Genetic relatedness and superantigen expression in group A streptococcus serotype MZ isolates from patients with severe and nonsevere invasive diseases
Genetic relatedness and superantigen expression in group A streptococcus serotype MZ isolates from patients with severe and nonsevere invasive diseases
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DOI：
10.1128/iai.68.6.3523-3534.2000
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发表时间：
2000-06-01
影响因子：
3.1
通讯作者：
Kotb, M
中科院分区：
文献类型：
--
作者：
Chatellier, S;Ihendyane, N;Kotb, M
采用多种分子生物学方法研究了从35例不同严重程度的加拿大侵袭性疾病患者中分离的A组链球菌（GAS）菌株的相关性。所有患者均感染M1T1菌株，根据临床标准，分为严重（n = 21）和非严重（n = 11）侵袭性GAS感染病例。所有M1菌株均具有emm1.0等位基因和相同的链球菌热原外毒素（Spe）基因型speA（+）speB（+）speC speF（+）speG（+）speH smeZ（+）ssa。所有分离株具有相同的speA同种异型，speA2。用两种不同的引物随机扩增的多态性DNA带型是相同的所有菌株，和脉冲场凝胶电泳分析表明，33和30个菌株具有相同的带型后，用SfiI或SmaI酶切，分别为不同的菌株，从主模式不同，只有一个带。在分离株中观察到sic基因特定区域的多态性程度相对较高，然而，这种多态性与疾病严重程度无关。同样，虽然SpeA，SpeB和SpeF蛋白的表型表达在M1T1分离株之间变化，但Spe表达量与疾病严重程度之间没有相关性。重要的是，由部分纯化的细菌培养物上清液诱导的促有丝分裂和细胞因子反应，其中含有表达的超抗原的混合物，对于来自严重和非严重病例的分离株而言非常相似（P > 0.1）。总之，这些数据表明，高度相关的侵袭性M1T1分离株，一些无法区分，可以在不同的个体中引起不同严重程度的疾病。这些发现强调了宿主因素对侵袭性GAS感染结果的贡献。
The relatedness of group A streptococcal (GAS) strains isolated from 35 Canadian patients with invasive disease of different severity was investigated by a variety of molecular methods. All patients were infected with M1T1 strains and, based on clinical criteria, were classified as severe (n = 21) and nonsevere (n = 11) invasive GAS infection cases. All the M1 strains studied had the emm1.0 allele and the same streptococcal pyrogenic exotoxin (Spe) genotype, speA(+) speB(+) speC speF(+) speG(+) speH smeZ(+) ssa. All isolates had the same speA allotype, speA2. The randomly amplified polymorphic DNA banding pattern with two different primers was identical for all strains, and pulsed field gel electrophoresis analysis showed that 33 and 30 isolates had identical banding patterns after DNA digestion with SfiI or SmaI, respectively; the nonidentical isolates differed from the main pattern by only one band. A relatively high degree of polymorphism in specific regions of the sic gene was observed among isolates; however, this polymorphism was not associated with disease severity. Likewise, although the phenotypic expression of SpeA, SpeB, and SpeF proteins varied among the M1T1 isolates, there was no correlation between the amount of Spe expressed and disease severity. Importantly, mitogenic and cytokine responses induced by partially purified bacterial culture supernatants containing a mixture of expressed superantigens mere very similar for isolates from severe and nonsevere cases (P > 0.1). Together, the data indicate that highly related invasive M1T1 isolates, some indistinguishable, can cause disease of varying severity in different individuals. These findings underscore the contribution of host factors to the outcome of invasive GAS infections.