Effects of 5-aminolevulinic acid-mediated photodynamic therapy on antibiotic-resistant staphylococcal biofilm: an in vitro study.

Background: Treatments of infections are not always successful because of multi-antibiotic-resistant organisms. It is therefore particularly urgent to provide more effective anti-infective strategy against these organisms. 5-Aminolevulinic acid (ALA), with the chemical structure C5H9NO3, is the only photodynamic therapy agent that is a biochemical precursor of a photosensitizer (protoporphyrin IX [PpIX]), which is naturally produced by the body.