New mycobacterium species

Leprosy Mailing List, January 18th, 2009

Ref.: New mycobacterium species
From: Spencer J S., Fort Collins , Colorado , USA


Dear Dr. Noto,
Dr. Brennan forwarded your message (de Koning P, LML Jan 11th, 2009) about AJCP paper concerning the new mycobacterium that was recently described by Dr. Xiang Han from the University of Texas M. D. Anderson Cancer Center in Houston, Texas, with collaboration from Colorado State University. Enclosed is the PDF of our recently published paper on this discovery.

Initially, I was contacted by Dr. Geetha Nair, a clinician at a clinic in Phoenix , Arizona , about a patient who had died from what seemed to be disseminated mycobacterial infection. Although leprosy was suspected at first, the antigen serological recognition pattern was not typical of what we had previously seen, and DNA sequencing of several genes that we use for typing M. leprae did not match the sequence data, and included a difference of 2.1% in the 16S rRNA gene compared with that of M. leprae, with lower identity with all other mycobacterial 16S sequences in the database. After sequencing over 20 genes (both partial and complete gene sequences) at M. D. Anderson and at CSU, our conclusion was that what we had identified was very different from M. leprae. Attempts to grow this mycobacterium from biopsy specimens from this patient were unsuccessful.

The pathology fit the criteria for diffuse lepromatous leprosy with Lucio's phenonmenon, a rare and frequently lethal form of leprosy since it was first described in Mexico by Lucio and Alvarado in 1852, and which is most commonly reported in Mexico , the Caribbean and countries in South America . We are acquiring additional samples from archived biopsy material from individuals diagnosed with DLL from Mexico and South America to confirm the 16S sequence findings. We are also trying to sequence the entire genome of this rare mycobacterium, and hope to obtain a fresh isolate to try to grow in the nude mouse footpad.

I had presented a poster and an oral presentation about this new mycobacterium at the 17th ILC meeting in Hyderabad , India last February, which generated some interest. I hope this has answered some of your questions about this discovery. I would be pleased to be added onto your leprosy mailing list.

Best regards.
John S. Spencer, Ph.D.
Assistant Professor