SARS-CoV-2 has become one of the most studied viruses of the last century. It was assumed that the only possible host for these types of viruses was mammalian eukaryotic cells. Our recent studies show that microorganisms in the human gastrointestinal tract affect the severity of COVID-19 and demonstrate for the first time that the virus replicates in gut bacteria. To complete this investigation, cultures of bacteria from the human microbiome and SARS-CoV-2 were analyzed by electron and fluorescence microscopy in this work. The images presented in this paper, in association with the Nitrogen (15N) isotope-labeled culture medium experiment, clearly show that SARS-CoV-2 infects bacteria in the gut microbiota, indicating that SARS-CoV-2 acts as a bacteriophage. Our results add new knowledge to the understanding of the mechanisms of SARS-CoV-2 infection and fill gaps in the study of the interactions between SARS-CoV-2 and non-mammalian cells. These conclusions could suggest specific new pharmacological solutions to support the vaccination campaign.

At the end of 2019, following the advent of the SARS-CoV-2 pandemic, many studies, research, and experiments focused on the interaction of human eukaryotic cell surface receptors and coronavirus viral surface proteins. In this study, controls between the virus and bacteria in the human microbiome are performed.