Anti-staphylococcal activity of Pseudomonas aeruginosa was studied on
a total of 118 strains of staphylococci. The results revealed the exis
tence of a highly active anti-staphylococcal Pseudomonas aeruginosa me
tabolite which appears to be pyocyanine. It was even active against me
thicillin resistant Staphylococcus aureus (MRSA) and coagulase negativ
e staphylococci (CONS).