PHÂN LẬP VÀ NGHIÊN CỨU HOẠT TÍNH KHÁNG STAPHYLOCOCCUS AUREUS KHÁNG METHICILLIN CỦA CÁC CHỦNG XẠ KHUẨN PHÂN LẬP TỪ TỈNH GIA LAI, VIỆT NAM

Abstract

Objectives: Isolation of Streptomyces strains from soil, water, plant samples collected in Gia Lai province, Vietnam and study of their antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA). Subjects and methods: Collection of soil, water, plant samples in Gia Lai and isolation of Streptomyces strains by conventional methods using specific culture media. Antimicrobial activity was examined by agar dilution method. The targeted Streptomyces strain was identified by morphological and molecular characterization. The chemical composition of the ethyl acetate extract was analyzed using gas chromatography-mass spectrometry (GC-MS). Results: Fifty-two Streptomyces strains were isolated from the soil, water, plant samples and among them, SS656 showed antimicrobial activity against MRSA with an inhibition zone of 19 mm. This strain was identified as Streptomyces sp. SS656 by morphological characteristics and molecular marker with 16S rRNA. This Streptomyces strain also showed activity on several bacterial pathogens. The antimicrobial activity was stable at temperatures up to 100^oC and at pH 2 and pH 12. Protease and ultraviolet showed no effect on the activity of SS656. Finally, the ethyl acetate extract from SS656 culture medium showed 37 known compounds. Conclusion: Streptomyces sp. SS656 isolated from Gia Lai had antimicrobial activity against MRSA and this strain was promising for further studies to find secondary metabolites associated with antimicrobial activity to fight antibiotic-resistant bacterial pathogens.