Occurrence of Multiple <i>stx1</i> Genes and Rare Genomic Variation in <i>stx1</i> Shiga Toxin-Producing <i>Escherichia coli</i>
Shiga toxin-producing <i>Escherichia coli</i> are important foodborne pathogens. There are several subtypes of the Shiga toxin Stx known, with Stx2 (a–o) being more diverse than Stx1 (a, c, d). Multiple occurrences of <i>stx2</i> genes as well as combinations of <i>stx1...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-05-01
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| Series: | Microorganisms |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2607/13/5/1079 |
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| Summary: | Shiga toxin-producing <i>Escherichia coli</i> are important foodborne pathogens. There are several subtypes of the Shiga toxin Stx known, with Stx2 (a–o) being more diverse than Stx1 (a, c, d). Multiple occurrences of <i>stx2</i> genes as well as combinations of <i>stx1</i> and <i>stx2</i> have been reported. However, there is a lack of knowledge on the occurrence of multiple <i>stx1</i> genes in STEC strains. Here, we report two strains from food and animal feces which show genomic variations in the <i>stx1</i> operon. The first strain harbors <i>stx1a</i> and <i>stx1c</i> genes, and the second strain shows an inactive <i>stx1</i> operon due to an insertion in the <i>stxA1a</i> subunit gene. The screening of publicly available complete genome sequences of STEC revealed further strains harboring multiple <i>stx1</i> genes, indicating that those strains also occur in human infections. This should be kept in mind when applying routine diagnostic methods like PCR, that do not detect multiple occurrences of <i>stx1</i> genes of the same subtype. Moreover, the impact on the severity of human infections due to multiple <i>stx1</i> genes has not been investigated well. |
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| ISSN: | 2076-2607 |