Chien H P, Yu M C, Ong T F, Lin T P, Luh K T
Taiwan Provincial Chronic Disease Control Bureau, Taipei, Taiwan.
J Formos Med Assoc. 2000 May;99(5):408-11.
To determine the in vitro activity of rifabutin against Mycobacterium tuberculosis (MTB) and the cross-resistance rate between rifampin and rifabutin.
A total of 56 clinical isolates of MTB, including 23 multidrug-resistant (MDR) isolates and 33 susceptible isolates, were tested for susceptibility to rifampin and rifabutin using the absolute concentration method. The concentrations of drugs tested were 2.5 and 5 mg/mL for rifampin and 0.1, 0.5, 1, 2.5, 5, and 10 mg/mL for rifabutin.
All 33 MTB isolates that were susceptible to rifampin were also susceptible to rifabutin. None of the 23 MDR-MTB isolates were inhibited by rifabutin at a concentration of 0.1 mg/mL. Among these 23 MDR isolates, three were susceptible to rifabutin at concentrations > or = 0.5 mg/mL, six were susceptible to rifabutin at concentrations > or = 5 mg/mL, 18 were susceptible to rifabutin at concentrations > or = 10 mg/mL and five were not inhibited at any of the concentrations tested. The cross-resistance rate between rifampin and rifabutin was 87%.
Our results indicate that the in vitro activity of rifabutin against drug-susceptible MTB isolates is greater than that of rifampin. For MDR-MTB isolates, the cross-resistance is high between rifampin and rifabutin.
确定利福布汀对结核分枝杆菌（MTB）的体外活性以及利福平与利福布汀之间的交叉耐药率。
采用绝对浓度法对56株MTB临床分离株进行利福平和利福布汀敏感性检测，其中包括23株耐多药（MDR）分离株和33株敏感分离株。利福平检测浓度为2.5和5mg/mL，利福布汀检测浓度为0.1、0.5、1、2.5、5和10mg/mL。
所有33株对利福平敏感的MTB分离株对利福布汀也敏感。23株MDR-MTB分离株在0.1mg/mL浓度下均未被利福布汀抑制。在这23株MDR分离株中，3株在浓度≥0.5mg/mL时对利福布汀敏感，6株在浓度≥5mg/mL时对利福布汀敏感，18株在浓度≥10mg/mL时对利福布汀敏感，5株在任何检测浓度下均未被抑制。利福平和利福布汀之间的交叉耐药率为87%。
我们的结果表明，利福布汀对药物敏感MTB分离株的体外活性大于利福平。对于MDR-MTB分离株，利福平和利福布汀之间的交叉耐药性较高。
