Enersen Morten, Olsen Ingar, van Winkelhoff Arie J, Caugant Dominique A
Institute of Oral Biology, Dental Faculty, University of Oslo, Norway.
J Clin Microbiol. 2006 Jan;44(1):35-41. doi: 10.1128/JCM.44.1.35-41.2006.
Porphyromonas gingivalis is an important periodontal pathogen that can be isolated from both active and inactive periodontal lesions. Apparently, differences in virulence between P. gingivalis strains exist, but the mechanisms underlying these differences are not yet fully understood. To obtain more information about pathogenicity and virulence of P. gingivalis, it is relevant to assess the genetic population structure of the species and to examine the occurrence of putative virulence factors against the genetic background. Presently, multilocus sequence typing (MLST) is the best method for analyzing bacterial population structures. Forty P. gingivalis strains from worldwide sources were analyzed by MLST. Internal 310- to 420-bp DNA fragments of the eight ubiquitous chromosomal genes, ftsQ, hagB, gdpxJ, pepO, mcmA, recA, pga, and nah, were amplified by PCR and then sequenced. The number of alleles at individual loci ranged from 2 to 19, and a total of 33 allelic profiles, or sequence types (STs), were identified. Nucleotide variation between alleles was located at one or a few sites. Identical or similar STs were found in isolates from different geographic regions. Our results showed signs of a clonal population structure with a level of recombination not as high as that previously suggested for the species. We also found that P. gingivalis isolates from individual patients were genetically heterogeneous.
牙龈卟啉单胞菌是一种重要的牙周病原体，可从活动期和静止期牙周病变中分离得到。显然，牙龈卟啉单胞菌菌株之间存在毒力差异，但其差异背后的机制尚未完全明确。为了获得更多关于牙龈卟啉单胞菌致病性和毒力的信息，评估该菌种的遗传群体结构并在遗传背景下检测假定毒力因子的存在情况具有重要意义。目前，多位点序列分型（MLST）是分析细菌群体结构的最佳方法。通过MLST分析了来自世界各地的40株牙龈卟啉单胞菌菌株。通过PCR扩增了八个普遍存在的染色体基因ftsQ、hagB、gdpxJ、pepO、mcmA、recA、pga和nah的310至420bp内部DNA片段，然后进行测序。各个位点的等位基因数量在2至19之间，共鉴定出33种等位基因谱或序列类型（STs）。等位基因之间的核苷酸变异位于一个或几个位点。在来自不同地理区域的分离株中发现了相同或相似的STs。我们的结果显示出克隆群体结构的迹象，其重组水平不像之前认为的该菌种那么高。我们还发现，来自个体患者的牙龈卟啉单胞菌分离株在遗传上具有异质性。
