Abstract:
Routine surface disinfection with antiseptics containing antimicrobial compounds is adopted as an important preventive measure against the transmission of nosocomial infections in healthcare settings. A variety of chemical agents have been currently employed as disinfectants, however, the recent evidence discloses the emergence of microbial resistance as well as the health concerns and environmental issues related to the long-term usage of these chemicals. Thus, the exploration and development of novel disinfectants, which are highly effective and less toxic, as alternatives to the existing agents is of great demand. Therefore, the present study was undertaken to synthesize silver nanoparticles from Argyreia populifolia (Girithilla); a plant widely utilized in antimicrobial remedies in Sri Lankan traditional medicine and to evaluate the antimicrobial and disinfectant properties of the nano-preparation. Sliver nanoparticles were synthesized after treating an aqueous solution of silver nitrate with an aqueous extract of A. populifolia. The antimicrobial activity of the silver nanopreparation was evaluated by broth microdilution method against Staphylococcus aureus, Staphylococcus saprophyticus and four different strains of methicillin resistant Staphylococcus aureus. A minimum inhibitory concentration value of 125 μg/mL and a minimum bactericidal concentration of 250 μg/mL were detected for most of the organisms tested. Thereafter, the quantitative surface disinfectant assay was employed with slight modifications to determine the disinfectant potential of the nano-preparation against S. aureus on smooth and rough surfaces at the concentration of 250 μg/mL. Briefly, the different surfaces were treated with the test preparation and thereafter inoculated with microbial preparations of different dilutions and observed the growth of colonies after 48 hours. Interestingly, not a single colony of microorganisms had grown on swab cultures obtained from the smooth and rough surfaces inoculated with S. aureus after exposure to the nanopreparation. However, a profuse growth of bacteria was observed on swab cultures obtained from these surfaces inoculated with S. aureus without the exposure to the nano-preparation. These preliminary results suggest that the silver nanoparticles synthesized from A. populifolia has a high potential to be developed into a novel disinfectant. Thus, the experiments are in progress to further confirm its disinfectant potential, mechanism of action and also to exclude the possible cytotoxic effects on human.
