Antimicrobial activity of Lactobacillus salivarius and Lactobacillus fermentum against Staphylococcus aureus

• Published in: Pathogens and disease Vol. 75; no. 2
• Main Authors: Kang, Mi-Sun, Lim, Hae-Soon, Oh, Jong-Suk, Lim, You-Jin, Wuertz-Kozak, Karin, Harro, Janette M, Shirtliff, Mark E, Achermann, Yvonne
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.03.2017
• Subjects: Anti-Bacterial Agents - pharmacology; Antibiosis; Antimicrobial activity; Antimicrobial agents; Bacterial Proteins - pharmacology; Bacterial Proteins - secretion; Biofilms; Biofilms - growth & development; Drug resistance; Endopeptidase K; Gram-positive bacteria; Health risks; Humans; Hydrogen ions; Lactobacilli; Lactobacillus; Lactobacillus fermentum - classification; Lactobacillus fermentum - genetics; Lactobacillus fermentum - isolation & purification; Lactobacillus fermentum - physiology; Lactobacillus salivarius - classification; Lactobacillus salivarius - genetics; Lactobacillus salivarius - isolation & purification; Lactobacillus salivarius - physiology; Methicillin; Microbial Viability; Mouth - microbiology; Penicillin; Peptidase; Peptidoglycans; pH effects; Planktonic cells; Proteinase; Proteins; Public health; Reduction; RNA, Ribosomal, 16S - genetics; Secretome; Staphylococcus aureus; Staphylococcus aureus - physiology; Staphylococcus infections; antibacterial activity; Lactobacillus fermentum; LysM; Lactobacillus salivarius; Staphylococcus aureus; biofilm
• ISSN: 2049-632X; 2049-632X
• DOI: 10.1093/femspd/ftx009

The increasing prevalence of methicillin-resistant Staphylococcus aureus has become a major public health threat. While lactobacilli were recently found useful in combating various pathogens, limited data exist on their therapeutic potential for S. aureus infections. The aim of this study was to determine whether Lactobacillus salivarius was able to produce bactericidal activities against S. aureus and to determine whether the inhibition was due to a generalized reduction in pH or due to secreted Lactobacillus product(s). We found an 8.6-log10 reduction of planktonic and a 6.3-log10 reduction of biofilm S. aureus. In contrast, the previously described anti-staphylococcal effects of L. fermentum only caused a 4.0-log10 reduction in planktonic S. aureus cells, with no effect on biofilm S. aureus cells. Killing of S. aureus was partially pH dependent, but independent of nutrient depletion. Cell-free supernatant that was pH neutralized and heat inactivated or proteinase K treated had significantly reduced killing of L. salivarius than with pH-neutralized supernatant alone. Proteomic analysis of the L. salivarius secretome identified a total of five secreted proteins including a LysM-containing peptidoglycan binding protein and a protein peptidase M23B. These proteins may represent potential novel anti-staphylococcal agents that could be effective against S. aureus biofilms.