Role cytolethal distending toxin B (CdtB)‎ in Salmonella enterica serovar Schwarzengrund

الملخص EN

Cytolethal distending toxin (CDT) expressed in various Gram-negative pathogenic bacteria is a virulence factor that induces distention or apoptosis in the host cells through DNA damage.

Salmonella enterica serovar Schwarzengrund isolates from clinical samples were screened for cdtB by PCR.

To understand the role of CdtB in S.

Schwarzengrund, a cdtB deletion mutant strain (∆cdtB) was constructed.

In vitro cultured rat epithelial cell were infected with a wild type strain and its isogenic ∆cdtB to determine whether the strains of S.

Schwarzengrund are responsible for typical signs of cytolethal distending intoxication, including cytoplasmic distension, and nuclear enlargement of host target cells.

The results showed that rat intestinal epithelial cells infected with S.

Schwarzengrund became distended and the nuclei were larger than those infected with ∆ cdtB.

In addition, the wild type strain induced an increased cytotoxic LDH (Lactate Dehydrogenase) release from rat epithelial cells up to 72 h after infection as compared with its isogenic cdtB mutant.

In conclusion, the CdtB from S.

Schwarzengrund damages DNA, resulting in cytoplasmic distension and nuclear enlargement of rat epithelial cells after 72 h of infection, similar to that from S.

Typhi.

Therefore, CdtB produced from non-typhi S.

Schwarzengrund strains may play an important role in pathogenesis in host cells.