Validation of a Multiplex Pneumococcal Serotyping Assay with Clinical Samples

Abstract

) were noted, but 46 were due to nonreproducible technical problems or insufficient growth of the pneumococci. All of the isolates grew well for a second test, and therefore, the culture medium used for the multibead assay is adequate. The discrepancies persisted for eight isolates, involving the 6A, 11A, and 18C serotypes. Additional studies of the eight isolates showed that the discrepancies were due to differences in the reagents used in the multibead or Neufeld tests for these three serotypes. For instance, five isolates were typed as 6A with the Neufeld test but as nontypeable by the multibead assay. Selection of another new monoclonal antibody (Hyp6AG1) for the multibead assay resulted in all five discrepant isolates typing as 6A. This finding indicates the validity of the multibead assay and emphasizes the need to validate any new pneumococcal serotyping assay with a large number of clinical isolates from different locations. It also suggests the presence of serological subtypes among isolates expressing the 6A serotype.

Discovery of Streptococcus pneumoniae Serotype 6 Variants with Glycosyltransferases Synthesizing Two Differing Repeating Units

“…As serogroup 6 reference strains, we used cps variants of TIGR4 (TIGR6A, TIGR6B, TIGR6C, and TIGR6D) (8,10,29). Although the reference strains showed expected binding patterns (Fig.…”

Streptococcus pneumoniae Serotype 11D Has a Bispecific Glycosyltransferase and Expresses Two Different Capsular Polysaccharide Repeating Units

“…Antibodies and Flow Cytometric Serotyping Analysis (FCSA)-Mouse hybridomas expressing monoclonal antibodies (mAbs) labeled Hyp11AM1 and Hyp11AM7 were derived from mice immunized with serotype 11A CPS, as described (11). Rabbit polyclonal factor sera 11b, 11c, and 11g were purchased from SSI.…”

Identification of natural pneumococcal isolates expressing serotype 6D by genetic, biochemical and serological characterization

“…Recently, we discovered a new member of serogroup 6 which we named 6C (Park et al, 2007b). Serotype 6C is distinguished serologically from serotypes 6A and 6B by its unique monoclonal antibody (mAb) binding profile (Lin et al, 2006). Subsequent genetic studies have shown that the capsule gene loci of serotypes 6A and 6B have wciN 6A (named alternatively as wciN a here), but that the 6C capsule gene locus has wciN 6C (or wciN b ) (Park et al, 2007a).…”