PSMD1 and infection: A study by Szabo et al. [31] revealed that Corynebacterium spp., especially C. accolens, showed significantly higher abundance in the nasopharynx of uninfected individuals versus patients with COVID-19, with the downregulation of angiotensin-converting enzyme 2 (ACE-2) and transmembrane serine protease 2 (TMPRSS2) and inhibition of S1–ACE-2 binding being proposed as the main mechanisms of reduced susceptibility to infection in patients who harbor Corynebacterium spp.