%0 Journal Article
%T Heterogeneity of the group B streptococcal type VII secretion system and influence on colonization of the female genital tract.
%A Spencer BL
%A Job AM
%A Robertson CM
%A Hameed ZA
%A Serchejian C
%A Wiafe-Kwakye CS
%A Mendonça JC
%A Apolonio MA
%A Nagao PE
%A Neely MN
%A Korotkova N
%A Korotkov KV
%A Patras KA
%A Doran KS
%J Mol Microbiol
%V 120
%N 2
%D 2023 08 26
%M 37357823
%F 3.979
%R 10.1111/mmi.15115
%X Type VIIb secretion systems (T7SSb) in Gram-positive bacteria facilitate physiology, interbacterial competition, and/or virulence via EssC ATPase-driven secretion of small ɑ-helical proteins and toxins. Recently, we characterized T7SSb in group B Streptococcus (GBS), a leading cause of infection in newborns and immunocompromised adults. GBS T7SS comprises four subtypes based on variation in the C-terminus of EssC and the repertoire of downstream effectors; however, the intraspecies diversity of GBS T7SS and impact on GBS-host interactions remains unknown. Bioinformatic analysis indicates that GBS T7SS loci encode subtype-specific putative effectors, which have low interspecies and inter-subtype homology but contain similar domains/motifs and therefore may serve similar functions. We further identify orphaned GBS WXG100 proteins. Functionally, we show that GBS T7SS subtype I and III strains secrete EsxA in vitro and that in subtype I strain CJB111, esxA1 appears to be differentially transcribed from the T7SS operon. Furthermore, we observe subtype-specific effects of GBS T7SS on host colonization, as CJB111 subtype I but not CNCTC 10/84 subtype III T7SS promotes GBS vaginal colonization. Finally, we observe that T7SS subtypes I and II are the predominant subtypes in clinical GBS isolates. This study highlights the potential impact of T7SS heterogeneity on host-GBS interactions.