| association between mycobacterium tuberculosis beijing/w lineage strain infection and extrathoracic tuberculosis: insights from epidemiologic and clinical characterization of the three principal genetic groups of m. tuberculosis clinical isolates. | clinical strains of mycobacterium tuberculosis can be divided into three principal genetic groups based on the single-nucleotide polymorphisms at the katg gene codon 463 and the gyra gene codon 95. one subgroup of genetic group 1, the beijing/w lineage, has been widely studied because of its worldwide distribution and association with outbreaks. in order to increase our understanding of the clinical and epidemiological relevance of the genetic grouping of m. tuberculosis clinical strains and the ... | 2007 | 17166963 |