Passive smoking and nasopharyngeal colonization by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis in daycare children

Exposure to tobacco smoke may be associated with higher risk of nasopharyngeal colonization and infection by Streptococcus pneumoniae (SP), Haemophilus influenzae (HI), and Moraxella catarrhalis (MC). This study was done to determine the influence of passive smoking on S. pneumoniae, H. influenzae, and M. catarrhalis colonization rates among children. This is a prospective cross-sectional study. Tertiary referral centers with accredited otorhinolaryngology-head and neck surgery and Microbiology Departments. In this cross-sectional study, 2–6 years old children in 10 randomly selected day-care centers in northeast of Iran (Mashad) were studied. Smoking exposure and medical history were recorded. Carriage rates for aforementioned bacteria were analyzed on the basis of smoking exposure. 1,125 children (Female/Male: 597/528) with the mean age of 5.05 ± 0.98 years were studied. Carriage rates of S. pneumoniae, H. influenzae and M. catarrhalis among children were 10.1, 8.8 and 6.7%, respectively. Mixed colonization was found in 2.7%. There was a significant difference in carriage rates between children who live in smoking families compare to those with nonsmoking families for M. catarrhalis (P = 0.001) but not for S. pneumoniae, and H. influenza (P = 0.798 and P = 0.117, respectively). It seems exposure to tobacco smoke is associated with increased carriage rate of M. catarrhalis in day-care children.