Genetic diversity and toxic activity of Aggregatibacter actinomycetemcomitans isolates
Genetic diversity and toxic activity of Aggregatibacter actinomycetemcomitans isolates
复制标题
DOI：
10.1111/j.1399-302x.2009.00547.x
复制
发表时间：
2009-12-01
影响因子：
--
通讯作者：
Mayer, M. P. A.
中科院分区：
文献类型：
--
作者：
Kawamoto, D.;Ando, E. S.;Mayer, M. P. A.
导言：目前对放线菌聚集菌血清型毒力因子的多样性和表达了解甚少。研究了放线菌对中国仓鼠卵巢（CHO）细胞的毒性活性，并对放线菌的cdt和ltx基因分型进行了评价。方法：对41株放线菌进行CHO细胞生长抑制分析。通过ltx启动子区特异性聚合酶链反应、血清型特异性聚合酶链反应和cdt区特异性聚合酶链反应以及cdtB测序进行基因分型。结果：40株菌株中检出cdtABC。cdtA上游区分析发现10个cdt基因型。对CHO细胞的毒性检测为92.7%；然而，毒性活性与CDT基因型之间没有相关性。血清c型在巴西样本中更为普遍（68.0%）。来自侵袭性牙周炎患者的4个血清型b分离株与高白毒素产生有关，并在CHO细胞中表现出中等至强的毒性活性，但被分类为不同的cdt基因型。CHO细胞的高毒性水平与特定血清型无关；57.1%的a血清型菌株对CHO细胞呈低毒性，而b血清型和c血清型菌株呈高毒性。cdtB测序显示281氨基酸单核苷酸多态性，但这与CHO细胞的毒性活性无关。结论：不同血清型放线菌a .放线菌comitans低毒株和高毒株流行率的差异，强化了b、c血清型菌株比a血清型菌株毒性更强的假设。
Introduction:Very little is known of the diversity and expression of virulence factors of serotypes of Aggregatibacter actinomycetemcomitans. Toxic activity on Chinese hamster ovary (CHO) cells and cdt and ltx genotyping were evaluated in A. actinomycetemcomitans serotypes.Methods:Forty-one A. actinomycetemcomitans isolates were analysed for CHO cell growth inhibition. Genotyping was performed by polymerase chain reactions specific to the ltx promoter region, serotype-specific and cdt region and by sequencing of cdtB.Results:cdtABC was detected in 40 strains. Analysis of the cdtA upstream region revealed 10 cdt genotypes. Toxicity to CHO cells was detected for 92.7% of the isolates; however, no correlation between the toxic activity and the cdt genotype was detected. Serotype c was more prevalent among Brazilian samples (68.0%). Four serotype b isolates from subjects with aggressive periodontitis were associated with high leukotoxin production and exhibited moderate to strong toxic activity in CHO cells, but were classified in different cdt genotypes. High levels of toxicity in CHO cells were not associated with a particular serotype; 57.1% of serotype a isolates presented low toxicity to CHO cells whereas the highly toxic strains belonged to serotypes b and c. Sequencing of cdtB revealed a single nucleotide polymorphism of amino acid 281 but this was not related to the toxic activity in CHO cells.Conclusion:Differences in prevalence of the low and highly cytotoxic strains among serotypes reinforce the hypothesis that serotype b and c isolates of A. actinomycetemcomitans are more virulent than serotype a strains.