title: [Cross-resistance between rifampin and rifabutin in multidrug resistant Mycobacterium tuberculosis complex strains].
abstract: OBJECTIVE
  To study the cross-resistance between rifampin and rifabutin in multidrug resistant Mycobacterium tuberculosis complex strains, and therefore to provide laboratory data for using rifabutin in the treatment of multidrug resistant tuberculosis.
  
  
  METHODS
  The MIC(90) of rifabutin and rifampin against 99 multidrug resistant Mycobacterium tuberculosis clinical strains were determined by microplate assays. Statistical analysis was performed by using the χ(2) test and the t test.
  
  
  RESULTS
  The cross-resistance rate between rifampicin and rifabutin was 85.9% (85/99), but the MIC(90) of rifabutin (≤ 16 mg/L, median 2 mg/L) was significantly lower than that of rifampicin (≥ 2 mg/L, median > 32 mg/L). The cross-resistance rate increased with the resistance level of rifampicin. The cross-resistance strains in the lower and the medium groups were 0/9 and 5/9 respectively, while the strains of the high rifampicin-resistant group were almost all cross-resistant (98.8%, 80/81).
  
  
  CONCLUSIONS
  Rifabutin had activities against rifampin resistant Mycobacterium tuberculosis complex strains in vitro, and therefore may be used as an alternative for the treatment of multidrug resistant tuberculosis.
authors.affiliation: School of Medicine, Soochow University, Suzhou 215123, China.
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.forename: He-ping
authors.initials: HP
authors.lastname: Xiao
authors.forename: Zhong-yi
authors.initials: ZY
authors.lastname: Hu
authors.forename: Zhen-ling
authors.initials: ZL
authors.lastname: Cui
authors.forename: Jun-mei
authors.initials: JM
authors.lastname: Lu
authors.forename: Xiao-na
authors.initials: XN
authors.lastname: Shen
mesh_terms: D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification; D017828:Rifabutin / Q000494:pharmacology*; D012293:Rifampin / Q000494:pharmacology*; D018088:Tuberculosis, Multidrug-Resistant / Q000382:microbiology
chemical_list: D017828:Rifabutin; D012293:Rifampin