The effect of hydrocarbon chain length, pH, and temperature on the binding and bactericidal effect of amphiphilic betaine esters on Salmonella tvphimurium

Abstract

Ahlstrom, B., Thompson, R. A. & Edebo, L. The effect of hydrocarbon chain length, pH, and temperature on the binding and bactericidal effect of amphiphilic betaine esters on Sulmonella typhimurium. APMIS 1999; 107:3 18-24. Amphiphilic betaine esters are quaternary ammonium compounds (QAC) with rapid microbicidal action. They are often labeled 'soft antimicrobial agents', since the compounds hydrolyze spontaneously into betaine and fatty alcohols, thus not only losing their surface active properties and toxicity but also becoming amenable to metabolic use. The present results show that the bactericidal effects of I-decyl (BlO), I-dodecyl (B12), and 1-tetradecyl (B14) betaine esters on Sulmonellu typhimurium 395 MS decreased with decreasing hydrocarbon chain lengths, decreased at pH below neutral, and were lower at 0°C that at 30°C. At least part of the decreased effect at pH 4.0 as compared to pH 6.0 can be explained by reduced binding. However, reduced binding cannot explain the decrease in the microbicidal effect at 0°C since the binding of B 14 was the same at 0°C and 30°C although 10-30 times higher concentrations were required at 0°C to achieve the same microbicidal effect as at 30°C. Neither can differences in binding explain the great differences seen in microbicidal effect between QAC with different chain lengths. It is proposed that the membrane deformation resulting in killing of S. typhimurium is more efficiently achieved with QAC with longer hydrocarbon chains and that reduced fluidity of the outer membrane of the bacteria at lower temperatures antagonizes the bactericidal effect. Charge interaction seems to be more important for the binding and bactericidal effect for the QAC with shorter hydrocarbon chains. The different effects of pH, temperature, and hydrocarbon chain length on binding, bactericidal effect, and hydrolysis have to be taken into account when optimizing disinfection and the subsequent elimination of disinfectants.

Synthesis and antimicrobial activity of quaternary ammonium-functionalized POSS (Q-POSS) and polysiloxane coatings containing Q-POSS

“…Thus, for Gram-negative bacteria, the outer membrane of the cell wall acts as an additional barrier to foreign molecules. Previous results have shown that QACs tend to be more effective toward Gram-positive bacteria than Gram-negative bacteria [36,38]. However, the data shown in Figs.…”

Anti‐microbial coatings by agent entrapment in coatings deposited via atmospheric pressure plasma liquid deposition

“…It is well known that quaternary ammonium compounds achieve biocidal action by disrupting the cell membrane, and studies have suggested that this kill mechanism can be affected by charge interactions. 11 Other authors have shown that charge-transfer reactions can strongly influence the activity of such biocidal agents. 12,13 Interestingly, it was cetylpyridinium chloride and benzalkonium chloride that showed reversible conversion to the neutral amine in pH12 washing conditions; this ability to lose and gain charge may give rise to the anti-microbial properties displayed in this work.…”

Action of Disinfectant Quaternary Ammonium Compounds against Staphylococcus aureus

“…A similar trend was observed in a previous study of QACs by Gélinas et al (16), where the activity between 4°C and 50°C increased with rising temperature and longer contact times. Ahlström et al (3) previously observed that amphiphilic betaine esters (QACs) at 0°C were less active than at 30°C even though binding affinities remained unchanged. The reduction in killing was believed to be due to the reduced fluidity of the outer membrane of Salmonella enterica serovar Typhimurium.…”