RNase R, a New Virulence Determinant of Streptococcus pneumoniae .
Cátia BárriaDalila Mil-HomensSandra Nunes PintoArsénio Mendes FialhoCecília M ArraianoSusana DominguesPublished in: Microorganisms (2022)
Pneumococcal infections have increasingly high mortality rates despite the availability of vaccines and antibiotics. Therefore, the identification of new virulence determinants and the understanding of the molecular mechanisms behind pathogenesis have become of paramount importance in the search of new targets for drug development. The exoribonuclease RNase R has been involved in virulence in a growing number of pathogens. In this work, we used Galleria mellonella as an infection model to demonstrate that the presence of RNase R increases the pneumococcus virulence. Larvae infected with the RNase R mutant show an increased expression level of antimicrobial peptides. Furthermore, they have a lower bacterial load in the hemolymph in the later stages of infection, leading to a higher survival rate of the larvae. Interestingly, pneumococci expressing RNase R show a sudden drop in bacterial numbers immediately after infection, resembling the eclipse phase observed after intravenous inoculation in mice. Concomitantly, we observed a lower number of mutant bacteria inside larval hemocytes and a higher susceptibility to oxidative stress when compared to the wild type. Together, our results indicate that RNase R is involved in the ability of pneumococci to evade the host immune response, probably by interfering with internalization and/or replication inside the larval hemocytes.
Keyphrases
- wild type
- antimicrobial resistance
- pseudomonas aeruginosa
- escherichia coli
- staphylococcus aureus
- biofilm formation
- immune response
- aedes aegypti
- oxidative stress
- drosophila melanogaster
- poor prognosis
- cardiovascular disease
- type diabetes
- dna damage
- dendritic cells
- cystic fibrosis
- metabolic syndrome
- high dose
- low dose
- insulin resistance
- skeletal muscle
- signaling pathway
- ischemia reperfusion injury
- multidrug resistant
- binding protein
- diabetic rats