ABSTRACT
Aims@#Maternal vaginal Group B Streptococcus (GBS) colonization is considered a risk factor for preterm delivery and, consequently, neonatal infections. Previous studies have portrayed the important roles of these virulence factors, including hemolytic pigment, hyaluronidase (HylB), serine-rich protein (Srr) and bacterial surface adhesion of GBS (BsaB) in mediating GBS colonization and intrauterine ascending infection, causing preterm delivery. This study aimed to investigate the association between mRNA expression of virulence genes in GBS isolates obtained from symptomatic pregnant women and preterm delivery.@*Methodology and results@#GBS isolates were obtained from high vaginal swabs of 40 symptomatic pregnant women of gestational age of less than 37 weeks. RNA was extracted from these GBS isolates and RT-qPCR was performed to determine the relative mRNA expression of GBS virulence genes, including CylE (encode enzyme required for the biosynthesis of the hemolytic pigment), HylB, Srr-1 and BsaB. Socio-demographic details and obstetric history were not found to be associated with the delivery outcomes of these women. The GBS isolates from symptomatic pregnant women who delivered prematurely showed a higher expression of CylE gene and a trend towards an elevated expression of HylB gene compared to women with term delivery. Meanwhile the expression of both Srr-1 and BsaB genes was similar between symptomatic pregnant women who had term or preterm delivery.@*Conclusion, significance and impact of study@#The results suggest that following vaginal colonization, both CylE and HylB genes are likely to contribute to intrauterine ascending infection and inflammation, leading to preterm delivery in humans. These virulence factors may be targeted for the pre-clinical stages of vaccine development or therapeutic intervention.
Subject(s)
Pregnant WomenABSTRACT
The SARS-CoV-2 has spread throughout the world since its discovery in China, and Malaysia is no exception. WGS has been a crucial approach in studying the evolution and genetic diversity of SARS-CoV-2 in the ongoing pandemic, and while an exceptional number of SARS-CoV-2 complete genomes have since been submitted to GISAID and NCBI, there is a scarcity of data from Malaysia. This study aims to report new Malaysian lineages responsible for the sustained spikes in COVID-19 cases during the third wave of the pandemic. Patients whose nasopharyngeal and oropharyngeal swabs were confirmed positive by real-time RT-PCR with Ct-value < 25 were chosen for WGS. The 10 SARS-CoV-2 isolates obtained were then sequenced, characterized and analyzed, including 1356 sequences of the dominant lineages of D614G variant currently circulating throughout Malaysia. The prevalence of clade GH and G formed strong ground of the discovery of two Malaysian lineages that caused sustained spikes of cases locally. Statistical analysis on the association of gender and age group with Malaysian lineages revealed a significant association (p < 0.05). Phylogenetic analysis revealed dispersion of 41 lineages, for which 22 lineages are still active. Mutational analysis observed unique G1223C missense mutation in Transmembrane Domain of Spike protein. Thus, calls for the large-scale WGS analysis of strains found around the world for greater understanding of viral evolution and genetic diversity especially in addressing the question of the effect of deleterious substitution mutation in transmembrane region of Spike protein.
