| 1. |
- Toledo, Carla Calderon, et al.
(författare)
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Circulation of enterotoxigenic Escherichia coli (ETEC) isolates expressing CS23 from the environment to clinical settings
- 2023
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Ingår i: mSystems. - 2379-5077. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- Enterotoxigenic Escherichia coli (ETEC) is one of the leading causes of infant diarrhea in low- and middle-income countries (LMICs). Diarrheal pathogens are transmitted through environmental reservoirs; however, the bacterial clones that spread across the human-environment interface remain unexplored. We aimed to determine the relationship and clonal dissemination of ETEC between children with diarrhea and polluted water samples from a local river in La Paz, Bolivia. By using WGS and the PhenePlates phenotypic system to analyze ETEC strains, we showed that ST218 and ST410 LT+STh ETEC expressing the colonization factor (CF) CS23 were found with high frequency in both samples. The CS23 ETEC isolates were found within several STs, E. coli phylogroups, and across ETEC lineages. Comparative genomic evaluation and PhenePlate screening of globally distributed clinical ETEC strains suggest that the CS23 gene is likely carried on plasmids acquired independently of the bacterial chromosomal background. Clinical strains were more often multidrug-resistant (MDR) than environmental isolates and harbored the class 1 integron-integrase gene intI1 next to the MDR cassettes. Retrospective analysis of antibiotic resistance in ETEC revealed a high frequency of MDR in clinical isolates. The LT+STh CS23 environmental ETEC isolates, showed an increased biofilmability at environmental temperature, equal cytotoxicity, and significantlylower adherence to human epithelial cells compared to ETEC expressing other CFs. Together, we suggest that CS23 is more prevalent in ETEC than previously estimated, and the Choqueyapu River is a reservoir for LT+STh CS23 ETEC containing strains capable of causing diarrheal cases in children.
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| 2. |
- Akeus, Paulina, et al.
(författare)
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Altered chemokine production and accumulation of regulatory T cells in intestinal adenomas of APC(Min/+) mice.
- 2014
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Ingår i: Cancer immunology, immunotherapy : CII. - : Springer Science and Business Media LLC. - 1432-0851 .- 0340-7004. ; 63:8, s. 807-19
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Tidskriftsartikel (refereegranskat)abstract
- Tumor progression in the colon moves from aberrant crypt foci to adenomatous polyps to invasive carcinomas. The composition of the tumor-infiltrating leukocyte population affects the ability of the immune system to fight the tumor. T cell infiltration into colorectal adenocarcinomas, particularly T helper 1 (Th1) type T cells as well as increased regulatory T cell (Treg) frequencies, is correlated with improved prognosis. However, whether Th1 cells and Tregs are already present at the adenoma stage is not known. In this study, the APC(Min/+) mouse model of intestinal adenomatous polyposis was used to investigate tumor-associated lymphocyte subsets and the mechanisms of their accumulation into gastrointestinal adenomas. Compared to unaffected tissue, adenomas accumulated CD4(+)FoxP3(+) putative Treg in parallel with lower frequencies of conventional T cells and B cells. The accumulation of Treg was also observed in human adenomatous polyps. Despite high Treg numbers, the function of conventional T cells present in the APC(Min/+) adenomas was not different from those in the unaffected tissue. Adenomas displayed an altered chemokine balance, with higher CCL17 and lower CXCL11 and CCL25 expression than in the unaffected tissue. In parallel, CXCR3(+) Tregs were largely absent from adenomas. The data indicate that already in early stages of tumor development, the balance of lymphocyte-recruiting chemokines is altered possibly contributing to the observed shift toward higher frequencies of Treg.
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| 3. |
- Akeus, Paulina, et al.
(författare)
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Treg-cell depletion promotes chemokine production and accumulation of CXCR3(+) conventional T cells in intestinal tumors.
