解脲支原体临床分离株生物被膜药物敏感性分析

目的 检测解脲支原体(Ureaplasma urealytium, Uu)临床分离株生物被膜的形成及其对抗菌药物的敏感性，为Uu临床治疗提供参考。方法 通过结晶紫染色半定量法检测Uu临床菌株生物被膜的形成能力；采用微量肉汤稀释法检测并分析Uu临床菌株在浮游状态与生物被膜状态下对四环素、红霉素、阿奇霉素、左氧氟沙星的敏感性。结果 在所检测的25株Uu中64%(16/25)菌株能形成生物被膜，9株不能形成生物被膜。16株Uu形成生物被膜后对四环素和左氧氟沙星的最小生物被膜药物抑制浓度(minimal biofilm inhibitory concentration, MBIC)比浮游菌的最小抑菌浓度(minimal inhibitory concentration, MIC)高4~8倍或以上，差异有统计学意义(P＜0.05)；对红霉素和阿奇霉素MBICs增加的0~2倍，差异有统计学意义(P＜0.05)。Uu形成生物被膜后对四环素和左氧氟沙星的耐药率显著提高，差异有统计学意义(P＜0.05)；对红霉素和阿奇霉素的耐药率无显著性差异(P＞0.05)。9株不能形成生物被膜Uu菌株，在浮游状态和生物被膜状态培养下对所选4种抗生素体外药敏试验的MIC和MBIC的差异无统计学意义(P＞0.05)；对所选4种抗生素耐药率的差异亦无统计学意义(P＞0.05)。结论 Uu临床菌株多数可形成生物被膜，生物被膜形成后降低对四环素和喹诺酮类抗菌药物的敏感性，对阿奇霉素和红霉素的敏感性影响较小。阿奇霉素和红霉素可用于Uu生物被膜临床菌株的治疗。

Biofilm formation and antibiotic susceptibility of Ureaplasma urealyticum clinical isolates#br#

Objective To study the biofilm-forming of Ureaplasma urealyticum clinical isolates and compare the antibiotic susceptibility of sessile cells in biofilms and the planktonic cells in vitro. Methods Biofilm formation of U. urealytium isolates were determined by the crystal-violet staining semi-quantitative method. The minimal inhibitory concentration (MIC) and minimal biofilm inhibitory concentration (MBIC) of U. urealytium isolates to tetracycline, erythromycin, azithromycin and levofloxacin were determined using the broth microdilution method. The statistical differences between the MIC and MBIC were analyzed by the χ2 test. Results In 25 strains, 16 (64%) were observed to form biofilm and nine did not form biofilm. To the four antibiotics, the MBICs of 16 biofilm-forming U. urealytium isolates were 1 to 8 times higher than the corresponding MICs, and the differences were statistically significant (P>0.05). Among them, MBICs against only increased 1~2 times. The resistance rate to tetracycline and levofloxacin significantly increased after U. urealytium formed biofilm (P>0.05)，but there were no significant differences in the resistance rates to erythromycin and azithromycin (P>0.05). There were no significant differences of MBICs and MICsfor 9 non-biofilm-forming U. urealytium isolates (P>0.05). Conclusion Most of U. urealytium clinical isolates could form biofilm. The sensitivity to tetracycline and quinolones decreased due to the biofilm formation of U. urealytium isolates, but the sensitivity to azithromycin and erythromycin did not decrease. Thus, azithromycin and erythromycin can be used to biofilm-forming U.