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Comparative analysis of the locus of enterocyte effacement and its flanking regions. Infect Immun 2009; 77:3501-13. [PMID: 19506015 DOI: 10.1128/iai.00090-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The attaching-and-effacing (A/E) phenotype mediated by factors derived from the locus of enterocyte effacement (LEE) is a hallmark of clinically important intestinal pathotypes of Escherichia coli, including enteropathogenic (EPEC), atypical EPEC (ATEC), and enterohemorrhagic E. coli strains. Epidemiological studies indicate that the frequency of diarrhea outbreaks caused by ATEC is increasing. Hence, it is of major importance to further characterize putative factors contributing to the pathogenicity of these strains and to gain additional insight into the plasticity and evolutionary aspects of this emerging pathotype. Here, we analyzed the two clinical ATEC isolates B6 (O26:K60) and 9812 (O128:H2) and compared the genetic organizations, flanking regions, and chromosomal insertion loci of their LEE with those of the LEE of other A/E pathogens. Our analysis shows that the core LEE is largely conserved-particularly among genes coding for the type 3 secretion system-whereas genes encoding effector proteins display a higher variability. Chromosomal insertion loci appear to be restricted to selC, pheU, and pheV. In contrast, striking differences were found between the 5'- and 3'-associated flanking regions reflecting the different histories of the various strains and also possibly indicating different lines in evolution.
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Albert MJ, Rotimi VO, Dhar R, Silpikurian S, Pacsa AS, Molla AM, Szucs G. Diarrhoeagenic Escherichia coli are not a significant cause of diarrhoea in hospitalised children in Kuwait. BMC Microbiol 2009; 9:62. [PMID: 19331674 PMCID: PMC2678128 DOI: 10.1186/1471-2180-9-62] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2008] [Accepted: 03/30/2009] [Indexed: 11/10/2022] Open
Abstract
Background The importance of diarrhoeagenic Escherichia coli (DEC) infections in the Arabian Gulf including Kuwait is not known. The prevalence of DEC (enterotoxigenic [ETEC], enteropathogenic [EPEC], enteroinvasive [EIEC], enterohemorrhagic [EHEC] and enteroaggregative [EAEC]) was studied in 537 children ≤ 5 years old hospitalised with acute diarrhoea and 113 matched controls from two hospitals during 2005–07 by PCR assays using E. coli colony pools. Results The prevalence of DEC varied from 0.75% for EHEC to 8.4% for EPEC (mostly atypical variety) in diarrhoeal children with no significant differences compared to that in control children (P values 0.15 to 1.00). Twenty-seven EPEC isolates studied mostly belonged to non-traditional serotypes and possessed β and θ intimin subtypes. A total of 54 DEC isolates from diarrhoeal children and 4 from controls studied for antimicrobial susceptibility showed resistance for older antimicrobials, ampicillin (0 to 100%), tetracycline (33 to 100%) and trimethoprim (22.2 to 100%); 43.1% of the isolates were multidrug-resistant (resistant to 3 or more agents). Six (10.4%) DEC isolates produced extended spectrum β-lactamases and possessed genetic elements (blaCTX-M, blaTEM and ISEcp1) associated with them. Conclusion We speculate that the lack of significant association of DEC with diarrhoea in children in Kuwait compared to countries surrounding the Arabian Gulf Region may be attributable to high environmental and food hygiene due to high disposable income in Kuwait.
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Affiliation(s)
- M John Albert
- Department of Microbiology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait.
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Jensen C, Ethelberg S, Olesen B, Schiellerup P, Olsen KEP, Scheutz F, Nielsen EM, Neimann J, Høgh B, Gerner-Smidt P, Mølbak K, Krogfelt KA. Attaching and effacing Escherichia coli isolates from Danish children: clinical significance and microbiological characteristics. Clin Microbiol Infect 2007; 13:863-72. [PMID: 17686138 DOI: 10.1111/j.1469-0691.2007.01773.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This study describes the prevalence, clinical manifestations and microbiological characteristics of attaching and effacing Escherichia coli isolates, i.e., enteropathogenic E. coli (EPEC) belonging to the classical EPEC serotypes, non-EPEC attaching and effacing E. coli (A/EEC) and verocytotoxin-producing E. coli (VTEC), isolated in a case-control study of Danish children aged <5 years. Among 424 children with diarrhoea and 866 healthy controls, EPEC and VTEC were more prevalent in cases (2.4% and 2.6%, respectively) than in controls (0.7% and 0.7%, respectively). There was a high frequency of A/EEC isolates (n = 121), but these were equally prevalent in cases (11.3%) and controls (12.5%), and comprised a heterogeneous distribution of O:H serotypes. The intimin (eae) subtypes in A/EEC isolates showed an even distribution; the eae-gamma subtype predominated in classical EPEC cases. The virulence genes encoding the bundle-forming pilus (bfpA) and enteroaggregative heat-stable enterotoxin (astA) were rare among all isolates, and seemed to be of limited pathogenic importance in this population. Virulence characterisation of A/EEC isolates did not reveal any significant differences between cases and controls. Colonisation of children with A/EEC was associated with contact with sheep or goats (OR 2.2). The role of A/EEC, not being VTEC or belonging to the classical EPEC serotypes, requires further clarification, but serotyping is useful in discriminating between EPEC and A/EEC strains.
