Lactic acid bacteria (LAB) can inhibit growth and eliminate methicillin-resistant Staphylococcus aureus (MRSA)

Abstract

Metabolites of lactic acid bacteria (LAB) are gaining renewed interest as postbiotics to curb the growth of undesirable microorganisms in food and pharmaceutical industries. The present study was aimed to extract and characterize the biosurfactants (BS) of Lactobacillus acidophilus NCFM and Lacticaseibacillus rhamnosus GG. Acceptable levels of emulsification index and oil displacement ability of cell-free supernatant as well as considerable cell surface hydrophobicity of LGG and NCFM confirmed the BS production. The cell wall-bound and extracellular BS were extracted by solvent extraction method. Chemical group characterization of BS through Fourier-Transform Infrared Spectroscopy specified the amalgamation of carbohydrates, lipids, and proteins in NCFM, whereas only the proteins and carbohydrates in LGG. Gas chromatography-mass spectrometry analysis of BS (NCFM) revealed hexadecanoic acid, 9-octadecenoic acid, and methyl stearate as principal fatty acids. BS showed dose-dependent antibacterial and antibiofilm activities against methicillin-resistant and sensitive staphylococcal isolates. Upon visual inspection through scanning electron microscopy confirmed the cell death via alternations in the cell surface coherence. Overall, our findings suggest that BS from LGG and NCFM may be the potential candidates to abrogate staphylococcal biofilms, and therefore further technology intervention to scale up the production process could be noteworthy.