Role of Enteroaggregative Escherichia coli Virulence Factors in Uropathogenesis

Boll, Erik J.; Struve, Carsten; Boisen, Nadia; Olesen, Bente; Stahlhut, Steen G.; Krogfelt, Karen A.

doi:10.1128/iai.01376-12

Cited by 75 publications

(78 citation statements)

References 57 publications

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“…We recently reported an outbreak of UTI in Copenhagen caused by a clonal group of E. coli O78:H10 that both fulfilled molecular criteria for EAEC and contained multiple ExPEC virulence genes (37). Intriguingly, the outbreak strain's EAEC-specific virulence factors were found to increase its uropathogenicity (38). The present finding of antimicrobial-resistant EAEC strains causing UTI replicates the previous study's results, only now with the ESBL phenotype.…”

Section: Discussionsupporting

confidence: 81%

Prevalence and Characteristics of the Epidemic Multiresistant Escherichia coli ST131 Clonal Group among Extended-Spectrum Beta-Lactamase-Producing E. coli Isolates in Copenhagen, Denmark

Olesen¹,

Hansen²,

Nilsson³

et al. 2013

J Clin Microbiol

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We report the characteristics of 115 extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli clinical isolates, from 115 unique Danish patients, over a 1-year study interval (1 October 2008 to 30 September 2009). Forty-four (38%) of the ESBL isolates represented sequence type 131 (ST13)1, from phylogenetic group B2. The remaining 71 isolates were from phylogenetic groups D (27%), A (22%), B1 (10%), and B2 (3%). Serogroup O25 ST131 isolates (n ‫؍‬ 42; 95% of ST131) comprised 7 different K antigens, whereas two ST131 isolates were O16:K100:H5. Compared to non-ST131 isolates, ST131 isolates were associated positively with CTX-M-15 and negatively with CTX-M-1 and CTX-M-14. They also were associated positively with 11 virulence genes, including afa and dra (Dr family adhesins), the F10 papA allele (P fimbria variant), fimH (type 1 fimbriae), fyuA (yersiniabactin receptor), iha (adhesin siderophore), iutA (aerobactin receptor), kpsM II (group 2 capsules), malX (pathogenicity island marker), ompT (outer membrane protease), sat (secreted autotransporter toxin), and usp (uropathogenicity-specific protein) and negatively with hra (heat-resistant agglutinin) and iroN (salmochelin receptor). The consensus virulence gene profile (>90% prevalence) of the ST131 isolates included fimH, fyuA, malX, and usp (100% each), ompT and the F10 papA allele (95% each), and kpsM II and iutA (93% each). ST131 isolates were also positively associated with community acquisition, extraintestinal pathogenic E. coli (ExPEC) status, and the O25, K100, and H4 antigens. Thus, among ESBL E. coli isolates in Copenhagen, ST131 was the most prevalent clonal group, was community associated, and exhibited distinctive and comparatively extensive virulence profiles, plus a greater variety of capsular antigens than reported previously. E scherichia coli is the most common agent of urinary tract infection (UTI) and Gram-negative bacteremia. E. coli sequence type 131 (ST131) is a recently emerged worldwide pandemic clonal group, causing widespread antimicrobial-resistant infections (1). Although many studies have examined various aspects of E. coli ST131 in diverse locales and clinical contexts (1, 2), little is known about ST131's O:K:H serotypes, especially in relation to community versus health care site of acquisition, coresistance phenotypes, extended-spectrum beta-lactamase (ESBL) variants, and pulse-field gel electrophoresis (PFGE) types. Such data are needed to more fully understand the epidemiology of ST131 and to help guide diagnostic and preventive efforts.CTX-M-type beta-lactamases have become the dominant ESBLs worldwide during the past decade (3). The responsible bla CTX-M genes are known to be associated with conjugative plasmids and certain successful bacterial clones, notably ST131 (4).Here we assessed the prevalence of E. coli ST131 among 115 consecutive ESBL-producing E. coli isolates from 115 patients (2008)(2009) from 3 hospitals and 100 general practitioners' offices in Copenhagen, Denmark. Subsequently, we compared ST131 and ...

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Section: Discussionsupporting

confidence: 81%

Prevalence and Characteristics of the Epidemic Multiresistant Escherichia coli ST131 Clonal Group among Extended-Spectrum Beta-Lactamase-Producing E. coli Isolates in Copenhagen, Denmark

Olesen¹,

Hansen²,

Nilsson³

et al. 2013

J Clin Microbiol

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“…The prevalence of EAEC marker genes in urine isolates has also been reported in Brazil (39,57), and E. coli strains with a typical EAEC virulence marker content have been recently isolated from patients with prostatitis (58). Together with the recent documentation of an UTI outbreak caused by an EAEC O78:H10 strain (55,59), this demonstrates the high heterogeneity of this pathotype and underlines that some EAEC strains have the potential to be uropathogenic. Against the background that EAEC represents a highly heterogeneous pathotype (42,60,61), clinically relevant EAEC subtyping should be improved, and the uropathogenicity of EAEC isolates from UTI cases requires further analysis.…”