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Affiliation(s)
- C Jensen
- Department of Bacteriology, Mycology and Parasitology, Statens Serum Institut, Copenhagen, Denmark
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Alikhani MY, Mirsalehian A, Aslani MM. Detection of typical and atypical enteropathogenic Escherichia coli (EPEC) in Iranian children with and without diarrhoea. J Med Microbiol 2006; 55:1159-1163. [PMID: 16914644 DOI: 10.1099/jmm.0.46539-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The present study was performed to investigate the contribution of typical and atypical enteropathogenic Escherichia coli (EPEC) as a cause of infectious diarrhoea among children less than 10 years old in Iran. During the summer months, 247 specimens from children with diarrhoea and 1108 from asymptomatic children were analysed for the presence of EPEC and other bacterial pathogens. Potential enteric pathogens were identified in 140 cases of children with diarrhoea (56.7%). EPEC was the most frequently identified agent (111 cases), followed by Shiga toxin-producing E. coli (13), Shigella (9), Salmonella (6) and Aeromonas sp. (1). EPEC isolates were examined for the presence of eaeA, bfpA and stx genes by PCR. EPEC isolates were classified as typical (eaeA+ bfpA+) or atypical (eaeA+ bfpA-). Typical EPEC was diagnosed in 35 cases (11.8%), compared with 8 (0.4%) in the asymptomatic group (P<0.05). Atypical EPEC strains were isolated from 23 cases (9.3%), compared with 13 (1.2%) of the healthy control group (P<0.05). In conclusion, the data suggest that typical and atypical EPEC are an important cause of diarrhoea in Iranian children.
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Affiliation(s)
- M Yousef Alikhani
- Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
- Department of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Akbar Mirsalehian
- Department of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - M Mehdi Aslani
- Department of Microbiology, Institute Pasteur of Iran, 69 Pasteur Avenue, Tehran, Iran
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Nguyen RN, Taylor LS, Tauschek M, Robins-Browne RM. Atypical enteropathogenic Escherichia coli infection and prolonged diarrhea in children. Emerg Infect Dis 2006; 12:597-603. [PMID: 16704807 PMCID: PMC3294699 DOI: 10.3201/eid1204.051112] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Some clinical isolates of enteropathogenic Escherichia coli (EPEC) lack bundle-forming pili and are termed atypical EPEC. The aim of this study was to determine if atypical EPEC are pathogens by comparing the clinical features of patients infected with atypical EPEC with those of children infected with other causative agents of diarrhea. Fecal samples obtained from children attending the Royal Children's Hospital in Melbourne for investigation of diarrhea were examined for adenovirus, rotavirus, Campylobacter spp., Salmonella spp., protozoa, and pathogenic E. coli. Clinical data were obtained by using a standardized pro forma and analyzed separately. Patients infected with atypical EPEC experienced mild, nondehydrating, and noninflammatory diarrhea that was not particularly associated with fever, vomiting, or abdominal pain. However, the duration of diarrhea in patients infected with atypical EPEC was significantly longer than that caused by the other species or where no pathogens were identified. Infection with atypical EPEC is associated with prolonged diarrhea.
