The virulence of Streptococcus pneumoniae partially depends on dprA

Abstract

Streptococcus pneumoniae is one of the most frequent opportunistic pathogens worldwide. DNA processing protein A (DprA) is an important factor involved in bacterial uptake and DNA integration into bacterial genome, but its role in S. pneumoniae virulence remains unclear. The aim of this study was to characterize the effects of the pneumococcal dprA gene on the pathogenesis of S. pneumoniae. To construct a dprA-deficient pneumococcal strain, the dprA gene of the S. pneumoniae strain D39 was inactivated. The virulence of this dprA-deficient strain, designated ΔD39, was compared with that of the wild-type strain by evaluating their respective capabilities to adhere to human pulmonary epithelial cells (PEC-A549) and by analyzing their choline-binding protein expression levels. In addition, the expression profiles of genes associated with virulence and host survival assays were also conducted with the mutant and the wild-type strain. Our results indicate that the capability of ΔD39 to adhere to the PEC-A549 airway cells was significantly lower (p < 0.01) compared with D39. Additionally, the 100-KD choline-binding protein was not detected in ΔD39. The addition of competence-stimulating peptide (CSP) lead to a significantly reduction of psaA mRNA expression in the dprA-deficient mutant and an increased level of psaA transcripts in the wild-type strain (p < 0.01). The median survival time of mice intraperitoneally infected with ΔD39 was significantly higher (p < 0.01) than that of mice infected with D39. The results of this study suggest that DprA has a significant effect on virulence characteristics of S. pneumoniae by influencing the expression of choline-binding protein and PsaA.

DprA-Dependent Exit from the Competent State Regulates Multifaceted Streptococcus pneumoniae Virulence

“…As previously shown by us and others, the ΔdprA mutant is attenuated in mouse models of infection (25,28). When competed against the WT, the ΔdprA mutant was less competitive in bacteremia, acute-pneumonia infections, and nasopharyngeal colonization (Fig.…”

A Novel Iron Transporter SPD_1590 in Streptococcus pneumoniae Contributing to Bacterial Virulence Properties

“…Adhesion and intracellular invasion capabilities were measured according to methods in a previous report ( Yu et al, 2017 ). A549 cells were cultured in DMEM (Thermo Fisher Scientific, United States) with 10% fetal bovine serum (FBS; Thermo Fisher Scientific, United States) at 37°C in 5% CO 2 .…”

Allele-specific collateral and fitness effects determine the dynamics of fluoroquinolone-resistance evolution

“…) was a composite parameter of the literature derived growth rate of D39 (38) and our experimental growth rate ratio between mutant and WT. The systems growth capacity limitation parameter (B max ) and the bacterial concentration at the start of the infection were obtained from an in vivo model of bacteraemia (39).…”