Mass spectrometric study of antibiotic resistance of S. aureus and P. aeruginosa using the MALDIquant package

• Published in: International journal of infectious diseases Vol. 116; p. S12
• Main Authors: Aleshukina, A., Denisenko, V., Aleshukina, I., Ermakova, L.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2022; Elsevier
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2021.12.028

The transfer of genetic information, including markers of antibiotic resistance in bacteria, is carried out with the participation of mobile elements - plasmids, transposons, integrons, and others. Antibiotic resistance plasmids are heavy (70 - 300 kDa) and encode a sign of resistance to one or more drugs. The revelation and study of such integrons has shown their important role in the evolution of bacterial genomes. The standard MALDI-TOF method does not detect the antibiotic resistance of the studied microorganisms. Because plasmids are proteins and its sizes are known, its presence in the mass spectra of resistant cultures may be detected. The aim of the study was to detect markers of antibiotic resistance in the mass spectra of S. aureus and P. aeruginosa using the R software environment and the MALDI quant package. We studied 10 strains of P. aeruginosa and S. aureus for sensitivity and pan-resistance to antibiotics. The resistance of the strains to azithromycin, meropenem, ciprofloxacin, amikacin, cefixime, cefotaxime was studied using the Vitek-2 bacteriological analyzer. Mass spectra were obtained using a MALDI-TOF mass spectrometer Bruker Microflex. The search for probable markers of antibiotic resistance was carried out in the R software environment. For the preliminary processing of the mass spectra, the MALDIquant package was used. The values of mass-charge (m / z) mass spectra and the presence of areas of mass spectrometric peaks, which may indicate the resistance of the strain to antibiotics were revealed. For each of bacteria, the 3 most probable m / z values responsible for resistance, which are present only in pan-resistant bacteria, were selected. The peaks in the ranges of values m / z 2275, 3875, 5600 were estimated as promising markers of resisnance for S. aureus while for P. aeruginosa - m / z = 5382, 6976, 4881. The analysis revealed differences in the mass spectra of antibiotic-sensitive and antibiotic-resistant strains. The possibility of clarifying the results obtained with respect to a larger number of S. aureus and P. aeruginosa strains is being considered.