[A nutrient medium for detecting the metallic luster of Pseudomonas aeruginosa colonies]

Almost 100% of P. aeruginosa strains, when inoculated in macrocolonies (plaques), show metallic (golden) luster of their colonies grown on the medium containing 2,3,5-triphenyltetrazolium chloride, milk and a higher concentration of peptone; such luster, though less intensive, can also be observed in nonpigmented strains. This phenomenon can be used in the diagnosis of P. aeruginosa infections as a decisive sign.