Abstract
BackgroundHuman nasopharynx is often colonized by potentially pathogenic bacteria. Gene polymorphisms in mannose-binding lectin (MBL), toll-like receptor (TLR) 2 and TLR4 have been reported. The present study aimed to investigate possible association between nasopharyngeal bacterial colonization and gene polymorphisms of MBL, TLR2 and TLR4 in healthy infants.Methodology/Principal FindingsFrom August 2008 to June 2010, 489 nasopharyngeal swabs and 412 blood samples were taken from 3-month-old healthy Finnish infants. Semi-quantitative culture was performed and pyrosequencing was used for detection of polymorphisms in MBL structural gene at codons 52, 54, and 57, TLR2 Arg753Gln and TLR4 Asp299Gly. Fifty-nine percent of subjects were culture positive for at least one of the four species: 11% for Streptococcus pneumoniae, 23% for Moraxella catarrhalis, 1% for Haemophilus influenzae and 25% for Staphylococcus aureus. Thirty-two percent of subjects had variant types in MBL, 5% had polymorphism of TLR2, and 18% had polymorphism of TLR4. Colonization rates of S. pneumoniae and S. aureus were significantly higher in infants with variant types of MBL than those with wild type (p = .011 and p = .024). Colonization rates of S. aureus and M. catarrhalis were significantly higher in infants with polymorphisms of TLR2 and of TLR4 than those without (p = .027 and p = .002).ConclusionsOur study suggests that there is an association between nasopharyngeal bacterial colonization and genetic variation of MBL, TLR2 and TLR4 in young infants. This finding supports a role for these genetic variations in susceptibility of children to respiratory infections.
Highlights
Nasopharynx is a complex ecosystem and contains various bacteria
Our study suggests that there is an association between nasopharyngeal bacterial colonization and genetic variation of mannosebinding lectin (MBL), TLR2 and TLR4 in young infants
No significant difference was found in colonization rates of S. pneumoniae, M. catarrhalis, H. influenzae, and S. aureus, when seasonal variation was examined
Summary
Nasopharynx is a complex ecosystem and contains various bacteria. These bacteria can asymptomatically colonize infants and young children but are associated with respiratory diseases [1,2]. Bacterial respiratory infections are mainly caused by extracellular encapsulated bacteria like Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis. S. pneumoniae and M. catarrhalis can colonize up to 54% and 72% of children, respectively, by 1 year of age [3]. Infants younger than 3 months of age, who have been colonized by these pathogens, have a greater risk in developing respiratory infections in the 6 to 9 months of their early life [5]. The present study aimed to investigate possible association between nasopharyngeal bacterial colonization and gene polymorphisms of MBL, TLR2 and TLR4 in healthy infants
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
