ABSTRACT
BACKGROUND:Previous studies discovered that pRST98, original y isolated from Salmonel a enterica serovar typhimurium (S.typhimurium) could promote bacterial biofilm formation. In addition, bacterial harboring pRST98 can promote the secretion and expression of interleukin-10 after infection in cells and animals. OBJECTIVE:In vitro studies have discovered the effects of interleukin-10 at varying concentrations and conjugative plasmid pRST98 on the biofilm formation of S.typhimurium. METHODS:S.typhimurium wild-type strainχ3306, virulence plasmid-deletion S.typhimurium strainχ3337 and pRST98-transconjugant S.typhimuriumχ3337/pRST98 were established in vitro and cultured for biofilm formation. 1, 10, 100 μg/L interleukin-10 were added during the biofilm formation. 0 μg/L interleukin-10 was set as a control. Crystal violet staining method, semi-quantitative method, confocal laser scanning microscopy and scanning electron microscopy were used to determine the effects of interleukin-10 on the biofilm formation and compare the effects of S.typhimurium with or without pRST98. RESULTS AND CONCLUSION:Intra-group comparison showed that, compared with the control group, S.typhimurium gathered together and formed thicker biofilm in concentration of 1 and 10 μg/L of interleukin-10. The promotion effects of S.typhimurium on biofilm formation were greatly improved in 10 μg/L. Interleukin-10 in 100 μg/L inhibited S.typhimurium biofilm formation. Inter-group comparison showed that, A570 inχ3337/pRST98 was greatly higher than that inχ3306 andχ3337 under the same concentration of interleukin-10. The results indicate that both 1 and 10 μg/L of interleukin-10 promote biofilm formation, especial y bacteria harboring pRST98.