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Cuénod A, Aerni M, Bagutti C, Bayraktar B, Boz ES, Carneiro CB, Casanova C, Coste AT, Damborg P, van Dam DW, Demirci M, Drevinek P, Dubuis O, Fernandez J, Greub G, Hrabak J, Hürkal Yiğitler G, Hurych J, Jensen TG, Jost G, Kampinga GA, Kittl S, Lammens C, Lang C, Lienhard R, Logan J, Maffioli C, Mareković I, Marschal M, Moran-Gilad J, Nolte O, Oberle M, Pedersen M, Pflüger V, Pranghofer S, Reichl J, Rentenaar RJ, Riat A, Rodríguez-Sánchez B, Schilt C, Schlotterbeck AK, Schrenzel J, Troib S, Willems E, Wootton M, Ziegler D, Egli A. Quality of MALDI-TOF mass spectra in routine diagnostics: results from an international external quality assessment including 36 laboratories from 12 countries using 47 challenging bacterial strains. Clin Microbiol Infect 2023; 29:190-199. [PMID: 35623578 DOI: 10.1016/j.cmi.2022.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/16/2022] [Accepted: 05/11/2022] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) is a widely used method for bacterial species identification. Incomplete databases and mass spectral quality (MSQ) still represent major challenges. Important proxies for MSQ are the number of detected marker masses, reproducibility, and measurement precision. We aimed to assess MSQs across diagnostic laboratories and the potential of simple workflow adaptations to improve it. METHODS For baseline MSQ assessment, 47 diverse bacterial strains, which are challenging to identify by MALDI-TOF MS, were routinely measured in 36 laboratories from 12 countries, and well-defined MSQ features were used. After an intervention consisting of detailed reported feedback and instructions on how to acquire MALDI-TOF mass spectra, measurements were repeated and MSQs were compared. RESULTS At baseline, we observed heterogeneous MSQ between the devices, considering the median number of marker masses detected (range = [2-25]), reproducibility between technical replicates (range = [55%-86%]), and measurement error (range = [147 parts per million (ppm)-588 ppm]). As a general trend, the spectral quality was improved after the intervention for devices, which yielded low MSQs in the baseline assessment as follows: for four out of five devices with a high measurement error, the measurement precision was improved (p-values <0.001, paired Wilcoxon test); for six out of ten devices, which detected a low number of marker masses, the number of detected marker masses increased (p-values <0.001, paired Wilcoxon test). DISCUSSION We have identified simple workflow adaptations, which, to some extent, improve MSQ of poorly performing devices and should be considered by laboratories yielding a low MSQ. Improving MALDI-TOF MSQ in routine diagnostics is essential for increasing the resolution of bacterial identification by MALDI-TOF MS, which is dependent on the reproducible detection of marker masses. The heterogeneity identified in this external quality assessment (EQA) requires further study.
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Affiliation(s)
- Aline Cuénod
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland; Division of Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland.
| | | | | | - Banu Bayraktar
- University of Health Sciences, Sisli Hamidiye Etfal Teaching and Research Hospital, Istanbul, Turkey
| | - Efe Serkan Boz
- Department of Medical Microbiology, University of Health Sciences, Haydarpasa Numune Teaching and Research Hospital, Istanbul, Turkey
| | | | - Carlo Casanova
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Alix T Coste
- Institute of Microbiology, University Hospital Lausanne, Lausanne, Switzerland
| | - Peter Damborg
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | - Mehmet Demirci
- Department of Medical Microbiology, Kirklareli University, Kirklareli, Turkey
| | - Pavel Drevinek
- Department of Medical Microbiology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | | | - José Fernandez
- Division of Laboratory Medicine, Laboratory of Bacteriology, University Hospital of Geneva, Geneva, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, University Hospital Lausanne, Lausanne, Switzerland
| | - Jaroslav Hrabak
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Plzen, Czech Republic
| | - Gülen Hürkal Yiğitler
- University of Health Sciences, Sisli Hamidiye Etfal Teaching and Research Hospital, Istanbul, Turkey
| | - Jakub Hurych
- Department of Medical Microbiology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Thøger Gorm Jensen
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark
| | | | - Greetje A Kampinga
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Sonja Kittl
- Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | | | | | | | - Julie Logan
- Reference Services Division, UK Health Security Agency, London, United Kingdom
| | | | - Ivana Mareković
- Department of Clinical and Molecular Microbiology, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Matthias Marschal
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
| | - Jacob Moran-Gilad
- School of Public Health, Ben Gurion University of the Negev and Soroka University Medical Center, Beer Sheva, Israel
| | - Oliver Nolte
- Center for Laboratory Medicine, St. Gallen, Switzerland
| | | | - Michael Pedersen
- Department of Clinical Microbiology, Hvidovre Hospital, Hvidovre, Denmark
| | | | | | - Julia Reichl
- Austrian Agency for Health and Food Safety, Vienna, Austria
| | | | - Arnaud Riat
- Division of Laboratory Medicine, Laboratory of Bacteriology, University Hospital of Geneva, Geneva, Switzerland
| | | | | | | | - Jacques Schrenzel
- Division of Laboratory Medicine, Laboratory of Bacteriology, University Hospital of Geneva, Geneva, Switzerland
| | - Shani Troib
- School of Public Health, Ben Gurion University of the Negev and Soroka University Medical Center, Beer Sheva, Israel
| | - Elise Willems
- Clinical Laboratory AZNikolaas, Sint-Niklaas, Belgium
| | - Mandy Wootton
- University Hospital of Wales, Cardiff, United Kingdom
| | | | - Adrian Egli
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland; Division of Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
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