g Mycobacterium abscessus is a rapidly growing mycobacterium that causes respiratory tract infections in predisposed patients, such as those with cystic fibrosis and nosocomial skin and soft tissue infections. In order to investigate the clonal relationships between the strains causing epidemic episodes, we evaluated the discriminatory power of the semiautomated DiversiLab (DL) repetitive extragenic palindromic sequence PCR (REP-PCR) test for M. abscessus genotyping. Since M. abscessus was shown to be composed of subspecies (M. abscessus subsp. massiliense, M. abscessus subsp. bolletii, and M. abscessus subsp. abscessus), we also evaluated the ability of this technique to differentiate subspecies. The technique was applied to two collections of clinical isolates, (i) 83 M. abscessus original isolates (43 M. abscessus subsp. abscessus, 12 M. abscessus subsp. bolletii, and 28 M. abscessus subsp. massiliense) from infected patients and (ii) 35 repeated isolates obtained over 1 year from four cystic fibrosis patients. The DL REP-PCR test was standardized for DNA extraction, DNA amplification, and electrophoresis pattern comparisons. Among the isolates from distinct patients, 53/83 (62%) isolates showed a specific pattern, and 30 were distributed in 11 clusters and 6 patterns, with 2 to 4 isolates per pattern. The clusters and patterns did not fully correlate with multilocus sequence typing (MLST) analysis results. This revealed a high genomic diversity between patients, with a discriminatory power of 98% (Simpson's diversity index). However, since some isolates shared identical patterns, this raises the question of whether it is due to transmission between patients or a common reservoir. Multiple isolates from the same patient showed identical patterns, except for one patient infected by two strains. Between the M. abscessus subspecies, the indexes were <70%, indicating that the DL REP-PCR test is not an accurate tool for identifying organisms to the subspecies level. REP-PCR appears to be a rapid genotyping method that is useful for investigating epidemics of M. abscessus infections.
Mycobacterium abscessus is an emerging pathogen responsible for lung disease, most often in predisposed patients, such as those with cystic fibrosis, bronchiectasis, and chronic obstructive pulmonary disease (1, 2), and it has also been described in patients without compromised lung defense (3). M. abscessus is among the top five mycobacteria responsible for respiratory tract infections. It represents half of the infections caused by nontuberculous mycobacteria (NTM) and 95% of infections due to rapidly growing mycobacteria (RGM) in patients with cystic fibrosis in France (4). M. abscessus infections may lead to a rapid decline in respiratory function, and relapses are observed in patients who have undergone organ transplants (5-7). M. abscessus is also responsible for extrapulmonary infections in immunocompetent patients with outbreaks, related to surgical and cosmetic procedures, reported in various countries (8)(9)(10)(11)(12)(13)(1...