Vaccine and Infectious Disease Organization, Saskatoon, Saskatchewan, Canada.
J Clin Microbiol. 2012 Dec;50(12):3823-30. doi: 10.1128/JCM.01402-12. Epub 2012 Sep 12.
A longitudinal study combining multilocus sequence typing with molecular evolutionary analysis determined the distribution, population structure, and evolution of antibiotic resistance in Neisseria gonorrhoeae isolates in Saskatchewan that were collected between 2005 and 2008. Of 195 gonococcal isolates examined, 29 sequence types (STs) were identified with 3 major circulating strains (ST-1 through ST-3) comprising 52% of all gonococcal isolates studied. The prevalences, persistence, distribution patterns, and clonalities of these isolates strongly suggest that gonorrhea endemicity within this broad geographic region was driven by these 3 circulating strains. ST-1 exhibited a significantly (P = 0.001) higher prevalence throughout the study than did the others, accounting for ∼25% of the tested isolates each year. The spatial distributions of the gonococcal strains indicated that ST-1 in 2007 entered a linear component of the sexual network, reaching the remote north and resulting in the further spread and maintenance of infection. Ciprofloxacin and azithromycin resistances were observed in distantly related gonococcal lineages, clearly indicating the convergent acquisition of these antibiotic-resistant phenotypes. In addition, all ciprofloxacin- and azithromycin-resistant lineages were found at the edges of the minimum spanning tree, far from the major lineages, suggesting that these antibiotic phenotypes were most likely introduced into the province. In contrast, resistance to penicillin was found mostly in the endemic gonococcal lineages, suggesting that penicillin resistance was probably acquired in Saskatchewan as a result of spontaneous mutations in already-established lineages. Tetracycline resistance was present in all STs except one, indicating its ubiquitous nature in the gonococcal population studied.
一项结合多位点序列分型和分子进化分析的纵向研究，确定了 2005 年至 2008 年间在萨斯喀彻温省采集的淋病奈瑟菌分离株中抗生素耐药性的分布、种群结构和进化。在检查的 195 个淋病奈瑟菌分离株中，确定了 29 个序列型（ST），其中 3 个主要流行株（ST-1 至 ST-3）占所有研究淋病奈瑟菌分离株的 52%。这些分离株的流行率、持续性、分布模式和克隆性强烈表明，在这个广泛的地理区域内，淋病的地方性是由这 3 个流行株驱动的。ST-1 在整个研究过程中的流行率明显更高（P = 0.001），每年约占检测分离株的 25%。淋病奈瑟菌菌株的空间分布表明，2007 年 ST-1 进入了性网络的线性成分，到达偏远的北部地区，导致感染的进一步传播和维持。在远缘淋病奈瑟菌谱系中观察到环丙沙星和阿奇霉素耐药性，这清楚地表明了这些抗生素耐药表型的趋同获得。此外，所有环丙沙星和阿奇霉素耐药谱系都位于最小生成树的边缘，远离主要谱系，这表明这些抗生素表型很可能是引入该省的。相比之下，青霉素耐药性主要存在于地方性淋病奈瑟菌谱系中，这表明青霉素耐药性可能是由于已建立的谱系中自发突变而在萨斯喀彻温省获得的。除了一个 ST 外，所有 ST 都存在四环素耐药性，这表明其在研究的淋病奈瑟菌群体中普遍存在。
