Adaptive microbial response to low-level benzalkonium chloride exposure

Publication date: Available online 31 May 2018Source: Journal of Hospital InfectionAuthor(s): G. KampfSummaryBenzalkonium chloride (BAC) is a widely used biocidal agent in health care, mainly in surface disinfectants and disinfectant cleaners. The aim of this review was to evaluate the potential of bacteria to adapt to low-level BAC exposure. A maximum four-fold increase in minimum inhibitory concentration (MIC) was found in most of the 57 bacterial species evaluated. A strong adaptive, mostly stable, change in MIC was described in strains or isolates of Pantoea spp., Enterobacter spp., Staphylococcus saprophyticus and Escherichia coli (up to 500-fold, 300-fold, 200-fold and 100-fold, respectively). The highest MIC values after adaptation were 3000 mg/L (Salmonella typhimurium), 2500 mg/L (Pseudomonas aeruginosa), 1500 mg/L (Enterobacter spp.) and 1000 mg/L (E. coli and S. saprophyticus). Cross-resistance to selected antibiotics (e.g. ampicillin, cefotaxime and ceftazidime) and biocidal agents (e.g. didecyldimethylammonium bromide, didecyldimethylammonium chloride, triclosan and chlorhexidine) was found in some isolates. A significant upregulation of transporter and efflux pump genes was found in Burkholderia cepacia complex and E. coli. It is probable that adapted isolates are not killed by BAC-based disinfectants at the recommended concentration. The use of BAC in patient care and all other settings, such as consumer products and households, should be critically asse...
Source: Journal of Hospital Infection - Category: Infectious Diseases Source Type: research