Direct identification of bacteria in urine samples by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and relevance of defensins as interfering factors

Köhling, Hedda Luise; Bittner, Anna; Müller, Karl-Dieter; Buer, Jan; Becker, Markus; Rübben, H.; Rettenmeier, Albert W.; Mosel, Frank

doi:10.1099/jmm.0.032284-0

Cited by 73 publications

(65 citation statements)

References 9 publications

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“…The agreement between conventional microbiology and MALDI identification varied from 79 to 92 % for mono-microbial urine samples, indicating the usefulness of the methods developed. Another team reported a sample preparation method combining centrifugation and filtration with a limited identification rate of 58 % [13]. In this case, antimicrobial human peptides in the urine sample impaired MALDI-mediated identification.…”

Section: Introductionmentioning

confidence: 98%

Rapid urine preparation prior to identification of uropathogens by MALDI-TOF MS

Véron

Mailler

Girard

et al. 2015

Eur J Clin Microbiol Infect Dis

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Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-ToF MS) has been introduced in clinical routine microbiology laboratories. For the rapid diagnosis of urinary tract infections, culture-independent methods prior MALDI-mediated identification have been described. Here, we describe a comparison of three of these methods based on their performance of bacterial identification and their potential as a routine tool for microbiology labs : (i) differential centrifugation, (ii) urine filtration and (iii) a 5-h bacterial cultivation on solid culture media. For 19 urine samples, all methods were directly compared and correct bacterial species identification by MALDI was used as performance indicator. A higher percentage of correct MALDI identification was obtained after filtration (78.9 %) and the growth-based method (84.2 %) as compared to differential centrifugation (68.4 %). Additional testing of 76 mono-microbial specimens (bacteriuria > 10(5) CFU/mL) confirmed the good performance of short growth with a 90.8 % correct MALDI score, with a potentially better fit to the routine workflow of microbiology labs.

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Section: Introductionmentioning

confidence: 98%

Rapid urine preparation prior to identification of uropathogens by MALDI-TOF MS

Véron

Mailler

Girard

et al. 2015

Eur J Clin Microbiol Infect Dis

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“…Although a smaller sample set than those used in studies discussed above in this section (n ϭ 107), the authors similarly determined that MALDI-TOF MS was a reliable methodology for detection of bacteria directly from urinary specimens. Additionally, the authors concluded that this reliability was applicable to samples with bacterial densities as low as 10 3 CFU/ml (302).…”

Section: Urinementioning

confidence: 99%

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

et al. 2013

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SUMMARY Within the past decade, clinical microbiology laboratories experienced revolutionary changes in the way in which microorganisms are identified, moving away from slow, traditional microbial identification algorithms toward rapid molecular methods and mass spectrometry (MS). Historically, MS was clinically utilized as a high-complexity method adapted for protein-centered analysis of samples in chemistry and hematology laboratories. Today, matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) MS is adapted for use in microbiology laboratories, where it serves as a paradigm-shifting, rapid, and robust method for accurate microbial identification. Multiple instrument platforms, marketed by well-established manufacturers, are beginning to displace automated phenotypic identification instruments and in some cases genetic sequence-based identification practices. This review summarizes the current position of MALDI-TOF MS in clinical research and in diagnostic clinical microbiology laboratories and serves as a primer to examine the “nuts and bolts” of MALDI-TOF MS, highlighting research associated with sample preparation, spectral analysis, and accuracy. Currently available MALDI-TOF MS hardware and software platforms that support the use of MALDI-TOF with direct and precultured specimens and integration of the technology into the laboratory workflow are also discussed. Finally, this review closes with a prospective view of the future of MALDI-TOF MS in the clinical microbiology laboratory to accelerate diagnosis and microbial identification to improve patient care.

