Cigarette smoke exposure induces expression of the pneumococcal erm(B) macrolide resistance gene.

Introduction: Cigarette smoking is a well-recognized risk factor for development of severe, invasive pneumococcal disease. However, little is known about the direct effects of exposure to cigarette smoke on the virulence mechanisms of the pathogen, particularly in respect of resistance to macrolide antibiotics, which are widely used in the treatment of pneumococcal infection. This study aimed to investigate the effects of exposure to cigarette smoke condensate (CSC, 80 and 160 mg/L) and clarithromycin (2 and 8 mg/L), alone and in combination , on expression of the (B) and (A) macrolide resistance genes of strains 2507 and 521 (both serotype 23F), respectively, of the pneumococcus.