Dissecting the effect of single- and co-infection of TB and COVID-19 pathogens on the sputum microbiome

The community of microbes in an individual's airway tract can play a complex role in respiratory diseases like tuberculosis (TB) and COVID-19. Although changes in microbial composition in TB and COVID-19 patients have been studied separately, we present a first-of-its-kind investigation of the airway-tract microbiome of individuals simultaneously infected with TB and COVID-19 pathogens. Our results highlight that co-infection with COVID-19 in TB patients alters the abundance of certain bacterial species and their related pathways. For instance, <i>Capnocytophaga gingivalis</i> is abundant in co-infected patients, but not in TB-only patients. This species and other differentially abundant species we identified in the co-morbid condition, if replicated in independent cohorts, can help explain how COVID-19 could exacerbate the severity of lung infection in TB patients. Our study also stimulates future longitudinal studies using expanded data sets to understand the role of concomitant pathogens and assess whether adjusting the antibiotic regimen accordingly can improve TB treatment outcomes.