The impact of smoking on oral and nasopharyngeal bacterial flora.

Exposure to direct and passive tobacco smoking has significant impact on the gingival and oropharyngeal flora. The effects of exposure to smoking are evident in both children as well as adults. It increases the acquisition of periodontal pathogens and periodontal disease, colonization by respiratory pathogens, and the occurrence of upper respiratory tract infections, including otitis media. The flora of smokers contains fewer aerobic and anaerobic organisms with interfering activity against bacterial pathogens and harbors more potential pathogens as compared with the flora of non-smokers. The high number of pathogens and the low number of interfering organisms found in the nasopharynx of smokers revert to normal levels after complete cessation of smoking. Since parents who smoke harbor more potential pathogens and fewer interfering organisms, they may serve as a source of pathogens that can colonize and/or infect their children. The reduction in the number of members of the normal flora that interfere with the growth of pathogens and the greater adherence of bacterial pathogens to the oral mucosa are associated with the greater frequency of respiratory infections. Analysis of the data presented illustrates the adverse effects of direct and indirect exposure to smoking on colonization with potential pathogens.