Argentina, (2) to establish the pheno-genotypic characteristics of STEC and non-toxigenic Escherichia coli of serogroups O26, O45, O103, O121, O111, O145 or O157 isolated from the analyzed samples and, (3) to study their clonal relatedness. Sixty hides and 60 carcasses were analyzed. At the screening step, 48% of hide and 80% of carcass samples tested positive for the stx gene by endpoint PCR. The STEC isolation rate was 5% for hides and 8% for carcasses. The isolation rate of STEC-positive for O26, O45, O103, O111, O145 or O157 serogroups was 0% for hides and 2% for carcasses. With the purpose of studying the clonal relatedness of isolates, macrorestriction fragment analysis by pulsed-field gel electrophoresis was performed. The results indicated cross-contamination between hides and between carcasses of animals in the same lot and, that the origin of carcass contamination was their own hide, or the hides of other animals in the same lot. The high detection rate at the screening step, especially in carcasses, and the evidence of cross-contamination show the need to apply additional in-plant intervention strategies aimed at preventing carcass contamination.
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Baranzoni GM, Fratamico PM, Gangiredla J, Patel I, Bagi LK, Delannoy S, Fach P, Boccia F, Anastasio A, Pepe T. Characterization of Shiga Toxin Subtypes and Virulence Genes in Porcine Shiga Toxin-Producing Escherichia coli. Front Microbiol 2016; 7:574. [PMID: 27148249 PMCID: PMC4838603 DOI: 10.3389/fmicb.2016.00574] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/07/2016] [Indexed: 11/18/2022] Open
Abstract
Similar to ruminants, swine have been shown to be a reservoir for Shiga toxin-producing Escherichia coli (STEC), and pork products have been linked with outbreaks associated with STEC O157 and O111:H-. STEC strains, isolated in a previous study from fecal samples of late-finisher pigs, belonged to a total of 56 serotypes, including O15:H27, O91:H14, and other serogroups previously associated with human illness. The isolates were tested by polymerase chain reaction (PCR) and a high-throughput real-time PCR system to determine the Shiga toxin (Stx) subtype and virulence-associated and putative virulence-associated genes they carried. Select STEC strains were further analyzed using a Minimal Signature E. coli Array Strip. As expected, stx2e (81%) was the most common Stx variant, followed by stx1a (14%), stx2d (3%), and stx1c (1%). The STEC serogroups that carried stx2d were O15:H27, O159:H16 and O159:H-. Similar to stx2a and stx2c, the stx2d variant is associated with development of hemorrhagic colitis and hemolytic uremic syndrome, and reports on the presence of this variant in STEC strains isolated from swine are lacking. Moreover, the genes encoding heat stable toxin (estIa) and enteroaggregative E. coli heat stable enterotoxin-1 (astA) were commonly found in 50 and 44% of isolates, respectively. The hemolysin genes, hlyA and ehxA, were both detected in 7% of the swine STEC strains. Although the eae gene was not found, other genes involved in host cell adhesion, including lpfAO113 and paa were detected in more than 50% of swine STEC strains, and a number of strains also carried iha, lpfAO26, lpfAO157, fedA, orfA, and orfB. The present work provides new insights on the distribution of virulence factors among swine STEC strains and shows that swine may carry Stx1a-, Stx2e-, or Stx2d-producing E. coli with virulence gene profiles associated with human infections.
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Affiliation(s)
- Gian Marco Baranzoni
- Eastern Regional Research Center, United States Department of Agriculture - Agricultural Research Service Wyndmoor, PA, USA
| | - Pina M Fratamico
- Eastern Regional Research Center, United States Department of Agriculture - Agricultural Research Service Wyndmoor, PA, USA
| | - Jayanthi Gangiredla
- Center of Food Safety and Applied Nutrition, U.S. Food and Drug Administration Laurel, MD, USA
| | - Isha Patel
- Center of Food Safety and Applied Nutrition, U.S. Food and Drug Administration Laurel, MD, USA
| | - Lori K Bagi
- Eastern Regional Research Center, United States Department of Agriculture - Agricultural Research Service Wyndmoor, PA, USA
| | - Sabine Delannoy
- Food Safety Laboratory, University of Paris-Est, Anses, Maisons-Alfort France
| | - Patrick Fach
- Food Safety Laboratory, University of Paris-Est, Anses, Maisons-Alfort France
| | - Federica Boccia
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples Italy
| | - Aniello Anastasio
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples Italy
| | - Tiziana Pepe
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples Italy
