A-54556A is a natural acyldepsipeptide (ADEP) antibiotic isolated from the fermentation broth of S. hawaiiensis. Like other ADEP antibiotics, A-54556A binds to the ATP-dependent Clp protease proteolytic subunit ClpP, resulting in constitutive activation of this bacterial protease. This leads to uncontrolled proteolysis, inhibition of bacterial cell division, and, ultimately, cell death. A-54556A preferentially targets Gram-positive bacteria, including staphylococci, streptococci, and enterococci, with minimum inhibitory concentration values in the submicrogram/milliliter range. ADEP antibiotics are effective against chronic infections as they are able to eradicate chronic biofilm infections, particularly when combined with rifampicin.
