Determination of virulence determinants of Escherichia coli strains isolated from patients with colorectal cancer compared to the healthy subjects (original) (raw)
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Canadian Journal of Infectious Diseases and Medical Microbiology, 2021
Accumulating evidence indicates that specific strains of mucosa-associated Escherichia coli (E. coli) can influence the development of colorectal carcinoma. This study aimed to investigate the prevalence and characterization of mucosa-associated E. coli obtained from the colorectal cancer (CRC) patients and control group. At two referral university-affiliated hospitals in northwest Iran, 100 patients, 50 with CRC and 50 without, were studied over the course of a year. Fresh biopsy specimens were used to identify mucosa-associated E. coli isolates after dithiothreitol mucolysis. To classify the E. coli strains, ten colonies per sample were typed using enterobacterial repetitive intergenic consensus-based PCR (ERIC-PCR). The strains were classified into phylogroups using the quadruplex PCR method. The PCR method was used to examine for the presence of cyclomodulin, bfp, stx1, stx2, and eae-encoding genes. The strains were tested for biofilm formation using the microtiter plate assay. ...
Frontiers in Cellular and Infection Microbiology
There is increasing evidence showing that microbial dysbiosis impacts the health and cancer risk of the host. An association between adherent–invasive Escherichia coli (AIEC) and colorectal cancer (CRC) has been revealed. Cyclomodulins (CMs) have been receiving increasing attention for carcinogenic changes. In this study, the incidence and features of intracellular AIEC and cyclomodulin-encoding genes were investigated and the phylogenetic grouping and genetic relatedness were evaluated. E. coli strains were isolated from the colorectal biopsies. Adhesion and invasion assays and intramacrophage cell survival test were performed to separate the AIEC isolates. Virulence genotyping for the genes htrA, dsbA, chuA, and lpfA and the cyclomodulin toxins was also conducted. In addition, phylogenetic grouping of the isolates was determined. Subsequently, repetitive element sequence-based PCR (rep-PCR) fingerprinting was performed. A total of 24 AIEC pathovars were isolated from 150 patients....
Relationship between Escherichia coli and colon cancer
GSC biological and pharmaceutical sciences, 2020
Microbiota in the intestine provides major benefits to human health. The development of these microbiota depends on the individual's diet and lifestyle and is reflected in the impact of the microbiota on the body's energy and metabolism. In a normal healthy environment, Escherichia coli grows healthy and reflecting in the human body's metabolism. However, it has been known that there is linking the community of bacterial structure factors of the intestinal microbiota to colorectal cancer development and progression, E. coli can infect and cause changes in the gut that can finally lead to cellular transformation. Thus, chronic inflammation induced by E. coli during inflammatory bowel disease predisposes an individual to colorectal cancer. E. coli is a type species of the genus Escherichia. E. coli is a Gram-negative bacillus, facultative anaerobe, motile. E. coli producing many of toxin such as colibactin is a hybrid nonribosomal peptide-polyketide encoded by polyketide synthase (pks) can induce DNA double-strand breaks leading to chromosomal aberrations and increases the frequency of gene mutations and able to induce senescence-associated secretome to contribute to colon cancer development. Therefore, the study aims to investigate the bioactivity of E. coli on colon cell that has transformed to a cancer cell and to understand the E. coli as microbiota behavior in a certain environment the effect of this new environment on its activities.
Journal of Applied Microbiology, 2000
Aims: The aim of this study was to investigate the influence of low iron availability on biofilm formation and adherence to HEp-2 cells of enteroaggregative Escherichia coli (EAEC) strains isolated from diarrhoea cases. Methods and Results: The ability of EAEC to form biofilm on a plastic surface was evaluated quantitatively and qualitatively after 3 and 18 h of incubation of strains with or without the iron chelator 2,2-dipyridyl. When submitted to low iron conditions, prototype EAEC 042 strain showed a decrease in biofilm formation. Conversely, an increase in biofilm formation was observed for the clinical EAEC strains cultured in restricted iron condition. Moreover, the reduction of iron concentration inhibited the aggregative adherence to HEp-2 cells of all EAEC strains tested. However, all effects promoted by iron chelation were suppressed by thiourea. Conclusions: Low iron availability may modulate biofilm formation and adhesive properties of EAEC strains to HEp-2 cells. Significance and Impact of the Study: The data obtained in this study provide useful insights on the influence of low iron conditions possibly associated with redox stress on the pathogenesis of EAEC strains.
