10.6084/m9.figshare.7936868.v2 Areej Alhhazmi Areej Alhhazmi Gregory J. Tyrrell Gregory J. Tyrrell Phenotypic and molecular analysis of nontypeable Group B streptococci: identification of <i>cps2a</i> and hybrid <i>cps2a/cps5</i> Group B streptococcal capsule gene clusters Taylor & Francis Group 2019 surface sialic acid group b streptococcus gene clusters identical decreased camp activity cpsv suggesting recombination based typing assay ten recognized cpss third isolate possessed dna sequence analysis phenotypic traits assayed assaying phenotypic changes 15 isolates assayed uncommon cpsiia type hybrid cluster containing ten cps types failed cps identification gbs nt isolates ten types molecular analysis gbs isolate cps cannot cps ). cps </ two groups sia (−)) sia (+)). second objective recently described orange pigmentation may potentially immundiffusion antisera human blood form biofilm first objective considered nontypeable capsular polysaccharide altered phenotypes 2019-10-24 12:12:16 Dataset https://tandf.figshare.com/articles/dataset/Phenotypic_and_molecular_analysis_of_nontypeable_Group_B_streptococci_identification_of_i_cps2a_i_and_hybrid_i_cps2a_cps5_i_Group_B_streptococcal_capsule_gene_clusters/7936868 <p>The Group B streptococcus (GBS) can express a capsular polysaccharide (CPS). There are ten recognized CPSs (Ia, Ib, and II–IX). A GBS isolate is considered nontypeable (NT) when CPS cannot be identified as one of ten types. Two groups of GBS NT isolates were studied, isolates without surface sialic acid (sia(−)) and isolates with surface sialic acid (sia(+)). The first objective was to characterize NT sia(−) isolates that failed CPS identification by an immunodiffusion antisera typing assay and a RT-PCR capsule typing assay. NT sia(−) isolates were characterized by assaying phenotypic changes and identifying <i>covR/S</i> mutations that may potentially have a role in the altered phenotypes. The second objective was to characterize NT sia(+) isolates that failed to identify as one of the ten CPS types by an immundiffusion antisera-based typing assay and a RT-PCR capsule typing assay yet expressed capsule. Fifteen NT sia(−) isolates displayed increased β hemolysis/orange pigmentation, decreased CAMP activity, inability to form biofilm, and susceptibility to phagocytosis by human blood. DNA sequence analysis of the <i>covR/S</i> genes in the sia(−) isolates found mutations in 14 of 15 isolates assayed. These mutations in the <i>covR/S</i> genes may potentially contribute to lack of expression of phenotypic traits assayed in vitro. For the three NT sia(+) isolates, whole-genome sequence analyses identified two isolates with <i>cps</i> gene clusters identical to the recently described and uncommon CPSIIa type. The third isolate possessed a hybrid cluster containing <i>cps</i> genes for both CPSIIa and CPSV suggesting recombination between these two gene clusters.</p>