Helpful nasal bacteria return after smokers quit

By Deborah Mitchell

SAN FRANCISCO (Reuters Health) - Researchers report another benefit from quitting smoking: beneficial bacteria in the nose and throat soon return to normal levels.

Harmless microbes that reside in the nasal passages and throat help prevent disease-causing bacteria from getting a foothold. Levels of these so-call "interfering bacteria" are reduced in smokers.

The new findings "illustrate for the first time that the high number of pathogens and the low number of interfering organisms found in the nasopharynx of smokers reverse to normal levels after complete cessation of smoking," researchers reported here at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

Swabs from the nose and throat were cultured from 20 smokers before they quit smoking and again 12 to 15 months after they stopped, explained Drs. Alan E. Gober and Itzhak Brook from Georgetown University in Washington, DC.

They initially identified 11 disease-causing microbes from nine subjects, but this was reduced to two pathogens in two subjects about a year after the participants stopped smoking.

The researchers documented 35 instances of bacterial interference against four potential pathogens before smokers quit. This increased to 116 instances of bacterial interference a year after the subjects quit smoking.

These findings provide evidence that smokers who quit lower their risk of respiratory infections, the investigators conclude.