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

Abstract

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.

Molecular Detection of Antibiotic Resistance Determinants in Lactobacillus Bacteria Isolated from Human Dental Plaques

“…In a study, Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) identified 88.6% of the lactobacilli isolates, as confirmed by 16S rRNA sequencing, in colonies grown from the saliva of the individuals with caries on Rogosa agar media. Their findings confirm the significant role of Lactobacillus in the development of dental caries which is in agreement with our findings [16]. Also, Nouri et al (2017) studied the prevalence of cariogenic bacteria in dog dental plaques and identified Streptococcus mutans and Streptococcus sobrinus in 8 (40%) and 2 (10%) of samples, respectively.…”

Novel approaches for the taxonomic and metabolic characterization of lactobacilli: Integration of 16S rRNA gene sequencing with MALDI-TOF MS and 1H-NMR

“…MALDI-TOF MS represents a simple, reliable and cost-saving tool for the rapid taxonomic characterization of lactobacilli of different origin [ 15 , 20 – 25 ]. Up to date, the use of MALDI-TOF MS for Lactobacillus species identification has been particularly pointed towards the analysis of strains originated from food and probiotics [ 15 , 22 , 49 , 50 ] and only a few studies focused on clinical isolates [ 21 , 24 , 51 ]. In this work, we gave particular attention to lactobacilli isolated from the human microbiota (gut/vagina), demonstrating the potential of MALDI-TOF MS to identify species that are of importance for the human health.…”

Identification, Classification and Screening for γ-Amino-butyric Acid Production in Lactic Acid Bacteria from Cambodian Fermented Foods

“…MALDI-TOF MS has been widely used for the rapid identification and taxonomic characterization of Lactobacillus spp. [15,30,[34][35][36][37][38][39][40][41][42], Enterococcus spp. [33], and Pediococcus spp.…”