Relationships of nontypeable Haemophilus influenzae strains to hemolytic and nonhemolytic Haemophilus haemolyticus strains
Relationships of nontypeable Haemophilus influenzae strains to hemolytic and nonhemolytic Haemophilus haemolyticus strains
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DOI：
10.1128/jcm.01832-07
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发表时间：
2008-02-01
影响因子：
9.4
通讯作者：
Gilsdorf, Janet R.
中科院分区：
文献类型：
--
作者：
McCrea, Kirk W.;Xie, Jingping;Gilsdorf, Janet R.
流感嗜血杆菌既是一种人类呼吸道病原体，也是一种咽部共生体，而溶血嗜血杆菌是流感嗜血杆菌的近亲，可以说是一种严格的咽部共生体。溶血表型历来将溶血嗜血杆菌与流感嗜血杆菌区分开来，但最近认识到溶血嗜血杆菌的非溶血定植显著降低了这一特征的可分辨性。考虑到这一点以及物种之间重组的可能性，我们研究了流感嗜血杆菌和溶血嗜血杆菌菌株在多位点序列分析（MLSA）获得的树形图中分离的微生物学和分子特征的分布。所有与流感嗜血杆菌免疫球蛋白a蛋白酶编码基因iga探针杂交的菌株都与未与探针杂交的菌株分开聚集。其他特征也沿着这条分界线显著分离，这表明了物种的分离。值得注意的是，流感嗜血杆菌的LOS基因licA、lic2A和lgtC在流感嗜血杆菌中的流行率分别是溶血嗜血杆菌的约2倍、6倍和54倍。与物种分离相反，种间重组表现为单基因序列无法在系统发育上分离物种，以及某些物种特异性特征在物种分界线上的“模糊”分布。总之，这些数据支持这些物种的历史准确和实用的划分，同时认识到它们重组的潜力。未来的比较基因组研究确定共同和独特的基因可能有助于评估它们在流感嗜血杆菌的共生或毒性生长中的作用。
Haemophilus influenzae is both a human respiratory pathogen and pharyngeal commensal, while H. haemolyticus, the closest phylogenetic relative of H. influenzae, is arguably a strict pharyngeal commensal. A hemolytic phenotype has historically differentiated H. haemolyticus from H. influenzae, but the recent recognition of significant nonhemolytic H. haemolyticus colonization has decreased this trait's resolvability. Given this and the potential of recombination between the species, we examined the distribution of microbiologic and molecular traits between collections of H. influenzae and H. haemolyticus strains separated within a dendrogram obtained by multilocus sequence analysis (MLSA). All strains hybridizing with a probe to iga, a gene encoding an immunoglobulin A protease of H. influenzae, clustered apart from strains that did not hybridize with the probe. Other traits also segregated significantly along this division, suggesting a separation of the species. Of note, the LOS genes licA, lic2A, and lgtC of H. influenzae were approximately 2, 6, and 54 times, respectively, more prevalent in H. influenzae than in H. haemolyticus. In contrast to species separation, interspecies recombination was evidenced by the inability of single gene sequences to phylogenetically separate the species and by the "fuzzy" distribution of some species-specific traits across the species dividing line. Together, these data support the historically accurate and pragmatic division of these species while recognizing their potential for recombination. Future comparative genomic studies identifying common and distinctive genes could be useful in evaluating their role in the commensal or virulent growth, respectively, of H. influenzae.