- 2015
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Ingår i: European journal of immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 45:6, s. 1654-66
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Tidskriftsartikel (refereegranskat)abstract
- Colorectal cancer (CRC) is one of the most prevalent tumor types worldwide and tumor-infiltrating T cells are crucial for anti-tumor immunity. We previously demonstrated that Treg cells from CRC patients inhibit transendothelial migration of conventional T cells. However, it remains unclear if local Treg cells affect lymphocyte migration into colonic tumors. By breeding APC(Min/+) mice with depletion of regulatory T cells mice, expressing the diphtheria toxin receptor under the control of the FoxP3 promoter, we were able to selectively deplete Treg cells in tumor-bearing mice, and investigate the impact of these cells on the infiltration of conventional T cells into intestinal tumors. Short-term Treg-cell depletion led to a substantial increase in the frequencies of T cells in the tumors, attributed by both increased infiltration and proliferation of T cells in the Treg-cell-depleted tumors. We also demonstrate a selective increase of the chemokines CXCL9 and CXCL10 in Treg-cell-depleted tumors, which were accompanied by accumulation of CXCR3(+) T cells, and increased IFN-γ mRNA expression. In conclusion, Treg-cell depletion increases the accumulation of conventional T cells in intestinal tumors, and targeting Treg cells could be a possible anti-tumor immunotherapy, which not only affects T-cell effector functions, but also their recruitment to tumors.
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| 4. |
- Chakraborty, S., et al.
(författare)
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Phenotypic and genomic analyses of bacteriophages targeting environmental and clinical CS3-expressing enterotoxigenic Escherichia coli (ETEC) strains
- 2018
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:12
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Tidskriftsartikel (refereegranskat)abstract
- Diarrhea due to infection of enterotoxigenic Escherichia coli (ETEC) is of great concern in several low and middle-income countries. ETEC infection is considered to be the most common cause of diarrhea in Bangladesh and is mainly spread through contaminated water and food. ETEC pathogenesis is mediated by the expression of enterotoxins and colonization factors (CFs) that target the intestinal mucosa. ETEC can survive for extended time periods in water, where they are likely to be attacked by bacteriophages. Antibiotic resistance is common amongst enteric pathogens and therefore is the use of bacteriophages (phage) as a therapeutic tool an interesting approach. This study was designed to identify novel phages that specifically target ETEC virulence factors. In total, 48 phages and 195 ETEC isolates were collected from water sources and stool samples. Amongst the identified ETEC specific phages, an enterobacteria phage T7, designated as IMM-002, showed a significant specificity towards colonization factor CS3-expressing ETEC isolates. Antibody-blocking and phage-neutralization assays revealed that CS3 is used as a host receptor for the IMM-002 phage. The bacterial CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR-associated) defence mechanism can invoke immunity against phages. Genomic analyses coupled with plaque assay experiments indicate that the ETEC CRISPR-Cas system is involved in the resistance against the CS3-specific phage (IMM-002) and the previously identified CS7-specific phage (IMM-001). As environmental water serves as a reservoir for ETEC, it is important to search for new antimicrobial agents such as phages in environmental water as well as the human gut. A better understanding of how the interplay between ETEC-specific phages and ETEC isolates affects the ETEC diversity, both in environmental ecosystems and within the host, is important for the development of new treatments for ETEC infections.
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| 5. |
- Iguchi, Atsushi, et al.
(författare)
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An untypeable enterotoxigenic Escherichia coli represents one of the dominant types causing human disease
- 2017
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Ingår i: Microbial Genomics. - : Microbiology Society. - 2057-5858. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhoea in children below 5 years of age in endemic areas, and is a primary cause of diarrhoea in travellers visiting developing countries. Epidemiological analysis of E. coli pathovars is traditionally carried out based on the results of serotyping. However, genomic analysis of a global ETEC collection of 362 isolates taken from patients revealed nine novel O-antigen biosynthesis gene clusters that were previously unrecognized, and have collectively been called unclassified. When put in the context of all isolates sequenced, one of the novel O- genotypes, OgN5, was found to be the second most common ETEC O-genotype causing disease, after O6, in a globally representative ETEC collection. It’s also clear that ETEC OgN5 isolates have spread globally. These novel O-genotypes have now been included in our comprehensive O-genotyping scheme, and can be detected using a PCR-based and an in silico typing method. This will assist in epidemiological studies, as well as in ETEC vaccine development.
