Background: The goal was to assess the antimicrobial efficacy of two commonly used biocides, chlorhexidine, and benzalkonium chloride, against MDR isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, and Escherichia coli ST131, as well as the prevalence of resistance genes.
Methods: MIC of chlorhexidine and benzalkonium chloride and their effects on both the planktonic phase and biofilm were determined. Finally, the presence of genes responsible for resistance to quaternary ammonium compounds was investigated by PCR.
Results: No significant relationship was observed between the presence of resistance genes and different concentrations of quaternary ammonium compounds (benzalkonium chloride). There was no association between biofilm formation and the presence of resistance genes.
Conclusions: Chlorhexidine digluconate and benzalkonium chloride at appropriate concentrations could prevent biofilm formation.