Open AccessRe-validation and update of an extended-specificity multiplex assay for detection of Streptococcus pneumoniae capsular serotype/serogroup-specific antigen and cell-wall polysaccharide in urine specimens
Author(s) -
Seyi Eletu,
Carmen Sheppard,
Samuel Rose,
Kenneth Smith,
Nick Andrews,
Wei Shen Lim,
D Litt,
Norman K. Fry
Publication year - 2020
Publication title -
access microbiology
Language(s) - English
Resource type - Journals
ISSN - 2516-8290
DOI - 10.1099/acmi.0.000094
Subject(s) - serotype , streptococcus pneumoniae , microbiology and biotechnology , immunoassay , multiplex , pneumococcal infections , antigen , virology , antibody , conjugate vaccine , multiplex polymerase chain reaction , pneumococcal polysaccharide vaccine , biology , urine , medicine , immunology , pneumococcal disease , antibiotics , polymerase chain reaction , gene , bioinformatics , biochemistry
National surveillance of pneumococcal disease at the serotype level is essential to assess the effectiveness of vaccination programmes. We previously developed a highly sensitive extended-specificity multiplex immunoassay for detection ofStreptococcus pneumoniaeserotype-specific antigen in urine in the absence of isolates. The assay uses human mAbs that detect the 24 pneumococcal serotype/groups targeted by the pneumococcal conjugate vaccines (PCVs) and pneumococcal polysaccharide vaccine (PPV-23) plus some cross-reactive types and the pneumococcal cell-wall polysaccharide. However, the previous assay had some limitations, namely the reduced specificity of the serotype 7F, 20 and 22F assays, for which non-specific binding in urine samples was observed. Here we report on the further development and re-validation of a new version of the assay (version 2.1), which offers improved sensitivity towards serotypes 7F, 18C and 19F and increased specificity for serotypes 7F, 20 and 22F by replacement of some of the antibody clones with new clones. Using a panel of urine specimens from patients diagnosed with community-acquired pneumonia or pneumococcal disease, the overall clinical sensitivity of this version of the assay based on isolation ofS. pneumoniaefrom a normally sterile site is 94.3 % and the clinical specificity is 93.6 %, in comparison with clinical sensitivity and specificity values of 96.2 % and 89.9 % in the previous assay.