Mycobacterial Early Ancestor is Discovered

Asian Indian scientists have discovered a new mycobacterial organism that might be the earliest ancestor of the generalist branch of such pathogens.

A team of researchers led by Seyed Hasnain of India’s Institute of Life Sciences at the University of Hyderabad determined a seemingly unknown mycobacterial organism — Mycobacterium indicus pranii, or MIP — might be the earliest ancestor of mycobacterial pathogens.

Generalist bacteria infect anything from cockroaches to humans and are capable of surviving in soil and water, as compared with human adapted specialists, such as tubercle and leprosy bacilli.

The researchers said their finding suggests the prominent generalist pathogen M. avium, which affects AIDS patients, together with M. avium paratuberculosis, or MAP — the agent of Crohn’s disease in humans and Johne’s disease in cattle — descended from MIP.

It was also found MIP and MAP bacilli initially inhabited water bodies and infected marine organisms, finally arriving on soil through bird-droppings.

The comparative genomics study that provides an evolutionary basis for the acquisition and optimization of virulence in mycobacteria appears in the current issue of the online journal PLoS One.