Infective endocarditis due to beta-haemolytic streptococci

Abstract Beta-haemolytic streptococci (BHS) produce number of toxins that play crucial roles in colonization, pathogenesis and dissemination. Infections caused by BHS include, but are not limited to pharyngitis, skin and soft tissue infections, pneumonia, infective endocarditis (IE), puerperal infection, and meningitis. The aim of the current study was to analyse cases of IE due to BHS at Mater Misericordiae University Hospital, Dublin in 14-year period. Clinical features and outcome was compared to the cases caused by viridans group streptococci (VGS).IE was diagnosed according to the 2000 and 2023 Criteria for infective endocarditis.16 cases of IE due to BHS and 66 cases due to VGS were identified. BHS were represented by group B streptococci in 8 cases (50.0%), and by group C/G in 8 cases (50.0%). All isolates were sensitive to penicillin and vancomycin, 25.0% were resistant to macrolides. Demographic data showed, that patients with IE due to BHS were older (55.8 versus 49.3 years), and male/female ratio was lower (1.7 versus 2.0) in comparison with the cases due to VGS.Cases of IE due to BHS yielded higher rate of valve abscesses (18.7% versus 12.1%), valve perforation (12.5% versus 10.6%), as well as higher rate of embolic events (37.5% versus 33.3%) in comparison with VGS cases.In conclusion, IE due to BHS was infrequent in our hospital setting in studied period 2010–2023. However, clinical presentation was severe, and all-cause mortality at 6 months was 31.2% in BHS group, significantly higher than 6.1% in VGS group.