Drug susceptibility analysis of the nitroimidazoles delamanid and pretomanid against multidrug-resistant Mycobacterium tuberculosis
This study analysed and compared the drug susceptibility of two nitroimidazoles drugs delamanid(DLM)and pretomanid(PMD)against multidrug-resistant tuberculosis(MDR-TB)isolates in vitro,so as to provide more datas for the clinical application.Culture positive isolates from 39 county TB dispensary were collected and sent to Chongqing Institute for Tuberculosis Control from November 2021 to February 2023.A total of 198 MDR-TB isolates based on simple random sam-pling were confirmed by strain identification and proportional susceptibility test,and the minimum inhibitory concentrations(MICs)of DLM and PMD were performed by broth microdilution testing.Among the 198 MDR isolates,the baseline resist-ance rates of DLM and PMD were 5.1%(10/198)and 3.5%(7/198)respectively.The MICs range of DLM and PMD against the 198 MDR-TB strains were mainly concentrated in 0.06~1 μg/mL and 0.03~2 μg/mL,respectively.Among the 13 nitroi-midazole resistant isolates,10 isolates were resistant to DLM,7 resistant to PMD,and 4(30.8%,4/13)showed cross-resist-ance between DLM and PMD.In conclusion,DLM and PMD showed excellent antibacterial activities against MDR-TB clinical isolates in vitro.DLM has lower MICs than that of PMD.However,the occurrence of baseline resistance in both new drugs suggested that drug susceptibility testing should be performed prior treatment.