The discovery was made in a particular sample of desert soil. Malacidin is short for metagenomic acidic lipopeptide antibiotic-cidins. (Also, “mal” means bad in Latin, and “cide” means to kill.) The malacidins are cyclic lipopeptides differing only by a methylene at their lipid tails. Even after 20 days of continued contact with malacidin , more than enough time for most bacteria to find a way to thwart an antibiotic’s effects , samples of MRSA bacteria showed no signs of evolving resistance to the newly discovered agent. The malacidins were shown to fight multidrug-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) skin infections in animals.
There are, however, limits: malacidins were shown to treat only gram-positive infections. The Centers for Disease Control and Prevention estimate that each year, at least 23,000 people now die as a direct result of bacterial infections that have become resistant to existing medicines. Unless new antibacterial agents are discovered and turned into medicines, mortality rates due to untreatable infections are predicted to rise. And many more die from other conditions that were complicated by an antibiotic-resistant infection.