Mycobacterium abscessus. "Pleased to meet you, hope you guess my name..."

Mycobacterium abscessus is a formidable and difficult-to-treat mycobacterial pathogen with multiple drug-resistance mechanisms. The most important of these mechanisms is the presence of an inducible erythromycin methylase (erm) gene, because it confers macrolide resistance. It has recently been found that "M. abscessus" can be split into three species or subspecies based on gene sequence analysis other than the 16S rRNA gene and the presence or absence of a functional erm(41) gene. Several names have been applied to these three organisms, including M. abscessus or M. abscessus subsp. abscessus, Mycobacterium massiliense or M. abscessus subsp. massiliense, and Mycobacterium bolletii or M. abscessus subsp. bolletii. No universally accepted or recognized species or subspecies designations have emerged, and no names have been universally adopted for these organisms. This uncertainty has led to inconsistencies in the medical literature and understandable confusion by clinicians about the appropriate labels for "M. abscessus" isolates. We discuss the complexities involved in mycobacterial species/subspecies identification and taxonomy and suggest possible ways to improve the present state of uncertainty surrounding the labels for "M. abscessus" clinical isolates. We also suggest necessary changes in mycobacterial laboratory processing and reporting procedures for mycobacterial isolates.