左氧氟沙星浸涂生物材料防止生物膜形成的体外研究

Levofloxacin-coating prevents the formation of biofilms on biomaterials： an in-vitro study

目的观察左氧氟沙星（LFX）浸涂生物材料在体外对铜绿假单胞菌黏附、定植及生物膜形成的影响。方法配置LFX与外消旋聚乳酸（PDLLA）比值（w／w）为1：4、1：32的丙酮溶液，分别浸涂聚氯乙烯（PVC）材料10min制备LFX浸涂生物材料，按LFX浓度分为LFX高浓度组和LFX低浓度组，以PVC材料（PVC组）作为对照。3组材料分别浸没在含铜绿假单胞菌PA01（细菌浓度为1X108CFU／m1）的LB培养液中，37℃孵育24、72h，分别进行各组材料表面细菌计数及扫描电子显微镜观察。结果孵育24h，LFX高浓度组、LFX低浓度组和PVC组材料表面细菌计数分别为8．02（7．93～8．08）、8．10（8．03～8．20）和8．36（8．26～8．49）logloCFU／ml；孵育72h，LFX高浓度组、LFX低浓度组和PVC组材料表面细菌计数分别为7．77（7．64～7．87）、8．31（8．14—8．44）和8．74（8．50～8．99）logloCFU／ml，LFX浸涂材料表面细菌计数均显著低于PVC组（均P〈O．05）。扫描电子显微镜观察显示，孵育24h，LFX高浓度组和LFX低浓度组材料表面见散在单个细菌，PVC组材料表面大量细菌分散存在；孵育72h，LFX高浓度组和LFX低浓度组材料表面未见细菌，PVC组材料表面可见微菌落及“珊瑚状”生物膜形成。结论LFX浸涂生物材料可抑制铜绿假单胞菌黏附、定植及生物膜的形成。

Objective To investigate the in-vitro effects of levofloxacin （LFX）-coating on the adherence, colonization and biofilm formation of Pseudomonas aeruginosa on biomaterials. Methods Acetone solutions of LFX and poly-D-L-lactide （PDLLA） with the LFX： PDLLA ratios （w/w） of 1：4 and 1：32 were prepared and used to coat polyvinyl chloride （PVC）for 10 min, respectively. Then, the LFX-coated biomaterials were divided into high- and low-concentration LFX groups based on the LFX concentration, and compared with non-coated PVC （PVC group）. The 3 groups of biomaterials were immersed in LB medium containing l x l0s CFU/ml Pseudomonas aeruginosa （PAO1）. After incubating for 24 h or 72 h at 37℃, the bacteria counting on the surface of biomaterials was employed, and the morphology of biomaterials was observed by scanning electron microscope （SEM） in each group. Results After 24 h incubation, the bacteria count on the biomaterial surface of high-, low-concentration LFX group and PVC group was 8.02 （7.93 to 8.08）, 8.10 （8.03 to 8.20） and 8.36 （8.26 to 8.49） log10CFU/ml, respectively, while those were 7.77 （7.64 to 7.87） , 8.31 （8.14 to 8.44） and 8.74 （8.50 to 8.99） log10CFU/ml after 72 h incubation, respectively. At all time points, the bacteria count on the biomaterial surface of the LFX-coated hiomaterials was significantly lower than that on the surface of PVC material （all P〈0.05）. Under SEM, single baeteria （at 24 h） and even no bacteria （at 72 h） adhering to the surface of LFX-coated biomaterials, while a large amount of dispersing bacteria （at 24 h） and tiny colonies or coral-shaped biofihn formation （at 72 h） adhering to the material surface of PVC group were observed. Conclusion LFX-coated biomaterial can inhibit the adherence, colonization and biofilm formation of Pseudomonas aeruginosa.