An animal derivative-free medium enhances Lactobacillus johnsonii LJO02 supernatant selective efficacy against the methicillin (oxacillin)-resistant Staphylococcus aureus virulence through key-metabolites

Abstract

The spread of multidrug-resistant bacteria, such as the skin commensal Staphylococcus aureus, is a worldwide health challenge; new methods to counteract opportunistic pathogen growth and virulence are urgent. We compared the activity of Lacticaseibacillus rhamnosus LR06 (DSM 21981) and Lactobacillus johnsonii LJO02 (DSM 33828) cell-free supernatants (CFSs) produced in the conventional animal derivative-based MRS medium and an innovative animal derivative-free broth (TIL) versus the MDR S. aureus (ATCC 43300). CFS influence was assessed towards the viability, metabolic activity, and ability to form biofilm of the MDR strain through optical density, alamarBlue assay, and crystal violet staining; their content in short-chain fatty acids, lactic acid, and proteins was analysed via high-resolution mass spectrometry and gas chromatography. All CFSs reduce viable and metabolically active S. aureus, being TIL more efficient compared to MRS in stimulating lactic acid bacteria metabolism and decreasing S. aureus biofilm formation. Particularly, the CFS from LJO02 grown in TIL has the best efficacy, revealing a high amount of lactic acid and 59 peculiar proteins; its effectiveness is partially maintained upon trypsin and proteinase K treatments, but not by pepsin and pH basification. Therefore, antagonistic CFSs may represent a strategic prevention approach, with bacteriotherapeutic and bio-repair potential.

Growth Conditions Influence Lactobacillus Cell-Free Supernatant Impact on Viability, Biofilm Formation, and Co-Aggregation of the Oral Periodontopathogens Fusobacterium nucleatum and Porphyromonas gingivalis

“…Specifically, L. fermentum SG-A95 showed a stronger effect when used as a viable strain, while L. salivarius SG-M6 was when its CFS was used [ 31 ]. This evidence, together with our results, highlight not only how the probiotic effect is strain specific, but also that by changing the growth conditions, the efficacy of a specific strain can be different due to distinct by-products produced from the nutrients available [ 15 ]. In addition, Keller and colleagues in 2011 conducted a spectrophotometric analysis on a selection of Lactobacillus probiotics, indicating that S. mutans growth inhibition was strain specific and the pH and cell concentration was dependent, indicating once more that the response to therapy with lactobacilli-derived probiotics might vary among individuals and depend on the strain used [ 32 ].…”

“…Moreover, their growth was even enhanced in TIL. However, this outcome can be probiotic strain specific; in fact, as shown by Squarzanti et al, other types of Lactobacillus did not show any significant growth difference when cultivated in MRS or TIL [ 15 ].…”

Synergistic Inhibitory Effect of Honey and Lactobacillus plantarum on Pathogenic Bacteria and Their Promotion of Healing in Infected Wounds

“…Probiotic-derived biologics, such as organic acids, antimicrobial peptides, extracellular polysaccharides, and biosurfactants, have antibacterial and antibiotic film potential against many pathogens, such as S. aureus , P. aeruginosa , and Salmonella enterica [ 36 , 37 , 38 ]. Moreover, honey has antibacterial and anti-biofilm activity against S. aureus and P. aeruginosa [ 39 , 40 ].…”

Synergistic inhibitory effect of honey and Lactobacillus plantarum on pathogenic bacteria and their promotion of healing in infected wounds

“…Probiotic-derived biologics, such as organic acids, antimicrobial peptides, extracellular polysaccharides, and biosurfactants, have antibacterial and antibiotic lm potential against many pathogens, such as S. aureus, P. aeruginosa, and Salmonella enterica [33][34][35]. Moreover, honey has antibacterial and anti-bio lm activity against S. aureus and P. aeruginosa [36,37].…”