Second-line injectable drugs resistance-associated mutation among multi-drug resistant tuberculosis strains in Ningbo, China / 中国人兽共患病学报

ABSTRACT

We identified the Beijing family strains of multiple drug-resistant tuberculosis and find out the distribution of second-line injectable drugs resistance-associated nucleotide alteration among the MDR strains in Ningbo.The 106 MDR isolates were selected from the first drug resistant survey in Ningbo during 2014 and 2016.The conventional drug susceptibility testing was used to detect the drug-resistant profiles against 3 second-line injectable drugs (kanamycin,amikacin,capreomycin).The RD105 deletion-targeted multiplex PCR method was used to distinguish the genotype among 106 MDR strains.The gene mutations of second-line injectable drugs resistance-associated among MDR-TB strains were detected by direct DNA sequencing.Results showed that out of the 106 MDR isolates,83(78.3％,83/106) belonged to Beijing genotype,while the other 23(21.7％,23/106) were non-Beijing genotype.There were 10 strains with second-line injectable drugs resistance in 83 Beijing genotype MDR strains and there were no strains with second-line injectable drugs resistance in 23 non-Beijing genotype MDR strains.The Beijing MDR strains had significantly higher proportions of second-line injectable drugs resistance than non-Beijing strains.There were 4 with mutations in 10 MDR-TB with second-line injectable drugs resistance and there were 24 with mutations in 96 MDR-TB without second-line injectable drugs resistance (x2=1.048,P＞0.05).Beijing genotype MDR strains revealed a significant association with second-line injectable drugs resistance.The mechanism of second-line injectable drugs resistance in MDR-TB is mainly in no connection with the mutation of the genes.