sodium-hypochlorite and Aspergillosis

Macrophages are important in wound defense and healing. Dakin's solution (DS), buffered sodium hypochlorite, has been used since World War I as a topical antimicrobial for wound care. DS has been shown to be toxic to host cells, but effects on immune cells are not well documented.. DS at 0.5%, 0.125%, and ten-fold serial dilutions from 0.25%-0.00025% were evaluated for cellular toxicity on murine macrophages (J774A.1). The effect of DS on macrophage adhesion, phagocytosis, and generation of reactive oxygen species was examined. Macrophage polarization following DS exposure was determined by gene expression using quantitative real-time polymerase chain reaction.. Concentrations of DS >0.0025% reduced macrophage viability to <5% in exposure times as short as 30 s. Similarly, phagocytosis of Staphylococcus aureus, Pseudomonas aeruginosa, and Aspergillus flavus were significantly reduced at all tested concentrations by macrophages pretreated with DS. H2O2 production was reduced by 8%-38% following treatment with 0.00025%-0.125% DS. Macrophage adherence was significantly increased with >0.0025% DS after 15 min of exposure compared with controls. Quantitative real-time polymerase chain reaction demonstrated that DS exposure resulted in classical macrophage activation, with increased expression of inducible nitric oxide synthase 2, interferon-γ, and interleukin (IL)-1β.. DS at clinically used concentrations (0.025%-0.25%) was detrimental to macrophage survival and function. For optimal clinical use, understanding the impact of DS on macrophages is important as depletion may result in impaired pathogen clearance and delayed healing. These findings indicate that 0.00025% DS is a safe starting dose; however, optimal use of DS requires further validation with in vivo models.

Topics: Adult; Animals; Aspergillosis; Cell Adhesion; Cell Line; Cell Polarity; Cell Survival; Disinfectants; Female; Humans; Macrophages; Mice; Phagocytosis; Pseudomonas Infections; Sodium Hypochlorite; Solutions; Staphylococcal Infections; Surgical Wound Infection; Wound Healing

Physical treatments, like heating or irradiation, may reduce the viability or eradicate Aspergillus conidia, which in turn might help to prevent infections by members of this genus. Chemical treatments can also prevent infection resulting from contaminated hospital fabrics or surfaces. Our objectives were to study the kinetics of survival of the conidia of pathogenic Aspergillus species, like A. fumigatus, A. flavus and A. niger, during exposure to heating at 60 degrees C and microwave irradiation. In addition, we evaluated the susceptibility patterns of Aspergillus conidia to such chemical agents as cupric sulphate and sodium hypochlorite. Heating the conidia of A. flavus and A. niger at 60 degrees C for 45 min was found to be fungicidal (reduction > 104 conidia/ml), but was not with A. fumigatus conidia. Short periods of microwave irradiation (40 s) resulted in a significant reduction of the viability of the conidia of these three Aspergillus species as a result of lethal membrane lesions. All Aspergillus species were similarly susceptible to cupric sulphate and sodium hypochlorite. Therefore, heating, microwave and the chemical treatments tested impaired significantly the viability of Aspergillus conidia, supporting the use of these methods as preventive measures among patients at risk.

Topics: Aspergillosis; Aspergillus; Cell Membrane; Copper Sulfate; Disinfectants; Hot Temperature; Humans; Microbial Sensitivity Tests; Microwaves; Sodium Hypochlorite; Species Specificity; Time Factors