INFECTIONS WITH PSEUDOMONAS AERUGINOSA TREATED WITH POLYMYXIN B

Abstract

PSEUDOMONAS aeruginosa derived its earlier name, Bacillus pyocyaneus, from the blue-green pus of wounds from which it was cultured. It is one of about 30 related species of Gram-negative bacilli which are predominantly freeliving in water and soil. Ps. aeruginosa is a normal inhabitant of the human intestinal tract, where it usually is present in small numbers and comes to the fore only when the normal coliform flora has been suppressed by antimicrobial drugs. This organism is not a pathogen in the usual sense of the word but may be called an "opportunist." It has no invasive powers and is ordinarily dealt with by the normal defenses of the body. Should these defenses not be developed, as in infants, or break down, as in debilitated persons, or should the bacillus be introduced passively into areas devoid of adequate natural defense mechanisms, it can set up an infection. Being closely related