Description of a novel Mycobacterium simiae allelic variant isolated from Caribbean AIDS patients by PCR-restriction enzyme analysis and sequencing of hsp65 gene.

A sudden upsurge in the isolation of Mycobacterium simiae from terminally ill AIDS patients was recently reported on the Caribbean island of Guadeloupe. Identification of these M. simiae isolates was achieved using biochemical tests and further confirmed by PCR-restriction analysis (PRA) of a 439-bp fragment of hsp65. A novel PRA profile III (three Bst EII fragments of 240/125/80 bp and four Hae III fragments of 145/125/40/25 bp) was observed in four blood isolates from two patients. The 16 S rRNA gene sequencing of the hypervariable A region confirmed that all the pattern III isolates were indeed M. simiae species, and the hsp65 sequencing confirmed the existence of a new hsp65 allele in these caribbean isolates. A hsp65 sequence-based phylogenetic tree was also created for 39 species including M. simiae and related mycobacterial species as well as other rapid and slow growing mycobacteria, and may serve as an useful tool for identification of mycobacteria to species level.