Cyclomodulins, Colibactin, and Biofilm-Associated Genes in E. coli from Colorectal Cancer and Precancerous Lesions
Introduction: Colorectal cancer (CRC) remains a significant global health challenge. Specific strains of Escherichia coli elaborating virulence factors, including cyclomodulins and colibactin, have been increasingly implicated in CRC pathogenesis. This study aimed to determine the prevalence of g...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Pasteur Institute of Iran
2025-03-01
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| Series: | Journal of Medical Microbiology and Infectious Diseases |
| Subjects: | |
| Online Access: | https://jommid.pasteur.ac.ir/article-1-691-en.html |
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| Summary: | Introduction: Colorectal cancer (CRC) remains a significant global health
challenge. Specific strains of Escherichia coli elaborating virulence factors,
including cyclomodulins and colibactin, have been increasingly implicated
in CRC pathogenesis. This study aimed to determine the prevalence of genes
encoding these toxins, namely cnf1, cdtB-I, and clbB, alongside genes
associated with biofilm formation, csgA and flu, in clinical E. coli isolates
from patients diagnosed with CRC or precancerous lesions. Methods: A
total of 44 E. coli isolates were obtained from colorectal tissue biopsies of
patients diagnosed with CRC or precancerous polyps, and from healthy
controls. PCR was employed to screen for the presence of the toxin-encoding
genes cnf1, cdtB-I, and clbB, as well as the biofilm-associated genes csgA
and flu. Biofilm formation was assessed quantitatively utilizing a standard
microtiter plate assay. Results: The toxin-encoding genes cnf1 and cdtB-I
were each detected in 14 isolates (31.8%) across all study groups (CRC,
polyp, and healthy controls). In contrast, the clbB gene was identified in 5
isolates (11.4%), exclusively within the polyp and healthy control groups.
The biofilm-associated genes csgA and flu exhibited the highest prevalence,
being detected in 41 (93.2%) and 22 (50.0%) isolates, respectively, across
all groups. Notably, none of the tested isolates demonstrated biofilm
formation capability under the experimental conditions employed.
Conclusions: This study demonstrated the presence of the cdtB-I gene in E.
coli isolates from both early-stage CRC (stages I and II), with a notably
higher prevalence in stage I. Furthermore, cdtB-I was also detected in
precancerous polyps classified as both high-grade dysplasia (HGD) and lowgrade
dysplasia (LGD). Intriguingly, the clbB gene was conspicuously
absent from all CRC isolates of stages I and II. These findings suggest a
potential role for cdtB-I in the early stages of CRC development, warranting
further research to elucidate its precise impact on the progression of CRC.
The presence of these virulence-associated genes, without significant
differences across groups, underscores the complexity of E. coli's
involvement in colorectal carcinogenesis. |
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| ISSN: | 2345-5349 2345-5330 |