Results indicate that alcohol ingestion results in a dose-dependent increase in movement of S. pneumoniae into the rats' lungs, which is further exacerbated by concurrent smoke exposure.

"Our study is the first to have reported showing that alcohol consumption in rats impairs the beating of their tracheal cilia, and that this correlates with increased movement of S. pneumoniae into their lungs," said Gentry-Nielsen. "This alcohol-induced defect was intensified in smoke-exposed animals, although smoke exposure without ethanol ingestion did not increase movement of organisms into the lungs. These results point to alcohol- and smoke-induced defects in ciliary beating that are likely to make hosts more susceptible to infections caused by microorganisms that colonize their upper respiratory tracts."

"This study points to the importance of understanding the potential combined adverse effects of alcoholism and cigarette smoking on lung defenses against pathogen infection," added Bagby. "It also illustrates the difficulty of studying combined effects of alcohol consumption and cigarette smoke exposure on lung host defense. Although the study identifies a potential adverse effect of the combined insult of alcohol consumption and smoke exposure on bacterial burden in the lower respiratory tract, the small sample size precluded definitive conclusions from being made on this adverse effect. Future studies are needed to both describe the effects of alcohol and cigarette smoking on lung-host defense as well as the mechanisms involved."

Gentry-Nielsen and her colleagues plan to continue testing the effects of smoking and drinking on other aspects of defense against S. pneumoniae infections, including examination of an anti-asthma drug that decreases binding of S. pneumoniae to epithelial cells, and treatment with an agent that stimulates
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15-May-2005