[Effect of chlorhexidine on Staphylococcus aureus hospital isolates under different environmental conditions]

Antiseptic agents are widely used in hospitals, being essential when prevention and control of nosocomial infections are required. It is necessary to consider several aspects that affect the biocide activity, since they have direct incidence in hospital hygiene, health and also in the nosocomial infection rate. Organisms belonging to Staphylococcus genus are involved in such infections and, digluconate of chlorhexidine is one of the most used antiseptic agents for human and animal health. The current study involved the evaluation of this biocide agent against 19 nosocomial isolates of Staphylococcus with and without organic substances and applying distilled water and water of 300 ppm hardness as dilution means. Results show that hard water was one of the factors that most highly affected the bactericidal activity of chlorhexidine. Moreover we found that it affected bactericidal activity more than the interference generated by organic substances. Our study proves that chlorhexidine is an effective antiseptic for these gram-positive microorganisms.