Heteroresistance - the simultaneous presence of drug-susceptible and -resistant organisms - is common in Mycobacterium tuberculosis. In this study, we aimed to determine the limit of detection (LOD) of genotypic assays to detect gatifloxacin-resistant mutants in experimentally mixed populations. A fluoroquinolone-susceptible M. tuberculosis mother strain (S) and its in vitro selected resistant daughter strain harbouring the D94G mutation in gyrA (R) were mixed at different ratio's. Minimum inhibitory concentrations (MICs) against gatifloxacin were determined, while PCR-based techniques included: line probe assays (Genotype MTBDRsl and GenoScholar-FQ + KM TB II), Sanger sequencing and targeted deep sequencing. Droplet digital PCR was used as molecular reference method. A breakpoint concentration of 0.25 mg/L allows the phenotypic detection of >= 1% resistant bacilli, whereas at 0.5 mg/L >= 5% resistant bacilli are detected. Line probe assays detected >= 5% mutants. Sanger sequencing required the presence of around 15% mutant bacilli to be detected as (hetero) resistant, while targeted deep sequencing detected

Originele taal-2Engels
Artikel nummer11760
TijdschriftScientific Reports
Aantal pagina's8
StatusGepubliceerd - 2019

ID: 3036533