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Beutin L, Delannoy S, Fach P. Sequence Variations in the Flagellar Antigen Genes fliCH25 and fliCH28 of Escherichia coli and Their Use in Identification and Characterization of Enterohemorrhagic E. coli (EHEC) O145:H25 and O145:H28. PLoS One 2015; 10:e0126749. [PMID: 26000885 PMCID: PMC4441469 DOI: 10.1371/journal.pone.0126749] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/07/2015] [Indexed: 11/19/2022] Open
Abstract
Enterohemorrhagic E. coli (EHEC) serogroup O145 is regarded as one of the major EHEC serogroups involved in severe infections in humans. EHEC O145 encompasses motile and non-motile strains of serotypes O145:H25 and O145:H28. Sequencing the fliC-genes associated with the flagellar antigens H25 and H28 revealed the genetic diversity of the fliCH25 and fliCH28 gene sequences in E. coli. Based on allele discrimination of these fliC-genes real-time PCR tests were designed for identification of EHEC O145:H25 and O145:H28. The fliCH25 genes present in O145:H25 were found to be very similar to those present in E. coli serogroups O2, O100, O165, O172 and O177 pointing to their common evolution but were different from fliCH25 genes of a multiple number of other E. coli serotypes. In a similar way, EHEC O145:H28 harbor a characteristic fliCH28 allele which, apart from EHEC O145:H28, was only found in enteropathogenic (EPEC) O28:H28 strains that shared some common traits with EHEC O145:H28. The real time PCR-assays targeting these fliCH25[O145] and fliCH28[O145] alleles allow better characterization of EHEC O145:H25 and EHEC O145:H28. Evaluation of these PCR assays in spiked ready-to eat salad samples resulted in specific detection of both types of EHEC O145 strains even when low spiking levels of 1-10 cfu/g were used. Furthermore these PCR assays allowed identification of non-motile E. coli strains which are serologically not typable for their H-antigens. The combined use of O-antigen genotyping (O145wzy) and detection of the respective fliCH25[O145] and fliCH28[O145] allele types contributes to improve identification and molecular serotyping of E. coli O145 isolates.
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Affiliation(s)
- Lothar Beutin
- National Reference Laboratory for Escherichia coli, Federal Institute for Risk Assessment (BfR), Diedersdorfer Weg 1, D-12277, Berlin, Germany
| | - Sabine Delannoy
- Université Paris-Est, Anses (French Agency for Food, Environmental and Occupational Health and Safety), Food Safety Laboratory, IdentyPath platform, 14 rue Pierre et Marie Curie, Fr-94700, Maisons-Alfort, France
| | - Patrick Fach
- Université Paris-Est, Anses (French Agency for Food, Environmental and Occupational Health and Safety), Food Safety Laboratory, IdentyPath platform, 14 rue Pierre et Marie Curie, Fr-94700, Maisons-Alfort, France
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Hofer E, Stephan R, Reist M, Zweifel C. Application of a real-time PCR-based system for monitoring of O26, O103, O111, O145 and O157 Shiga toxin-producing Escherichia coli in cattle at slaughter. Zoonoses Public Health 2012; 59:408-15. [PMID: 22348425 DOI: 10.1111/j.1863-2378.2012.01468.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Faecal samples were collected from 573 slaughtered cattle aged between three and 24 months in seven abattoirs. After enrichment (mTSB with novobiocin), samples were screened by real-time PCR first for stx and if positive, tested for the top-five Shiga toxin-producing Escherichia coli (STEC) serogroups using PCR assays targeting genes specific for serogroups O26, O103, O111, O145 and O157. Of 563 samples with available results, 74.1% tested positive for stx genes. Amongst them, the serogroups O145, O103, O26, O157 and O111 were detected in 41.9%, 25.9%, 23.9%, 7.8% and 0.8%, respectively. From 95 O26, 166 O145 and 30 O157 PCR-positive samples, 17 O26, 28 O145 and 12 O157 strains were isolated by colony hybridization after immunomagnetic separation. The 17 O26 strains were eae-positive, but only nine strains harboured stx (eight possessing stx1 and one stx2). Of the 28 O145 strains, ten were eae-positive including four harbouring stx1 or stx2, whereas 18 were negative for stx and eae. Five of the 12 O157 strains harboured stx2 and eae, did not ferment sorbitol, and were identified as STEC O157:H7/H⁻. The other seven O157 strains were negative for stx and eae or positive only for eae. Shiga toxin genes and the top-five STEC serogroups were frequently found in young Swiss cattle at slaughter, but success rates for strain isolation were low and only few strains showed a virulence pattern of human pathogenic STEC.
