SARS-CoV-2 and Mycobacterium tuberculosis co-infection in vitro

In less than a year, SARS-CoV-2 (SARS2) has managed to displace Mycobacterium tuberculosis (Mtb) as the leading cause of death worldwide due to a single infectious agent. Both pathogens affect the respiratory tract, mainly the lungs. However, the impact that a possible Mtb + SARS2 co-infection can have on the host response is still unknown. Herein we propose (depict) a rigorous system to evaluate the complex interaction between the two infections in vitro in a lung epithelial cell line (A549). Overall, the process includes eight steps: (I) Mtb culture, (II) cell maintenance, (III) preparation of viral stocks, (IV) determination of infectious titers, (V) Mtb and SARS2 co-infection, (VI) determination of intracellular bacterial load, (VII) SARS2 viability test, and (VIII) decontamination of supernatants. This comprehensive protocol will allow experimentalists to study the pathogenesis of co-infection in vitro, and facilitate collaborative work in the literature.