The differences of rpoB mutations in rifampicin/rifabutin cross-resistant clinical isolates of Mycobacterium tuberculosis / 中华检验医学杂志

ABSTRACT

ObjectiveTo learn the rpoB mutation difference in rifampicin/rifabutin cross-resistant (RIF/Rfb-R)clinical isolates and in rifampicin-resistant/rifabutin-susceptible (RIF-R/Rbo-S)clinical isolates of Mycobacterium tuberculosis.Methods To sequence the full-length genome of rpoB gene,and analyze the rpoB full-length gene mutation differences in 278 RIF/Rfb-R clinical isolates,40 RIF-R/Rfb-S clinical isolates,30 rifampicin-susceptible/rifabutin-susceptible (RIF-S/Rfb-S) and in 1 reference strain ofH37Rv.ResultsNo mutations of rpoB full-length gene were found in H37Rv reference strain and RIF-S/Rfb-S clinical isolates.In RIF/Rfb-R clinical isolates,531 (70.5％ ) and 526 (20.9％ ) were the most frequent mutation codons.223 (80.2％ ) isolates possesed single mutations as S531L,S531W,H526D,H526Y,H526R,Q513K,Q513P,Q510H,V176F,P287R,Y395C and H404Y.55 (19.8％) isolates had multiple mutations,and among these the S531L,H526 R,H526Y,H526D,D516G and Q513K were the main substitutions which were in combination with other points.In RIF-R/Rfb-S clinical isolates,516 (65.0％),526 ( 17.5％ ) and 533 ( 10.0％ ) were the most frequent mutation codons.21 (52.5％ ) isolates possesed single mutations as L533P,H526L,H526S,S522L,D516V,D516Y and D516F.19 (47.5％)isolates had multiple mutations and among these the D516V and L533P were the main substitutions which were in combination with other points.CondusionsIn our study,100％ rifamycin-resistant clinical isolates of Mycobacterium tuberculosis had rpoB mutations,but the mutations in RIF/Rfb-R clinical isolates were sharply different from RIF-R/Rfb-S clinical isolates in mutation positions or amino acids substitutions of single mutations strains,mutation positions or combination types and the most frequently mutation codons or amino acids substitutions of multiple mutations strains.Thus,DNA sequencing is instructive and meaningful to choose rifampicin or rifabutin for tuberculosis treatment.