Activity of Trimethoprim and Sulphonamides against Pseudomonas Aeruginosa

Abstract

Infections with Pseudomonas aeruginosa, although relatively uncommon under normal conditions, may cause serious clinical problems because of the considerable intrinsic resistance of this species. This applies especially to urinary tract infections, where oral therapy, such as with co-trimoxazole (Brumfitt & Pursell 1972), is highly desirable. Ps.aeruginosa is generally regarded as being resistant to co-trimoxazole, which is not therefore used for the treatment of urinary tract infections of such aetiology. However, we have noticed that a high proportion of Ps.aeruginosa isolated at this Hospital appear to be sensitive to a 300 p,g. disk of “triple sulphonamides”. Consequently, we decided to investigate further the activity of different sulphonamides against Ps.aeruginosa and also the occurrence of synergism between trimethoprim (tm) and sulphamethoxazole (SMZ).