Background
The GNRCS monitors invasive streptococcal disease in Germany. This includes Streptococcus pneumoniae, Streptococcus pyogenes (GAS), Streptococcus agalactiae (GBS), Streptococcus dysgalactiae (SD) and all other 107 currently validly published streptococcal species. Here, we discuss potential transmission routes of streptococcal infections based on species specific reductions in case numbers during the SARS-CoV-2 pandemic.
Methods
Species identification was performed using a combination of hemolysis-assessment, catalase-, pyrrolidonyl-arylamidase- and leucine-aminopeptidase-test, optochine- and bile-susceptibility, Lancefield-typing, emm-typing, serotyping and multiple PCR-sequence analyses.
Results
SARS-CoV-2 reached Germany beginning of March 2020. A strong reduction in case numbers of invasive pneumococcal disease up to 75% was reported shortly after. A comparable reduction of 67% was observed for invasive GAS infections, accompanied with a disproportional decrease of emm1 (-85%) and emm12 (-73%). However, no effect was seen for GBS and SD. Among other streptococcal species, a decline of 40% was observed for oral-streptococci of the Mitis-, Salivarius- and Mutans-, but not for the Anginosus-group, while species not commonly associated with the oral microbiome were not affected.
Conclusions
The SARS-CoV-2 pandemic had a strong reducing effect on invasive streptococcal disease. Reductions seem to be related to non-pharmaceutical interventions (face masks, social distancing, working from home, school closures) during the SARS-CoV-2 pandemic and therefore appear limited to respiratorily transmitted streptococci. Vice versa, the results indicate that GBS and SD are less likely to be transferred via a respiratory route. Interestingly enough, also for the members of the anginosus-group no significant effect was observed.