Elucidating constraints for differentiation of major human Klebsiella pneumoniae clones using MALDI-TOF MS.
The establishment of matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) in routine microbial identification boosted many developments towards high-throughput applications, including bacterial typing. However, results are still controversial for different bacterial species. We aim to evaluate the suitability of MALDI-TOF MS for typing clinically relevant multidrug resistant (MDR) Klebsiella pneumoniae subsp. pneumoniae clones using routine conditions and a previously validated chemometric analysis workflow. Mass spectra of 83 K. pneumoniae clinical isolates representing major human MDR clones [11 sequence types (STs), 22 PFGE-types] recovered in Portugal and Spain during outbreaks and non-outbreak situations (2003-2012) were obtained from cell extracts (CE) and intact cells (IC), and analysed with different chemometric tools. We observed a highly consistent peak pattern among isolates from different clones either with CE or IC, suggesting a high degree of conservation of biomolecules analysed (a large part corresponding to ribosomal proteins). Moreover, the low degree of agreement between MALDI-TOF MS and other methods (from 34.9 % to 43.4 % of correct assignments for CE and from 40.8 % to 70.1 % for IC) corroborates the low discriminatory potential of the technique at infraspecies level. Our results suggest a low discriminatory power of MALDI-TOF MS for clinically relevant MDR K. pneumoniae clones and highlight the need of developing tools for high-resolution typing in this species.
UCIBIO-REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Rua Jorge de Viterbo Ferreira, n. 228, 4050-313, Porto, Portugal.
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Rodrigues
UCIBIO-REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Rua Jorge de Viterbo Ferreira, n. 228, 4050-313, Porto, Portugal.
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Novais
LAQV-REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
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Sousa
Serviço de Microbiologia, Centro Hospitalar do Porto, Porto, Portugal.
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Ramos
Servicio de Microbiologia, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.|CIBER Epidemiología y Salud Pública, Madrid, Spain.
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Coque
Servicio de Microbiologia, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.|Red Española de Investigación en Patología Infecciosa (REIPI), Madrid, Spain.
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Cantón
Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal.
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Lopes
UCIBIO-REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Rua Jorge de Viterbo Ferreira, n. 228, 4050-313, Porto, Portugal. lpeixe@ff.up.pt.
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Peixe
D015373:Bacterial Typing Techniques / Q000379:methods*; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000737:chemistry* / Q000145:classification*; D011174:Portugal; D013030:Spain; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*