Identification of Pseudomonas pyocyanea by the Oxidase Reaction

Abstract

ALTHOUGH the identification of Pseudomonas pyocyanea is generally very simple, the diagnosis of ‘atypical’ strains may take several days, and, as Schaub and Foley¹ stress, “its identification may present a problem”. Yow and Townsend², in their study on the sensitivity of Ps. pyocyanea to various antibiotics, limit the scope of their examinations: “Because of the difficulty in positively identifying the non-pigment-producing strains of Pseudomonas, only those producing either pyocyanin, fluorescin, or both, were included in this study”. However, apyocyanogenic strains are common. These strains are either primarily deficient in producing pigment or may have lost their ability to do so. Haynes³ therefore points out: “Strains not producing pyocyanin, from whatever source, cannot be dismissed from consideration as Ps. pyocyanea.”