MALDI-TOF MS Application for Susceptibility Testing of Microorganisms

Rapid identification and susceptibility testing are still major challenges in recent medical microbiology, in particular in the era of multi-/pan-resistant microorganisms. DNA/RNA-based molecular assays were able to solve only partially these demands. Although being a phenotyping approach, matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)-based analysis of the whole-organism protein mass spectra offers the closest approximation to the ribosomal sequence information due to the dominance of ribosomal proteins. Thus, this method has been successfully established for the identification and subtyping of bacterial and fungal microorganisms. Meanwhile, this MALDI-TOF MS has become a routine method in many diagnostic laboratories and contributed enormously to a reduction of the time-to-result in identification procedures. However, for susceptibility testing, a rapid phenotypic approach is still missing. DNA-based molecular assays are limited to the gene level that does not cover the resistance phenotype as well as the detection of unknown resistance mechanisms. Here, the MALDI-TOF MS approach may give solutions to determine rapidly antibiotic susceptibilities independently of the underlying resistance phenotype, e.g. by the analysis of degradation products of tested antibiotics or by measuring microbial growth in defined solutions with addition of antibiotic compounds.

This Frontiers Research Topic aims to illustrate studies for the development, adaptation and evaluation of MALDI-TOF MS-based procedures that are directed to the determination of the susceptibilities of microorganisms (bacteria, fungi) to antibiotics or other antimicrobial agents. Moreover, studies are welcome, that describe novel software developments for this purpose and that analyze the implementation of this approach into the routine laboratory and its impact on patient care, laboratory organization and health economics. We encourage submissions of original research articles, (mini-) reviews, methods article, perspectives, technology report, opinions and commentaries that make a novel and substantial contribution for the scientific community.