The recovery of other pathogens in COVID-19 patients has been reported. The presence of either co-infection or superinfection with bacterial pathogens was associated with poor outcomes, including increased mortality. The recognition of possibility of SARS-CoV-2 co-infection is important as it enables the implementation of appropriate infection control measures and therapy. This is a proof-of-concept study uses in vitro approaches (including crystal violet assay, microrheology, and LC-MS-based prote-omics) to investigate the interaction between SARS-CoV-2 and biofilms of bacteria (S. pneumoniae and S. aureus). SARS-CoV-2 spike protein S1 subunit was found to suppress biofilm formation of both bacteria. The effect of coronavirus and spike protein on bac-terial biofilm was supported by proteomics data that shows variations in proteins in-volved in quorum sensing and biofilm formation/maturation. Preliminary in vitro data suggest that dispersion of opportunistic pathogens from biofilm may be associated with poor prognosis in co-infections. However, further investigations are needed to establish bacterial biofilm as a risk factor for secondary pneumonia in COVID-19 patients.