【摘要】 肠菌素(Ent)介导的铁摄取系统在病原细菌生长和定植过程中发挥关键作用。胸膜肺炎放线杆菌是引起猪传染性胸膜肺炎的病原，为鉴定该菌不同血清型菌株能否利用肠菌素摄取铁发挥促生长作用，试验选用胸膜肺炎放线杆菌血清1～12型参考菌株，首先在限铁条件下通过肠菌素促生长试验鉴定不同血清型菌株能否利用肠菌素；进而通过添加不同浓度的铁螯合剂DFO、细菌接种量、肠菌素等因子，筛选胸膜肺炎放线杆菌利用肠菌素促生长的最适培养条件；最后分别在限铁和富铁培养条件下通过生长曲线鉴定肠菌素对胸膜肺炎放线杆菌12个血清型菌株的促生长作用。结果显示，在测定的胸膜肺炎放线杆菌血清1～12型参考菌株中，除血清2型和10型外，其他型菌株在限铁条件下均可利用肠菌素促生长。不同因子筛选结果显示，最适细菌接种浓度为1×10~4 CFU/mL,添加DFO浓度为20μmol/L,而添加0.4、2.0、10.0μg/mL等不同浓度的肠菌素对胸膜肺炎放线杆菌均有显著促生长作用，且随肠菌素浓度升高而促生长能力显著增强。试验证实胸膜肺炎放线杆菌可利用肠菌素促进其生长，同时证实不同血清型利用肠菌素方面存在显著差异，为解析肠菌素介导的铁摄取系统在胸膜肺炎放线杆菌中的作用机制奠定了基础。更多还原

【Abstract】 Enterobactin-mediated iron uptake system plays an essential role in growth and colonization of pathogenic bacteria.Actinobacillus pleuropneumoniae is the aetiological agent of porcine pleuropneumonia.In this study, serovars 1-12 reference strains of A.pleuropneumoniae were used to identify growth promotion of different serovars of A.pleuropneumoniae through enterobactin-mediated iron utilization.Firstly, growth effects of different serovars of A.pleuropneumoniae were evaluated under iron-limited conditions by enterobactin growth promotion assay.The optimal growth promotion effects of A.pleuropneumoniae were screened by adding different concentrations of iron chelator DFO,bacterial inoculation amount, and enterobactin.Finally, the growth promotion effects of enterobactin on 12 serovars of A.pleuropneumoniae were identified by bacterial growth curves under iron-limited and iron-rich conditions, respectively.The results showed that the reference strains of serovars 1-12 of A.pleuropneumoniae,except serovars 2 and 10,can use enterobactin to promote bacterial growth under iron-limited conditions.The screening assay showed that the optimal bacterial inoculation concentration was 1×10~4 CFU/mL,the concentration of DFO was 20 μmol/L.The growth effects on A.pleuropneumoniae were significantly promoted under different enterobactin concentrations of 0.4,2.0,and 10.0 μg/mL,with a positive correlation between the growth promotion ability and enterobactin concentration.This study first demonstrated that A.pleuropneumoniae can utilize enterobactin for growth promotion, with different growth promotion effects among serovars of A.pleuropneumoniae,which lays a foundation for understanding the mechanism of enterobactin-mediated iron uptake system in A.pleuropneumoniae.更多还原