Impact of cigarette smoke on respiratory pathogens in biofilm production

Biofilm formation by respiratory pathogen favour their colonization, persistence and virulence. Cigarette smoke have the ability to cause induction and increase in biofilm formation. This quantitative in vitro study is aimed at understanding the dose-dependent change in the biofilm formation, which can be correlated to the degree of virulence of the respiratory pathogens.

In the present study, 77 respiratory isolates of non-smokers were included. They were processed and exposed to varying concentrations of Cigarette Smoke Extract (CSE). Quantification of biofilm production was done according to the Microtitre dish biofilm formation assay. Fischer's exact test was used to compare the biofilm production status.

We observed that 42[80.77%] isolates out of 52 biofilm producers and 12[48%] isolates out of 25 non-biofilm producers were found to show an increase in Biofilm index (BFI) with exposure to CSE. Among the total of 77 respiratory isolates, 32 isolates accounting for 41.57% [95% CI; 30.6% to 52.6%] showed a dose-related augmentation of biofilm formation on exposure to CSE.

Progressive increase of biofilm with increase in concentration of CSE was the major finding. This emphasizes the need to initiate appropriate empirical therapy for smokers at the earliest.