Co-infection by Streptococcus anginosus and Mycobacterium tuberculosis: three case reports

INTRODUCTION: Bacterial infections may appear as sequelae of remote tuberculous infections, especially thoracic infections. The simultaneous appearance of tuberculosis and bacterial infection is not common, and, to our knowledge, the association of infection by Streptococcus anginosus and Mycobacterium tuberculosis has not been reported previously in the literature. CASE PRESENTATION: We report three cases of dual infection with Streptococcus anginosus and Mycobacterium tuberculosis that were first diagnosed as pyogenic abscesses because of an isolation of Streptococcus anginosus. Despite a course of antibiotics and drainage, the outcome of this initial treatment was unfavourable. A re-evaluation yielded a diagnosis of mixed infection with Streptococcus anginosus and Mycobacterium tuberculosis. CONCLUSION: In a geographical area with a high prevalence of tuberculous disease, the rare possibility of dual infection with Streptococcus anginosus and Mycobacterium tuberculosis should be considered.