Molecular characterization of virulence factors in diarrhoeagenic Escherichia coli isolates from children in Nairobi, Kenya.

Makobe, Celestine; Sang, Willie; Kikuvi, Gideon; Kariuki, Samuel

doi:10.3855/jidc.2082

Cited by 20 publications

(21 citation statements)

References 26 publications

(24 reference statements)

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“…On the other hand, EPEC and STEC were detected more frequently in children less than 5 years of age but ETEC and EIEC were isolated from children of 6–10 years of age. Several studies with stool samples from children under five showed similar results to the ones demonstrated in our study (Franzolin et al, 2005; Amisano et al, 2011; Makobe et al, 2012). Whereas, the frequency of DAEC strains in our study was in general low, DAEC strains have been recovered frequently from adults with diarrhea in Brazil (Mansan-Almeida et al, 2013).…”

Section: Discussionsupporting

confidence: 91%

“…In addition, we identified DAEC, STEC and observed a very low frequency of EIEC. Previous studies from Kenya and Brazil reported similar findings in children (diarrhea) with prevalence of less than 1% for STEC and EIEC (Franzolin et al, 2005; Makobe et al, 2012). All STEC strains identified in this study were negative for the O157:H7 serotype.…”

Section: Discussionsupporting

confidence: 71%

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Surveillance of Diarrheagenic Escherichia coli Strains Isolated from Diarrhea Cases from Children, Adults and Elderly at Northwest of Mexico

et al. 2016

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Diarrheagenic Escherichia coli (DEC) strains are a main cause of gastrointestinal disease in developing countries. In this study we report the epidemiologic surveillance in a 4-year period (January 2011 to December 2014) of DEC strains causing acute diarrhea throughout the Sinaloa State, Mexico. DEC strains were isolated from outpatients of all ages with acute diarrhea (N = 1,037). Specific DEC pathotypes were identified by PCR-amplification of genes encoding virulence factors. The adhesion phenotype and antibiotic resistance were also investigated. DEC strains were detected in 23.3% (242/1037) of cases. The most frequently DEC strain isolated was EAEC [(12.2%), 126/242] followed by EPEC [(5.1%), 53/242], ETEC [(4.3%), 43/242] DAEC [(1.4%), 15/242], STEC [(0.3%), 3/242], and EIEC [(0.2%), 2/242]. EHEC strains were not detected. Overall DEC strains were more prevalent in children ≤2 years of age with EPEC strains the most common of DEC pathotypes. While ∼65% of EAEC strains were classified as typical variant based on the aggregative adherence to in vitro cultures of HEp-2 cells, a high proportion of EPEC strains was classified as atypical strains. EAEC, EPEC, ETEC, and DAEC strains were distributed in the north, central and south regions of Sinaloa state. Among all DEC strains, >90% were resistant to at least one commonly prescribed antibiotic. Strains were commonly resistant to first-line antibiotics such as tetracycline, ampicillin, and sulfamethoxazole-trimethoprim. Furthermore, more than 80% of DEC isolates were multi-drug resistant and EPEC and DAEC were the categories with major proportion of this feature. In conclusion, in nearly one out of four cases of acute diarrhea in Northwestern Mexico a multi-drug resistant DEC strain was isolated, in these cases EAEC was the most prevalent (52%) pathotype.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 71%

Surveillance of Diarrheagenic Escherichia coli Strains Isolated from Diarrhea Cases from Children, Adults and Elderly at Northwest of Mexico

et al. 2016

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“…nteropathogenic Escherichia coli (EPEC) is a human pathogen that causes infantile diarrhea in developing countries (1)(2)(3)(4)(5)(6)(7). EPEC adheres to host intestinal epithelium and induces attaching and effacing (A/E) lesions, which are characterized by intimate attachment of the organisms to host epithelial cells and effacement of the surrounding enterocyte microvilli (8).…”

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confidence: 99%

Expression of Enteropathogenic Escherichia coli Map Is Significantly Different than That of Other Type III Secreted Effectors In Vivo

2015

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The enteropathogenic Escherichia coli (EPEC) locus of enterocyte effacement (LEE)-encoded effectors EspF and Map are multifunctional and have an impact on the tight junction barrier while the non-LEE-encoded proteins NleH1 and NleH2 possess significant anti-inflammatory activity. In order to address the temporal expression of these important genes in vivo, their promoters were cloned upstream of the luxCDABE operon, and luciferase expression was measured in EPEC-infected mice by bioluminescence using an in vivo imaging system (IVIS). Bioluminescent images of living mice, of excised whole intestines, and of whole intestines longitudinally opened and washed were assessed. The majority of bioluminescent bacteria localized in the cecum by 3 h postinfection, indicating that the cecum is not only a major colonization site of EPEC but also a site of EPEC effector gene expression in mice. espF, nleH1, and nleH2 were abundantly expressed over the course of infection. In contrast, map expression was suppressed at 2 days postinfection, and at 4 days postinfection it was totally abolished. After 2 to 4 days postinfection, when map is suppressed, EPEC colonization is significantly reduced, indicating that map may be one of the factors required to maintain EPEC colonization. This was confirmed in a competitive colonization study and in two models of chronic infection, repeated exposure to ketamine and Citrobacter rodentium infection. Our data suggest that map expression contributes to the maintenance of EPEC colonization. E nteropathogenic Escherichia coli (EPEC) is a human pathogen that causes infantile diarrhea in developing countries (1-7). EPEC adheres to host intestinal epithelium and induces attaching and effacing (A/E) lesions, which are characterized by intimate attachment of the organisms to host epithelial cells and effacement of the surrounding enterocyte microvilli (8). A pathogenicity island known as the locus of enterocyte effacement (LEE) encodes the proteins that promote the attachment and effacement phenotype, including the type III secretion system (T3SS) and T3SS effector proteins (9, 10). The T3SS translocates bacterial effector proteins into host cells, thus mediating host cell responses and alterations. Effector proteins secreted through the T3SS are comprised of not only LEE-encoded proteins but also non-LEEencoded proteins. The temporal hierarchy of translocated effectors through the T3SS has been defined using in vitro models. Tir is the first effector to be translocated from EPEC into cultured cells, followed by EspZ, EspF, EspH, EspG, and Map (11). Therefore, it is likely that the expression of effector proteins in vivo also varies in accordance with time and localization of infection. A recent report described the expression of virulence genes in Citrobacter rodentium, a natural mouse pathogen, by studying the expression of Ler, a regulator for most LEE genes (12). This study showed that virulence genes were expressed and required for pathogen growth during early infection but that they were downre...

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“…Application of PCR methods allows identification of all known Afa/Dr adhesins [18,19]. the F1845 gene probe) consisting of a 390-bp polynucleotide fragment from the daaC gene, which encodes a molecular usher necessary for expression of the F1845 fimbriae, enables detection of about 75% of DAEC strains.…”

Section: Detectionmentioning

confidence: 99%

Diarrhoeagenic Escherichia coli

Liu

2015

Molecular Medical Microbiology

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Molecular characterization of virulence factors in diarrhoeagenic Escherichia coli isolates from children in Nairobi, Kenya.

Cited by 20 publications

References 26 publications

Surveillance of Diarrheagenic Escherichia coli Strains Isolated from Diarrhea Cases from Children, Adults and Elderly at Northwest of Mexico

Surveillance of Diarrheagenic Escherichia coli Strains Isolated from Diarrhea Cases from Children, Adults and Elderly at Northwest of Mexico

Expression of Enteropathogenic Escherichia coli Map Is Significantly Different than That of Other Type III Secreted Effectors In Vivo

Diarrhoeagenic Escherichia coli

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