双组分信号转导系统saeRS对表皮葡萄球菌生存能力的影响

Regulatory Effect of Two Component Signal Transduction System saeRS on the Survival of Staphylococcus Epidermidis

目的研究不同浓度的葡萄糖对表皮葡萄球菌野生株、saeRS基因删除突变株及回复株生存能力的影响及机制。方法在BM培养基中添加不同浓度(7.0mmol/L、14mmol/L、28mmol/L、56mmol/L)的葡萄糖,分析3种表皮葡萄球菌的生存能力、生物膜形成能力、培养基的酸度及抵抗抗生素生存的能力。结果与表皮葡萄球菌野生株相比,葡萄糖能明显促进saeRS删除突变株的生存能力和生物膜形成能力,但能够明显降低其对抗生素(比如青霉素、苯唑西林、庆大霉素、环丙沙星和丁胺卡那霉素)的抵抗能力;saeRS删除突变株和回复株在14mmol/L浓度时生存能力最强,在28mmol/L浓度时生物膜形成能力最强,而葡萄糖浓度对于野生株的生存能力及生物膜形成能力无显著影响。在添加14mmol/L葡萄糖时,saeRS删除突变株培养基(pH=8.07)的酸度比野生株(pH=7.0)明显降低。结论 SaeRS可能通过介导葡萄糖的利用影响了表皮葡萄球菌的生存能力;双组分信号转导系统saeRS影响抗生素如青霉素、苯唑西林、庆大霉素、环丙沙星和丁胺卡那霉素对表皮葡萄球菌的杀菌作用。

Objective To investigate the survival ability of Staphylococcus epidermidis （S. epidermidis） wildtype （WT）, saeRS mutant （SAE） and saeRS complementary （SAEC） strains under different concentrations of glucose. Methods We measured the survival ability, biofilm forming ability, medium acidity and aneimicrobial susceptibility of S. epidermidis in medium containing different concentrations of glucose. Results Compared with WT, the survival ability, biofilm forming ability and resistance to antibiotics （such as penicillin, oxacillin, gentamicin, ciprofloxacin and amikacin） of saeRS mutant increased significantly in response to glucose. SAE and SAEC showed the strongest survival ability and biofilm forming ability when grown in medium containing 14 mmol/ L glucose and 28 mmol/L, respectively. WT showed no significant different survival and biofilm forming abilities when cultured with various concentrations of glucose. The medium acidity of saeRS mutant （pH=8.07） was lower than the WT （pH= 7.0） in the presence of 14 mmol/L glucose. Conclusion SaeRS may influence the survival ability of S. epidermidis by affecting glucose utilization.