Clinical and taxonomic status of pathogenic nonpigmented or late-pigmenting rapidly growing mycobacteria

Historical evolution of the diseases caused by non-pigmented rapidly growing mycobacteria in a University Hospital

OBJECTIVE

Non-pigmented rapidly growing mycobacteria (NPRGM) are a group of organisms of increasing interest due to the growing number of potential patients and the difficulties for a proper treatment in many of them. However, the evolution of these diseases in a long period of time and its evolutionary changes has been described only in a scanty number of reports.

METHODS

We performed a retrospective study between January 1st 2004 and December 31st 2017 in order to evaluate the clinical significance and types of diseases caused by NPRGM. Patients with isolates of NPRGM during this period were selected for the study, and clinical charts were reviewed using a predefined protocol.

RESULTS

During this period we identified 59 patients (76 clinical samples) with isolates of NPRGM, with 12 cases of clinical disease and one patient with doubtful significance (including 6 respiratory tract infections, 2 catheter infections, 1 skin and soft tissue infection, 1 disseminated infection, 1 conjunctivitis, 1 prosthetic joint infection and 1 mastitis). Fifty percent of M. chelonae isolates, 37.5% of M. abscessus isolates and 23.33% of M. fortuitum isolates were clinically significant. None of the isolates of other species were significant.

CONCLUSIONS

Most isolates in respiratory samples were contaminants/colonizations. M. abscessus was the main etiological agent in respiratory syndromes, whereas M. chelonae and M. fortuitum were more frequently associated with other infections, especially clinical devices and skin and soft tissue infections.