Objective: To investigate the role of ompR gene from Salmonella enteritidis in biofilm formation and virulence.
Methods: We constructed an ompR mutant of Salmonella enteritidis by suicide plasmid pGMB151. Biofilm forming ability of the mutant was detected by crystal violet assay and scanning electron micrography. Virulence of the mutant was determined by assay of adherence to and invasion of epithelial cells, and mouse challenge experiments.
Results: The ompR mutant was confirmed by RT-PCR and the pattern of outer membrane protein. The mutant did not produce cellulose, curli, and biofilm, and showed similar adherence percentage to and invasion percentage of epithelial cells as wild type strain. In addition, intraperitoneal challenge of bacteria in BALB/c mice revealed that LD50 of the mutant strain was 10(6.67) CFU, while that of the wild type strain was less than 2 CFU.
Conclusion: These data indicate that the ompR gene is involved in both biofilm formation and virulence in Salmonella enteritidis.