Novel species including Mycobacterium fukienense sp. is found from tuberculosis patients in Fujian Province, China, using phylogenetic analysis of Mycobacterium chelonae/abscessus complex / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To identify the novel species 'Mycobacterium fukienense' sp. nov of Mycobacterium chelonae/abscessus complex from tuberculosis patients in Fujian Province, China.</p><p><b>METHODS</b>Five of 27 clinical Mycobacterium isolates (Cls) were previously identified as M. chelonae/abscessus complex by sequencing the hsp65, rpoB, 16S-23S rRNA internal transcribed spacer region (its), recA and sodA house-keeping genes commonly used to describe the molecular characteristics of Mycobacterium. Clinical Mycobacterium isolates were classified according to the gene sequence using a clustering analysis program. Sequence similarity within clusters and diversity between clusters were analyzed.</p><p><b>RESULTS</b>The 5 isolates were identified with distinct sequences exhibiting 99.8% homology in the hsp65 gene. However, a complete lack of homology was observed among the sequences of the rpoB, 16S-23S rRNA internal transcribed spacer region (its), sodA, and recA genes as compared with the M. abscessus. Furthermore, no match for rpoB, sodA, and recA genes was identified among the published sequences.</p><p><b>CONCLUSION</b>The novel species, Mycobacterium fukienense, is identified from tuberculosis patients in Fujian Province, China, which does not belong to any existing subspecies of M. chelonea/abscessus complex.</p>

Study on the characteristics of mutation on Mycobacterium tuberculosis rifampicin-resistance gene / 中华流行病学杂志

<p><b>OBJECTIVE</b>To elucidate the characters of rpoB mutation in rifampin-resistant clinical isolates of Mycobacterium tuberculosis.</p><p><b>METHODS</b>286 bp DNA fragment of rpoB gene including 81 bp code region (rifampin resistance deteremination region, RRDR) was analyzed by PCR-single-strand conformation polymorphism(SSCP). The 286 bp DNA fragment of each strain which had been proved to have mutation by PCR-SSCP was then sequenced. 110 strains of M. tuberculosis, including 73 rifampin-resistant strains, 11 rifampin-susceptible drug-resistant strains and 26 drug-susceptible strains were studied.</p><p><b>RESULTS</b>47 rifampin-resistant strains were detected to have mutations by PCR-SSCP method. 76.6% rifampin-resistant strains showed that rpoB gene was carrying single point mutation analyzed by direct sequencing technique, which mainly located at 531-Ser (61.1%) and 526-His (25.0%). The combined mutation rate was 23.4%. In addition, 2 rifampin-susceptible drug-resistant strains and 1 drug-susceptible strain were mutated, detected by PCR-SSCP method. Sequencing results showed that the mutations located at 511-Leu, 526-His and 535-Pro.</p><p><b>CONCLUSION</b>Mutations in the 81 bp RRDR of rpoB were the main reasons of M. tuberculosis resistant to rifampin. 531-Ser and 526-His were the most common positions of mutations.</p>