Infection and Immunity, 2000
Phenotypic analysis of Escherichia coli strains causing bacteremia in cancer patients suggests that they possess specific virulence properties. To investigate this hypothesis, we compared the frequency of the virulence-related genes cnf1, cnf2, papC, hlyC, and iut in 155 E. coli strains isolated from hospitalized cancer patients with epidemiologically unrelated cases of bacteremia to their frequency in 70 E. coli strains isolated from the feces of healthy unrelated volunteers. Of the blood isolates, 24, 37, and 26% were positive for cnf1, papC, and hlyC, respectively, versus only 6, 17, and 6% of the fecal isolates (P < 0.05 in all instances). By contrast, 47% of both isolates carried the iut gene. The patients' clinical characteristics did not significantly influence these frequencies. The presence on various pathogenicity islands (PAIs) of a combination of the cnf1, papC, and hlyC genes on the chromosome was strongly suggested by Southern blotting of pulsed-field gel electrophoresis (PFGE) patterns with specific DNA probes. The phylogenetic relatedness among 60 strains carrying three, two, one, or no virulence genes and 6 ECOR strains included as references was determined by neighbor joining, the unweighted pair-group method with arithmetic mean, and Wagner analysis of the randomly amplified polymorphic DNA (RAPD) patterns generated by 11 primers. Identification of a major cluster including 96.4% of the strains carrying the cnf1, papC, and hlyC genes and ECOR subgroup B2 strains suggested that the virulent E. coli strains causing bacteremia in cancer patients are closely related to ECOR B2 strains. The presence in the E. coli population surveyed of a strong linkage disequilibrium, and especially of a highly significant correlation between PFGE and RAPD genetic distances, confirms that clonal propagation has a major impact on the E. coli population structure. Nevertheless, low bootstrap values in the phylogenetic tree suggested that frequent genetic exchange inhibits the individualization of discrete genetic lineages, which are stable on an evolutionary scale.
Gastroenterology, 2004
Background & Aims: Altered mucosal glycosylation in inflammatory bowel disease and colon cancer could affect mucosal bacterial adherence. This study aimed to quantify and characterize mucosa-associated and intramucosal bacteria, particularly Escherichia coli, in these conditions. Methods: Mucosa-associated bacteria were isolated, after dithiothreitol mucolysis, from biopsy samples obtained at colonoscopy (Crohn's disease, n ؍ 14 patients; ulcerative colitis, n ؍ 21; noninflamed controls, n ؍ 24) and at surgical resection (colon cancer, n ؍ 21). Intramucosal bacteria were grown after gentamicin treatment followed by hypotonic lysis. Results: Mucosa-associated and intramucosal bacteria were cultured more commonly in Crohn's disease (79%, P ؍ 0.03; and 71%, P < 0.01, respectively), but not ulcerative colitis (38% and 48%), than in noninflamed controls (42% and 29%) and were commonly cultured from colon cancers (71% and 57%). Mucosa-associated E. coli, which accounted for 53% of isolates, were more common in Crohn's disease (6/14; 43%) than in noninflamed controls (4/24, 17%), as also were intramucosal E. coli: Crohn's disease, 29%; controls, 9%. E. coli expressed hemagglutinins in 39% of Crohn's cases and 38% of cancers but only 4% of controls, and this correlated (P ؍ 0.01) with adherence to the I407 and HT29 cell lines. Invasion was cell-line dependent. E. coli, including nonadherent isolates, induced interleukin-8 release from the cell lines. E. coli adhesins showed no blood group specificity, excepting 1 cancer isolate (HM44) with specificity for the Thomsen-Friedenreich antigen, but they could be blocked by soluble plantain fiber. Conclusions: These studies support a central role for mucosally adherent bacteria in the pathogenesis of Crohn's disease and colon cancer. Soluble plant fibers that inhibit their adherence have therapeutic potential.
