Streptococcus pneumoniae is a bacterium that can infect the upper respiratory tract and cause pneumonia, as well as infections in other parts of the body such as the bloodstream (bacteremia), lining of the brain and spinal cord (meningitis), bones (osteomyelitis), joints (arthritis), ears (otitis media) and sinuses (sinusitis). Alcoholics and cigarette smokers are particularly susceptible to pulmonary infections caused by S. pneumoniae. A rodent study in the May issue of Alcoholism: Clinical & Experimental Research has found that alcohol consumption increases movement of S. pneumoniae toward the lungs, and that smoke exposure exacerbates the alcohol-induced increase in bacterial penetration.
"All of the infections caused by S. pneumoniae start with the bacterium colonizing or binding to cells in the upper part of the nose, which is called the nasopharynx," said Gentry-Nielsen, professor of microbiology and immunology at Creighton University School of Medicine, research microbiologist at the Omaha Veterans Affairs Medical Center, and corresponding author for the study. "The trachea that leads from the nasopharynx to the lungs is lined with cells that have hair-like projections called cilia. These cilia beat in an upward direction to sweep mucus and microorganisms like S. pneumoniae upward and prevent their movement into the lungs. Disease normally occurs when the immune system is compromised or the person is colonized with a new or especially virulent strain of S. pneumoniae that