Benzalkonium chloride: A potential disinfecting irrigation solution

Objective: To determine the disinfecting properties of benzalkonium chloride as an irrigation agent. Design: Comparison was made between irrigation of contaminated muscle strips with benzalkonium chloride and normal saline (control). Summary of Background Data: Benzalkonium chloride is a cationic disinfectant. which has questionable able efficacy in an organic environment. However, no previous study has attempted to use high volumes of this cationic solution to overcome the neutralizing effect of organic tissue and thus maintain this-detergent's germicidal properties. Methods: 2.5cm x 0.5cm x 0.5cm pieces of bovine muscle were aseptically cut from the center of freshly harvested beef muscle and incubated with 1.0 x 10(7) colony form in units of bacteria for 15 minutes. The muscle strips were then irrigated with either 100mL, 1L, or 10L of benzalkonium chloride at a 1:2000 concentration in normal saline. Normal saline was used as the control. The muscle strips were sonicated to remove adherent bacteria; the number of living organisms was determined by quantitatively culturing the sonicate. Results: In vitro, benzalkonium chloride was superior to normal saline at disinfecting bovine muscle (p less than or equal to 0.001). When 10L of benzalkonium chloride irrigation was used, no living bacteria could be recovered (p less than or equal to 0.012). Conclusion: In this experimental setting benzalkonium chloride was an effective disinfection agent, with enhanced activity at large volumes.