摘要
为了解人型枝原体 (Mh)对喹诺酮类药物的耐药机理 ,指导临床合理用药 ,采用肉汤稀释法测定了临床标本中 10 0株 Mh对 9种喹诺酮类药物的敏感性。用 PCR对交叉耐药 Mh菌株旋转酶 A亚单位(gyr A)的基因进行扩增 ,将扩增的 DNA片段测序。结果 ,Y98- 37、Y98- 2 3、Y98- 31 、Y98- 32 显示出强大的抗 Mh作用 ,其 MIC5 0 为 0 .0 6 2 5 mg/L,MIC90 为 0 .12 5～ 0 .5 mg/L;其次为 SPL X和 L VL X,MIC5 0 为 0 .2 5、1mg/L,MIC90 为0 .2 5、2 mg/L,OFL X与 CPL X呈现耐药 ,MIC5 0 为 4mg/L,MIC90 为 8mg/L。NAL高度耐药 ,其 MIC5 0 与 MIC90为 12 8mg/L。选出 3株对 9种喹诺酮类药物呈交叉耐药 Mh株 ,PCR扩增 gyr A后得到一大小为 35 0 bp的目的 DNA,测序后将结果与标准敏感株 Mh PG2 1的 gyr A核苷酸序列进行比较 ,3株耐药株中均有 113位碱基C→ T的改变 ,使其编码的 83位氨基酸由丝氨酸变为亮氨酸。提示 Mh gyr A的 113位 C→ T突变 。
Objective: To acquire the information about the resistant mechanism of M.hominis to quinolones, and to instruct reasonable application of antibiotics clinically. Methods: Susceptibilities of 100 clinical isolates of M.hominis to 9 quinolones were detected using the broth dilution method. The gyrA of M.hominis was amplified by polymerase chain reaction and the amplified DNA fragments were sequenced. Results: Y 98 37 , Y 98 23 , Y 98 31 , Y 98 32 were highly active against M. hominis , MIC 50 0.0625 mg/L and MIC 90 0.125~0.5 mg/L. Sparfloxacin, levofloxacin were also active against M.hominis , MIC 50 0.25~1 mg/L, MIC 90 0.25~2 mg/L. M.hominis was resistant to ciprofloxacin and ofloxacin (MIC 50 4 mg/L and MIC 90 8 mg/L) and was highly resistant to nalidixic acid (MIC 50 and MIC 90 128 mg/L). Three strains of M.hominis cross resistance to 9 quinolones were selected and their gyrA were amplified, each yielded a 350 bp DNA fragments. After sequencing, the nucleotide sequenes of these three resistant strains were compared with that of susceptible strain PG21. For all the three cross resistant strains, Mh1, Mh2, Mh3, a C→T base change was found at base position 113. This mutation led to a Ser→ Leu substitution at the position corresponding to amino acid 83 in GyrA from the wild type strain PG21. Conclusion: These results suggest that in M.hominis a C→T mutation at position 113 of gyrA is associated with quinolones cross resistance.
出处
《中国抗生素杂志》
CAS
CSCD
北大核心
2001年第3期211-214,共4页
Chinese Journal of Antibiotics
基金
湖南省教委资助重点课题 (0 0 A0 0 9)
湖南省自然基金资助课题部分工作