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“…De las 220 muestras con recuentos de colonias >10 5 UFC/mL, la identificación por MALDI-TOF MS fue concordante a nivel de especie en 91,8% de los aislamientos. Sin embargo, el desempeño para la identificación de microorganismos en muestras con recuentos bacterianos inferiores no fue satisfactorio, hallazgo confirmado en otros estudios [45][46][47][48] .…”

Section: Orinaunclassified

“…Köhling y colaboradores 46 , tras el análisis de 107 muestras de orina de pacientes con sospecha clínica de infección, encontraron una identificación inequívoca del microorganismo por el espectrómetro de masas Voyager DE™ STR MALDI-TOF (Applied Biosystems™, Foster City, CA) de 60,7% de las muestras; sin embargo, en los espectros de 40 de las 45 muestras positivas para las cuales no se obtuvo identificación, se observó un triplete de picos intensos correspondientes a las defensinas humanas 1, 2 y 3, que redujeron la intensidad de los picos de las proteínas bacterianas impidiendo la comparación con la base de datos, lo que demuestra que tanto los bajos recuentos bacterianos como la presencia de sustancias interferentes presentes en las muestras, reducen el desempeño del MALDI-TOF MS para la identificación de microorganismos en muestras de orina.…”

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La espectrometría de masas MALDI-TOF en el laboratorio de microbiología clínica

Maldonado

Robledo

2017

Infect

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ResumenLos métodos fenotípicos empleados para la identificación de microorganismos dependen de procesos metabólicos que requieren de tiempos de incubación mínimos para alcanzar resultados confiables. La espectrometría de masas MALDI-TOF (desorción/ionización láser asistida por una matriz con detección de masas por tiempo de vuelo) se ha instaurado como una metodología relevante para la identificación de microorganismos mediante el análisis de proteínas, a través de la creación de un espectro de masas específico de género y especie. En esta revisión, se presenta MALDI-TOF MS como una tecnología precisa para la identificación de bacterias, levaduras, mohos, en incluso de virus, que además, permite la reducción del tiempo para obtener un resultado de identificación, que puede impactar los costos de atención y duración de la estancia hospitalaria. La identificación de microorganismos directamente de muestras biológicas y la detección de mecanismos de resistencia a antimicrobianos, prometen un mayor impacto clínico y epidemiológico con el desarrollo e implementación de esta tecnología en los laboratorios de microbiología clínica.Palabras clave: MALDI-TOF MS, espectrometría de masas, diagnóstico microbiológico, identificación de patógenos, proteómica, infección del torrente sanguíneo, infección del tracto urinario. MALDI-TOF mass spectrometry in clinical microbiology laboratories. AbstractPhenotypic methods used for the identification of microorganisms depend on metabolic processes that require minimum incubation times to achieve reliable results. For this reason, MALDI-TOF MS (Matrix Assisted Laser Desorption/Ionization Mass Spectrometry) has been established as a relevant methodology for the identification of microorganisms using analysis of proteins, through the creation of a mass spectrum specific for genus and species. In the present review, MALDI-TOF MS is presented as an accurate technology for identifying bacteria, yeasts, molds and viruses; Its use allows reduction of the time to obtain an identification result, which may impact the costs of care and length of hospital stay. The identification of microorganisms directly from biological samples and the detection of mechanisms of antimicrobial resistance, promise an additional clinical and epidemiological impact with the development and implementation of this technology in clinical microbiology laboratories.Keywords: MALDI-TOF MS, mass spectrometry, microbiological diagnostic, pathogen identification, proteomics, blood stream infection, urinary tract infection. REVISIÓN IntroducciónLa identificación de microorganismos se ha realizado tradicionalmente por métodos basados en tinciones que permiten la clasificación de la morfología microscópica con el fin de apoyar decisiones diagnósticas y terapéuticas tempranas; así como en pruebas in vitro basadas en reacciones bioquímicas utilizadas por sistemas manuales o automatizados, que integran pruebas con diferentes sustratos, incrementando la rapidez y simplicidad de la identificación. Sin embargo, estos métodos fenotí...

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Direct identification of bacteria in urine samples by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and relevance of defensins as interfering factors

Cited by 73 publications

References 9 publications

Rapid urine preparation prior to identification of uropathogens by MALDI-TOF MS

Rapid urine preparation prior to identification of uropathogens by MALDI-TOF MS

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

La espectrometría de masas MALDI-TOF en el laboratorio de microbiología clínica

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