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.

Assessment of periodontal and opportunistic flora in patients with peri‐implantitis

“…In addition, chlorhexidine, which is in general use for treating peri‐implantitis, may present some problems, because it is not effective and can enhance the growth of P. aeruginosa at some low concentrations (Morales‐Fernández et al. ). A microbiological analysis should be considered when designing peri‐implantitis therapy and further studies are needed to assess the role of opportunistic flora in these infections.…”

“…We evaluated the possibility that the periimplant pockets might be colonized by pathogens other than anaerobic periodontal flora. In vitro studies have identified the high affinity of P. aeruginosa (Truong et al 2010), S. aureus (Truong et al 2010) and yeast (do Nascimento et al 2013) for titanium surfaces. Some of these pathogens can cause early post-surgical infections (Cobo et al 2011;D'Ovidio et al 2011).…”

“…Several studies have indicated the possibility that some cases may harbour microorganisms that are not frequently found among oral flora, such as Staphylococcus aureus, Enterobacteriaceae, Candida albicans, Pseudomonas aeruginosa (Alcoforado et al 1991;Leonhardt et al 1999;Renvert et al 2008;Salvi et al 2008). All of these associated only very rarely with periodontal disease but are able to successfully attach themselves to titanium surfaces (Truong et al 2010;do Nascimento et al 2013). In addition, these pathogens have been found to cause orthopaedic device-related infections, such as early mandibular osteomyelitis after implant surgery (Rokadiya & Malden 2008).…”

The Toxicity and Antibacterial Effects of Povidone‐Iodine Irrigation in Fracture Surgery

“…The OD value was recorded at 650 nm Every hour for nine hand marked as A t ( t = 1, 2, 3, 4, 5, 6, 7, 8, 9). Bacterial algebra (g) and growth rate ( μ ) were calculated by absorbance: 23 …”

Research on the preparation and characterization of chitosan grafted polyvinylpyrrolidone gel membrane with iodine

“…As a broad‐spectrum fungicide that against most bacteria, fungi, and viruses, iodine showed excellent advantages like high efficiency, low toxicity, cheap, and no drug resistance, and so forth . However, the iodine is not stable and difficult to store in a solvent or creams, and the iodine is easily sublimated and decomposed when in use, which could lead to the reduction of effective iodine content, shorten of efficacy time, and difficulties in controlling the dose .…”