枸橼酸钠对肺炎克雷伯菌生物被膜形成的影响

Effect of sodium citrate on the formation of Klebsiella Pneumoniae biofilm

目的探讨枸橼酸钠对肺炎克雷伯菌生物被膜(Biofilm,BF)形成的影响。方法采用刚果红培养基筛选肺炎克雷伯菌BF阳性菌株;筛选后的阳性菌株体外培养构建BF模型;于实验初期添加15%枸橼酸钠,采用结晶紫法连续4天检测BF的吸光度变化。并于第4天用扫描电镜观察其镜下形态。未添加枸橼酸钠的肺炎克雷伯菌同步实验作为对照组。结果肺炎克雷伯菌BF阳性菌株在刚果红培养基中呈黑色菌落。与未添加枸橼酸钠的阴性对照组相比,添加枸橼酸钠后其BF的吸光度值在570 nm处明显受到抑制,至第4天依然无明显升高第1天:枸橼酸钠组吸光值为(0.168±0.006),阴性对照组为(0.166±0.007);第4天:枸橼酸钠组为(0.183±0.011),阴性对照组为(0.667±0.030)。第4天两组吸光值差异有统计学意义(P<0.05)。扫描电镜可见添加枸橼酸钠后BF逐天解聚,至第4天BF完全消散。结论枸橼酸钠可以抑制肺炎克雷伯菌BF的形成。

OBJECTIVE To investigate the effect of sodium citrate on the formation of Klebsiella Pneumoniae biofilm. METHODS Modified Congo red-based agar medium was used to screen biofilm positive strains. Biofilm growth model was established in vitro by the screened strains. 15% sodium citrate was added at the beginning of the experiment, the changes of BF absorbance was detected by crystal violet staining assay for 4 consecutive days, and the morphology was observed by scanning electron microscopy on day 4. The Klebsiella pneumonia synchronous experiment without adding sodium citrate was used as control group. RESULTS Klebsiella pneumonia biofilm positive strains were presented black on modified Congo red-based agar medium. Compared with negative control group without sodium citrate, the absorbances of bioflim were significantly inhibited at 570 nm after sodium citrate addition, and there was no significant increase by day 4 [Day 1: absorbance value of sodium citrate group(0.168±0.006), negative control(0.166±0.007);Day 4: Absorbance value of sodium citrate group(0.183±0.011), negative control(0.667±0.030)]. On day 4, the difference in absorbance between the two groups was stastically significant(P<0.05). Under scanning electron microscope, the BF depolymerized day by day after the addition of sodium citrate, and the BF completely dissipated on the 4 th day. CONCLUSION Sodium citrate can significantly inhibit the formation of K. Pneumoniae biofilm.