<b>Background and Objective:</b> Peatlands are unique ecosystems rich in microbial diversity, including bacteria with potential antibiotic activity. This study focuses on the isolation and characterization of bacteria from Indonesian peat soil, particularly their potential to produce antibiotics against multidrug-resistant (MDR) pathogens, including Methicillin-Resistant <i>Staphylococcus aureus</i> (MRSA). <b>Materials and Methods:</b> Bacterial isolates were rejuvenated on nutrient agar and subjected to antimicrobial activity testing using the Bauer & Kirby diffusion method against MRSA. The bacterial strain exhibiting the strongest activity was further analyzed using 16S rRNA sequencing for genetic identification. Phylogenetic analysis was performed using NCBI BLAST, followed by a statistical comparison of inhibition zones to assess antimicrobial efficacy. <b>Results:</b> Antimicrobial activity testing revealed that isolate 10 PS exhibited a larger inhibition zone against MRSA than the positive control, Ampicillin, indicating its strong antibiotic potential. Phylogenetic analysis further confirmed that the isolate belonged to the <i>Lysinibacillus</i> genus, though significant branch divergence suggested it may represent a novel species. This isolate's lack of endospore production, typically characteristic of the genus, alongside its isolation from the unique Indonesian peatland ecosystem, suggests potential microbial adaptations to environmental pressures. <b>Conclusion:</b> These findings highlight the potential of peat soil bacteria as a valuable source of novel antibiotics, particularly against MDR pathogens like MRSA. The proposed new species, isolate 10 PS (cataloged as SUB14736623), expands taxonomic knowledge of <i>Lysinibacillus</i> and holds promise for developing natural antibiotic treatments.
