Farghaly M M, Eklund S, Loesche W J
J Dent Res. 1984 Jan;63(1):52-5. doi: 10.1177/00220345840630011201.
Several studies indicated that serotype/biotype c strains are the most common on a global basis, but that regional differences may occur relative to other serotype/biotypes. Of particular interest is the observation that individuals residing in the Middle East have higher incidences of serotype e and d strains relative to their levels in American citizens. This could reflect exposure to different Streptococcus mutans serotypes during the period in which the teeth are colonized, or might reflect other factors local to the region, such as diet. The purpose of the present study was to observe Egyptian and Saudi Arabian students during the first four months after their arrival in the United States, in order to determine whether this change in habitat affected the levels and biotypes of S. mutans. The results of this study showed that biotype c strains were the most prevalent in saliva and plaque of these Egyptians and Saudi Arabian students, followed by biotype e and biotype d. There was a drop in the number of S. mutans in the saliva and the proportions of S. mutans in the plaque after two months of residence in the United States, followed by a significant increase after four months of residence. This increase was most noticeable in subjects who had a higher number of decayed surfaces. In these subjects, the percentage of S. mutans in pooled occlusal plaque increased significantly, from 6.1 to 13.2%.
多项研究表明，血清型/生物型c菌株在全球范围内最为常见，但相对于其他血清型/生物型可能存在区域差异。特别值得关注的是，观察发现居住在中东地区的个体相对于美国公民，血清型e和d菌株的发生率更高。这可能反映出在牙齿定植期间接触到不同的变形链球菌血清型，或者可能反映该地区的其他局部因素，如饮食。本研究的目的是观察埃及和沙特阿拉伯学生抵达美国后的头四个月，以确定这种栖息地的变化是否会影响变形链球菌的水平和生物型。这项研究的结果表明，生物型c菌株在这些埃及和沙特阿拉伯学生的唾液和牙菌斑中最为普遍，其次是生物型e和生物型d。在美国居住两个月后，唾液中变形链球菌的数量和牙菌斑中变形链球菌的比例有所下降，而在居住四个月后显著增加。这种增加在龋面较多的受试者中最为明显。在这些受试者中，混合咬合面菌斑中变形链球菌的百分比从6.1%显著增加到13.2%。