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| 6. |
- Joffre, Enrique, et al.
(författare)
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Allele Variants of Enterotoxigenic Escherichia coli Heat-Labile Toxin Are Globally Transmitted and Associated with Colonization Factors
- 2015
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Ingår i: Journal of Bacteriology. - : American Society for Microbiology. - 0021-9193 .- 1098-5530. ; 197:2, s. 392-403
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Tidskriftsartikel (refereegranskat)abstract
- Enterotoxigenic Escherichia coli (ETEC) is a significant cause of morbidity and mortality in the developing world. ETEC-mediated diarrhea is orchestrated by heat-labile toxin (LT) and heat-stable toxins (STp and STh), acting in concert with a repertoire of more than 25 colonization factors (CFs). LT, the major virulence factor, induces fluid secretion after delivery of a monomeric ADP-ribosylase (LTA) and its pentameric carrier B subunit (LTB). A study of ETEC isolates from humans in Brazil reported the existence of natural LT variants. In the present study, analysis of predicted amino acid sequences showed that the LT amino acid polymorphisms are associated with a geographically and temporally diverse set of 192 clinical ETEC strains and identified 12 novel LT variants. Twenty distinct LT amino acid variants were observed in the globally distributed strains, and phylogenetic analysis showed these to be associated with different CF profiles. Notably, the most prevalent LT1 allele variants were correlated with major ETEC lineages expressing CS1 + CS3 or CS2 + CS3, and the most prevalent LT2 allele variants were correlated with major ETEC lineages expressing CS5 + CS6 or CFA/I. LTB allele variants generally exhibited more-stringent amino acid sequence conservation (2 substitutions identified) than LTA allele variants (22 substitutions identified). The functional impact of LT1 and LT2 polymorphisms on virulence was investigated by measuring total-toxin production, secretion, and stability using GM1-enzyme-linked immunosorbent assays (GM1-ELISA) and in silico protein modeling. Our data show that LT2 strains produce 5-fold more toxin than LT1 strains (P < 0.001), which may suggest greater virulence potential for this genetic variant. Our data suggest that functionally distinct LT-CF variants with increased fitness have persisted during the evolution of ETEC and have spread globally.
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| 7. |
- Joffre, Enrique, et al.
(författare)
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Identification of new heat-stable (STa) enterotoxin allele variants produced by human enterotoxigenic Escherichia coli (ETEC)
- 2016
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Ingår i: International Journal of Medical Microbiology. - : Elsevier BV. - 1438-4221 .- 1618-0607. ; 306:7, s. 586-594
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Tidskriftsartikel (refereegranskat)abstract
- We describe natural variants of the heat stable toxin (STa) produced by enterotoxigenic Escherichia coli (ETEC) isolates collected worldwide. Previous studies of ETEC isolated from human diarrheal cases have reported the existence of three natural STa gene variants estA1, estA2 and estA3/4 where the first variant encodes STp (porcine, bovine, and human origin) and the two latter ones encode STh (human origin). We identified STa sequences by BLASTn and profiled ST amino acid polymorphisms in a collection of 118 clinical ETEC isolates from children and adults from Asia, Africa and, Latin America that were characterized by whole genome sequencing. Three novel variants of STp and STh were found and designated STa5 and STa6, and STa7, respectively. Presence of glucose significantly decreased the production of STh and STp toxin variants (p < 0.05) as well as downregulated the gene expression (STh: p < 0.001, STp: p < 0.05). We found that the ETEC isolates producing the most common STp variant, STa5, co-expressed coli surface antigen CS6 and was significantly associated with disease in adults in this data set (p < 0.001). Expression of mature STa5 peptide as well as gene expression of tolC, involved in ST secretion, increased in response to bile (p < 0.05). ETEC expressing the common STh variant STa3/4 was associated with disease in children (p < 0.05). The crp gene, that positively regulate estA3/4 encoding STa3/4, and estA3/4 itself had decreased transcriptional levels in presence of bile. Since bile levels in the intestine are lower in children than adults, these results may suggest differences in pathogenicity of ETEC in children and adult populations. (C) 2016 The Author(s). Published by Elsevier GmbH.
