Analysis of drug susceptibility profiles of multidrug-resistant M.tuberculosis isolated from China

Objective To analyze drug susceptibility profiles of multi-drug resistant(MDR)M.tuberculosis isolated from China,and provide the scientific evidence for MDR-tuberculosis(MDR-TB)control and prevention.Methods One hundred and twenty-six MDR isolates were selected from the first drug resistant survey in China between April 2008 and July 2008.The conventional drug susceptibility testing was used to detect the drug-resistant profiles against 2 first-line(streptomycin and ethambuol)and 7 second-line anti-tuberculosis drugs(ofloxacin,kanamycin,capreomycin,ethionamide,protionamide,cycloserine and 4-Amino-2-hydroxybenzoicacid).The drug-resistant proportion and cross resistance were analyzed.Results For first-line drugs,the drug-resistant proportions against streptomycin and ethambuol were 73.0%(92/126)and 58.7%(74/126),respectively.For second-line drugs,the percentages of the resistance to ofloxacin and ethionamide were the highest,accounting for 25.4%(32/126)and 23.0%(29/126),respectively.Then,17.5%(22/126)and 13.5%(17/126)of MDR strains were resistant to kanamycin and cycloserine,respectively.In addition,the drug-resistant rates of capreomycin,protionamide and 4-Amino-2-hydroxybenzoicacid were all 3.2%(4/126).The drug-resistant proportions of kanamycin(χ2=20.025,P0.01)and cysloserine(χ2=6.558,P=0.017)in new case group were significantly higher than that in re-treated case group.In addition,there were the cross-resistances between kanamycin and capreomycin,or ethionamide and protionamide.Three of four capreomycin-resistant isolates were resistant to kanamycin,and all four protionamide-resistant strains were resistant to ethionamide meanwhile.Conclusion The high prevalence of M.tuberculosis strains with the resistance to second-line anti-tuberculosis drugs,especially to ofloxacin and ethionamide in MDR-TB patients was the major challenge on the prevention and control of TB and MDR-TB in China.