TITLE:
MALDI-TOF MS Assessment to Identify Environmental Mycobacteria
AUTHORS:
Camilla Pereira de Paula Uzam, Urze Adomaitis Brianesi, Camila Romagnoli, Karen Machado Gomes, Rafael Silva Duarte, Erica Chimara, Julio Cezar Franco de Oliveira, Marcelo Affonso Vallim, Renata Castiglioni Pascon, Cristina Viana-Niero
KEYWORDS:
MALDI-TOF MS, Environmental Mycobacteria, Identification, PRA-Hsp65
JOURNAL NAME:
Advances in Microbiology,
Vol.5 No.9,
August
26,
2015
ABSTRACT: Over the past few decades, there has been a significant increase
in the number of mycobacterial species described. Currently, the genusMycobacteriumconsists of 170 species. Most species are called nontuberculous
mycobacteria (NTM) and are potentially or rarely pathogenic and ubiquitous. One
of the main challenges in mycobacteriology is the rapid and precise
identification of these microorganisms. In this work, we compared two protein
extraction protocols for the identification of 38 reference strains and clinical
isolates, representing 27 species, by mass spectrometry (MALDI-TOF MS) to
subsequently use the best method for identifying environmental mycobacteria.
The results obtained with reference strains and clinical isolates showed that
protocol A was effective in identifying 92.1% of mycobacterial specimens at the
species level and protocol B, 50%. Therefore, protocol A was evaluated for the
rapid identification of 27 environmental mycobacterial
isolates. These isolates were subjected to PCR-restriction enzyme analysis
(PRA-hsp65). Two isolates were misidentified by PRA-hsp65,
whereas MALDI-TOF MS was able to identify them correctly. The results were
confirmed byhsp65 and 16S
rRNA gene sequencing. Mass spectrometry has the advantage of being a simpler
and faster technique than PRA-hsp65, and our results showed that
MALDI-TOF MS is a valuable tool for the identification of environmental
mycobacterial isolates.