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Affiliation(s)
- Rang N Nguyen
- University of Melbourne, Parkville, Victoria, Australia
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Robins-Browne RM, Bordun AM, Tauschek M, Bennett-Wood VR, Russell J, Oppedisano F, Lister NA, Bettelheim KA, Fairley CK, Sinclair MI, Hellard ME. Escherichia coli and community-acquired gastroenteritis, Melbourne, Australia. Emerg Infect Dis 2004; 10:1797-805. [PMID: 15504266 PMCID: PMC3323264 DOI: 10.3201/eid1010.031086] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
As part of a study to determine the effects of water filtration on the incidence of community-acquired gastroenteritis in Melbourne, Australia, we examined fecal samples from patients with gastroenteritis and asymptomatic persons for diarrheagenic strains of Escherichia coli. Atypical strains of enteropathogenic E. coli (EPEC) were the most frequently identified pathogens of all bacterial, viral, and parasitic agents in patients with gastroenteritis. Moreover, atypical EPEC were more common in patients with gastroenteritis (89 [12.8%] of 696) than in asymptomatic persons (11 [2.3%] of 489, p < 0.0001). Twenty-two random isolates of atypical EPEC that were characterized further showed marked heterogeneity in terms of serotype, genetic subtype, and carriage of virulence-associated determinants. Apart from the surface protein, intimin, no virulence determinant or phenotype was uniformly present in atypical EPEC strains. This study shows that atypical EPEC are an important cause of gastroenteritis in Melbourne.
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Affiliation(s)
- Roy M Robins-Browne
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria 3010, Australia.
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Gärtner JF, Schmidt MA. Comparative analysis of locus of enterocyte effacement pathogenicity islands of atypical enteropathogenic Escherichia coli. Infect Immun 2004; 72:6722-8. [PMID: 15501811 PMCID: PMC523029 DOI: 10.1128/iai.72.11.6722-6728.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The pathogenicity of enteropathogenic Escherichia coli (EPEC) is linked to the locus of enterocyte effacement, or LEE, encoding a type III secretion system (T3SS) that directly transfers bacterial effector proteins into eukaryotic cells. Atypical diffusely adhering EPEC (DA-EPEC) strains that harbor homologues of the LEE but lack the EPEC adherence factor plasmid have been increasingly associated with outbreaks of diarrhea. In this study, we have completely sequenced and functionally characterized LEE pathogenicity islands derived from the clinical DA-EPEC isolates 3431 (O8:H-) and 0181 (O119:H9:K61). LEE3431 and LEE0181 exhibit genetic organization analogous to that of the prototype LEE(E2348/69). Genes constituting the T3SS apparatus are highly conserved. However, LEE-encoded effector proteins exhibit major differences. Transfer and functional expression of LEE0181 in an E. coli XL1 blue MR background demonstrated that LEE0181 contains all the information for signal transduction and pedestal formation.
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Affiliation(s)
- Julia F Gärtner
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung, Universitätsklinikum Münster, Von-Esmarch-Str. 56, D-48149, Germany
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Picot L, Mezghani-Abdelmoula S, Chevalier S, Merieau A, Lesouhaitier O, Guerillon J, Cazin L, Orange N, Feuilloley MGJ. Regulation of the cytotoxic effects of Pseudomonas fluorescens by growth temperature. Res Microbiol 2004; 155:39-46. [PMID: 14759707 DOI: 10.1016/j.resmic.2003.09.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2003] [Accepted: 09/20/2003] [Indexed: 11/17/2022]
Abstract
We had previously shown that the psychrotrophic bacterium Pseudomonas fluorescens can act as a pathogen, inducing apoptosis and necrosis in neurons and glial cells. In the present study, we investigated the influence of the growth temperature of P. fluorescens on its infectious potential. Adherence of P. fluorescens to glial cells was found to be maximal with bacteria grown at a low temperature (8 degrees C). At that temperature the swimming behaviour was markedly reduced. An increase in the growth temperature to 19, 28 or 32 degrees C strongly diminished the binding of bacteria to host cells. Thus, the adhesion phenotype of P. fluorescens appears to be independent of the motility of the bacteria. The apoptotic effect of P. fluorescens, determined by morphological (nuclear condensation) and biochemical (induction of nitric oxide synthase activity) indicators, correlated well with its binding activity on glial cells. In contrast, there was a clear dissociation between maximum binding and maximal necrotic action (measured by the release of lactate dehydrogenase) observed with bacteria grown at 19 degrees C. As suggested by capillary electrophoresis analysis, the differences in apoptotic effects may be related to variations in the molecular structure of LPS originating from bacteria grown at low and high temperatures, whereas the necrotic effect, which was maximal at the optimum temperature for the secretion of exoenzymes, could reflect variations in the metabolic activity of bacteria.
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Affiliation(s)
- Laurent Picot
- Laboratory of Cold Microbiology, UPRES2123, University of Rouen, 55, rue Saint Germain, 27000 Evreux, France
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