Comparative Proteomic Analysis of Lactobacillus pentosus MP-10 for the Identification of Key Proteins Involved in Triclosan Tolerance

Introduction: Lactobacillus pentosus MP-10 isolated from brines of naturally fermented Aloreña green table olives has potential probiotic traits including inhibition of human pathogenic bacteria, survival at low pH (1.5) and bile salt tolerance (3%). Lactobacillus pentosus MP-10 was intrinsically resistant to some antibiotics but sensitive to different biocides including triclosan. 

Purpose: In order to elucidate cellular mechanisms that facilitate triclosan tolerance, the proteome response of Lb. pentosus MP-10 induced or not by triclosan has been analyzed in this study.

Methods: Qualitative and quantitative differences in proteomes were analyzed using two-dimensional electrophoresis (2-DE), tryptic digestion, liquid chromatography-mass spectrometry analysis and database search for protein identification.

Results: The results obtained showed that sub-lethal concentrations of triclosan induced discernible changes in the proteome of exposed Lb. pentosus MP-10 and provide insights into mechanisms of response and tolerance. In this way, the proteins differentially expressed in Lb. pentosus MP-10 in response to triclosan exposure were those involved in carbohydrate and protein metabolism to sustain energy supply for cell survival under stress conditions.

Significance: Our study suggests that reinforcing carbohydrate and protein metabolism are the major ways of leading to triclosan tolerance in Lb. pentosus MP-10.