All issues > Volume 50(2); 2007

Original Article

Korean J Pediatr. 2007;50(2):151-156. Published online February 15, 2007.

A study of serotyping of Streptococcus pneumoniae by multibead assay

Ky Young KY Cho¹, Jung Ah JA Lee¹, Sung Eun SE Cho², Nam Hee NH Kim³, Jin A JA Lee³, Ki Sook KS Hong², Hoan Jong HJ Lee³, Kyung Hyo KH Kim¹

¹Departments of Pediatrics, College of Medicine Ewha Woman's University
²Departments of Laboratory Medicine, College of Medicine Ewha Woman's University
³Department of Pediatrics, College of Medicine, Seoul National University

Correspondence Kyung Hyo KH Kim ,Email: kaykim@ewha.ac.kr

Abstract

Purpose
: Streptococcus pneumoniae is a major etiologic agent for pneumonia, meningitis, otitis media, and sepsis among young children. Multi-drug resistant strains have raised great concern worldwide, thus the importance of prevention with vaccines has been emphasized. However, vaccines may force the appearance of pneumococcal infections by nonvaccine serotypes. Thus, distribution of pneumococcal serotypes should be monitored to estimate vaccine efficacy. We used a new and efficient multibead assay in determining pnemococcal serotypes.
Methods
: From January to February 2005, 643 children were recruited from ten day care centers to isolate pneumococci from their oropharynx. Pneumococcal serotyping was performed on 62 pneumococcal isolates from 60 children by multibead assay. This immunoassay required two sets of latex particles coated with pneumococcal polysaccharides and serotype-specific antibodies. Twenty four newly developed monoclonal antibodies specific for common serotypes and a pool of polyclonal rabbit sera for some of the less common serotypes were used.
Results
: The most prevalent pneumococcal serotypes were serotype 6A, 19A, 19F, 23F, and 11A/ D/F which accounted more than 50 precent of all the 62 pneumococcal isolates. We found that multibead assay can be performed very rapidly and objectively.
Conclusion
: This multibead immunoassay was very useful in serotyping clinical isolates of S. pneumoniae because it was simple, reliable and fast.

Keywords :Streptococcus pneumoniae , Serotyping , Immunoassay