In vitro susceptibility of multidrug resistant Pseudomonas aeruginosa clinical isolates to common biocides

Abstract

Biocides (antiseptics and disinfectants) play an essential role in infection control and the prevention of hospital acquired infections of pathogenic microorganisms. Now days, rates of antibiotic resistance in Pseudomonas aeruginosa are increasing worldwide and emerging of biocides resistant strains may lead to a failure in disinfection program. Until now, very few studies have investigated the susceptibility profile of nosocomial pathogens in particularly P. aeruginosa to antiseptics and disinfectant compounds and there are no reports available in the Kingdom of Saudi Arabia. Hence the aim of this study was to detect the minimum inhibitory concentrations (MIC) of a range of multidrug resistant (MDR) P. aeruginosa against three disinfectants common to the pharmaceutical and healthcare sectors: biguanide (chlorhexidine) and two quaternary ammonium compounds   (benzalkonium chloride and cetrimide). The in vitro bactericidal activities of the three biocides were studied against 11 MDR P. aeruginosa organisms, isolated from various clinical specimens in the Qassim region, Kingdom of Saudi Arabia. The susceptibility testing performed by broth microdilution method following Clinical and Laboratory Standards Institute guidelines. Among 11 isolates tested, two (22%) were showed reduced susceptibility against benzalkonium chloride and cetrimide. Our observations imply an increased resistance observed against quaternary ammonium compounds among clinically isolated MDR P. aeruginosa isolates and further molecular studies are required to confirm these results in terms of resistance to the disinfectants.