Polysaccharide capsule allows Group B Streptococcus to avoid killing in a newborn pneumonia model

• DOI: 10.4049/jimmunol.200.supp.117.30
• Publication Date: 2023-01-01T11:30:41Z
• Authors: Sean J Lund; Kathryn A Patras; Jacqueline M Kimmey; Asami Yamamura; Gilberto Hernandez; Omar Lakhdari; Alyssa M McCoy; Victor Nizet; Lawrence S Prince
• Keywords: Group B; Neonatal Infection

Abstract Group B Streptococcus (Streptococcus agalactiae, GBS) causes severe infections in neonates. While not a common adult pathogen, GBS is the leading cause of congenital pneumonia. To determine molecular mechanisms neonatal susceptibility, we developed murine pneumonia model. Neonatal, juvenile, and C57BL/6 mice were inoculated intranasally with 2800 CFU/g (COH1). After 7 d, survival was 100 % adults juveniles, 10 neonates dying within 3 d after infection. Histopathological assessments showed lung injury scores 24 h infection, juvenile demonstrating resolution at post infection normal histology d. In contrast, lungs had persistent up to By FACS, induced rapid neutrophil recruitment into increased CD11b expression on macrophages. lungs, neither numbers nor altered macrophage marker expression. Confocal imaging almost entirely localized alveolar phagolysosomes. However only rarely phagocytosed by These data consistent killing data, which complete mice, but viability for Defective appeared require capsule. Neonatal much more efficient ΔcpsD capsule mutant compared wild type GBS. Adult equal or Our suggest that prevents newborn innate immune system, disease susceptibility.