Putative Adhesins of Enteropathogenic and Enterohemorrhagic<i>Escherichia coli</i>of Serogroup O26 Isolated from Humans and Cattle

Bardiau, Marjorie; Labrozzo, Sabrina; Mainil, Jacques

doi:10.1128/jcm.02048-08

Cited by 20 publications

(28 citation statements)

References 44 publications

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“…The genes nleB and efa1, located on O island 122 (OI-122), as well as the fimbrial genes lpfA O113 and lpfA R141 , were present in all human and ovine E. coli O26:H11 isolates, in agreement with previous findings (4,36). In contrast, yjaA was absent from all isolates.…”

Section: Discussionsupporting

confidence: 78%

Norwegian Sheep Are an Important Reservoir for Human-Pathogenic Escherichia coli O26:H11

Brandal

Sekse

Lindstedt

et al. 2012

Appl Environ Microbiol

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ABSTRACTA previous national survey ofEscherichia coliin Norwegian sheep detectedeae-positive (eae+)E. coliO26:H11 isolates in 16.3% (80/491) of the flocks. The purpose of the present study was to evaluate the human-pathogenic potential of these ovine isolates by comparing them withE. coliO26 isolates from humans infected in Norway. All humanE. coliO26 isolates studied carried theeaegene and shared flagellar type H11. Two-thirds of the sheep flocks and 95.1% of the patients harbored isolates containingarcAallele type 2 andespKand were classified as enterohemorrhagicE. coli(EHEC) (stxpositive) or EHEC-like (stxnegative). These isolates were further divided into group A (EspK2 positive), associated withstx2-EDL933andstcEO103, and group B (EspK1 positive), associated withstx1a. Although thestxgenes were more frequently present in isolates from patients (46.3%) than in those from sheep flocks (5%), more than half of the ovine isolates in the EHEC/EHEC-like group had multiple-locus variable number of tandem repeat analysis (MLVA) profiles that were identical to those seen instx-positive human O26:H11 isolates. This indicates that EHEC-like ovine isolates may be able to acquirestx-carrying bacteriophages and thereby have the possibility to cause serious illness in humans. The remaining one-third of the sheep flocks and two of the patients had isolates fulfilling the criteria for atypical enteropathogenicE. coli(aEPEC):arcAallele type 1 andespKnegative (group C). The majority of these ovine isolates showed MLVA profiles not previously seen inE. coliO26:H11 isolates from humans. However, according to their virulence gene profile, the aEPEC ovine isolates should be considered potentially pathogenic for humans. In conclusion, sheep are an important reservoir of human-pathogenicE. coliO26:H11 isolates in Norway.

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Section: Discussionsupporting

confidence: 78%

Norwegian Sheep Are an Important Reservoir for Human-Pathogenic Escherichia coli O26:H11

Brandal

Sekse

Lindstedt

et al. 2012

Appl Environ Microbiol

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“…Several adherence-related factors have been described as being present in EPEC or STEC isolates, such as, the enterohemorrhagic E. coli (EHEC) autotransporter C, encoded by ehaC (Abreu et al, 2013); the Iha virulence factor, encoded by iha (Tarr et al, 2000; Bardiau et al, 2009); ToxB, encoded by toxB on the pO157 plasmid (Tatsuno et al, 2001); an autoagglutinating adhesin, Saa (Paton et al, 2001); porcine attaching and effacing-associated adhesin (Paa), encoded by paa (Batisson et al, 2003; Maluta et al, 2014); long polar fimbria (LPF) (Bardiau et al, 2010). …”

Section: Introductionmentioning

confidence: 99%

High Prevalence of Virulence Genes in Specific Genotypes of Atypical Enteropathogenic Escherichia coli

Bai

Jin

et al. 2017

Front. Cell. Infect. Microbiol.

