J Med Microbiol 57 (2008), 171-178; DOI: 10.1099/jmm.0.47549-0
© 2008 Society for General Microbiology
ISSN 1473-5644
A rapid pneumococcal serotyping system based on monoclonal antibodies and PCR
J. Yu1,
M. da G. S. Carvalho2,
B. Beall2 and
M. H. Nahm1
1 Department of Pathology, University of Alabama at Birmingham, 845 19th Street South, BBRB 614, Birmingham, AL 35294, USA
2 Division of Bacterial Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, GA 30333, USA
Correspondence
M. H. Nahm
nahm{at}uab.edu
Received 1 August 2007
Accepted 30 September 2007
Streptococcus pneumoniae expresses at least 91 different polysaccharide (PS) capsules and the currently available serotyping methods are tedious to perform. We have been developing a rapid pneumococcal serotyping assay (named the multibead assay) based on the capacity of pneumococcal lysates to inhibit the ability of 24 different anti-capsule antibodies to bind to latex beads coated with 24 different PSs (serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9N, 9V, 14, 18C, 19A, 19F, 23F, 2, 8, 10A, 11A, 12F, 15B, 17F, 20, 22F and 33F). Because the polyclonal antibodies used for 10 serotypes (2, 8, 10A, 11A, 12F, 15B, 17F, 20, 22F and 33F) had limited serotype specificity, we replaced them with monoclonal antibodies for the 10 serotypes. To extend the serotype coverage beyond the 24 serotypes, we have adapted multiplexed PCR for five additional serotypes (15A, 15C, 16F, 35B and 38) to be useful with the pneumococcal lysates prepared for the multibead assay. We then validated the combined assay with 157 clinical isolates from the Centers for Disease Control and Prevention and found that the new combined assay produced results that are concordant with the quellung reaction. The combined assay is robust and could be used to rapidly identify the serotypes of the majority of pneumococci (
90 %). In addition, the assay validation study suggests the presence of serological subtypes within serotype 11A.
Abbreviations: CDC, Centers for Disease Control and Prevention; DMTMM, 4-(4,6-dimethoxy[1,3,5]triazin-2-yl)-4-methyl-morpholinium; EDC, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride; PLL, poly-L-lysine; PS, polysaccharide; RT, room temperature; UAB, University of Alabama at Birmingham.
Copyright © 2008 Society for General Microbiology.