Antibacterial agents not presently employed as preservatives in ophthalmic preparations found effective against Pseudomonas aeruginosa

Effects of copper and zinc ions on the germicidal properties of two popular pharmaceutical antiseptic agents cetylpyridinium chloride and povidone-iodine†

“…(3) At 10 min intervals and for 40 min subcultures were made into Tryptone Soya Broth which contained 3% m/v Tween 80 as neutralising agent (the recovery medium). A level of 3% m/v Tween 80 has been shown by several researchers [1][2][3][4][5] to neutralise many antiseptic agents without inhibiting or killing the microorganisms themselves. In preliminary tests this concentration was found to have no inhibitory effects on the test microorganisms used in this study.…”

“…(1) Solutions in Normal Saline containing the MMC 30/40 for the antiseptic agents plus 5, 10, 50 or 100 3 10 23 g dm 3 of the metal ions were prepared for each antiseptic agent, for each metal salt and for each micro-organism. These solutions were sterilised at 115 °C for 30 min.…”

Resistance of Pseudomonas aeruginosa to chemical inactivation

“…There was no appreciable effect upon the growth rate in nutrient broth when benzalkonium chloride 35 pg/ml was added to log phase Ps. This effect is particularly remarkable in view of the fact that Tween 80 is an antagonist of benzalkonium (Kohn, Gershenfeld & Barr, 1963). The same concentration immediately reduced to zero the rate in broth containing 0.02% Tween 80 (Fig.…”

Colonial Variants of Proteus Species: Their Growth Requirements, Biochemical Characters and Resistance to Antibacterial Agents

“…The number of colony-forming units in the culture was estimated, the drug was added, and the culture incubated at 37°C. Samples were taken at intervals and the drug action was stopped by tenfold dilution in NUB in the experiments with phenol (Russell, Ahonkhai and Rogers, 1979), in lecithin-glycerol broth for polymyxin, or in lecithin-tween broth for cetrimide and for chlorhexidine (Kohn, Gershenfeld and Barr, 1963). Survival was calculated from the number of colony-forming units after drug treatment, expressed as a percentage of the initial count.…”