[Subspecies identification for Mycobacterium abscessus group]

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• The Mycobacterium abscessus group comprises rapidly growing mycobacteria that can cause significant human infections.
• Accurate subspecies identification is crucial for effective treatment strategies, particularly concerning antibiotic susceptibility.

Purpose of the Study:

• To differentiate and identify the subspecies within the Mycobacterium abscessus group using molecular methods.
• To investigate the genotypic and phenotypic characteristics related to clarithromycin resistance in clinical isolates.

Main Methods:

• Utilized PCR to amplify hsp65 and rpoB genes from 19 clinical isolates.
• Performed phylogenetic analyses using Mega and PhyML programs, with ITS sequencing for conflicting identifications.
• Conducted PCR sequencing of rrl and erm(41) genes and determined clarithromycin Minimum Inhibitory Concentrations (MICs).

Main Results:

• hsp65 and rpoB sequencing identified M. massiliense, M. abscessus, and M. bolletii, with ITS confirming subspecies for conflicting cases.
• Distinct genotypic features in erm(41) sequences, including deletions in M. massiliense, were observed.
• Clarithromycin inducible resistance varied among subspecies, with M. abscessus and M. bolletii showing higher resistance.

Conclusions:

• hsp65 gene sequencing is effective for identifying M. abscessus group subspecies.
• Combined analysis of hsp65 and erm(41) genetic features, along with phenotypic clarithromycin susceptibility, provides robust subspecies identification.
• The findings offer valuable data for clinical diagnosis and treatment of M. abscessus complex infections.