Prevalence of Enterotoxigenic
            <i>Escherichia coli</i>
            Strains Harboring the Longus Pilus Gene in Brazil

Nishimura, Lucilia S.; Girón, Jorge A.; Nunes, Solange Lessa; Guth, Beatriz E. C.

doi:10.1128/jcm.40.7.2606-2608.2002

Cited by 15 publications

(14 citation statements)

References 28 publications

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“…CS21 is common in ETEC strains from Argentina, Brazil, Bolivia, Egypt, and Bangladesh (13,21,23,24). In a previous study carried out with Chilean ETEC isolates, CS21 was detected by probe hybridization in a lower percentage of strains (28%) than that in our current study (71.8%) (13).…”

Section: Discussioncontrasting

confidence: 50%

“…In a previous study carried out with Chilean ETEC isolates, CS21 was detected by probe hybridization in a lower percentage of strains (28%) than that in our current study (71.8%) (13). The higher proportion of isolates with CS21 in this study might be due to the fact that we included ETEC strains only from children with diarrhea, in which CS21 ETEC seems to be more common (21). To date the immunogenic potential of CS21 is unknown.…”

Section: Discussionmentioning

confidence: 96%

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Distribution of Classical and Nonclassical Virulence Genes in Enterotoxigenic Escherichia coli Isolates from Chilean Children and tRNA Gene Screening for Putative Insertion Sites for Genomic Islands

et al. 2011

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Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea. Three adhesins (Tia, TibA, EtpA), an iron acquisition system (Irp1, Irp2, and FyuA), a GTPase (LeoA), and an autotransporter (EatA) are ETEC virulence-related proteins that, in contrast to the classical virulence factors (enterotoxins and fimbrial colonization factors) have not heretofore been targets in characterizing isolates from epidemiological studies. Here, we determined the occurrence of these nonclassical virulence genes in 103 ETEC isolates from Chilean children with diarrhea and described their association with O serogroups and classical virulence determinants. Because tia, leoA, irp2, and fyuA are harbored by pathogenicity islands inserted into the selC and asnT tRNA genes (tDNAs), we analyzed the regions flanking these loci. Ten additional tDNAs were also screened to identify hot spots for genetic insertions. Associations between the most frequent serogroups and classical colonization factor (CF)-toxin profiles included O6/LT-STh/CS1-CS3-CS21 (i.e., O6 serogroup, heat-labile [LT] and human heat-stable [STh] enterotoxins, and CFs CS1, -3 and -21), O6/LT-STh/CS2-CS3-CS21, and O104-O127/STh/ CFAI-CS21. The eatA and etpA genes were detected in more than 70% of the collection, including diverse serogroups and virulence profiles. Sixteen percent of the ETEC strains were negative for classical and nonclassical adhesins, suggesting the presence of unknown determinants of adhesion. The leuX, thrW, and asnT tDNAs were disrupted in more than 65% of strains, suggesting they are hot spots for the insertion of mobile elements. Sequences similar to integrase genes were identified next to the thrW, asnT, pheV, and selC tDNAs. We propose that the eatA and etpA genes should be included in characterizations of ETEC isolates in future epidemiological studies to determine their prevalence in other geographical regions. Sequencing of tDNAassociated genetic insertions might identify new ETEC virulence determinants.Enterotoxigenic Escherichia coli (ETEC) causes nearly 400 million diarrhea episodes every year in children younger than 5 years of age and is responsible for approximately 50% of all traveler's diarrhea episodes (35). ETEC colonizes the smallbowel epithelium, producing heat-labile (LT) and/or heat-stable (ST) enterotoxins (7) that cause secretion of water and electrolytes. Toxin variants LT-I and STh are produced only by strains that infect humans. LT-II and STp are expressed by strains that infect mostly piglets, although they occasionally also infect humans (20).Other classical ETEC virulence determinants are the colonization factors (CFs), also referred to as coli surface antigens (20), adhesins that direct colonization of the small bowel epithelium. Currently, 22 different putative ETEC CFs have been identified, designated CS followed by a number depending on their order of discovery, with the exception of CFAI, which maintains its original denomination (10, 31). The most prevalent CFs associated with the occurrence of diarrhea worldwi...

