Efficacy of chlorhexidine gluconate against Staphylococcus aureus in a respiratory epithelial infection model
Abstract number: P1906
Anderson M.J., Lin Y.C., Parks P.J., Peterson M.L.
Background:Staphylococcus aureus, a significant pathogen, can invade via skin or mucosal epithelium. Chlorhexidine gluconate (CHG) is a common antiseptic agent used at concentrations from 0.12% (oral rinses) to 4% (surgical site preparations) to minimise the risk of nosocomial infections. This study evaluated the efficacy of CHG against a clinical isolate of Staphylococcus aureus, MN8, using two in vitro respiratory epithelial infection models.
Methods:S. aureus MN8 invasion of lung epithelial cells (A549) was characterised using fluorescently labeled bacteria (BacLight, Molecular Probes), and flow cytometry. Extracellular fluorescence (bound but not internalised bacteria) was quenched using trypan blue. Confluent nasal (RPMI 2650) and lung (A549) epithelial cells were infected with S. aureus MN8 1×106 CFU/mL for 15 min prior to treatment with CHG (2.0128 ug/mL; 0.0002 to 0.0128%) for 2 h. Antiseptic efficacy was evaluated by serial diluting and plating supernatants. Intracellular bacteria were enumerated by washing the adherent cells with PBS, resuspending in Triton X-100, serial dilution and plating. Cytotoxicity was evaluated by Cell Titer Aqueous One (Promega).
Results:S. aureus were bound to A549 within 10 min (16% of fluorescence) with approximately 50% being internal; therefore, we determined the ability of CHG to kill intra and extra-cellular S. aureus. At 2 h, complete S. aureus killing was observed in the supernatant at CHG 64 ug/mL; and cell associated was achieved at CHG 128 ug/mL.
|Session name:||19th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Helsinki, Finland, 16 - 19 May 2009|
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