Methods for detection and isolation of Pseudomonas aeruginosain mouse breeding colonies

Abstract

Methods for detection and isolation of Pseudomonas aeruginosa in mouse breeding colonies were compared using the following selective media ; BGLB broth Eiken, glycerol broth [13], NAC broth (Peptone 20 g, K₂HPO₄ 0.3 g, MgSO₄ 7H₂O 0.3 g, Cetrimide 0.2 g, Nalidixic acid 15 mg, Distilled water 1, 000 ml, pH 7.4), DHL agar Eiken, glycerol agar [13] and NAC agar Eiken [5] . As shown in Tables 1. and 2., the following procedure seemed to be most effective in detecting and isolating Ps, aeruginosa. NAC broth was inoculated with test materials such as feces and drinking water and incubated for 48 hours at 37°C. Although the production of green or blue pigment in the NAC broth culture revealed already the presence of Ps. aeruginosa in the materials (Table 3.), a loopful of the culture was streaked on an NAC agar plate which was incubated aerobically for 48 hours at 37°C. Colonies of Ps. aeruginosa were distinguishable from those of other microorganisms by the characteristic pigmentation on NAC agar. Solari's medium [10] was shown to be less sensitive for detection of Ps. aeruginosa than NAC broth.
As seen in Table 4., drinking water in contaminated mouse breeding colonies showed a high incidence of Ps. aeruginosa in agreement with many earlier publications. Samples of the oral cavity seemed to be less frequently positive than those of feces and large intestinal contents.