Molecular Genetics Microbiology and Virology (Russian version), 2016
The facultative aerobic bacteria isolated from the mucosa of rectum in patients with colorectal cancer in the zone of malignant tumor and neighboring normal mucosa was studied using molecular-genetic methods. The species attribution of bacteria was implemented using the cultural-morphological analysis and sequencing of the 16S rRNA locus. The microorganisms with the intraepithelial invasion to rectal mucosa isolated were identified as representatives of the adherent-invasive (AIEC) subgroup of Escherichia coli and species Klebsiella pneumonia. The molecular analysis by genetic determinants controlling adhesive, hemolytic, and toxigenic activity revealed that some bacterial isolates were able to produce toxins with potential cancerogenic activity (e.g., colibactin and cytotoxic necrotic factor I). Certain bacterial species isolated from malignant and normal rectum epithelium of the same patient demonstrated no difference between analyzed factors of toxigenicity.
Association of oncogenic bacteria with colorectal cancer in South China
Oncotarget, 2016
To quantify Fusobacterium spp., Enterococcus faecalis (E.faecalis), Enterotoxigenic Bacteroides fragilis (ETBF), and Enteropathogenic Escherichia coli in colorectal cancer (CRC) patients and their possible association with CRC clinicopathogical features, we collected the resected tumors and adjacent normal tissues (N) from 97 CRC patients. 48 age-and sex-matched healthy controls (HC) were also recruited. Real-time PCR was used for bacterial quantification. The median abundance of Fusobacterium spp. (p < 0.001, vs. N; p < 0.01,vs. HC), E.faecalis (p < 0.05, vs. N; p < 0.01, vs. HC) and ETBF (p < 0.001, vs. N; p < 0.05,vs. HC) in tumor tissues was significantly higher than that detected in normal tissue and HC. E.faecalis was detected in 95.88% of tumors and 93.81% of adjacent tissues. Fusobacterium spp. was detected in 72.16% of tumors and 67.01% of adjacent tissues. The combined E.faecalis and Fusobacterium spp. were detected in 70.10% of tumors and 36.08% of adjacent normal tissues. All four bacteria were detected in 33.72% and 22.09% of paired tumor and adjacent normal tissues, respectively. E.faecalis and Fusobacterium spp. are enriched in both tumor and adjacent tissue of CRC patients when compared to HC, suggesting that it is possible to be previously undetected changes in the pathohistologically normal colon tissue in the proximity of the tumor.
PLOS ONE
Escherichia coli (E. coli) from the B2 phylogenetic group is implicated in colorectal cancer (CRC) as it possesses a genomic island, termed polyketide synthetase (pks), which codes for the synthesis of colibactin, a genotoxin that induces DNA damage, cell cycle arrest, mutations and chromosomal instability in eukaryotic cells. The aim of this study was to detect and compare the prevalence of E. coli expressing pks (pks + E. coli) in CRC patients and healthy controls followed by investigating the virulence triggered by pks + E. coli using an in-vitro model. Mucosal colon tissues were collected and processed to determine the presence of pks + E. coli. Thereafter, primary colon epithelial (PCE) and colorectal carcinoma (HCT116) cell lines were used to detect cytopathic response to the isolated pks + E. coli strains. Our results showed 16.7% and 4.3% of CRC and healthy controls, respectively were pks + E. coli. Further, PCE displayed syncytia and cell swelling and HCT116 cells, megalocytosis, in response to treatment with the isolated pks + E. coli strains. In conclusion, pks + E. coli was more often isolated from tissue of CRC patients compared to healthy individuals, and our in-vitro assays suggest these isolated strains may be involved in the initiation and development of CRC.