左氧氟沙星浸涂导管对铜绿假单胞菌生物膜的影响

目的评估左氧氟沙星（levofloxacin,LFX）浸涂导管抑制铜绿假单胞菌粘附、定植,防止生物膜形成的能力。方法体外部分：制备LFX浸涂导管。LFX浸涂导管、PVC导管分别浸没在5 mL 50%LB培养液中（含PAO1 108CFU/mL）,37℃孵育6、12、24和48 h,在各时间点,予导管表面和导管培养液进行细菌计数。体内部分：小鼠皮下植入LFX浸涂导管或PVC导管,沿着导管注射PAO1菌液50μL（107CFU）。第1、5天,对植入导管及导管周围组织进行细菌计数及扫描电镜（SEM）观察。结果 （1）LFX浸涂导管显示药物的快速释放。（2）在各孵育时间点,LFX浸涂导管及导管培养液的细菌数较PVC导管均明显减少（P〈0.05）。（3）小鼠感染第1、5天,LFX浸涂植入导管表面没有或很少细菌;LFX浸涂导管较PVC导管能明显减少植入导管周围组织的细菌量（P〈0.05）。（4）SEM观察：感染第1、5天,LFX浸涂导管表面散在单个细菌或者没有细菌;而第1天,PVC导管表面大量细菌分散存在。第5天,导管表面＂珊瑚状＂生物膜形成。结论 LFX浸涂导管能抑制铜绿假单胞菌粘附、定植,防止生物膜形成,从而有效降低导管生物膜相关感染的发生。

Role of levofloxacin-coated catheter in Pseudomonas aeruginosa biofilm development

Objective To evaluate the inhitory effect of levofloxacin-coated catheter on the adherence,colonization and biofilm development of Pseudomonas aeruginosa. Methods In vitro part-Levofloxacin（ LFX）-coated catheters and polyvinyl chloride（ PVC） catheters were immersed in 5 mL of 50% LB liquid culture containing108 CFU /mL of P. aeruginosa（ PAO1） respectively and incubated at 37 ℃; the bacteria adhered to the surface of the catheters and in the culture were counted at the time points of 6,12,24 and 48 hours. In vivo part-LFX-coated or PVC catheters were implanted subcutaneously in mice,then 50 μL（ 107CFU） of PAO1 was injected subcutaneously asong the implanted catheters. At Day 1 and 5 after challenging,bacteriological features of the bacteria on implanted catheters and in peri-implant tissue were assessed. Results（ 1） Fast release of drug from LFX-coated catheters was observed.（ 2） At each time point,bacteria on LFX-coated catheters and in the culture medium were reduced significantly compared to PVC catheters.（ 3） At Day 1 and 5 after challenging,no or less bacteria adhered to the surface of implanted LFX-coated catheters,and bacteria in peri-implant tissues were significantly reduced compared to PVC implanted catheters.（ 4） Scanning electron microscope at Day 1 and 5 after challenging showed no or single bacteria adhering to the implanted LFX-coated catheters,while extensive dispersal of bacteria adhering to the implanted PVC catheters at Day 1 and coral-shaped biofilm formation at Day 5 were seen.ConclusionLFX-coated catheters can strongly inhibit the adherence,colonization and biofilm development of Pseudomonas aeruginosa on catheters,thus decrease the incidence of catheter-biofilm associated infections.