Potensi Aktinomisetes Laut Kawasan Pantai Cermin Kabupaten Serdang Bedagai dalam Menghambat Methicillin-Resistant Staphylococcus Aureus (MRSA)

Abstract

Actinomycetes are a group of bacteria that produce antibiotics. Until now, actinomycetes are still being explored to determine the potential to produce compounds to inhibit methicillin-resistant Staphylococcus aureus (MRSA). This research was conducted to determine the potential of the actinomycetes at the Cermin Beach area into inhibiting MRSA. Actinomycetes were isolated using Starch Casein Agar (SCA) and Humid Acid Vitamin Agar (HVA) media, then characterized. Actinomycetes selection of inhibiting MRSA and S. aureus (ATCC 25923) bacteria was carried out qualitatively through an antagonist test. Quantitatively by testing to MeOH and EtOAc extracts at concentrations of 75, 50, and 25% respectively from actinomycetes cultures fluid against MRSA and S. aureus (ATCC 25923). Potential actinomycetes with the highest inhibitory ability were identified molecularly based on the 16S rRNA gene. The results of the research showed there were 15 isolates obtained from the Cermin Beach, called by 12 sand sediment isolates and 3 seawater isolates. A total of seven actinomycete isolates, SPC 1, SPC 3, SPC 4, SPC 5, SPC 6, SPC 9, and SPC 10, showed inhibitory activity against MRSA and S. aureus (ATCC 25923) with diameters ranging from 15 mm to 28 mm. The ability of MeOH and EtOAc extracts from Actinomycete cultures produced almost the same inhibition zone ranging from 33% to 86% against MRSA and S. aureus (ATCC 25923). The higher the concentration, the greater the inhibition zone produced, however the inhibition zone obtained was lower than chloramphenicol. Molecular identification showed that potential actinomycetes, SPC 3 and SPC 9, had a high similarity percentage of 99% compare to Streptomyces antibioticus.