Antibacterial and probiotic properties of lactic acid bacteria isolated from bee bread of stingless bee farm in Malaysia
Information relating to the types of lactic acid bacteria (LAB) present in stingless bee bread farm in Malaysia, their antimicrobial and probiotic properties is lacking. Bee bread is rich in nutrients, acidic in nature and may support growth of many microorganisms including LAB. The purpose of this...
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| Summary: | Information relating to the types of lactic acid bacteria (LAB) present in stingless bee bread farm in Malaysia, their antimicrobial and probiotic properties is lacking. Bee bread is rich in nutrients, acidic in nature and may support growth of many microorganisms including LAB. The purpose of this study was to isolate lactic acid bacteria from bee bread of stingless-bee obtained from different stingless bee species and sources. The isolated LAB were evaluated for their antibacterial activity against three pathogenic bacteria (Staphylococcus aureus ATCC 25923, Salmonella Typhimurium ATCC 1331 1 and Escherichia coli ATCC 25922) and, the probiotic properties namely, tolerance to low pH, and survival in 0.1 to 0.5% bile-salt and antibiotic resistant. Pre-enrichment of bee bread in MRS broth facilitate isolation of fifteen LAB strains on MRS agar with 0.8% 〖CaCO〗_3 compared to tomato juice agar with 0.8% 〖CaCO〗_3. The isolates were assured LAB by negative catalase test and Gram positive. LAB isolates showed significant (p<0.05) inhibitory activity against targeted bacteria. LAB isolated from Thorasica spp., Itama spp. and Terminata spp. isolated from Negeri Sembilan (NS) was more effect against S. Typhimurium and E. coli while LAB isolated from Sungai Merab (SM) showed the highest inhibitory activity against S. aureus as indicated by the diameter of inhibition zone: S. aureus (14.0-25.8 mm), Salmonella typhimurium (23.1 to 37.6 mm) and Escherichia coli (17 to 39.6 mm) after 24 h incubation at 37°C by dual agar overlay method. Supernatants of all LAB isolates showed an excellent antibacterial activity against all target bacteria at 50% of the cell free supernatant. Loss of antibacterial activity was observed after adjustment of supernatant to pH 5, 6, 7 and 8. All LAB isolates survived in 0.1 to 0.5 % (w/v) bile-salt and pH 2 to 4. The LAB isolated from bee bread SM were more resistant to high pH and bile-salt than LAB isolated from bee bread NS. All LAB isolates were resistant to vancomycin (5 µm) and streptomycin (10 µm); LAB from bee bread SM were resistant to gentamycin (10 µm) while LAB from bee bread NS were less resistant. All LAB isolates were sensitive to tetracycline (30 µn), penicillin G (10 µm) and chloramphenicol (30 µm). It can be concluded that bee bread of stingless bees obtained from different sources contains LAB with good antimicrobial activity against the target pathogens, but variable probiotic properties and less susceptibility to some antibiotics. |
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