Pneumococcal carriage is more common in asthmatic than in non-asthmatic young men.

INTRODUCTION: The aim was to investigate the prevalence of oropharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Neisseria meningitidis and beta-haemolytic streptococci among asthmatic and non-asthmatic young Finnish men and to identify putative risk factors. OBJECTIVES: A total of 224 asthmatics and 668 non-asthmatic men (mean age 19.6 years) from two intakes of conscripts to the Kainuu Brigade, Finland in July 2004 and January 2005 were enrolled upon entering military service. METHODS: Oropharyngeal specimens were examined for bacteria by routine culture methods. All the participants filled in questionnaires concerning risk factors for asthma and respiratory infections. RESULTS: S. pneumoniae (48 cases, 5.4%), Group A streptococci (16, 1.8%), H. influenzae (45, 5.0%), M. catarrhalis (24, 2.7%) and N. meningitidis (20, 2.2%) were isolated from the 892 participants. Ten putative risk factors for oropharyngeal colonization (asthma, atopy, allergic rhinitis, smoking, current use of asthma medication, history of adeno/tonsillectomy, level of highly sensitive C-reactive protein, peak expiratory flow, results of a 12-min running test and body mass index) were evaluated. The only significant risk factor for S. pneumoniae carriage was asthma (OR, 2.04; 95% CI 1.12 to 3.72). CONCLUSIONS: Pneumococcal carriage is more common in asthmatic than in non-asthmatic young men.

Smoking status interacts with the association between mannose-binding lectin serum levels and gene polymorphism and the carriage of oropharyngeal bacteria.

Mannose-binding lectin (MBL) role in the carriage of oropharyngeal bacteria is not known. We investigated the association of smoking, MBL2 polymorphisms, and MBL concentrations with oropharyngeal carriage of respiratory bacteria in young men. Oropharyngeal specimens, MBL concentrations, and MBL2 gene polymorphisms were measured in 124 asthmatic and 394 nonasthmatic Finnish military recruits. The carriage rates of S. pneumoniae (p = 0.002), N. meningitidis (p = 0.005), and beta-hemolytic streptococci (p < 0.001) throughout the military service were significantly higher among smokers than in nonsmokers. An MBL level below the median proved to be a significant risk factor for the carriage of N. meningitidis (odds ratio [OR] = 1.9; 95% confidence interval [CI] 1.0-3.6) and beta-hemolytic streptococci (OR = 2.0; 95% CI 1.2-3.2) in the nonsmokers and a borderline significant risk factor for the carriage of S. pneumoniae (OR = 1.5; 95% CI 0.9-2.6), whereas low MBL levels producing MBL2 haplotypes (LXA/LXA, LXA/O, HYA/O, LYA/O, O/O) seemed to be associated with the carriage of N. meningitidis (OR = 1.8; 95% CI 1.0-3.4) and S. pneumoniae (OR = 1.6; 95% CI 0.9-2.7). Thus, MBL deficiency may predispose nonsmokers to oropharyngeal carriage of these bacteria. We hypothesize that the major factor contributing to elevated bacterial carriage in smokers might be increased bacterial adherence to epithelial cells, which obscures the effect of MBL.