Phosphate antimicrobial activity

Several factors influence the antimicrobial activity of silver salts [19]. Silver has a marked tendency to adsorb to surfaces and bactericidal activity is reduced in the presence of phosphates, chlorides, sulphides and hard water. Activity is increased as the temperature is raised (Q,o = 1.6, that is, a 1.6-fold increase in activity per 10°C rise in temperature) and is pH-dependent, increasing with increasing pH [19, 20]. Sodium thioglycol-late has been recommended as a suitable neutralizing agent for use in... 

Of the hundreds of chemicals that are efiective as antimicrobials, only a few are used in plastics applications. The most common group of active ingredients consists of 10,16-oxybisphenoxy arsine (OBPA, tradenames Intercide, Akzo Chemical Vinyzene, Morton International), 2- -octyl-4-isothia-zolin-3-one (tradenames Micro-Check 11, Ferro Corporation Vinyzene IT, Morton International), N-trichloro-methylthio-4-cycIohexene-l,2-dicarboximide (Captan, tradenames Vancide 89, R.T. Vanderbilt Fungitrol C, Hiils America), and N-(trichloromethylthio) phthalimide (Flopet, trade name Fungitrol 11, Huls America). Other antimicrobial active ingredients include amine-neutralized phosphate and zinc 2-pyridinethiol-l-oxide. 

A 24 hour nutrient broth culture of S. aureus was diluted with sterilised 0.3 mM phosphate buffer to give a final concentration of 1-2 x lO CPU / ml. 50 ml of the diluted bacterial culture was transferred to sterilised 250 nd glass jars to tiriiich 1.0 g of test fabric, which had been cut into approximately 1 cm pieces then autoclaved, was added. The tops were screwed onto the jars and they were incubated and shaken at 120 rpm at 37 °C for 1 hour or 24 hours. After incubation, serial dilutions were performed and were plated onto nutrient agar using the Miles Misra method. The plates were incubated for 24 hours at 37 °C and the number of CPU / g of fabric was calculated. The antimicrobial activity of the tested fabric samples was expressed as a log reduction in which the mean loglO density of bacteria for the jar containing the test samples after... 

Cieniecka et al. [120] synthesized bis(trifluorDmethylsulfortyl)imide nitrate, dialkylphosphinate, trifluoromethanesulfonate, tetrafluoroborate, and hexafluoro-phosphate phosphonimn ILs and tested for antimicrobial activity and anti-electrostatic properties. They reported that phosphonium salts, in contrast to their 1-alkyl-3-methylimidazolium analogues, both cation structure and the type of anion, have effects on their biological activity. 

Inorganic compounds exhibiting antimicrobial activity also include hydrogen peroxide, phosphates or carbon dioxide, which is effective against fungi and gram-negative psychrotropic bacteria, but lactic acid bacteria and anaerobes are less inhibited. 

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