IN THIS INVENTION, THERE IS PROVIDED A NOVEL ANTIBIOTIC, BISPOLIDE A1, BISPOLIDE A2 OR BISPOLIDE A3 WHICH IS A COMPOUND HAVING THE FORMULA (I): WHEREIN R¹ AND R² EACH DENOTE A HYDROGEN ATOM OR METHYL GROUP (-CH3), AND R¹ AND R² ARE EACH A HYDROGEN ATOM FOR BISPOLIDE A1 R¹ IS A HYDROGEN ATOM AND R² IS METHYL GROUP FOR BISPOLIDE A2 AND R¹ AND R² ARE EACH METHYL GROUP FOR BISPOLIDE A3. BISPOLIDE A1, BISPOLIDE A2 AND BISPOLIDE A3 MAY COLLECTIVELY BE NAMED AS A BISPOLIDE A AND ARE EACH AN ANTIBIOTIC HAVING A HIGH ANTIBACTERIAL ACTIVITY AGAINST BACTERIA SUCH AS GRAM-POSITIVE BACTERIA, INCLUDING METHICILLIN-RESISTANT STRAIN OF STAPHYLOCOCCUS AUREUS. IN THIS INVENTION, THERE IS ALSO PROVIDED A PROCESS OF PRODUCING A BISPOLIDE A COMPRISING CULTIVATING A MICROBIAL STAIN DESIGNATED AS MICROBISPORA SP. A34030 (DEPOSITED UNDER AN ACCESS NUMBER OF FERM BP-10505). THERE IS FURTHER PROVIDED A PHARMACEUTICAL COMPOSITION COMPRISING A BISPOLIDE A AS AN ACTIVE INGREDIENT.
