Fluoroquinolone resistance among Neisseria gonorrhoeae isolates from Shanghai, China: detection of quinolone resistance-determining region mutations.
OBJECTIVE
Fluoroquinolone has a broad spectrum of antimicrobial activity, and is widely used for gonorrhoea treatment. However, its efficacy can be compromised by the drug-resistance property of Neisseria gonorrhoeae isolates. Most resistant cases of N. gonorrhoeae are associated with mutations in the quinolone-resistance-determining-region (QRDR) within genes of gyrA and parC. This study was undertaken to describe resistance profile of N. gonorrhoeae to fluoroquinolones in Shanghai, P.R. of China, and also associated resistance mutations in gyrA and parC.


METHODS
Eighty N. gonorrhoeae isolates were collected from Shanghai Skin Disease & Sexually Transmitted Disease Hospital or DongFang Hospital during April 2005 to April 2006 in Shanghai, P.R. of China. The minimum inhibitory concentrations (MIC) of fluoroquinolones for these isolates were determined by an agar dilution method. Mutation patterns within gyrA and parC were determined by direct sequencing or by using established restriction fragment length polymorphisms (RFLP) methods.


RESULTS
Ninety five per cent (76 of 80) of isolates were resistant, 3.75 per cent (3 of 80) intermediate resistant, and 1.25 per cent (1 of 80) were sensitive to fluoroquinolone drug ciprofloxacin. Sequencing and RFLP analysis of gyrA and parC revealed that all resistant isolates had dual mutations of S91F and D95A/G/N in gyrA. Some isolates had an extra mutation within parC either of D86N, S87N or E91A/G. Mutation patterns for gyrA and parC were significantly (P<0.05) associated with MICs level.


CONCLUSIONS
Mutations of S91F and D95A/G/N in gyrA combined with S87N in parC was the most prevalent mutation pattern of fluoroquinolone resistant N. gonorrhoeae isolates. This mutation pattern was associated with a high level of quinolone resistance (MIC >16.0 microg/ml) which can serve as a maker for quinolone-resistance prediction in Shanghai, P.R. of China.
Tiejun
Zhang
Z
Department of Epidemiology, School of Public Health, Fudan University, PR of China.
Xiaoming
Zhou
Z
Jilun
Zhang
Z
Yinghu
Zhang
Z
Yanhua
Ren
R
Yue
Chen
C
Weiming
Gu
G
Tao
Zhang
Z
Qingwu
Jiang
J
D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D002681:China; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D024841:Fluoroquinolones / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009344:Neisseria gonorrhoeae / Q000187:drug effects / Q000235:genetics; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones