Enhancement of Benzalkonium Chloride and Chlorhexidine Acetate Activity against Pseudomonas aeruginosa by Aromatic Alcohols

The actions of benzalkonium chloride and chlorhexidine acetate in combination with benzyl alcohol, 2-phenylethanol, or 3-phenylpropanol were evaluated at subinhibitory concentrations by measuring the growth rates of Pseudomonas aeruginosa NCTC 6750. When tested separately, all three alcohols had an effect on both benzalkonium chloride and chlorhexidine acetate that was more than additive. Phenylpropanol showed the greatest enhancement and benzyl alcohol showed the least enhancement.