Molecular typing of isolated from cystic fibrosis patients.

Background: The possibility of inter-human transmission of Mycobacterium abscessus in cystic fibrosis centres has been recently hypothesized suggesting the need for the molecular characterization of strains isolated from such patients.

Materials And Methods: One hundred and forty one isolates of M. abscessus grown from sputum samples of 29 patients with cystic fibrosis were genotyped resorting to variable number of tandem repeats (VNTR) determination and whole genome sequencing (WGS).

Results: Out of 29 VNTR profiles, 15 were unique to the same number of patients while seven were shared by multiple patients. WGS showed that only two of the patients sharing common VNTR patterns were indeed infected by the same strain. The shared VNTR patterns were mostly present among the isolates of M. abscessus subsp. abscessus.

Conclusion: As expected WGS showed a clearly higher discriminatory power in comparison with VNTR and appeared the only molecular epidemiology tool suitable to effectively discriminate the isolates of M. abscessus subsp. abscessus.