Survey of chronological changes of azithromycin resistance and analyses of azithromycin resistance mechanisms in clinical strains of Neisserira gonorrhoeae

对2010年、2011年和2012年分离的淋病奈瑟菌临床菌株进行了阿奇霉素药物敏感性检查。2010年、2011年和2012年的MIC 50和MIC 90（定义为抑制50%和90%分离株生长的最低浓度）分别为0.25 μg/ml和0.5 μg/ml、0.5 μg/ml和1 μg/ml以及0.25 μg/ml和1 μg/ml。检查菌株中的23 S rRNA基因是否存在阿奇霉素耐药相关突变。我们目前的研究表明，在日本出现了一些对阿奇霉素具有中等耐药性的临床菌株，并且这种耐药性与23 S rRNA基因突变有关。

Clinical strains of Neisseria gonorrhoeae isolated in 2010, 2011 and 2012 were examined for antimicrobial susceptibility to azithromycin. The MIC50 and MIC90, which were defined as minimum concentrations inhibiting the growth of 50% and 90% of the isolates, were 0.25 μg/ml and 0.5 μg/ml, 0.5 μg/ml and 1 μg/ml, and 0.25 μg/ml and 1 μg/ml for the isolates in 2010, 2011, and 2012, respectively. The 23S rRNA genes in the strains were examined for the presence of azxithromycin resistance-associated mutations. Our current study demonstrated that some clinical strains with intermediate resistance to azithromycin have emerged in Japan and that the resistance was associated with the mutation in the 23S rRNA gene.