Dormant Mycobacterium tuberculosis reactivates ex vivo in blood from HIV infected individuals

Reports of tuberculosis in Human Immunodeficiency Virus infected patients despite high CD4+ T-cell counts suggest different mechanisms of reactivation. In vitro developed dormant Mycobacterium tuberculosis H37Rv were cultured in HIV blood and normal blood. Colony forming units analysis was performed and expression of mycobacterial Resuscitation Promomoting Factor genes was analyzed by qRT-PCR. The in vitro developed dormant M. tb resuscitated in HIV blood as evident from increase in CFUs and up-regulation in the expression of mycobacterial rpf genes. Reactivation of dormant tubercle bacilli following HIV infection in spite of high CD4+ T-cell counts could be due to some viral or host factors which needs further studies.