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Affiliation(s)
- E Hofer
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Zurich, Switzerland
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Fratamico PM, DebRoy C, Miyamoto T, Liu Y. PCR Detection of Enterohemorrhagic Escherichia coli O145 in Food by Targeting Genes in the E. coli O145 O-Antigen Gene Cluster and the Shiga Toxin 1 and Shiga Toxin 2 Genes. Foodborne Pathog Dis 2009; 6:605-11. [DOI: 10.1089/fpd.2008.0254] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Pina M. Fratamico
- Microbial Food Safety Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania
| | - Chitrita DebRoy
- Department of Veterinary and Biomedical Sciences, E. coli Reference Center, The Pennsylvania State University, University Park, Pennsylvania
| | - Takahisa Miyamoto
- Laboratory of Food Hygienic Chemistry, Kyushu University, Hakozaki, Japan
| | - Yanhong Liu
- Microbial Food Safety Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania
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Beutin L, Jahn S, Fach P. Evaluation of the 'GeneDisc' real-time PCR system for detection of enterohaemorrhagic Escherichia coli (EHEC) O26, O103, O111, O145 and O157 strains according to their virulence markers and their O- and H-antigen-associated genes. J Appl Microbiol 2009; 106:1122-32. [PMID: 19191965 DOI: 10.1111/j.1365-2672.2008.04076.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS To evaluate the GeneDisc multiplex real-time PCR assay for detection of enterohaemorrhagic Escherichia coli (EHEC) O26, O103, O111, O145 and O157 strains. METHODS AND RESULTS GeneDiscs for detection of genes encoding Shiga toxins (stx), intimins (eae), E. coli O157 (rfbE(O157)) and H7 (fliC(H7)) antigens as well as genes specific for EHEC O26 (wzx(O26)), O103 (wzx(O103)), O111 (wbd1(O111)), O145 (ihp1(O145)) and O157 (ihp1(O157)) were evaluated. The assay was run with native bacteria in 1 h in a GeneDisc Cycler. All genotypes of stx and eae, except stx(2f) and eae-rho, were identified. Escherichia coli strains belonging to O-groups O26, O103, O111, O157 as well as EHEC O145:[H28] strains were specifically detected with this assay. The ihp1(O157) gene was not found specific for EHEC O157. O-rough mutants of EHEC and non-motile EHEC O157 strains were reliably identified with the GeneDisc assay. Two to three colonies of EHEC strains were still detectable in a lawn of 50 000 apathogenic E. coli from agar plates. CONCLUSIONS The GeneDisc assay is a specific and reliable assay for detection of major EHEC strains. It is robust enough to detect few EHEC colonies in mixed cultures of bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY The assay is promising for its use in EHEC diagnostics and for EHEC monitoring with different kinds of samples.
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Affiliation(s)
- L Beutin
- Centre for Infectiology and Pathogen Characterization, Federal Institute for Risk Assessment, Berlin, Germany.
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Stefan A, Scaramagli S, Bergami R, Mazzini C, Barbanera M, Perelle S, Fach P. Real-time PCR and enzyme-linked fluorescent assay methods for detecting Shiga-toxin-producingEscherichia coliin mincemeat samples. Can J Microbiol 2007; 53:337-42. [PMID: 17538642 DOI: 10.1139/w06-142] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This work aimed to compare real-time polymerase chain reaction (PCR) with the commercially available enzyme-linked fluorescent assay (ELFA) VIDAS ECOLI O157™ for detecting Escherichia coli O157 in mincemeat. In addition, a PCR-based survey on Shiga-toxin-producing E. coli (STEC) in mincemeat collected in Italy is presented. Real-time PCR assays targeting the stx genes and a specific STEC O157 sequence (SILO157, a small inserted locus of STEC O157) were tested for their sensitivity on spiked mincemeat samples. After overnight enrichment, the presence of STEC cells could be clearly determined in the 25 g samples containing 10 bacterial cells, while the addition of five bacteria provided equivocal PCR results with Ct values very close to or above the threshold of 40. The PCR tests proved to be more sensitive than the ELFA-VIDAS ECOLI O157™, whose detection level started from 50 bacterial cells/25 g of mincemeat. The occurrence of STEC in 106 mincemeat (bovine, veal) samples collected from September to November 2004 at five different points of sale in Italy (one point of sale in Arezzo, Tuscany, central Italy, two in Mantova, Lombardy, Northern Italy, and two in Bologna, Emilia-Romagna, upper-central Italy) was less than 1%. Contamination by the main STEC O-serogroups representing a major public health concern, including O26, O91, O111, O145, and O157, was not detected. This survey indicates that STEC present in these samples are probably not associated with pathogenesis in humans.
