喹诺酮类药物对嗜水气单胞菌体外生物被膜形成能力的影响

Effect of fluoroqinolones on the biofilm formation in Aeromonas hydrophila

采用微量肉汤稀释法测定3种喹诺酮类药物对21株嗜水气单胞菌的最小抑菌浓度(MIC),体外建立其生物被膜(BF),采用结晶紫法和扫描电镜的方法研究生物被膜的形成和结构,并观察喹诺酮类药物对生物被膜形成能力的影响。结果表明:喹诺酮类药物对嗜水气单胞菌有较强的抑制作用,诺氟沙星、环丙沙星、恩诺沙星的抑菌率分别为90.5%,95.25%和85.7%,其中环丙沙星的抑菌作用最强,对21株菌的最小抑菌浓度均在0.7813μg/mL以下。21株嗜水气单胞菌均可在24～48 h内体外形成较为稳定的BF,但不同菌株之间形成BF的能力有所不同。嗜水气单胞菌对喹诺酮类药物较为敏感,环丙沙星浓度在1倍MIC以上即可抑制嗜水气单胞菌生物被膜的早期形成,但细菌形成成熟的生物被膜后,较高浓度药物对生物被膜的影响不明显。

The minimal inhibitory concentrations （MICs） of 21 isolates of Aeromonas hydrophila against three kinds of fluoroquinolones were determined. And the biofilm formation capabilities in vitro were investigated by the crystal violet assay and scanning election microscope. Alteration of biofilm was measured at different concentrations of fluoroquinolones. Fluoroquinolones could inhibit strongly the bacterial growth, and the inhibition rates of norfloxacin, ciprofloxacin and enrofloxacin were 90. 5% , 95.25% and 85.7% , respectively. Especially for ciprofloxacin, the MICs of 21 isolates were all below 0. 7813 μg/mL. Significant differences were observed in formation ability of biofilm among strains. Initial biofilm synthesis was inhibited by fluoroquinolones at the concentrations over 1 xMIC. However, fluoroquinolones had no obvious inhibition on A. hydrophila growth after the mature biofilm was formed, even at higher concentrations.