Comparison of circulating bacterial profiles between mild and severe COVID-19 patients

Recent reports revealed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients can develop bacteremia; however, the circulating bacterial profile is not well studied. Therefore, this study has aimed to investigate circulating bacterial profile in mild (n = 15) and severe (n = 13) SARS-CoV-2-infected patients as well as healthy controls (n = 10), using 16S rDNA (V4) sequencing approach. The alpha diversity indexes and Bray-Curtis dissimilarity matrix revealed that the bacterial profiles between the two conditions are significantly different. Correspondingly, the relative abundance indicates that the predominant bacterial phylum in both conditions was Proteobacteria. At genus level, the dominant bacterial genera in the mild patients belonged to Sphingomonas, Stenotrophomonas, and Achromobacter, while bacterial genera belonging to Enhydrobacter, Comamonas, and Acinetobacter were dominant in the severe patients. Furthermore, Linear discriminant analysis (LDA) Effect Size (LEfSe). revealed that Stenotrophomonas, Delftia, Achromobacter, and Neisseria were enriched in the mild condition, while Agrobacterium, Comamonas, Pseudomonas, Corynebacterium, Alkaliphilus, and Kocuria were enriched in the severe patients. These results revealed a distinct circulating bacterial profile in the mild and severe SARS-CoV-2-infected patients, which may provide an insight for further therapeutic strategy.