Identification of Lactobacillus from the Saliva of Adult Patients with Caries Using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry

• Published in: PloS one Vol. 9; no. 8; p. e106185
• Main Authors: Zhang, Yifei, Liu, Yingyi, Ma, Qingwei, Song, Yeqing, Zhang, Qian, Wang, Xiaoyan, Chen, Feng
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28.08.2014; Public Library of Science (PLoS)
• Subjects: Adolescent; Adult; Adults; Aged; Body fluids; Dental caries; Dental Caries - microbiology; Desorption; Humans; Identification; Ionization; Ions; Laboratories; Lactobacilli; Lactobacillus; Lactobacillus - classification; Lactobacillus - isolation & purification; Lasers; Mass spectrometry; Mass spectroscopy; Medicine and Health Sciences; Microorganisms; Middle Aged; Patients; Research and Analysis Methods; RNA; RNA, Bacterial - analysis; RNA, Ribosomal, 16S - analysis; rRNA 16S; Saliva; Saliva - microbiology; Scientific imaging; Sequence Analysis, RNA; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Spectroscopy; Studies; Young Adult; Beijing China; New York; United States > US; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0106185

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) has been presented as a superior method for the detection of microorganisms in body fluid samples (e.g., blood, saliva, pus, etc.) However, the performance of MALDI-TOF MS in routine identification of caries-related Lactobacillus isolates from saliva of adult patients with caries has not been determined. In the present study, we introduced a new MALDI-TOF MS system for identification of lactobacilli. Saliva samples were collected from 120 subjects with caries. Bacteria were isolated and cultured, and each isolate was identified by both 16S rRNA sequencing and MALDI-TOF MS. The identification results obtained by MALDI-TOF MS were concordant at the genus level with those of conventional 16S rRNA-based sequencing for 88.6% of lactobacilli (62/70) and 95.5% of non-lactobacilli (21/22). Up to 96 results could be obtained in parallel on a single MALDI target, suggesting that this is a reliable high-throughput approach for routine identification of lactobacilli. However, additional reference strains are necessary to increase the sensitivity and specificity of species-level identification.