Components of cigarette smoke can cause bacteria in the nose to increase their production of biofilms — sticky structures that help the microorganisms to establish an infection.
Cigarette smoke is known to impair the immune system and to irritate the lining of the lungs. Adam Ratner and his team at Columbia University, New York, exposed Staphylococcus aureus to cigarette smoke and found that some of the toxic molecules in smoke switched on biofilm-forming signalling pathways. The smoke also boosted bacterial adherence to cultures of the cells that line the lungs.
The findings offer another explanation for why smokers and those exposed to second-hand smoke are prone to respiratory infections.
Infect. Immun. http://dx.doi.org/10.1128/IAI.00689-12 (2012)