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

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。

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

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.fol1owed 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 μg/mL to 8 μg/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.