| Objectives: To understand the role of thiocyanate (SCN -) in CF airway infection, we will determine potential antimicrobial mechanisms of SCN- on P. aeruginosa and the influence of SCN- on hypochlorite (HClO) -killing (a major microbicidal mechanism of inflammatory cells) on P. aeruginosa; and compare the effects of these antimicrobial reagents on mucoid and non-mucoid strains of P. aeruginosa.;Materials and Methods: The conventional strain PAO1 and its mucoidy mutant (PAM) and a mucoidy clinical isolate (C3873) of P. aeruginosa were included. Target bacteria were exposed to different treatments including H2O2, LPO/H2O2 and HClO with and without SCN-. Three distinct techniques were employed to examine the antimicrobial effects of these treatments including influence on planktonic growth, recovery of colony forming units and inhibition of growth on an agar surface.;Results: SCN with LPO is able to enhance the inhibitory effect of H2O2 on P. aeruginosa, due to conversion to the antimicrobial species OSCN. SCN can also rescue the P. aeruginosa from HClO-killing at optimal concentrations. The mucoidy character did not afford protection to P. aeruginosa from inhibition by H2O2, HClO or LPO/SCN/H2O2 system under either planktonic or biofilm condition.;Conclusion: SCN might play a role in airway defense by preventing P. aeruginosa infection. Diminshed amounts of SCN- resulting from CFTR mutation may contribute to CF lung damage. |
