[In vitro study on cross resistance of rifampin and rifapentine for Mycobacterium tuberculosis].
OBJECTIVE
To study the bactericidal effect of rifapentine and its cross-resistance with rifampin for Mycobacterium tuberculosis and to determine the critical concentration of rifapentine for laboratory drug susceptibility test and therefore to provide the laboratory data for using rifapentine in the treatment of tuberculosis, particularly rifampin resistant tuberculosis.


METHODS
We detected the minimal inhibitory concentrations (MICs) of rifampin and rifapentine to H(37) Rv and isolated strains of rifampin susceptible and resistant Mycobacterium tuberculosis by using Middlebrook 7H9, Sauton and Lowenstein-Jensen media.


RESULTS
The MICs of rifampin were > or = 0.32 microg/ml for 80% of the 19 rifampin susceptible strains on Middlebrook 7H9 and the MICs of rifapentine ranged from 0.02 microg/ml to 0.32 microg/ml for most of the strains (84%). The MICs of rifapentine were 2 - 4 times lower than those of rifampin to H(37) Rv and most clinical isolates. The rifapentine susceptible isolates were mostly separated from resistant strains at MICs 5-10 microg/ml.


CONCLUSIONS
Our results demonstrate the cross resistance of rifampin and rifapentine and the stronger bactericidal potency of rifapentine than rifampin. Some rifampin resistant strains still show susceptibility to rifapentine, which suggests rifapentine may be effective in the treatment of rifampin resistant tuberculosis. Our results also determined a critical resistant concentration of rifapentine for routine drug susceptibility test.
Duanmu
Hong-Jin
HJ
Beijing Tuberculosis & Thoracic Tumor Research Institute, Chinese Disease Prevention and Control Centre, Tuberculosis Prevention and Medicine Centre, Beijing 101149, China.
Liu
Yu-hong
YH
Jiang
Guang-lu
GL
Wang
Su-min
SM
Fu
Yu-hong
YH
D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D003470:Culture Media; D024881:Drug Resistance, Bacterial; D008826:Microbial Sensitivity Tests / Q000379:methods; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D012293:Rifampin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D012680:Sensitivity and Specificity
D000904:Antibiotics, Antitubercular; D003470:Culture Media; D012293:Rifampin; C018421:rifapentine