Phenazine degrading agents and related compositions, methods and systems for interfering with viability of bacteria

A method for treating and/or preventing a bacterial infection by bacteria producing pyocyanin-like phenazines of formula (III) in an individual, the method comprising

• administering to the individual an effective amount of one or more phenazine degrading agents comprising a pyocyanin demethylase and/or a derivative thereof, alone or in combination with an antibiotic and/or other antimicrobial,
• wherein formula (III) is
• where R1-R7 are independently selected from hydrogen, hydroxy, alkoxy, alkyl, alkenyl, alkynyl, aryl, heteroaryl, acyl, R10 is a methyl group, R9 is hydrogen and R8 is a negatively charged substituent,
• wherein the pyocyanin demethylase comprises the amino acid sequence of SEQ ID NO:
• 1 having demethylating residues D68, D72, H121, E154, and Y156;
• wherein the derivative has at least 30% sequence identity with SEQ ID NO:1, and comprises the demethylating residues of SEQ ID NO:
• 1 and/or a functional equivalent residue of the demethylating residues;
• and
• wherein the derivative has the ability to demethylate the pyocyanin-like phenazines of formula (III).