title: Study of the hormetic effect of disinfectants chlorhexidine, povidone iodine and benzalkonium chloride.
abstract: The study of the dose-response relationship of disinfectants is of great importance in treating infection, the objective being to use concentrations above the minimal bactericidal concentration (MBC). Below these concentrations, the bacteriostatic or bactericidal effect may be insufficient. Moreover, at low concentrations, a hormetic effect may be observed, producing a stimulation of growth instead of inhibitory action. Hormesis is not well known in the context of antimicrobial substances. This study investigates the possible existence of a hormetic effect in three commonly used antiseptics-chlorhexidine digluconate, povidone iodine and benzalkonium chloride-on strains of reference of Staphylococcus aureus and Pseudomonas aeruginosa. Growth curves were determined for different concentrations of the disinfectants. The variables studied-concentration of disinfectant, instantaneous growth rate and number of generations-were analysed using linear, quadratic and cubic models to adjust for the variables. The three disinfectants tested show a significant hormetic effect with P. aeruginosa and a less significant effect with S. aureus. These findings point to a dose-response effect that is not linear at low concentrations, while hormetic effects observed at some low concentrations result in greater bacterial growth. In infected wounds, materials or surfaces where microorganisms may occupy zones of difficult access for a disinfectant, the hormetic effect may have important consequences.
authors.affiliation: Department of Preventive Medicine and Public Health, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071, Granada, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Morales-Fernández
authors.forename: M
authors.initials: M
authors.lastname: Fernández-Crehuet
authors.forename: M
authors.initials: M
authors.lastname: Espigares
authors.forename: E
authors.initials: E
authors.lastname: Moreno
authors.forename: E
authors.initials: E
authors.lastname: Espigares
mesh_terms: D001548:Benzalkonium Compounds / Q000494:pharmacology*; D002710:Chlorhexidine / Q000494:pharmacology*; D004202:Disinfectants / Q000494:pharmacology*; D059165:Hormesis; D011206:Povidone-Iodine / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000254:growth & development; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
chemical_list: D001548:Benzalkonium Compounds; D004202:Disinfectants; D011206:Povidone-Iodine; D002710:Chlorhexidine
references.citation: Annu Rev Pharmacol Toxicol. 2003;43:175-97
references.pmid: 12195028
references.citation: Environ Sci Technol. 2012 Jul 17;46(14):7746-54
references.pmid: 22715968
references.citation: Risk Anal. 2004 Feb;24(1):65-72
references.pmid: 15028001
references.citation: Mutat Res. 2012 Jul 4;746(1):89-93
references.pmid: 22484510
references.citation: Environ Health Perspect. 2006 Nov;114(11):1631-5
references.pmid: 17107845
references.citation: Toxicol Pathol. 1999 Mar-Apr;27(2):187-94
references.pmid: 10207983
references.citation: Chemosphere. 2003 Aug;52(7):1233-44
references.pmid: 12821004
references.citation: J Appl Toxicol. 2000 Mar-Apr;20(2):121-5
references.pmid: 10715609
references.citation: Environ Toxicol Chem. 2008 Jul;27(7):1451-74
references.pmid: 18275256
references.citation: J Appl Microbiol. 2000 May;88(5):907-13
references.pmid: 10792552
references.citation: Risk Anal. 2011 Dec;31(12):1949-60
references.pmid: 21545627
references.citation: Transfusion. 2010 Jan;50(1):59-64
references.pmid: 19821950
references.citation: Mutat Res. 2012 Aug 30;747(1):157
references.pmid: 22565222
references.citation: J Hosp Infect. 2003 May;54(1):63-7
references.pmid: 12767849
references.citation: J Antimicrob Chemother. 2002 Apr;49(4):631-9
references.pmid: 11909837
references.citation: Sci Total Environ. 1982 Feb;22(3):213-34
references.pmid: 7043732
references.citation: Transfusion. 2010 Jan;50(1):53-8
references.pmid: 19682338
references.citation: Clin Microbiol Rev. 1999 Jan;12(1):147-79
references.pmid: 9880479
references.citation: J Hosp Infect. 2000 Dec;46(4):297-303
references.pmid: 11170761
references.citation: J Bacteriol. 1974 Sep;119(3):736-47
references.pmid: 4604283
references.citation: Mutat Res. 1983 May;113(3-4):173-215
references.pmid: 6341825