Arthur Rodrigo Alex, Cury Altair Antoninha Del Bel, Graner Renata Oliveira Mattos, Rosalen Pedro Luiz, Vale Gláuber Campos, Paes Leme Adriana Franco, Cury Jaime Aparecido, Tabchoury Cínthia Pereira Machado
Piracicaba Dental School, UNICAMP - University of Campinas, Piracicaba, SP, Brazil.
Braz Dent J. 2011;22(4):267-74. doi: 10.1590/s0103-64402011000400001.
The oral cavity harbors several Streptococcus mutans genotypes, which could present distinct virulence properties. However, little is known about the diversity and virulence traits of S. mutans genotypes isolated in vivo under controlled conditions of high cariogenic challenge. This study evaluated the genotypic diversity of S. mutans isolated from dental biofilms formed in vivo under sucrose exposure, as well as their acidogenicity and aciduricity. To form biofilms, subjects rinsed their mouths with distilled water or sucrose solution 8 times/day for 3 days. S. mutans collected from saliva and biofilms were genotyped by arbitrarily-primed PCR. Genotypes identified in the biofilms were evaluated regarding their ability to lower the suspension pH through glycolysis and their acid susceptibility and F-ATPase activity. Most subjects harbored only one genotype in saliva, which was detected in almost all biofilm samples at high proportions. Genotypes isolated only in the presence of sucrose had higher acidogenicity than those isolated only in the presence of water. Genotypes from biofilms formed with sucrose were more aciduric after 30 and 60 min of incubation at pH 2.8 and 5.0, respectively. The present results suggest that biofilms formed under high cariogenic conditions may harbor more aciduric and acidogenic S. mutans genotypes.
口腔中存在多种变形链球菌基因型，这些基因型可能具有不同的毒力特性。然而，在高致龋性挑战的可控条件下，关于体内分离的变形链球菌基因型的多样性和毒力特征知之甚少。本研究评估了在蔗糖暴露下体内形成的牙菌斑中分离出的变形链球菌的基因型多样性，以及它们的产酸性和耐酸性。为了形成生物膜，受试者每天用蒸馏水或蔗糖溶液漱口8次，持续3天。通过任意引物PCR对从唾液和生物膜中收集的变形链球菌进行基因分型。评估生物膜中鉴定出的基因型通过糖酵解降低悬浮液pH值的能力、它们的酸敏感性和F-ATP酶活性。大多数受试者唾液中仅含有一种基因型，几乎所有生物膜样本中都能高比例检测到该基因型。仅在蔗糖存在下分离出的基因型比仅在水存在下分离出的基因型具有更高的产酸性。在pH值分别为2.8和5.0的条件下孵育30分钟和60分钟后，由蔗糖形成的生物膜中的基因型更耐酸。目前的结果表明，在高致龋条件下形成的生物膜可能含有更多耐酸和产酸的变形链球菌基因型。
