Characterization of a Verocytotoxin-Producing Enteroaggregative Escherichia coli Serogroup O111:H21 Strain Associated with a Household Outbreak in Northern Ireland

Dallman, Tim; Smith, Geoffrey; O’Brien, B. J.; Chattaway, Marie Anne; Finlay, D.; Grant, Kathie; Jenkins, Claire

doi:10.1128/jcm.02047-12

Cited by 49 publications

(55 citation statements)

References 20 publications

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“…PCR assay with E coli clinical isolate C338-14 and BLAST analysis revealed an uncharacterized gene, agg5A, whose sequence has been deposited in GenBank (AB571097, AB571098) and which was mentioned in three recent studies (27,41,42). However, as of this writing no experimental characterization of this gene is available.…”

Section: Figmentioning

confidence: 99%

“…Prototype strains JM221, 042, 55989, and C1010-00, each expressing one of the four AAFs, were used in this study (21,22,25,26). E. coli strain 226 was isolated from a 3-year-old female with hemolytic-uremic syndrome (HUS) by the Laboratory of Gastrointestinal Pathogens at the Health Protection Agency in Colindale, United Kingdom, in February 2012; it harbored the Shiga toxin (Stx) type 2c-encoding gene stx 2c as well as aggR and AggR-regulated genes (27).…”

Section: Methodsmentioning

confidence: 99%

“…When EAEC strains from a case-control study performed in Mali were tested (12), AAF/V was present in 8 to 9% of strains in both cases and controls, supporting the endemic situation of EAEC in Africa. The facts that AAF/V exhibits high binding capacity to HEp-2 cells and plastic surfaces and that it was present in a recent outbreak strain causing HUS in Northern Ireland (27) suggest that this variant can result in a highly pathogenic combination.…”

Section: Figmentioning

confidence: 99%

“…BLAST analysis of the agg5A gene from C338-14 revealed four other agg5A sequences; three previously submitted to NCBI (accession numbers AB513347, AB571097, and AB571098) and one agg5A sequence found in a Shiga toxin (Stx) type 2c-producing EAEC strain termed 226 (NCBI Short Read Archive accession number SRA055981) (27). Translation of the five nucleotide sequences showed that several of the unconserved regions had both silent point mutations and altered amino acid composition among the sequences.…”

Section: Aaf Characterization Of Danish Eaec Isolatesmentioning

confidence: 99%

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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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Section: Figmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Section: Aaf Characterization Of Danish Eaec Isolatesmentioning

confidence: 99%

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Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

et al. 2015

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“…The stx-carrying phage was shown to be most closely related to the phage of an STEC O111:NM strain (592) and was probably acquired quite recently in the phylogenetic history of the outbreak strain. EAEC has an established pattern of acquiring Shiga toxins, as reports from Japan (42), France (43), Northern Ireland (593), and Central African Republic (594) describe stx-positive EAEC isolates from patients with HUS. These cases indicate the possibility of outbreaks in the future.…”

Section: Epidemiologymentioning

confidence: 99%

Recent Advances in Understanding Enteric Pathogenic Escherichia coli

et al. 2013

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SUMMARY Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli .

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Environmental Persistence of Shiga Toxin–producingE. coli

Auraß

Flieger

2016

Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria

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Characterization of a Verocytotoxin-Producing Enteroaggregative Escherichia coli Serogroup O111:H21 Strain Associated with a Household Outbreak in Northern Ireland

Cited by 49 publications

References 20 publications

Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

Recent Advances in Understanding Enteric Pathogenic Escherichia coli

Environmental Persistence of Shiga Toxin–producingE. coli

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