Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran.
Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran.
Arch Oral Biol. 2022 Jul;139:105431. doi: 10.1016/j.archoralbio.2022.105431. Epub 2022 Apr 13.
This study evaluated the frequency and the effects of S. mutans and S. sobrinus on Decayed, Missing, and Filled Teeth (DMFT) scores in Iranian and Afghan populations. Serotyping of S. mutans isolates and multi-locus sequence typing (MLST) were the secondary goals.
This study was performed on 360 saliva and plaque samples from people from age groups of 4-7 and 15-17 years with Iranian and Afghan nationality who were residents of Tehran province. The DMFT index of the study population was determined, and S. mutans and S. sobrinus were identified using species-specific primers. Following the collagen-binding protein of S. mutans (cnm) gene identification, serotypes were determined, and genotyping was performed on eight selected isolates by assessing eight loci in the existing MLST scheme.
Of 360 samples, 300 were recruited as population study. Of these, 204 (51%) harbored S. mutans alone. In 42 specimens (10.5%), both specious were detected, and 54 (13.5%) were free of both. The frequencies of c, f, e, and k serotypes were 47.5%, 17.9%, 13.8%, and 8.1%, respectively. The frequency of serotype f was significantly higher in four-year-old Iranian children. MLST showed eight different sequence types (STs), which were confirmed as novel singleton sequence types.
The high frequency of serotypes k and f as systemic serotypes with the cnm gene among the Iranian population suggests the need for more worldwide studies on serotype distribution. Since very few studies have reported the epidemiological status of mutans streptococci (MS), the molecular properties of the isolates are unknown. Thus, the STs reported in this study should be considered as emerging strains.
本研究评估了变形链球菌和远缘链球菌对伊朗和阿富汗人群的龋齿、失牙和补牙（DMFT）评分的影响频率。其次是对变形链球菌分离株进行血清分型和多位点序列分型（MLST）。
本研究对来自德黑兰省伊朗和阿富汗籍年龄在 4-7 岁和 15-17 岁的 360 名唾液和菌斑样本进行了研究。对研究人群的 DMFT 指数进行了测定，并使用种特异性引物鉴定了变形链球菌和远缘链球菌。在鉴定出变形链球菌的胶原结合蛋白（cnm）基因后，对其血清型进行了确定，并通过评估现有 MLST 方案中的 8 个基因座对 8 个选定分离株进行了基因分型。
在 360 个样本中，300 个被招募为人群研究。其中 204 例（51%）单独携带变形链球菌。在 42 个样本（10.5%）中同时检测到两种菌，54 个样本（13.5%）两种菌均未携带。c、f、e 和 k 血清型的频率分别为 47.5%、17.9%、13.8%和 8.1%。4 岁的伊朗儿童中 f 血清型的频率显著较高。MLST 显示了 8 种不同的序列型（STs），被证实为新型单峰序列型。
伊朗人群中系统性血清型 k 和 f 以及 cnm 基因的高频率表明需要进行更多关于血清型分布的全球研究。由于很少有研究报告了变形链球菌（MS）的流行病学状况，因此对分离株的分子特性尚不清楚。因此，本研究中报告的 STs 应被视为新兴菌株。
