伤寒沙门菌质粒pR_(ST98)对细菌生物膜形成能力及毒力的影响

The influence of Salmonella typhi plasmid pR(ST98) on bacterial biofilm formation and virulence

目的探讨伤寒沙门菌质粒pRST98对鼠伤寒沙门菌和大肠埃希菌生物膜形成能力及毒力的影响。方法将伤寒沙门菌质粒pRST98接合转移导入鼠伤寒沙门菌和大肠埃希菌,制备单个游离悬浮状态下的细菌菌液;将接合导入质粒pRST98前、后的受试菌分别在相同条件下形成生物膜,制备生物膜状态下的菌液。浮游细菌与生物膜形成细菌调节至同一浓度后分别与CT26细胞进行黏附侵袭、血清杀菌以及抗巨噬细胞吞噬实验,比较不同状态下受试菌毒力的差异。结果伤寒沙门菌质粒pRST98能够促进鼠伤寒沙门菌和大肠埃希菌形成生物膜;黏附实验显示除大肠埃希菌外,鼠伤寒沙门菌在生物膜状态下对CT26细胞的黏附力明显增强,形成生物膜的细菌对CT26细胞的侵袭力明显下降;生物膜状态的鼠伤寒沙门菌和大肠埃希菌在兔血清和豚鼠血清中的存活率均高于浮游状态;生物膜状态下的鼠伤寒沙门菌在巨噬细胞内的存活率明显高于浮游状态下的细菌。结论质粒pRST98能够促进鼠伤寒沙门菌和大肠埃希菌形成生物膜;生物膜的形成能促进细菌对细胞的黏附,同时抑制细菌对细胞的侵袭力;增强细菌抵抗血清杀菌及巨噬细胞吞噬的能力。

Objective To investigate the influence of Salmonella typhi plasmid pRST98 on bacterial biofilm formation and virulence. Methods Salmonella typhi plasmid pRST98 was conjugated into Salmonella typhimurium and Escherichia coli to form Salmonella typhimurium / pRST98 and Escherichia coli / pRST98. These bacteria were cultured under suitable conditions to form biofilm. The planktonic bacteria were prepared. Biofilm bacteria and planktonic bacteria were adjusted to the same concentration then carried on adhesion and invasion experiments with CT26,anti-serum killing experiments and anti-macrophage phagocytosis experiments to compare virulence in different states. Results Salmonella typhi plasmid pRST98 can advance biofilm formation of Salmonella typhimurium and Escherichia coli,and biofilm promoted all bacterium adhesion capabilities to CT26 except for Escherichia coli. The biofilm formation of Salmonella typhimurium and Escherichia coli decreased invasion capabilities to CT26. The survival rates of Salmonella typhimurium and Escherichia coli in biofilm were higher than the bacteria in planktonic states for rabbit serum and guinea pig serum.Salmonella typhimurium survival rate within macrophages in biofilm state was significantly higher than that under planktonic state. Conclusions Plasmid pRST98 can promote the biofilm formation of Salmonella typhimurium and Escherichia coli. Biofilm formation promotes adhesion to cells while inhibiting invasion capability,and enhances antiserum killing and anti-macrophage phagocytosis.