脲原体属感染及相关耐药基因研究

Study on resistance genes in Ureaplasma isolates

目的探讨脲原体的耐药性及其相关耐药基因分布。方法采用支原体培养、鉴定和药敏一体化试剂盒对疑似脲原体感染患者的泌尿道分泌物标本进行检测;将筛选得到的脲原体株进行耐药相关基因gyr A、par C、23Sr RNA、tet M PCR扩增并测序分析。结果 1 117份泌尿道分泌物标本检出54株脲原体。药敏结果显示,脲原体对四环素类药物中的米诺环素敏感率最高(92.6%),耐药率最低(5.6%);对喹诺酮类药物中氧氟沙星敏感率最低(5.6%),耐药率最高(53.7%)。2基因测序结果显示:耐药基因tet M在2316、2526二个位点发生突变,分别为G突变为A、T突变为C;par C基因于248位点发生突变,碱基C突变为T,结果导致83位丝氨酸被亮氨酸替换(S83L);gyr A基因未检测出突变;23Sr RNA基因于2149、2181、2230三个位点发生突变,分别为T突变为G、T突变为A、A突变为G。结论脲原体对四环素类药物敏感率最高,尤其是米诺环素;对喹诺酮类药物耐药最严重,尤其是氧氟沙星,为临床合理用药提供一定依据;par C、23Sr RNA、tet M基因相关突变可能与脲原体耐药机制有关。

Objective To examine the relationship between resistance genes and antibiotic resistance in Ureaplasma isolates. Methods Mycoplasma assay kits were used to culture and identify Ureaplasma isolates and perform antimicrobial susceptibility testing. PCR and DNA sequencing analysis were conducted to analyze relevant genes, including gyrA, parC, 23SrRNA, tetM. Results The results of susceptibility testing showed that more than 92.6% of Ureaplasma isolates were susceptible to minocycline and doxycycline. More than half （53.7%） of Ureaplasma isolates were resistant ofloxacin. One isolate was resistant to all the drugs tested. Sequencing analysis of resistance genes revealed two mutations in tetM gene, one mutation in parC gene, and three mutations in 23SrRNA gene, but no mutation in gyrA. Conclusions Ureaplasma isolates were relatively sensitive to tetracyclines, but more resistant to quinolones. The resistant genes like parC, 23SrRNA and tetM play an important role in development of resistance in Ureaplasma.