RESUMEN
Background: Streptococcal toxic shock syndrome (STSS) is a life-threatening condition caused by beta-hemolytic streptococci (BHS). Streptococcus pyogenes is the main causative agent of this disease; other BHS such as Streptococcus agalactiae or Streptococcus dysgalactiae could also cause STSS. However, the clinical characteristics of STSS caused by other types of BHS remain poorly understood. In this study, we evaluated the likelihood of STSS development in various streptococcal species. Methods: We conducted a retrospective observational study using adult medical records of patients with invasive BHS in a tertiary care institution from 2002 to 2022 and classified them into STSS or non-STSS groups. Multivariable analysis of bacterial species adjusted for age and diabetes mellitus was conducted. S pyogenes cases were propensity-matched (1:4) to non-pyogenes BHS cases. Results: A total of 43 STSS and 285 non-STSS cases were identified. S pyogenes, S agalactiae, and S dysgalactiae accounted for 17, 13, and 13 STSS cases, respectively. The crude mortality of STSS was approximately 35% in all groups. A multivariable analysis suggested that STSS was less frequent in S agalactiae and S dysgalactiae cases with odds ratio 0.24 (95% confidence interval [CI], 0.10-0.54; P < .001) and 0.23 (95% CI, .10-.55; P < .001), respectively. Propensity score matching showed that S pyogenes caused STSS more frequently than other BHS cases with an odds ratio of 3.28 (95% CI 1.21-8.77; P = .010). Conclusions: This study described and compared the clinical characteristics of STSS caused by different BHS. We demonstrated that S pyogenes caused STSS more often than other BHS.
RESUMEN
EG.5.1 is a subvariant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron XBB variant that is rapidly increasing in prevalence worldwide. However, the pathogenicity, transmissibility, and immune evasion properties of isolates of EG.5.1 are largely unknown. Here, we show that there are no obvious differences in growth ability and pathogenicity between EG.5.1 and XBB.1.5 in hamsters. We also demonstrate that, like XBB.1.5, EG.5.1 is transmitted more efficiently between hamsters compared to its predecessor, BA.2. In contrast, unlike XBB.1.5, we detect EG.5.1 in the lungs of four of six exposed hamsters, suggesting that the virus properties of EG.5.1 are different from those of XBB.1.5. Finally, we find that the neutralizing activity of plasma from convalescent individuals against EG.5.1 was slightly, but significantly, lower than that against XBB.1.5 or XBB.1.9.2. Our data suggest that the different virus properties after transmission and the altered antigenicity of EG.5.1 may be driving its increasing prevalence over XBB.1.5 in humans.