香港海鸥型菌耐喹诺酮类抗菌药物机制的研究

摘要

Objective To establish the in vitro biofilm model of Laribacter hongkongensis(LH),to analyze the type Ⅰ integron related genes carried by LH and to investigate the mechanism of LH resistance to quinolones.Methods The biofilm forming abilities of LH clinical isolates were determined by Giemsa staining qualitative method and by crystal violet staining semi-quantitative method.The sensitivity of LH to norfloxacin,ofloxacin,levofloxacin,ciprofloxacin and lomefloxacin in both planktonic and biofilm conditions were dectermined by broth microdilution susceptibility tests.Type I integron related genes carried in 18 LH strains resistant to quinolone were detected by PCR amplification method.Results The detection results by Giemsa staining demonstrated that 36 strains in 55 LH clinical isolates formed visible biofilm,and the biofilm formation rate was 65.4%(36/55).In the biofilm forming ability detected by crystal violet staining semi-quantitative method,OD560≤0.15 was in 8 strains of LH,0.150.20 in 7 strains respectively.The levels of minimal biofilm inhibitory concentration in norfloxacin,ofloxacin,levofloxacin,ciprofloxacin and lomefloxacin to LH were respectively higher than the minimal inhibitory concentration(MIC) in the corresponding floating bacteria(P<0.05).Among 55 strains of LH,18 strains were resistant to quinolones,the resistance rate was 32.7%,and the type I integron in 18 strains of LH carried the drug resistant genes,these drug resistant genes played the drug resistance role in corresponding bacterial strains.Conclusion Drug resistance gene formation and widespread of LH may be associated with type I integron.%目的 建立香港海鸥型菌生物被膜体外模型,对香港海鸥型菌携带的Ⅰ类整合子相关基因进行分析,探讨香港海鸥型菌耐喹诺酮类抗菌药物的机制.方法 吉姆萨染色法形态学角度分析及生结晶紫染色法半定量检测香港海鸥型菌临床分离株生物被膜的形成能力;微量肉汤稀释法测定香港海鸥型菌临床分离株在浮游生长状态与生物被膜状态下对诺氟沙星、氧氟沙星、左氧氟沙星、环丙沙星、洛美沙星的敏感性;PCR法检测耐喹诺酮类香港海鸥型菌菌株携带的Ⅰ类整合子相关基因.结果 吉姆萨染色法定性结果显示,在55株香港海鸥型菌临床分离株中,有36株形成生物被膜,生物被膜形成率为65.4%(36/55);结晶紫染色法半定量检测香港海鸥型菌生物被膜的形成能力,其中8株香港海鸥型菌的吸光度OD560≤0.15,16株香港海鸥型菌的吸光值0.150.20;诺氟沙星、氧氟沙星、左氧氟沙星、环丙沙星、洛美沙星对香港海鸥型菌的最小生物被膜抑菌浓度均高于相应浮游菌的最小抑菌浓度(P<0.05);55株香港海鸥菌中共有18株耐喹诺酮类药物,耐药率32.7%,且18株香港海鸥型菌菌Ⅰ类整合子均含有耐药基因,该耐药基因在相应菌株中发挥耐药作用.结论 香港海鸥型菌耐喹诺酮类基因的形成和耐药基因的播散可能与Ⅰ类整合子有关.