Heterogeneity of Enteroaggregative Escherichia Coli Virulence Demonstrated

Nataro, James P.; Yikang, Deng; Cookson, Susan T.; Cravioto, Alejandro; Savarino, Stephen J.; Guers, Linda; Levine, Myron M.; Tacket, Carol O.

doi:10.1093/infdis/171.2.465

Cited by 304 publications

(325 citation statements)

References 14 publications

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“…34 According to other studies, these observations point to the existence of different mechanisms by which EAggEC strains may cause disease exist. 29,33,35 These isolates are under investigation for their epidemiologic features. The importance of coccidia as a widespread cause of diarrhea is now increasing.…”

Section: Discussionmentioning

confidence: 99%

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Etiologies of acute, persistent, and dysenteric diarrheas in adults in Bangui, Central African Republic, in relation to human immunodeficiency virus serostatus.

Germani¹,

Minssart²,

Vohito³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

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Abstract. A study of the etiologies of diarrhea in adults in relation to their human immunodeficiency virus (HIV) serostatus and number of CD4ϩ cells was carried out in the Central African Republic. In cases and controls, multiparasitism was observed. Salmonella spp. were identified mainly during acute diarrhea, with 50% of the S. enteritidis isolated during the study being responsible for septicemia and/or urinary tract infection in immunodeficient patients. Enteroaggregative Escherichia coli (EAggEC) were the most frequently identified agent in HIVϩ patients with persistent diarrhea; 42.8% of the patients with EAggEC as sole pathogens had bloody diarrhea, and these strains were negative for the presence of a virulence plasmid. Coccidia were found in those with acute and persistent diarrhea. Blood was observed in 53.3% of infections involving coccidia as the sole pathogen. Microsporidium spp. and Blastocystis hominis were found only in HIVϩ patients with persistent diarrhea. Shigella spp., Campylobacter spp., and Entamoeba histolytica were found in HIVϩ and HIVϪ dysenteric patients; bacteria resembling spirochetes that could not be cultivated were identified only in HIVϩ cases with dysentery. Shiga-like toxin-producing E. coli O157:HϪ was isolated from two cases with hemolytic-uremic syndrome. Fungi were identified as the sole pathogen in 6.4% of the HIVϩ patients with persistent diarrhea. Most of enteropathogenic bacteria identified were resistant to ampicillin and trimethoprim-sulfamethoxazole, remained susceptible to ampicillin plus clavulanic acid, and were susceptible to amikacin, gentamicin, and ciprofloxacin.

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Section: Discussionmentioning

confidence: 99%

“…The prevalence of coccidia is similar to that observed in other developing African countries. [31][32][33][34][35][36][37] The prevalence of Cryptosporidium spp. in control patients is high.…”

Section: Discussionmentioning

confidence: 99%

Etiologies of acute, persistent, and dysenteric diarrheas in adults in Bangui, Central African Republic, in relation to human immunodeficiency virus serostatus.

Germani¹,

Minssart²,

Vohito³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

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“…At pH 5.5, the aggR deletion mutant expressed the aggA fusion to a significantly greater degree than it did at pH 7.5, suggesting that aggA was responsive to pH by aggRdependent and aggR-independent mechanisms. DISCUSSION EAggEC strains have been shown to be diarrheal pathogens in both epidemiologic and volunteer studies (2,3,12,33,34), yet the basic features of EAggEC pathogenesis are unknown. We have previously shown that the AA phenotype in EAggEC 17-2 is associated with the presence of a ca.…”

Section: Properties Of Aggr Deletion Mutants 17-2aaggr Was Testedmentioning

confidence: 99%

“…Enteroaggregative Escherichia coli (EAggEC) is a class of diarrheagenic E. coli associated with diarrhea in both epidemiologic and volunteer studies (2,3,13,33,34). EAggEC is defined by its characteristic aggregative adherence (AA) to HEp-2 cells in cell culture (33).…”

