Abstract
The 16S rRNA gene is commonly used to identify Mycobacterium spp., but alternative DNA targets can provide better resolution to the species level. We evaluated a novel system that enables simultaneous amplification, sequencing, and analysis of two different DNA targets in a single tube to identify clinical isolates of Mycobacterium spp. For 139 clinical isolates, we found that the 16S rRNA gene alone identified 67 (48%) isolates as single species, 68 (49%) isolates to the complex or group level, and 4 (3%) isolates to the genus level only. The rpoB gene alone identified 117 (84%) isolates as single species, 10 (7%) isolates to the complex or group level, and 12 (8%) isolates to the genus level only. Combining the separate analyses for sequencing of two gene targets, 119 (86%) isolates were identified as single species and 10 (7%) isolates were identified to the complex or group level. Seven (5%) isolates were identified as novel species within established groups, and 3 (2%) were identified to the genus level only. Dual-locus identification identified 110 (79%) isolates as single species and 22 (16%) isolates to the complex or group level. Six (4%) were identified as novel species within established groups, and 1 (1%) was identified to the genus level only. Identifications were more accurate when both the 16S rRNA and rpoB genes were screened, and reliance on a single gene target was suboptimal. RipSeq dual-locus software provides an accurate alternative method for laboratories using two different gene targets for microorganism identification.