Antimicrobial Effects of Lactobacillus Plantarum and Lactobacillus Paracasei Isolated from Honey against Staphylococcus Aureus

Lactobacilli are gram positive, catalase-negative, and found in a variety of fermented foods such as honey, as well as human normal flora. The aim of this study was to identify lactobacillus Plantarum and lactobacillus Paracasei in Iranian honey samples and to investigate the probiotic and antimicrobial properties of them against Staphylococcus aureus.
This cross-sectional study investigated 88 honey samples from different areas in Iran at 6 months, from May to September, 2016. Samples were cultured in MRS broth and after were cultured on MRS agar. Sequencing of 16S rDNA gene was used to detect lactobacillus isolates. Then probiotic capacity (acid and bile resistance) of isolates was measured. Antimicrobial activity of lactobacillus isolates was investigated by diffusion method from wells and antibiotic resistance by disc diffusion method.
FINDINGS: From 88 honey samples, 39 Lactobacillus isolates were isolated, four L. plantarum and two L. paracasei were identified by molecular technique. Every six isolates tolerated acidity but were sensitive to bile salt. Five isolates inhibited the growth of S. aureus. The most antibiotic resistance of Lactobacillus strains was seen to vancomycin(100%), nalidixic acid(100%) and streptomycin(100%).
Iranian honey samples can be a source for different Lactobacillus species as L. plantarum and L. Paracasei which some of these species could have wonderful inhibitory effects against pathogen bacteria like S. aureus.