title: Recovery of potential pathogens and interfering bacteria in the nasopharynx of smokers and nonsmokers.
abstract: BACKGROUND
  Active smoking and passive exposure to cigarette smoke are associated with colonization by some potentially pathogenic species of bacteria and an increased risk of respiratory tract infection in both adults and children. In an attempt to explain these observations, this study compared the frequency of isolation of potential pathogens, and aerobic and anaerobic bacteria that possess interfering capabilities (ie, interfering with the in vitro growth of potential pathogens) in the nasopharynx of smokers to their recovery in nonsmokers.
  
  
  METHODS
  Nasopharyngeal specimens for cultures were taken from 20 smokers and 20 nonsmokers. Potential pathogens, and aerobic and anaerobic bacteria with interfering capabilities against these organisms were identified.
  
  
  RESULTS
  Fourteen potential pathogens (0.7 per patient) were isolated from nasopharyngeal cultures obtained from 11 of the 20 smokers, and 4 (0.2 per patient) were recovered from 3 of the 20 nonsmokers (p < 0.01). In vitro bacterial interference between two aerobic (alpha-hemolytic and nonhemolytic streptococci) and two anaerobic species (Prevotella and Peptostreptococcus species), and four potential pathogens (Streptococcus pneumoniae, Haemophilus influenzae [non-type b], Moraxella catarrhalis, and Streptococcus pyogenes) was observed. Bacterial interference was noted in 61 instances against the four potential pathogens by 22 normal flora isolates that were recovered from the group of smokers, and in 155 instances by 50 isolates from the group of nonsmokers (p < 0.01).
  
  
  CONCLUSIONS
  These findings illustrate for the first time that the nasopharyngeal flora of smokers contains fewer aerobic and anaerobic organisms with interfering capabilities and more potential pathogens compared with those of nonsmokers.
authors.affiliation: Department of Pediatrics, Georgetown University School of Medicine, Washington, DC, USA. ib6@georgetown.edu
authors.forename: Itzhak
authors.initials: I
authors.lastname: Brook
authors.forename: Alan E
authors.initials: AE
authors.lastname: Gober
mesh_terms: D000328:Adult; D001420:Bacteria, Aerobic / Q000145:classification / Q000302:isolation & purification*; D001421:Bacteria, Anaerobic / Q000145:classification / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009305:Nasopharynx / Q000382:microbiology*; D012016:Reference Values; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000209:etiology*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012907:Smoking / Q000009:adverse effects*; D013048:Specimen Handling