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| 8. |
- Nicklasson, Matilda, 1978, et al.
(författare)
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Expression of colonization factor CS5 of enterotoxigenic Escherichia coli (ETEC) is enhanced in vivo and by the bile component Na glycocholate hydrate.
- 2012
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Enterotoxigenic Escherichia coli (ETEC) is an important cause of acute watery diarrhoea in developing countries. Colonization factors (CFs) on the bacterial surface mediate adhesion to the small intestinal epithelium. Two of the most common CFs worldwide are coli surface antigens 5 and 6 (CS5, CS6). In this study we investigated the expression of CS5 and CS6 in vivo, and the effects of bile and sodium bicarbonate, present in the human gut, on the expression of CS5. Five CS5+CS6 ETEC isolates from adult Bangladeshi patients with acute diarrhoea were studied. The level of transcription from the CS5 operon was approximately 100-fold higher than from the CS6 operon in ETEC bacteria recovered directly from diarrhoeal stool without sub-culturing (in vivo). The glyco-conjugated primary bile salt sodium glycocholate hydrate (NaGCH) induced phenotypic expression of CS5 in a dose-dependent manner and caused a 100-fold up-regulation of CS5 mRNA levels; this is the first description of NaGCH as an enteropathogenic virulence inducer. The relative transcription levels from the CS5 and CS6 operons in the presence of bile or NaGCH in vitro were similar to those in vivo. Another bile salt, sodium deoxycholate (NaDC), previously reported to induce enteropathogenic virulence, also induced expression of CS5, whereas sodium bicarbonate did not.
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| 9. |
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| 10. |
- Scheutz, Flemming, et al.
(författare)
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Construction of the ETECFinder database for the characterization of enterotoxigenic Escherichia coli (ETEC) and revision of the VirulenceFinder web tool at the CGE website
- 2024
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Ingår i: JOURNAL OF CLINICAL MICROBIOLOGY. - 0095-1137 .- 1098-660X. ; 62:6
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Tidskriftsartikel (refereegranskat)abstract
- The identification of pathogens is essential for effective surveillance and outbreak detection, which lately has been facilitated by the decreasing cost of whole-genome sequencing (WGS). However, extracting relevant virulence genes from WGS data remains a challenge. In this study, we developed a web-based tool to predict virulence-associated genes in enterotoxigenic Escherichia coli (ETEC), which is a major concern for human and animal health. The database includes genes encoding the heat-labile toxin (LT) (eltA and eltB), heat-stable toxin (ST) (est), colonization factors CS1 through 30, F4, F5, F6, F17, F18, and F41, as well as toxigenic invasion and adherence loci (tia, tibAC, etpBAC, eatA, yghJ, and tleA). To construct the database, we revised the existing ETEC nomenclature and used the VirulenceFinder webtool at the CGE website [VirulenceFinder 2.0 (dtu.dk)]. The database was tested on 1,083 preassembled ETEC genomes, two BioProjects (PRJNA421191 with 305 and PRJNA416134 with 134 sequences), and the ETEC reference genome H10407. In total, 455 new virulence gene alleles were added, 50 alleles were replaced or renamed, and two were removed. Overall, our tool has the potential to greatly facilitate ETEC identification and improve the accuracy of WGS analysis. It can also help identify potential new virulence genes in ETEC. The revised nomenclature and expanded gene repertoire provide a better understanding of the genetic diversity of ETEC. Additionally, the user-friendly interface makes it accessible to users with limited bioinformatics experience. IMPORTANCE Detecting colonization factors in enterotoxigenic Escherichia coli (ETEC) is challenging due to their large number, heterogeneity, and lack of standardized tests. Therefore, it is important to include these ETEC-related genes in a more comprehensive VirulenceFinder database in order to obtain a more complete coverage of the virulence gene repertoire of pathogenic types of E. coli. ETEC vaccines are of great importance due to the severity of the infections, primarily in children. A tool such as this could assist in the surveillance of ETEC in order to determine the prevalence of relevant types in different parts of the world, allowing vaccine developers to target the most prevalent types and, thus, a more effective vaccine.
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