Potensi Actinomycetes Rhizosfer Etlingera Asal Taman Hutan Raya Bukit Barisan dalam Menghambat Methicillin-Resistant Staphylococcus Aureus (MRSA)

Abstract

Microorganism resistance to antibiotics requires effort to explore potential microorganisms as antibiotic producers, such as actinomycetes. Actinomycetes isolated from nature are expected to inhibit resistant microorganisms such as Methicillin-resistant Staphylococcus aureus (MRSA). This research aims to determine the potency of actinomycetes to inhibit MRSA from Etlingera rhizospheric at the Bukit Barisan Grand Forest Park, North Sumatera area. Actinomycetes were isolated from the rhizosphere of Etlingera using a Starch Casein Nitrate Agar medium. Actinomycetes colonies were characterized macroscopically and microscopically. Primary selection of actinomycetes for antagonism against MRSA and Staphylococcus aureus ATCC 25923 was conducted using the Agar Plug Diffusion method. The isolates with the highest inhibition zone were extracted for its secondary metabolites using methanol and ethyl acetate. The methanol extracts and ethyl acetate extracts were assayed at 25, 50, and 75% using the Kirby-Bauer Disk Diffusion method. The potential isolates with the highest antibacterial activity were identified molecularly based on the 16s rRNA gene. The results show that 11 isolates with morphological characteristics indicated actinomycetes, such as opaque surfaces and filamentous cells. Eight of eleven isolates had inhibition zones against the test bacteria, namely THR02, THR04, THR06, THR07, THR08, THR09, THR10, and THR11. An assay of secondary metabolite isolate extracts using two solvents showed that the ethyl acetate extract had higher antibacterial activity than the methanol extract. Based on the molecular identification, THR04 isolate has high inhibitory ability was Amycolatopsis nivea.