hsp65 sequencing for identification of rapidly growing mycobacteria

Partial sequencing of the hsp65 gene was used for the identification of rap idly growl ng mycobacteria (RGM). A 441-bp fragment (A. Telenti, F. Marches i, M. Balz, F. Bally, E. Bottger, and T. Bodmer, J. Clin, Microbiol. 31:175 -178, 1993) was amplified and sequenced by an automated fluorescence-based method involving capillary electrophoresis, Type strains of 10 RGM species were first studied. Each species had a unique nucleotide sequence, distingu ishing it clearly from the other species. A panel of strains from the four main RGM species responsible for human infections, Mycobacterium abscessus, Mycobacterium chelonae, Mycobacterium fortuitum, and Mycobacterium peregri num, was also studied. There were few sequence differences within each of t hese species (<2% of bases were different from the type strain sequence), a nd they had no effect on species assignment. hsp65 sequencing unambiguously differentiated M. chelonae and M. abscessus, two species difficult to iden tify by classical methods and 16S rRNA gene sequencing. The devised procedu re is a rapid;rnd reliable tool for the identification of RGM species.