Unemo Magnus, Olcén Per, Berglund Torsten, Albert Jan, Fredlund Hans
National Reference Laboratory for Pathogenic Neisseria, Department of Clinical Microbiology, Orebro University Hospital, SE-701 85 Orebro, Sweden.
J Clin Microbiol. 2002 Oct;40(10):3741-9. doi: 10.1128/JCM.40.10.3741-3749.2002.
The phenotypic and genotypic characteristics of Neisseria gonorrhoeae strains fluctuate over time both locally and globally, and highly discriminative and precise characterization of the strains is essential. Conventional characterization of N. gonorrhoeae strains for epidemiological purposes is mostly based on phenotypic methods, which have some inherent limitations. In the present study sequence analysis of porB1b gene sequences was used for examination of the genetic relationships among N. gonorrhoeae strains. Substantial genetic heterogeneity was identified in the porB genes of serovar IB-2 isolates (8.1% of the nucleotide sites were polymorphic) and serovar IB-3 isolates (5.2% of the nucleotide sites were polymorphic) as well as between isolates of different serovars. The highest degree of diversity was identified in the gene segments encoding the surface-exposed loops of the mature PorB protein. Phylogenetic analysis of the porB1b gene sequences confirmed previous findings that have indicated the circulation of one N. gonorrhoeae strain each of serovar IB-2 and serovar IB-3 in the Swedish community. These strains caused the majority of the cases in two domestic core groups comprising homosexual men and young heterosexuals, respectively, and were also detected in other patients. The phylogenetic analyses of porB gene sequences in the present study showed congruence, but not complete identity, with previous results obtained by pulsed-field gel electrophoresis of the same isolates. In conclusion, porB gene sequencing can be used as a molecular epidemiological tool for examination of genetic relationships among emerging and circulating N. gonorrhoeae strains, as well as for confirmation or discrimination of clusters of gonorrhea cases.
淋病奈瑟菌菌株的表型和基因型特征在本地和全球范围内都会随时间波动，因此对菌株进行高度鉴别性和精确的特征描述至关重要。出于流行病学目的，淋病奈瑟菌菌株的传统特征描述大多基于表型方法，而这些方法存在一些固有局限性。在本研究中，使用porB1b基因序列分析来检测淋病奈瑟菌菌株之间的遗传关系。在血清型IB - 2分离株（8.1%的核苷酸位点具有多态性）和血清型IB - 3分离株（5.2%的核苷酸位点具有多态性）的porB基因中以及不同血清型的分离株之间发现了大量的遗传异质性。在编码成熟PorB蛋白表面暴露环的基因片段中发现了最高程度的多样性。对porB1b基因序列的系统发育分析证实了先前的研究结果，即表明血清型IB - 2和血清型IB - 3的淋病奈瑟菌菌株在瑞典社区中传播。这些菌株分别在两个国内核心群体（分别为同性恋男性和年轻异性恋者）中导致了大多数病例，并且在其他患者中也被检测到。本研究中porB基因序列的系统发育分析显示与通过对相同分离株进行脉冲场凝胶电泳获得的先前结果一致，但并非完全相同。总之，porB基因测序可作为一种分子流行病学工具，用于检测新出现和正在传播的淋病奈瑟菌菌株之间的遗传关系，以及用于确认或鉴别淋病病例集群。