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Section: Discussioncontrasting

confidence: 50%

Section: Discussionmentioning

confidence: 96%

Distribution of Classical and Nonclassical Virulence Genes in Enterotoxigenic Escherichia coli Isolates from Chilean Children and tRNA Gene Screening for Putative Insertion Sites for Genomic Islands

et al. 2011

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“…It is well established that ETEC strains colonize the small intestine mediated by appendices called colonization factors (39). CFA III from ETEC is a type IV pilus that has been found only in LT-producing strains of the O25:H16 and O25:H2 serotypes and has been associated with CS6 (21,34).…”

Section: Discussionmentioning

confidence: 99%

Longus, a Type IV Pilus of Enterotoxigenic Escherichia coli , Is Involved in Adherence to Intestinal Epithelial Cells

et al. 2010

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4 CFU/ml in Caco-2, and 107.11 ؋ 10 4 CFU/ml in T84 cells. In addition, the E9034A⌬lngA strain showed a significant reduction in longus adherence of 32% in HT-29, 22.28% in Caco-2, and 21.68% in T84 cells compared to the wild-type strain. In experiments performed with nonintestinal cells (HeLa and HEp-2 cells), significant differences were not observed in adherence between E9034A and derivative strains. Interestingly, the E9034A and E9034A⌬lngA(pLngA) strains were 30 to 35% more adherent in intestinal cells than in nonintestinal cells. Twitching motility experiments were performed, showing that ETEC strains E9034A and E9034A⌬lngA(pLngA) had the capacity to form spreading zones while ETEC E9034A⌬lngA does not. In addition, our data suggest that longus from ETEC participates in the colonization of human colonic cells.

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“…Longus, a bundle-forming, pilus, is comprised of CS21 units and appears to be more common in ST-producing strains [98,99]. Between 8% and 36% of ETEC isolates from different locations express the longus pilus, generally in conjunction with other CS antigens [100][101][102][103]. ETEC strains may possesses one or more nonfimbrial adhesins (recently reviewed by Fleckenstein et al [104]).…”

Section: Enteropathogenic E Colimentioning

confidence: 99%

Diarrheagenic Escherichia coli in sub-Saharan Africa: Status, Uncertainties and Necessities

Okeke

2009

J Infect Dev Ctries

127

103

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Diarrhea is a leading cause of illness and death, particularly in developing countries. Enteropathogenic Escherichia coli, enterotoxigenic E. coli (ETEC), enteroinvasive E. coli, enterohemorrhaghic E. coli (EHEC), enteroaggregative E. coli (EAEC) and diffusely adherent E. coli (DAEC) have been associated with diarrheal disease in different parts of Africa, particularly among young children, HIV-positive individuals, and visitors from abroad. Each of these E. coli pathotypes uses distinct mechanisms, which are only partially understood, to colonize infected hosts and produce diarrhea. All known diarrheagenic E. coli pathotypes have been reported from diverse locations within Africa but the true burden from these pathogens is unknown because very few studies seeking these organisms with discriminatory methodology have been performed. Recent reports implicate ETEC and EAEC in a considerable proportion of childhood and travellers' diarrheas and suggest that some sub-types of these categories may have greater epidemiological significance than others. The significant contribution of EHEC to bloody diarrhea and hemolytic uremic syndrome is underappreciated because diagnostic capacity for this pathotype is generally inferior to that for confounders such as Shigella and Entamoeba. Recent studies in Africa have revealed the worrisome emergence of antimicrobial resistance and high asymptomatic carriage rates for diarrheagenic E. coli but bacterial and host factors that predispose to disease, as well as non-human reservoirs, are largely unknown. Future diarrheal disease research needs to focus on broadening the repertoire of pathogens sought in epidemiological surveys to include multiple categories of diarrheagenic E. coli while building capacity to detect these pathogens in local reference laboratories.

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Prevalence of Enterotoxigenic Escherichia coli Strains Harboring the Longus Pilus Gene in Brazil

Cited by 15 publications

References 28 publications

Distribution of Classical and Nonclassical Virulence Genes in Enterotoxigenic Escherichia coli Isolates from Chilean Children and tRNA Gene Screening for Putative Insertion Sites for Genomic Islands

Distribution of Classical and Nonclassical Virulence Genes in Enterotoxigenic Escherichia coli Isolates from Chilean Children and tRNA Gene Screening for Putative Insertion Sites for Genomic Islands

Longus, a Type IV Pilus of Enterotoxigenic Escherichia coli , Is Involved in Adherence to Intestinal Epithelial Cells

Diarrheagenic Escherichia coli in sub-Saharan Africa: Status, Uncertainties and Necessities

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