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Journal of Clinical Microbiology, August 2005, p. 4010-4014, Vol. 43, No. 8
0095-1137/05/$08.00+0 doi:10.1128/JCM.43.8.4010-4014.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
and
Christophe Sola1*
Unité de la Tuberculose et des Mycobactéries, Institut Pasteur de Guadeloupe, Pointe-à-Pitre, Guadeloupe,1 Division of International Medicine and Infectious Diseases, Department of Medicine, Joan and Sanford I. Weill Medical College, Cornell University, New York, New York2
Received 21 February 2005/ Returned for modification 6 April 2005/ Accepted 21 May 2005
A well-characterized collection of Mycobacterium tuberculosis complex (MTC) isolates, representing all known subspecies as well as some relevant genotypic families of M. tuberculosis, was analyzed for the newly discovered narGHJI 215 C-to-T promoter single-nucleotide polymorphism (SNP). This point mutation has been shown in earlier studies to be responsible for the differential nitrate reductase activity of M. tuberculosis versus M. bovis. As previously defined by the presence or the absence of the TbD1 genetic locus, the group included both the "modern" W-Beijing, Haarlem, and Central-Asian1 (CAS1) families as well as the "ancestral" East-African-Indian (EAI) clade. Interestingly, among "modern" M. tuberculosis isolates, those previously classified as Principal Genetic Group 1 (PGG1) organisms by katG463-gyrA95 polymorphism analysis did not present the two-banded narGHJI restriction fragment length polymorphism analysis of PCR products pattern common to the other PGG1 MTC members, including the "ancestral" M. tuberculosis isolates. Instead, they showed a one-banded pattern, aligning them with other evolutionarily recent M. tuberculosis isolates of the PGG2 and PGG3 groups, such as Haarlem, Latin-American and Mediterranean (LAM), and X families. The presence of a nitrate reductase producer phenotype in "Mycobacterium canettii" and some "ancestral" M. tuberculosis isolates, despite a two-band 215C genotype, argues in favor of an alternate mechanism to explain the differential nitrate reductase activity of certain PGG1 subspecies of the MTC. Overall, these findings may help to establish the precise evolutionary history of important genotype families such as W-Beijing and suggest that the 215T genotype may have contributed the virulence, spread, and evolutionary success of "modern" M. tuberculosis strains compared to the remaining MTC organisms.
Present address: Clinical Microbiology Laboratory Service and the Department of Pathology in Medicine, New York Presbyterian Hospital, Columbia Medical Center, New York, NY.
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