2001 OPEN FORUM Abstracts
Direct,Rapid Detection for Rifampin Susceptibility to M. Tuberculosis
Weimin Wang Departmentof Respiratory, Tianjin Red Cross Hospital, Tianjin China 300211 Wenxuan Cao, Liu Li Department ofPharmacology, Tianjin Bailou Hospital, Tianjin China 300040
Objective Toevaluate the use of molecular biotechnology for direct, rapid detection of rifampicin-resistancemutations in M. tuberculosis.
Methods 45 M.tuberculosis clinical isolates and 70 sputum samples were tested by polymerasechain reaction-single stranded conformation polymorphism (PCR-SSCP) technique.M. tuberculosis strain H37 Rv was used as control and compared withthe result of susceptibility test. DNA sequencing was also performed in someof the strains.
Results All testedsusceptible isolates displayed identical SSCP patterns. Of 29 RFP resistancestrains, 26 (90%) had distinct mobility shifts that can be discriminated fromsusceptible isolates. 9 sputum samples which were successfully evaluated byPCR-SSCP showed concordant result acquired from BACTEC 460 method. As the resultof DNA sequencing, it was observed that seven RFP-resistance phenotype of M.tuberculosis strains had missense mutation, in which 5 isolates displayed TCG?TTGor CAC mutations at codon 531, 2 had CAC?TAC mutation at codon 526. On the otherhand, one strain which was susceptible to rifampin exhibited identical nucleotidealignment to be sequence of rpoB gene.
Conclusions RCR-SSCPcould be used as a method for simple, rapid, and reliable detection of rifampicin-resistancemutations in clinical samples of M. tuberculosis.