Poster Presentation Lancefield International Symposium for Streptococci and Streptococcal Diseases 2025

Novel Transporters Impacting the Pathophysiology of Group A Streptococcal Infections (#245)

Emily Reagle 1 , Rezia Era D Braza 1 , Aolani A Perry 1 , Sarah E Davis 1 , Patrick Cho 1 , Afrooz Razi 1 , Ashton T Belew 1 , Najib M El-Sayed 1 2 , Yoann Le Breton 1 , Kevin S McIver 1
  1. Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, College Park, Maryland, USA
  2. Center for Bioinformatics and Computation Biology, College Park, Maryland, USA

Human-adapted Group A Streptococcus (GAS) causes a wide range of diseases in various host tissues. Host sequestration can prevent access to nutrients, thereby limiting GAS infection. We have used Tn-seq in human blood, human neutrophils, and murine soft tissue to identify novel transporters critical for GAS pathogenesis. The scfCDEoperon encodes a predicted ABC importer and mutants are highly attenuated for virulence in soft tissue and growth in human blood. Purified substrate-binding ScfC-His bound specifically to L-tryptophan (L-Trp) and scfCDE transcription was repressed by L-Trp.  L-Trp rescued the growth defect of ∆scfC in defined media lacking L-Trp and a ∆scfDpermease mutant is defective for uptake of L-Trp.  RNA-seq and metabolomics of ∆scfD showed a broad impact on GAS. Finally, subcutaneous immunization with ∆scfD protected mice from subsequent i.v. challenge. A putative L-methionine (L-Met) ABC transporter operon, metQNP, was important for survival in all Tn-seq screens. Mutants (∆metN or ∆metNP) showed significant growth defects in nutrient-limiting RPMI. Supplementation with tryptone rescued both mutants; however supplementation with L-Met only rescued growth of ∆metN. The metQNP operon was induced in the absence of L-met. Finally, ∆metNP was attenuated for survival from PMN killing compared to WT. The scfAB locus was identified in our and in many published GAS Tn-seq studies.  The scfAB locus encodes a putative permease with no known substrate. A ∆scfAB mutant is highly attenuated in blood, PMNs, mouse, and published NHP models of infection. Thus, uptake of key nutrients via transporters play an integral role in GAS pathophysiology.