中文摘要：

目的研究酸性环境对变形链球菌黏附能力的影响。方法课题组前期获得的变形链球菌（血清C型）临床分离株20株及参考株UA159。用唾液包被的羟磷灰石（saliva coated hydroxyapatite,SHA）模拟口腔中牙面情况。各菌株分别在含3H并且初始pH分别为5.5和7.0的1%葡萄糖TPY液体培养基中培养,然后配成细菌悬液。菌悬液与SHA作用90min,清洗、吸干,液体闪烁计数法检测各样本中黏附于SHA的细菌量。黏附量以每分钟闪烁计数值（CPM）表示。结果pH5.5与pH7.0组变形链球菌对SHA的黏附量分别为469.4333±272.6408和3447.343±2837.8149,P〈0.05。结论酸性环境抑制变形链球菌的黏附力。

英文摘要：

Objective To study the effect of acidic environment on the initial adherence of Streptococcus mutans （S. mutans） to saliva-coated hydroxyapatite （SHA）. Methods 20 clinical isolates of S. mutans and strain UA159 of S. mutans were included in this experiment. SHA was used to simulate tooth surface in oral cavity. S. mutans strains were cultured in pH 5.5 and 7.0 TPY liquid medium containing 3H-TDR in the same radioactive concentration. SHA and radiolabeUed bacterial liquid （A550 nm = 0.52） were mixed for 90 minutes, samples were assayed by using liquid scin- tillation counter, and binding abilities of strains were evaluated by the count per minute （CPM）. Results S. mutans cultured in medium of pH 5.5 exhibited lower adherence ability than those cultured in pH 7.0 medium （ P 〈 0.05 ）. Conclusion Acidic environment inhibits S. mutans initial adherence.