Abstract
Introduction: The leading cause of COPD in developed nations is exposure to tobacco smoke and the role of bacterial colonization and infection in COPD has not yet been elucidated. Further, the direct effect of cigarette smoke on bacteria present in the COPD lung remains to be determined. This preliminary study aimed to determine the effect of cigarette smoke extract (CSE) on the growth of the principal COPD bacterial pathogens.
Methods: CSE was prepared as described previously (Cromer et alEur Respir J. 2013 May;41(5):1058-67). Bacterial type strains (Pseudomonas aeruginosa, Moraxella catarrhalis, Streptococcus pneumonia, Prevotella spp and Haemophilus influenzae) were inoculated into growth medium +/- CSE and cultured in appropriate conditions. Total viable counts (TVC cfu/ml) were estimated at each time point.
Results: The growth of P.aeruginosa, S. pneumoniae ,H. influenza and Prevotella spp were not completely inhibited by any concentration of CSE; however a reduction in growth rate at higher concentrations was observed. M. catarrhalis growth was completely inhibited at higher concentrations.
Conclusions: The growth of principal bacterial pathogens frequently isolated from COPD patients are not affected by concentrations of CSE utilized in this study. Work currently underway aims to determine whether CSE induces key phenotypic changes (virulence factor expression, biofilm production and/or antibiotic susceptibility), which might enhance the pathogenicity of these bacteria and result in poorer outcomes for patients with COPD.
- © 2014 ERS
