Investigation of Some Lactobacillus SPP. against Methicillin-Resistant Staphylococcus aureus Isolated from Iraqi Patients

Investigation of Some Lactobacillus SPP

Abstract

Evaluate the antimicrobial activity of some Lactobacillus (L.) species against Staphylococcus aureus isolates with varying biofilm-forming capacities is the aim of this study. L. acidophilus, L. rhamnosus, and L. johnsonii were assessed using the microtiter plate method based on minimum inhibitory concentration (MIC) across serial dilutions. The result demonstrated a significant reduction in bacterial growth at lowered dilutions, with a gradual decrease in inhibition at higher dilutions. L. rhamnosus exhibited the highest inhibitory activity, particularly against strong biofilm-production isolates, reaching up to 94.8% inhibition at low dilutions. In contrast, L. johnsonii showed the lowest activity, especially at higher dilutions. Moderate biofilm-formation isolates were more susceptible to inhibition compared to strong biofilm. The analysis of supernatants indicated that antimicrobial activity was mainly associated with organic acids, as NaOH treatment reduced inhibitory effects, while trypsin and catalase treatments showed minimal impact. L. rhamnosus could be a good alternative to the use of antimicrobial agents in the treatment of S. aureus biofilm associated infections.