Studies on the Pigment Production of Pseudomonas aeruginosa

Especially of the Glutamic Acid Medium for the Isolation of Pseudomonad

Abstract

The fact that Ps. aeruginosa produces blue color, pyocyanin, has been well known and is one of the important indecies for the clinical detection and isolation of the bacilli. But many strains of Ps. aeruginosa produce yellow, red or brown color together with or instead of pyocyanin, and some other strains show no pigment visible in ordinary light.
Though these findings are quite important in the clinical examination they were left scarcely noticed up to the present.
In such a situation, Prof. Osawa and his colleagues devised a simple synthetic medium containing glutamic acid, suitable to observe the pigment production of Pseudomonas group. In this paper, results will be presented on the isolation of Ps. aeruginosa from feces by the use of the glutamic acid medium and the comparison of pseudomonal coloration between our medium and King A & B media on the 50 strains preserved in our laboratory.
On the glutamic acid medium, pigment and fluorescens always appear more rapidly and the colors are more brilliant than that on King's media. When the patients' specimen (feces) is smeared on the glutamic acid medium the coloration and fluorescence in an early stage of cultivation made the isolation of Pseudomonad easy and precise.
Moreover, as far as the preserved strains are concerned, various kinds of cocci and bacilli other than Pseudomonad hardly grow on this medium.
From these findings it is considered that the glutamic acid medium is very suitable not only for the observation of pigment production but also for the isolation of Ps. aeruginosa.