Although the factors that contributed to the emergence of GBS in human populations are not fully understood, acquisition of PI-1 through horizontal gene transfer may

have facilitated this process. PI-1 likely increased the fitness and colonization potential of some strains within the human host, thereby allowing them to establish a niche within a pregnant mother, for instance, and enhancing the likelihood of an opportunistic infection and subsequent transmission to a susceptible neonate. Additional studies, however, are required to test whether strains with different STs and PI profiles vary in their ability to colonize, persist, and invade host tissues relevant to the disease process. In the meantime, enhancing our understanding of PI selleck inhibitor Selleck BMS-907351 distribution patterns and genetic diversity in strains from different sources and geographic locations is critical for future efforts aimed at the development of pilus-based GBS vaccines, which were effective in neonatal mice [24, 27]. The variable presence GF120918 of PI-1 among human strains and the possibility of PI-1 loss in vivo may limit protection elicited through a vaccine targeting PI-1

alone. Consequently, enhancing our understanding of PI distribution patterns and genetic diversity in strains from different sources and geographic locations is critical for future efforts aimed at the development of pilus-based GBS vaccines, which were effective in neonatal mice [24, 27]. The variable presence of PI-1 among human strains and the possibility of PI-1 loss in vivo may limit protection elicited through a vaccine targeting PI-1 alone. Conclusions The analysis of 295 isolates from diverse sources demonstrated significant variation in the distribution of PI types across phylogenetic lineages and sources, suggesting that pilus combinations impact host specificity and disease outcomes. Moreover, we observed that diversification of specific Fenbendazole GBS lineages within certain populations can involve the loss or acquisition of PIs. The variable presence of specific PIs has considerable implications for the

development of GBS vaccines targeting these pili. Methods Bacterial population A total of 295 bacterial isolates were included in the study. Most isolates were originally recovered from neonatal blood or cerebral spinal fluid (invasive isolates; n = 120) [36] and vaginal/rectal swabs of pregnant women (maternal colonizing isolates; n = 89) [37]. Approval to collect specimens was granted by the University of Calgary Ethics Board; informed consent was obtained prior to sample collection. Approval to characterize the de-identified bacterial isolates was provided by both the University of Calgary Ethics Board and Michigan State University Institutional Review Board. Isolates were characterized by multilocus sequence typing to group isolates in to sequence types (STs) and clonal complexes (CCs).