A Novel DNA Chromatography Method to DistinguishM. abscessusSubspecies and Macrolide Susceptibility

Rationale The clinical impact of infection with Mycobacterium abscessus complex (MABC), a group of emerging non-tuberculosis mycobacteria (NTM), is increasing. Mycobacterium abscessus subsp. abscessus / bolletii frequently shows natural resistance to macrolide antibiotics, whereas Mycobacterium abscessus subsp. massiliense is generally susceptible. Therefore, rapid and accurate discrimination of macrolide-susceptible MABC subgroups is required for effective clinical decisions about macrolide treatments for MABC infection. Objectives To develop a simple and rapid diagnostic that can identify MABC isolates showing macrolide susceptibility. Methods Whole genome sequencing (WGS) was performed for 148 clinical or environmental MABC isolates from Japan to identify genetic markers that can discriminate three MABC subspecies and the macrolide-susceptible erm (41) T28C sequevar. Using the identified genetic markers, we established PCR based- or DNA chromatography-based assays. Validation testing was performed using MABC isolates from Taiwan. Measurements and Main Results We identified unique sequence regions that could be used to differentiate the three subspecies. Our WGS-based phylogenetic analysis indicated that M. abscessus carrying the macrolide-susceptible erm (41) T28C sequevar were tightly clustered, and identified 11 genes that were significantly associated with the lineage for use as genetic markers. To detect these genetic markers and the erm (41) locus, we developed a DNA chromatography method that identified three subspecies, the erm (41) T28C sequevar and intact erm (41) for MABC in a single assay within one hour. The agreement rate between the DNA chromatography-based and WGS-based identification was 99.7%. Conclusions We developed a novel, rapid and simple DNA chromatography method for identification of MABC macrolide susceptibility with high accuracy.