Section: Discussionmentioning

confidence: 83%

“…This gene combination was also found by Cerna and coworkers (54) in patients suffering from diarrhea, and these genes were therefore recommended as target genes for the rapid diagnosis of EAEC infection. Boll and coworkers reported that an EAEC strain of serotype O78 caused an UTI outbreak and that AAF fimbriae as specific EAEC virulence factors can promote urovirulence (55). Interestingly, isolate 1352 carried the aaf5 determinant (GenBank accession no.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Escherichia coli Isolates from Hospital Inpatients or Outpatients with Urinary Tract Infection

et al. 2014

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e Uropathogenic Escherichia coli (UPEC) is the most common cause of community-and hospital-acquired urinary tract infections (UTIs). Isolates from uncomplicated community-acquired UTIs express a variety of virulence traits that promote the efficient colonization of the urinary tract. In contrast, nosocomial UTIs can be caused by E. coli strains that differ in their virulence traits from the community-acquired UTI isolates. UPEC virulence markers are used to distinguish these facultative extraintestinal pathogens, which belong to the intestinal flora of many healthy individuals, from intestinal pathogenic E. coli (IPEC). IPEC is a diarrheagenic pathogen with a characteristic virulence gene set that is absent in UPEC. Here, we characterized 265 isolates from patients with UTIs during inpatient or outpatient treatment at a hospital regarding their phylogenies and IPEC or UPEC virulence traits. Interestingly, 28 of these isolates (10.6%) carried typical IPEC virulence genes that are characteristic of enteroaggregative E. coli (EAEC), Shiga toxin-producing E. coli (STEC), and atypical enteropathogenic E. coli (aEPEC), although IPEC is not considered a uropathogen. Twenty-three isolates harbored the astA gene coding for the EAEC heat-stable enterotoxin 1 (EAST1), and most of them carried virulence genes that are characteristic of UPEC and/or EAEC. Our results indicate that UPEC isolates from hospital patients differ from archetypal community-acquired isolates from uncomplicated UTIs by their spectrum of virulence traits. They represent a diverse group, including EAEC, as well as other IPEC pathotypes, which in addition contain typical UPEC virulence genes. The combination of typical extraintestinal pathogenic E. coli (ExPEC) and IPEC virulence determinants in some isolates demonstrates the marked genome plasticity of E. coli and calls for a reevaluation of the strict pathotype classification of EAEC.

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“…All primers used are listed in Table 2. The aggR cassette was generated by PCR amplification from a previously constructed JM221⌬aggR mutant strain using primers UpaggR_F and DwaggR_R (29).…”

Section: Methodsmentioning

confidence: 99%

Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

et al. 2015

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Enteroaggregative Escherichia coli (EAEC) organisms belong to a diarrheagenic pathotype known to cause diarrhea and can be characterized by distinct aggregative adherence (AA) in a stacked-brick pattern to cultured epithelial cells. In this study, we investigated 118 EAEC strains isolated from the stools of Danish adults with traveler's diarrhea. We evaluated the presence of the aggregative adherence fimbriae (AAFs) by a multiplex PCR, targeting the four known major subunit variants as well as their usher-encoding genes. Almost one-half (49/118) of the clinical isolates did not possess any known AAF major fimbrial subunit, despite the presence of other AggR-related loci. Further investigation revealed the presence of an AAF-related gene encoding a yet-uncharacterized adhesin, termed agg5A. The sequence of the agg5DCBA gene cluster shared fimbrial accessory genes (usher, chaperone, and minor pilin subunit genes) with AAF/III, as well as the signal peptide present in the beginning of the agg3A gene. The complete agg5DCBA gene cluster from a clinical isolate, EAEC strain C338-14, with the typical stacked-brick binding pattern was cloned, and deletion of the cluster was performed. Transformation to a nonadherent E. coli HB101 and complementation of the nonadherent C338-14 mutant with the complete gene cluster restored the AA adhesion. Overall, we found the agg5A gene in 12% of the 118 strains isolated from Denmark, suggesting that this novel adhesin represents an important variant. During the past decades, enteroaggregative Escherichia coli (EAEC) has emerged as an important pathogen, causing diarrhea in adults and children in both industrialized and nonindustrialized countries (1-5). Moreover, EAEC has also been linked to diarrheal outbreaks (6, 7) including a recent outbreak of foodborne hemorrhagic colitis in Germany affecting more than 4,000 individuals and resulting in a high case fatality rate (8, 9). Additionally, an EAEC urinary tract infection-related outbreak was reported in Denmark (10). Nevertheless, despite EAEC implications in several clinical scenarios, the molecular epidemiology of this pathogen remains unclear. This is mostly due to the heterogeneity of strains, and even though several virulence genes have been identified in EAEC, none have shown to be present in all strains (11)(12)(13)(14), making the recognition of truly virulent strains difficult.Several reports suggest that the key step in EAEC pathogenesis is the ability of the pathogen to adhere to and colonize the intestinal tract, which in EAEC prototype strains is facilitated by aggregative adherence fimbriae (AAF), followed by heavy biofilm formation (15-18). Four variants of the AAF major structural subunit have been described so far: AggA (AAF/I), AafA (AAF/II), Agg3A (AAF/III), and Agg4A (AAF/IV), all regulated by the transcriptional activator AggR, situated on the EAEC virulence plasmid pAA (19)(20)(21)(22)(23). AAFs are distantly related to the Dr family of adhesins, whose biogenesis requires a dedicated periplasmic chaperone, an out...

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Role of Enteroaggregative Escherichia coli Virulence Factors in Uropathogenesis

Cited by 75 publications

References 57 publications

Prevalence and Characteristics of the Epidemic Multiresistant Escherichia coli ST131 Clonal Group among Extended-Spectrum Beta-Lactamase-Producing E. coli Isolates in Copenhagen, Denmark

Prevalence and Characteristics of the Epidemic Multiresistant Escherichia coli ST131 Clonal Group among Extended-Spectrum Beta-Lactamase-Producing E. coli Isolates in Copenhagen, Denmark

Characterization of Escherichia coli Isolates from Hospital Inpatients or Outpatients with Urinary Tract Infection

Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

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