The effect of pH on the multiplication of a pseudomonad in chlorhexidine and cetrimide.

Pseudomonas cepacia (Ps. multivorans) can become adapted to a 1 in 30 dilution of Savlon hospital concentrate in distilled water, and can multiply in it. The organism so adapted did not survive in Savlon of the same strength made with hard tap water (pH 7.2). This effect was due to the difference of pH between the two solutions. At the pH of the distilled water solution (pH 6.0) Savlon also showed reduced activity against Proteus vulgaris, but activity against Ps. aeruginosa was not affected.