Rapid identification and differentiation of the species of the Mycobacterium chelonae /abscessus complex by hsp65 and rpoB PCR-RFLP / 中国人兽共患病学报

ABSTRACT

The Mycobacterium chelonae/abscessus (M.chelonae/abscessus) complex belongs to the rapidly growing genus Mycobacterium (RGM).It is one of the most important pathogenic members of Mycobacterium leading to nosocomial infections and outbreaks.It includes members of M.chelonae,M.immnunogenum,M.abscessus,M.massiliense,and M.bolletii.In order to investigate the epidemiological characteristics of the M.chelonae/abscessus complex in China and to conduct the molecular methods for species identification of M.chelonae/abscessus,we collected clinical M.chelonae/abscessus complex strains identified by phenotypic tests.Members were verified by sequencing of 16S rRNA,Species and subspecies were identified by hsp65 and rpoB PCR RFLP methods.In total,27 clinical specimens were identified as Mycobacterium chelonae/abscessus complex by phenotypic tests.16s rRNA gene sequence analysis of all 27 clinical samples shared over 99.7％ similarity with M.chelonae and M.abscessus.Species identification with hsp65 PCR-RFLP and rpoB PCR-RFLP revealed that 18 specimens were M.abscessus and 4 were M.absecces.The remaining 5 samples displayed a pattern that failed to match any previously reported pattern.Thus,this might represent a novel species that is part of the Mycobacterium chelonae/abscessus complex.We identified that a majority of the chronic lung infection in China is caused by the M.chelonae/abscessus complex.Specifically,the M.abscessus species might be the most infectious,while other species in the complex can still cause infection.Interestingly,there may be a novel or previously unidentified species that is a part of the complex.Finally,we show that species identification can be carried out more accurately by combined use of hsp65 and rpoB PCR-RFLP.