Musser J M, Kroll J S, Moxon E R, Selander R K
University of Rochester School of Medicine and Dentistry, NY 14642.
Proc Natl Acad Sci U S A. 1988 Oct;85(20):7758-62. doi: 10.1073/pnas.85.20.7758.
Genetic relationships among 2209 isolates of Haemophilus influenzae of polysaccharide capsule serotypes a, b, c, d, e, and f were determined by analyzing electrophoretically demonstrable allelic variation at 17 chromosomal enzyme loci. We distinguished 280 electrophoretic types (ETs), representing distinctive multilocus genotypes. Genetic diversity among ETs of isolates of the same serotype was, on average, only 67% of that in the total sample, and no ETs were shared among isolates of different serotypes. Cluster analysis of the ETs revealed 2 primary phylogenetic divisions at a genetic distance of 0.66 and 12 major lineages diverging from one another at distances greater than 0.42. In general, strains of different phylogenetic lines or groups of allied lineages have characteristic cap region restriction fragment length polymorphism patterns obtained by digestion of genomic DNA with EcoRI. Strains producing serotype c, e, and f capsules have no close relationships to those of other encapsulated strains. Lineages of both serotype a and b strains occur in each primary phylogenetic division, most probably as a result of the transfer of serotype-specific sequences of the cap region between clonal lineages. Serotype a strains allied in division I with a group of abundant serotype b clones and the serotype d strains apparently are more virulent than the serotype a strains in division II, which are related to serotype b and f strains that rarely cause invasive disease.
通过分析17个染色体酶位点上可电泳显示的等位基因变异，确定了2209株a、b、c、d、e和f多糖荚膜血清型流感嗜血杆菌之间的遗传关系。我们区分出280种电泳类型（ETs），代表独特的多位点基因型。同一血清型分离株的ETs之间的遗传多样性平均仅为总样本的67%，不同血清型的分离株之间没有共享的ETs。对ETs进行聚类分析，发现在遗传距离为0.66时存在2个主要的系统发育分支，在距离大于0.42时彼此分歧出12个主要谱系。一般来说，不同系统发育谱系或相关谱系组的菌株具有通过用EcoRI消化基因组DNA获得的特征性帽区限制性片段长度多态性模式。产生c、e和f血清型荚膜的菌株与其他有荚膜菌株没有密切关系。a和b血清型菌株的谱系出现在每个主要的系统发育分支中，很可能是由于克隆谱系之间帽区血清型特异性序列的转移。在第一分支中与一组丰富的b血清型克隆相关联的a血清型菌株和d血清型菌株显然比第二分支中的a血清型菌株更具致病性，第二分支中的a血清型菌株与很少引起侵袭性疾病的b和f血清型菌株有关。
