Genomic-based genotype and drug susceptibility profile of Mycobacterium kansasii in China

To analyze subtypes, microbiological characteristics and antimicrobial susceptibility of <i>Mycobacterium kansasii</i> in China, a total of 153 <i>M. kansasii</i> isolates, collected from national drug resistance surveillance, were genotyped with whole genome sequencing and explored the antimicrobial susceptibility with broth microdilution. All isolates were classified as <i>M. kansasii</i> type I based on Average Nucleotide Identity(ANI). The 153 <i>M. kansasii</i> representatives were differentiated into 3 clusters with 141 genotypes, including 17 isolates from a cluster and 136 isolates with unique patterns. The EXS-1, EXS-3 and EXS-5 regions were involved in all isolates. Rifabutin and clarithromycin were the most highly active against <i>M. kansasii</i> strains, with the susceptible rate of 100 and 99.35%, respectively. Followed by amikacin and linezolid, the resistance rate was 5.88 and 7.19%, respectively. The resistance rate to rifampin (RIF) was 22.22%. As for the antibiotics without the breakpoint values, all isolates had very low MIC₅₀ (0.03 μg/mL) and MIC₉₀ (≤0.06 μg/mL) values against bedaquiline, sutezolid, delamanid, and clofazimine. Except for ciprofloxacin and moxifloxacin, the resistance rate of other drugs in cluster 3 was higher than that in cluster 1 and cluster 2. In conclusion, <i>M. kansasii</i> type I was the predominant genotype in China, and rifabutin and clarithromycin presented strong activities. The new drugs, used for the treatment of multidrug - resistant tuberculosis, have the potential to be potent agents in the treatment of <i>M. kansasii</i> infection. The clustering might contribute to the high resistance rate of <i>M. kansasii</i>.