Abstract: Liu Pai, Jiang Juan, Zhang Jinping, You Yongyan, Sha Zhong, Sun Houhua, Gong Kuanglong, Sun Jianfang. Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China Corresponding authors: Jiang Juan, Email: drjjiang@vip.163.com; Sun Jianfang, Email: sunjf57@163.com 【Abstract】 Objective To detect point mutations associated with macrolide resistance in the 23S rRNA gene of M. genitalium. Methods Ninty-one patients with persistent or recurrent urethritis, who had been treated with macrolides in the past one month but achieved no obvious improvement, were included in this study. Urethral swab and first-void urine samples were collected from these patients. Gram′s staining, culture and fluorescence-based quantitative PCR were carried out to detect Neisseria gonorrhoeae, Ureaplasma urealyticum and Chlamydia trachomatis respectively in these urethral swab samples, and PCR was performed to detect M. genitalium in the urine samples. For patients positive to only M. genitalium, nested PCR was conducted to amplify the domain V of the 23S rRNA gene followed by direct automatic sequencing, and the resulting sequences were compared to the corresponding sequences of M. genitalium G37 strain submitted to the National Center for Biotechnology Information. Results Of the 91 patients, 21 were positive for M. genitalium, 18 for C. trachomatis, 10 for U. urealyticum, 2 for both M. genitalium and U. urealyticum, 3 for both C. trachomatis and U. urealyticum, and 37 for none of the tested pathogens. The domain V of the 23S rRNA gene, which was amplified from 18 of the 21 M. genitalium-positive samples, carried an A to G transition at position 2059 in 10 samples, an A to G transition at position 2058 in 5 samples, an A to T transition at position 2058 in 2 samples, but no point mutations in 1 sample. Conclusion The point mutations in domain V of the 23S rRNA gene may contribute to macrolide resistance in M. genitalium in Nanjing and its surrounding areas.

Key words: Mycoplasma genitalium, Drug resistance, bacterial, Anti-bacterial agents