Abstract

This study evaluated the reliability of MALDI-TOF MS coupled with statistical tools for the identification of Streptococcus mutans in comparison with PCR-based techniques. Bacterial isolates were identified and serotyped by conventional PCR, using S. mutans species and serotype-specific primers. For bacterial identification, mass spectra data from S. mutans and other streptococci were compared with Biotyper V 3.1 database and the mass peak lists were examined by cluster and principal component (PCA) analysis. Identification of potential biomarkers was performed using UniProtKB/Swiss-Prot and UniProtKB/TrEMBL databases and BLAST tool of the NCBI database. PCR identified 100% of the isolates as S. mutans. S. mutans strains were typed as serotypes c (85.6%), e (8.6%), k (4.8%), and f (0.9%). Although only the 70% of the strains tested were identified at species level by the Biotyper database, PCA and cluster analysis of mass peaks allowed the identification of 100% S. mutans isolates and its differentiation from the other oral and non-oral streptococci. One mass peak at m/z value of 9572.73 was identified as species-specific biomarker for S. mutans. No biomarkers were identified for S. mutans serotypes.

Key points

• MALDI-TOF MS coupled with statistical tools for the identification of S. mutans.

• Detection of species identifying biomarkers by MALDI-TOF MS.

• PCR identification and serotyping of S. mutans from saliva samples.

中文翻译：

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基质辅助激光解吸电离/飞行时间质谱在鉴定变形链球菌中的用途

摘要

这项研究与基于PCR的技术相比，评估了MALDI-TOF MS的可靠性以及用于鉴定变形链球菌的统计工具。使用变形链球菌物种和血清型特异性引物，通过常规PCR鉴定细菌并进行血清分型。为了进行细菌鉴定，将变形链球菌和其他链球菌的质谱数据与Biotyper V 3.1数据库进行了比较，并通过聚类和主成分（PCA）分析检查了质谱峰列表。使用UniProtKB / Swiss-Prot和UniProtKB / TrEMBL数据库以及NCBI数据库的BLAST工具进行潜在生物标志物的鉴定。PCR鉴定出100％的分离株为变形链球菌。变形链球菌将菌株分为血清型c（85.6％），e（8.6％），k（4.8％）和f（0.9％）。尽管只有70％的菌株是通过Biotyper数据库在物种水平上鉴定的，但是PCA和质量峰的聚类分析可以鉴定100％变形链球菌分离株，并将其与其他口腔和非口腔链球菌区分开。在m / z值为9572.73的一个质量峰被确定为变形链球菌的物种特异性生物标记。未发现变形链球菌血清型的生物标记。

关键点

• MALDI-TOF MS与统计工具一起用于识别变形链球菌。

•通过MALDI-TOF MS检测鉴定生物标记的物种。

• PCR鉴定和唾液样本中变形链球菌的血清分型。