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confidence: 99%

AggR, a transcriptional activator of aggregative adherence fimbria I expression in enteroaggregative Escherichia coli

et al. 1994

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Enteroaggregative Escherichia coli (EAggEC) has been associated with persistent pediatric diarrhea in the developing world, yet the pathogenetic mechanisms of EAggEC infection are unknown. Our previous data have suggested that aggregative adherence of some EAggEC strains to HEp-2 cells is mediated by flexible, bundle-forming fimbriae, which we have termed aggregative adherence fimbriae I (AAF/I). Genes sufficient to confer expression of AAF/I are located on the 60-MDa plasmid of EAggEC 17-2; AAF/I genes are present as two unlinked plasmid regions (regions 1 and 2), separated by 9 kb of DNA. Here we report the complete DNA sequencing of region 2 and the identification of an open reading frame which is involved in the expression of AAF/I. One open reading frame of 794 bp encodes a protein (designated AggR) with a predicted molecular size of 29.4 kDa, which shows a high degree of amino acid sequence identity to CfaR and other members of the AraC class of gene regulators. The cloned aggR gene (or, alternatively, a cloned cfaR gene) was sufficient to complement a region 1 clone to confer AAF/I expression. To further substantiate the role of aggR in the regulation of AAF/I, we constructed a 289-bp in-frame aggR deletion and replaced the native gene in 17-2 by allelic exchange, using the temperature-sensitive vector pIB307. The resulting aggR deletions were negative for AAF/I expression, but expression was restored when the aggR gene (cloned into pBluescript II SK) was reintroduced into the aggR mutant. RNA slot blot experiments using a probe for the putative AAF/I pilin subunit (aggA) revealed that aggR operates as a transcriptional activator of aggA expression. aggA::phoA fusions were constructed in 17-2 and in 17-2 delta aggR. AggR was found to promote expression of the aggA gene under a variety of conditions of temperature, osmolarity, oxygen tension, and medium. At acid pH, aggA expression was maximal and was regulated by both AggR-dependent and AggR-independent mechanisms.

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“…Volunteers ingesting EAEC strain 042 experienced more severe clinical symptoms than those given EAEC strain 17-2, JM221, or 34-b. 4 Enteroaggregative E. coli strains have been shown to cause acute and persistent (lasting longer than 2 weeks) diarrhea in young children in developing countries. 5 Enteroaggregative E. coli has also been reported as a cause of diarrhea in developed nations 6 and in AIDS patients, particularly those with low CD4 counts.…”

Section: Introductionmentioning

confidence: 99%

Markers of enteric inflammation in enteroaggregative Escherichia coli diarrhea in travelers.

Bouckenooghe¹,

DuPont²,

Jiang³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

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Abstract. As part of a traveler's diarrhea study carried out in Guadalajara, Mexico, and Goa, India, we conducted a case control study to evaluate fecal markers of enteric inflammation in three groups. Forty-five cases of enteroaggregative Escherichia coli (EAEC) diarrhea were compared to 56 controls with enterotoxigenic E. coli (ETEC) diarrhea, and 126 controls with diarrhea without identifiable pathogens. For EAEC cases we found fecal leukocytes, occult blood, and lactoferrin in 13 (28.9%), 14 (31.1%), and 27 (60.0%) patients, respectively; for ETEC controls they were 15 (26.8%), 16 (28.6%), and 15 (26.8%) respectively; and for patients without identifiable pathogens 19 (15.1%), 34 (27.0%) and 27 (21.4%). were seen for The presence of a positive fecal lactoferrin test in EAEC cases was statistically significant compared to both control groups. The study provides evidence that EAEC infection is associated with an intestinal inflammatory response.

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Heterogeneity of Enteroaggregative Escherichia Coli Virulence Demonstrated

Cited by 304 publications

References 14 publications

Etiologies of acute, persistent, and dysenteric diarrheas in adults in Bangui, Central African Republic, in relation to human immunodeficiency virus serostatus.

Etiologies of acute, persistent, and dysenteric diarrheas in adults in Bangui, Central African Republic, in relation to human immunodeficiency virus serostatus.

AggR, a transcriptional activator of aggregative adherence fimbria I expression in enteroaggregative Escherichia coli

Markers of enteric inflammation in enteroaggregative Escherichia coli diarrhea in travelers.

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