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Affiliation(s)
- A Stefan
- Laboratorio COOP ITALIA, Via del Lavoro 6/8, Casalecchio di Reno, Bologna, Italy
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Hsu CF, Tsai TY, Pan TM. Use of the duplex TaqMan PCR system for detection of Shiga-like toxin-producing Escherichia coli O157. J Clin Microbiol 2005; 43:2668-73. [PMID: 15956382 PMCID: PMC1151888 DOI: 10.1128/jcm.43.6.2668-2673.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Real-time PCR assays have been applied for the detection and quantification of pathogens in recent years. In this study two combinations of primers and fluorescent probes were designed according to the sequences of the rfb(Escherichia coli O157) and stx2 genes. Analysis of 217 bacterial strains demonstrated that the duplex real-time PCR assay successfully distinguished the Escherichia coli O157 serotype from non-E. coli O157 serotypes and that it provided an accurate means of profiling the genes encoding O antigen and Shiga-like toxin 2. On the other hand, bacterial strains that lacked these genes were not detected by this assay. The quantitative ranges of the real-time PCR assay for these two genes were linear for DNA concentrations ranging from 10(3) to 10(9) CFU/ml of E. coli O157:H7 in pure culture and milk samples. The real-time PCR allowed the construction of standard curves that facilitated the quantification of E. coli O157:H7 in feces and apple juice samples. The detection sensitivity of the real-time PCR assay ranged from 10(4) to 10(9) CFU/g (or 10(4) to 10(9) CFU/ml) for feces and apple juice and 10(5) to 10(9) CFU/g for the beef sample without enrichment. After enrichment of the food samples in a modified tryptic soy broth, the detection range was from 10(0) to 10(3) CFU/ml. The real-time PCR assays for rfb(E. coli) (O157) and stx2 proved to be rapid tests for the detection of E. coli O157 in food matrices and could also be used for the quantification of E. coli O157 in foods or fecal samples.
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Affiliation(s)
- Ching-Fang Hsu
- Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan 106, Republic of China
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Perelle S, Dilasser F, Grout J, Fach P. Detection of Escherichia coli serogroup O103 by real-time polymerase chain reaction. J Appl Microbiol 2005; 98:1162-8. [PMID: 15836486 DOI: 10.1111/j.1365-2672.2005.02545.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS The aims of the study were to identify the specific genes of O-antigen gene cluster from Shiga toxin-producing Escherichia coli (STEC) O103 and to provide the basis for a specific real-time PCR test for rapid detection of E. coli O103. METHODS AND RESULTS The published primers complementary to JUMPstart and gnd gene, the conserved flanking sequences of O-antigen genes clusters in E. coli and related species, were used to amplify the 12-kbp O103 O-antigen biosynthesis locus of STEC O103. A DNA library representative of this cluster allowed two O103-specific probes to be identified in the flippase (wzx) and UDP-galactose-4-epimerase (galE) genes. Two specific O103 serotyping real-time PCR tests based on these two genes were successfully developed. CONCLUSIONS These results confirm that the O-antigen gene cluster sequences of E. coli allow rapidly a specific O-antigen real-time PCR assay to be designed. SIGNIFICANCE AND IMPACT OF THE STUDY These findings increase the number of real-time PCR-assays available to replace the classical O-serotyping among E. coli O-antigen.
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Affiliation(s)
- S Perelle
- Agence Française de Sécurité Sanitaire des Aliments, Laboratoire d'Etudes et de Recherches sur la Qualité des Aliments et sur les Procédés Agroalimentaires, Unité EBA: Etude moléculaire des contaminants biologiques alimentaires, Maisons-Alfort, France
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Perelle S, Dilasser F, Grout J, Fach P. Detection by 5'-nuclease PCR of Shiga-toxin producing Escherichia coli O26, O55, O91, O103, O111, O113, O145 and O157:H7, associated with the world's most frequent clinical cases. Mol Cell Probes 2004; 18:185-92. [PMID: 15135453 DOI: 10.1016/j.mcp.2003.12.004] [Citation(s) in RCA: 210] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2003] [Accepted: 12/08/2003] [Indexed: 12/28/2022]
Abstract
This paper describes 5'-nuclease PCR assays for detecting eight O-serogroups, H7 flagellar antigen and stx genes from the Shiga toxin-producing Escherichia coli (STEC) associated with the world's most frequent clinical cases. A single set of primers was used to detect the genes stx1 and stx2 in the same reaction by 5'-nuclease PCR. Serotyping by 5'-nuclease PCR of STEC was based on the selection of primers and probes targeting the O-antigen gene clusters of E. coli O26, O55, O91, O111, O113, O157, the eae gene of E. coli O103, the O-island 29 of E. coli O145, and the flagellar H7 antigen gene. Results obtained on a collection of 190 strains indicate that the 5'-nuclease PCR assays used here could serve as a basis for rapid specific stx, O and H7 typing of these major pathogenic serogroups of E. coli. This work provides sensitive and specific tests for the rapid, reliable detection of the main pathogenic E. coli O-serogroups of major public health concern.
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Affiliation(s)
- Sylvie Perelle
- Agence Française de Sécurité Sanitaire des Aliments (AFSSA), Laboratoire d'Etudes et de Recherches sur la Qualité des Aliments et sur les Procédés Agroalimentaires, Unité: Etude moléculaire des contaminants biologiques alimentaires, Maisons-Alfort, France
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