Pengaruh Penambahan Lisat Methicillin-Resistant Staphylococcus aureus (MRSA) terhadap Aktivitas Senyawa Anti-MRSA oleh Streptomyces spp.

Abstract

Tiga strain Streptomyces spp. yaitu APM21 yang diisolasi dari tanah Pulau Muna, Sulawesi Tenggara, DBK2 dan DBK3 yang diisolasi dari daun bidara (Ziziphus sp.) telah diketahui memiliki aktivitas anti-MRSA, namun aktivitasnya tergolong rendah. Optimasi kondisi kultur perlu dilakukan untuk meningkatkan produksi metabolit sekunder dengan aktivitas antibakteri yang kuat. Penelitian ini bertujuan untuk mengoptimasi kondisi kultur melalui penambahan lisat MRSA dan menganalisis pengaruhnya terhadap aktivitas anti-MRSA. Pengaruh teknik elisitasi terhadap aktivitas anti-MRSA menunjukkan hasil yang bervariasi antar strain. Penentuan Minimum Inhibitory Concentration (MIC) menggunakan metode micro dilution assay menunjukkan bahwa MIC yang diperoleh berkisar 1.250 hingga >5000 µg/mL. Hasil menunjukkan hanya strain DBK3 yang mengalami peningkatan aktivitas anti-MRSA. Analisis High Performance Liquid Chromatography (HPLC) terhadap lisat MRSA menunjukkan adanya kehadiran Nasetilglukosamin (NAG) sebagai kandidat molekul pensinyalan. NAG diduga berperan dalam meningkatkan biosintesis senyawa anti-MRSA melalui mekanisme derepresi protein DasR.

Three strains of Streptomyces spp. APM21 isolated from the soil of Muna Island, Southeast Sulawesi, DBK2 and DBK3 isolated from bidara leaves (Ziziphus sp.) have been known to have anti-MRSA activity, but the activity is relatively low. Optimization of culture conditions is necessary to increase the production of secondary metabolites with strong antibacterial activity. This study aims to optimize culture conditions by adding MRSA lysate and analyze its effect on anti-MRSA activity. The effect of elicitation techniques on anti-MRSA activity showed varying results between strains. Determination of the Minimum Inhibitory Concentration (MIC) using the micro dilution assay method showed that the MIC obtained ranged from 1,250 to >5,000 µg/mL. The results showed that only isolate DBK3 experienced increased anti-MRSA activity. High Performance Liquid Chromatography (HPLC) analysis of MRSA lysate showed the presence of N-acetylglucosamine (NAG) as a candidate signaling molecule. NAG is thought to play a role in increasing the biosynthesis of anti-MRSA compounds through a mechanism of derepression of the DasR protein.