%0 Generic %A Alhhazmi, Areej %A Tyrrell, Gregory J. %D 2019 %T Phenotypic and molecular analysis of nontypeable Group B streptococci: identification of cps2a and hybrid cps2a/cps5 Group B streptococcal capsule gene clusters %U 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 %R 10.6084/m9.figshare.7936868.v2 %2 https://tandf.figshare.com/ndownloader/files/14767223 %2 https://tandf.figshare.com/ndownloader/files/14767226 %2 https://tandf.figshare.com/ndownloader/files/14767229 %2 https://tandf.figshare.com/ndownloader/files/14767232 %K surface sialic acid %K group b streptococcus %K gene clusters identical %K decreased camp activity %K cpsv suggesting recombination %K based typing assay %K ten recognized cpss %K third isolate possessed %K dna sequence analysis %K phenotypic traits assayed %K assaying phenotypic changes %K 15 isolates assayed %K uncommon cpsiia type %K hybrid cluster containing %K ten cps types %K failed cps identification %K gbs nt isolates %K ten types %K molecular analysis %K gbs isolate %K cps cannot %K cps ). %K cps 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 covR/S 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 covR/S genes in the sia(−) isolates found mutations in 14 of 15 isolates assayed. These mutations in the covR/S 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 cps gene clusters identical to the recently described and uncommon CPSIIa type. The third isolate possessed a hybrid cluster containing cps genes for both CPSIIa and CPSV suggesting recombination between these two gene clusters.

%I Taylor & Francis