Abstract
Mycobacterium (M.) abscessus complex (MABC), which consists of three subspecies: M. abscessus (a.) subsp. abscessus, M. a. subsp. massiliense, and M. a. subsp. bolletii, is one of the most pathogenic non-tuberculosis mycobacteria with increasing clinical concern. Macrolide, especially CLA is a key antibiotic in the treatment of MABC infection, and thus bacterial mechanisms for macrolide resistance have been studied deeply. However, we noticed that a part of our clinical isolates didn't follow known rules of macrolide resistance, implying the unrevealed mechanisms. To approach this question, here we analyzed the WGS and DST data of clinical MABC isolates.
We performed whole-genome shotgun sequencing of 147 clinical isolates all of which were isolated in Japan. Based on a phylogenetic analysis using concatenated sequence of 2964 core genes, 91 (61.9%), 52 (35.4%), and 4 (2.7%) isolates were categorized to M. a. abscessus, M. a. massiliense, and M. a. bolletii, respectively. We determined minimum inhibitory concentration of CLA for the 147 isolates. Five M. a. abscessus isolates with acquired CLA resistance had no mutation on the rrl gene. An M. a. massiliense isolate with truncated erm(41) gene showed inducible CLA resistance. We also found that two M. a. abscessus isolates having erm(41) T28 failed to show inducible CLA resistance. Interestingly, these isolates clearly decreased expression of Erm(41) compared to the type strain, suggesting that these isolates were defective in expressing Erm(41). We will present further genome analysis of above clinical isolates.
Footnotes
Cite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 2330.
This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2020