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Atypical enteropathogenic Escherichia coli (aEPEC) strains are emerging enteropathogens that have been detected worldwide. A collection of 228 aEPEC strains (121 from diarrheal patients, 27 from healthy carriers, 47 from animals and 33 from raw meats) were investigated for serotypes, virulence gene profiles and phylogenetic relationships. Sixty-six O serogroups were identified. Serogroup O51 was the most prevalent, followed by O119, O26 and O76. For the 20 virulence genes detected, statistically significant differences were observed in the overall prevalence of efa1 (lifA), nleB, nleE, set/ent, paa, and ehxA genes among strains from diarrheal patients, healthy carriers, animals and raw meats, respectively. Strains from diarrheal patients had significantly higher levels of efa1 (lifA) (29.8 vs. 0%, P = 0.0002), nleB (41.3 vs. 7.4%, P = 0.0004), nleE (43.8 vs. 7.4%, P = 0.0002) and set/ent (41.3 vs. 7.4%, P = 0.0004) genes than strains obtained from healthy carriers. The paa gene was identified more often in isolates from raw meats (63.6 vs. 14.8%, P < 0.0001), animals (42.6 vs. 14.8%, P < 0.0122), and diarrheal patients (36.4 vs. 14.8%, P < 0.0225) than in strains obtained from healthy carriers. The ehxA gene was detected more frequently in strains from raw meats than in strains from diarrheal patients (27.3 vs. 2.5%, P = 0.0000) and healthy carriers (27.3 vs. 7.4%, P = 0.0474). The phylogenetic marker, yjaA, was more frequently observed in strains among healthy carriers than in diarrheal patient strains. Among the 228 aEPEC strains, 79 sequence types (STs) were identified. The prominent STs, which comprised strains carrying the four OI-122 genes and lpfA, were ST40, ST328, and ST29. Overall, the results indicate that aEPEC strains isolated in China are highly heterogeneous. aEPEC strains that are potentially more pathogenic appear to be related to specific STs or clonal complexes and serotypes. The high prevalence of diarrhea-associated genes in animal or raw meat strains suggests a zoonotic transmission pathway for potentially human pathogenic aEPEC.

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“…The presence of chromosomally encoded virulence attributes such as the LEE effectors and putative adhesins was also found to be conserved in EHEC and EPEC pathotypes (21)(22)(23)(24)(25)(26)(27)(28). Some of these adhesins include the long polar fimbriae (21); Iha, a 67-kDa adherence-conferring protein (22); Efa1, an EHEC factor for adherence (23); ToxB, a protein encoded by a gene located on the virulence plasmid (24); Paa, the porcine attaching-and-effacing-associated adhesin (25,26); and a diffuse adherence (ldaH) locus in an aEPEC strain of the O26 serogroup (27).…”

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confidence: 99%

Molecular and Phenotypic Characterization of Escherichia coli O26:H8 among Diarrheagenic E. coli O26 Strains Isolated in Brazil

Piazza¹,

Delannoy²,

Fach³

et al. 2013

Appl Environ Microbiol

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f Escherichia coli strains of serogroup O26 comprise two distinct groups of pathogens, characterized as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC). Among the several genes related to type III secretion system-secreted effector proteins, espK was found to be highly specific for EHEC O26:H11 and its stx-negative derivative strains isolated in European countries. E. coli O26 strains isolated in Brazil from infant diarrhea, foods, and the environment have consistently been shown to lack stx genes and are thus considered atypical EPEC. However, no further information related to their genetic background is known. Therefore, in this study, we aimed to discriminate and characterize these Brazilian O26 stx-negative strains by phenotypic, genetic, and biochemical approaches. Among 44 isolates confirmed to be O26 isolates, most displayed flagellar antigen H11 or H32. Out of the 13 nonmotile isolates, 2 tested positive for fliC H11 , and 11 were fliC H8 positive. The identification of genetic markers showed that several O26:H11 and all O26:H8 strains tested positive for espK and could therefore be discriminated as EHEC derivatives. The presence of H8 among EHEC O26 and its stx-negative derivative isolates is described for the first time. The interaction of three isolates with polarized Caco-2 cells and with intestinal biopsy specimen fragments ex vivo confirmed the ability of the O26 strains analyzed to cause attaching-and-effacing (A/E) lesions. The O26:H32 strains, isolated mostly from meat, were considered nonvirulent. Knowledge of the virulence content of stx-negative O26 isolates within the same serotype helped to avoid misclassification of isolates, which certainly has important implications for public health surveillance.

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Putative Adhesins of Enteropathogenic and EnterohemorrhagicEscherichia coliof Serogroup O26 Isolated from Humans and Cattle

Cited by 20 publications

References 44 publications

Norwegian Sheep Are an Important Reservoir for Human-Pathogenic Escherichia coli O26:H11

Norwegian Sheep Are an Important Reservoir for Human-Pathogenic Escherichia coli O26:H11

High Prevalence of Virulence Genes in Specific Genotypes of Atypical Enteropathogenic Escherichia coli

Molecular and Phenotypic Characterization of Escherichia coli O26:H8 among Diarrheagenic E. coli O26 Strains Isolated in Brazil

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