Department of Preventive Dentistry, School of Dentistry, National University of Tucuman, San Miguel de Tucuman, Tucumán, Argentina.
Department of Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
Arch Oral Biol. 2020 Feb;110:104595. doi: 10.1016/j.archoralbio.2019.104595. Epub 2019 Oct 31.
The objective of this study was to evaluate the efficiency of SB-20 M culture medium to perform differential morphological identification of S. mutans and S. sobrinus compared to biochemical identification and to proteomic identification by the MALDI-TOF mass spectrometry technique.
Unstimulated saliva samples from 266 dental students were seeded on SB-20 M culture medium by the wooden spatula technique. After incubation, S. mutans and S. sobrinus colonies were identified by stereomicroscopy based on their differential morphological characteristics. Following these procedures, 135 colonies with characteristic morphology of S. mutans (89 colonies) and S. sobrinus (46 colonies) were randomly selected, submitted to biochemical identification (biotyping) and proteomic identification by the MALDI-TOF mass spectrometry technique. The results were compared using the Kappa test, with a 5% significance level.
All (100%) S. mutans colonies were correctly identified after culture in SB-20 M medium compared to biotyping and proteomic identification. For S. sobrinus, morphological identification in SB-20 M medium was correct for 43 colonies (93.5%) compared to biotyping and proteomic identification. However, there was no statistically significant difference when comparing the capacity to identify S. mutans and S. sobrinus of the three techniques (p < 0.001; K = 0.951).
It was concluded that the SB-20 M culture medium for morphological identification of S. mutans and S. sobrinus was highly reliable, being comparable to the MALDI-TOF mass spectrometry technique.
The efficiency evaluation of identification methods of S. mutans and S. sobrinus is clinically relevant in order to determine caries risk and activity of patients.
本研究旨在评估 SB-20M 培养基在对变形链球菌和远缘链球菌进行差异形态学鉴定方面的效率，与生化鉴定和 MALDI-TOF 质谱技术的蛋白质组学鉴定进行比较。
通过木质刮刀技术，将 266 名牙科学生的未刺激唾液样本接种到 SB-20M 培养基上。孵育后，通过立体显微镜基于其差异形态特征鉴定变形链球菌和远缘链球菌的菌落。在这些步骤之后，随机选择具有变形链球菌（89 个菌落）和远缘链球菌（46 个菌落）特征形态的 135 个菌落，进行生化鉴定（生物分型）和 MALDI-TOF 质谱技术的蛋白质组学鉴定。使用 Kappa 检验比较结果，显著性水平为 5%。
与生物分型和蛋白质组学鉴定相比，所有（100%）变形链球菌在 SB-20M 培养基中的培养物都被正确识别。对于远缘链球菌，在 SB-20M 培养基中的形态鉴定与生物分型和蛋白质组学鉴定相比，正确识别了 43 个菌落（93.5%）。然而，当比较三种技术识别变形链球菌和远缘链球菌的能力时，没有统计学上的显著差异（p<0.001；K=0.951）。
得出结论，用于变形链球菌和远缘链球菌形态鉴定的 SB-20M 培养基具有高度可靠性，与 MALDI-TOF 质谱技术相当。
评估变形链球菌和远缘链球菌鉴定方法的效率在临床上具有相关性，以便确定患者的龋齿风险和活性。
