解脲脲原体的耐药性分析及其耐氟喹诺酮的分子机制研究

Study on the Drug-resistant and the Molecular Mechanism of Resistant to Fluoroqninolones of Ureaplasma Urealyticum

目的检测128株临床分离解脲脲原体(UU)对9种药物的敏感性,并检测喹诺酮类耐药UU对5种喹诺酮药物的MIC以及gyrA和parC基因突变情况。方法应用支原体分离鉴定、计数药敏试剂盒检测UU对9种药物的敏感性,用微量肉汤稀释法检测耐药UU菌株对5种喹诺酮类药物的MIC,用PCR和DNA测序及序列比较检测基因突变。结果UU对多西环素最敏感,其次为米诺环素、交沙霉素、司帕沙星及克林霉素,对大环内酯类药物阿奇霉素和罗红霉素高度耐药。而司帕沙星、加替沙星和左氧氟沙星的MIC范围在0.25～8μg/mL,抑制UU活性强于氧氟沙星和环丙沙星。10株喹诺酮类耐药UU中有3株只有parC基因第80位TCA→TTA的突变,氨基酸由丝氨酸→亮氨酸,1株GyrA基因第95位密码子GAC→GAA的突变,氨基酸由天冬氨酸→谷氨酸。6株两者同时存在。结论在UU治疗中可首选多西环素,其次为米诺环素和交沙霉素。gyrA基因95位密码子和parC基因80位的突变密码子与UU耐喹诺酮类药物密切相关。

Objective To detect the susceptibility of 128 Ureaplasma urealyticum （UU） to 9 drugs and gyrA gene and parC gene mutation in quinolone-resistant isolates. Methods Mycoplasma IES test kit was used to test the susceptibility of UU to 9 drugs, Broth microdilution method was used to detect the MIC of 5 fluroquinolones to UU and the mutation of gyrA and parC gene was analyzed by PCR, sequencing and sequence comparison. Results Of 9 drugs, doxycycline was the most active against UU. followed by minocycline, josamycin, sparfloxacin and clindamycin. Azithromycin and roxithromycin of macrolides were the highest drug resistance. Sparfloxacin,gatifloxacin and levofoxacin which MIC ranged from 0.25 pμ/mL to 8 pμ/mL were more active than that of ciprofloxacin and ofloxacin. Of the 10 fluroquinolone resistance isolates, one carried an alteration of Asp95 to glutamic acid in gyrA,three carried a change of Ser80 to leucine in parC, and six carried both. Conclusion These results suggest that doxycycline, minocycline, josamycin of 9 drugs are active against UU and that 95 codon of gyrA QRDR and 80 codon of parC QRDR are associated with fluoroquinolone resistance of UU.