Infección meningocócica en paciente vacunado y en tratamiento con eculizumab / Meningococcemia in vaccinated patient under treatment with eculizumab

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Eficacia de la espectrometría de masas MALDI-TOF en la identificación de bacterias anaerobias / No disponible

Objetivo. La espectrometría de masas (EM) MALDI-TOF se ha convertido en un recurso de referencia para la identificación de microorganismos en los servicios de microbiología clínica. No obstante, los datos relativos a algunos grupos de microorganismos son todavía controvertidos. En el presente estudio se ha determinado la fiabilidad de la EM MALDI-TOF para la identificación de aislamientos clínicos de bacterias anaerobias, en comparación con técnicas bioquímicas convencionales, y usando como referencia en caso de discrepancias las secuenciación de ARNr 16S.Material y métodos Se analizaron 126 aislamientos clínicos de bacterias anaerobias mediante el sistema API 20A (bioMérieux, Marcy l’Étoile, Francia) y mediante EM MALDI-TOF (Autoflex II, Bruker Daltonics, Alemania), utilizando la base de datos BioTyper 2.0 (Bruker Daltonics, Alemania). Cuando se produjeron discrepancias, o la EM MALDI-TOF no fue capaz de identificar microorganismo alguno, se usó como método de identificación de referencia la secuenciación del ARNr 16S.ResultadosEl método bioquímico y la EM MALDI-TOF coincidieron, a nivel de especie, en el 60,9% de los casos, y solo a nivel de género en el 20,3%. De las 48 identificaciones discrepantes, la secuenciación respaldó la identificación por EM MALDI-TOF a nivel de especie en 32 casos (66,7%), y a nivel de género en 8 (16,7%). Dicha secuenciación apoyó la identificación bioquímica a nivel de especie solamente en 2 casos (..) (AU)

Aim of the study: MALDI-TOF mass spectrometry (MS) is becoming a major resource in the Clinical Microbiology laboratory. Results on some groups of microorganisms are still controversial. We have studied the reliability of MALDI-TOF MS for the identification of anaerobic clinical isolates was studied compared to conventional biochemical methods, with rRNA 16S sequencing being used as a reference when discrepancies arose. Material and methods: A total of 126 anaerobic bacteria clinical isolates were studied by using API20Akits (bioMérieux, Marcy l’Étoile, France) and MALDI-TOF MS (Autoflex II, Bruker Daltonics, Germany), and using the data library BioTyper 2.0 (Bruker Daltonics, Germany). When discrepancies arose, or MALDI-TOFMS was not able to identify any microorganism, rRNA 16S sequencing was used as the reference standard. Results: The biochemical method and MALDI-TOF MS agreed in identifying 60.9% of isolates at species level, and 20.3% of isolates at genus level. Among the 48 discrepancies observed, rRNA 16S sequencing (..) (AU)

Aplicaciones de la proteómica en el laboratorio de Microbiología Clínica / Proteomic applications in the Clinical Microbiology laboratory

La espectrometría de masas (EM) matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) se ha impuesto rápidamente en numerosos Servicios de Microbiología Clínica como un nuevo recurso tecnológico. Su utilidad en la identificación bacteriana está contrastada, aunque existen todavía dudas respecto a la identificación de grupos bacterianos concretos y de otros microorganismos, como los hongos filamentosos. Existen además otras diversas aplicaciones potenciales de esta tecnología en Microbiología Clínica, que están empezando a desarrollarse. En esta revisión se resumen los datos existentes respecto a la identificación de diferentes grupos de microorganismos, incluyendo aquellas que han planteado mayores problemas, como micobacterias, anaerobios y hongos filamentosos. Se analizan también sus aplicaciones en diagnóstico directo sobre muestra, su repercusión en la consideración como patógenos de diferentes microorganismos, y sus potenciales aplicaciones epidemiológicas. Finalmente, se resumen también los estudios existentes sobre su uso potencial en la determinación de sensibilidad a antimicrobianos, y su potencial utilización usando como sustrato amplificados génicos en lugar de extractos proteicos de los microorganismos (AU)

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is rapidly becoming a new routine resource in Clinical Microbiology laboratories. Its usefulness for bacterial identification is now generally accepted, although there is still some reluctance as regards specific bacterial groups and some other microorganisms, such as moulds. There are other potential applications of this technology in Clinical Microbiology, which are beginning to be developed. A review is presented on the current data on the identification of microorganisms, including the most problematic groups, such as mycobacteria, anaerobic bacteria and moulds. We also analyse its applications for direct sample (..) (AU)

[Reliability of MALDI-TOF mass spectrometry in the identification of anaerobic bacteria]. / Eficacia de la espectrometría de masas MALDI-TOF en la identificación de bacterias anaerobias.

AIM OF THE STUDY: MALDI-TOF mass spectrometry (MS) is becoming a major resource in the Clinical Microbiology laboratory. Results on some groups of microorganisms are still controversial. We have studied the reliability of MALDI-TOF MS for the identification of anaerobic clinical isolates was studied compared to conventional biochemical methods, with rRNA 16S sequencing being used as a reference when discrepancies arose. MATERIAL AND METHODS: A total of 126 anaerobic bacteria clinical isolates were studied by using API20A kits (bioMérieux, Marcy l'Étoile, France) and MALDI-TOF MS (Autoflex II, Bruker Daltonics, Germany), and using the data library BioTyper 2.0 (Bruker Daltonics, Germany). When discrepancies arose, or MALDI-TOF MS was not able to identify any microorganism, rRNA 16S sequencing was used as the reference standard. RESULTS: The biochemical method and MALDI-TOF MS agreed in identifying 60.9% of isolates at species level, and 20.3% of isolates at genus level. Among the 48 discrepancies observed, rRNA 16S sequencing supported MALDI-TOF MS identification, at species level, in 32 isolates (66.7%), and in 8 isolates (16.7%) at genus level. rRNA 16S sequencing supported biochemical identification in only two isolates (4.2%) at species level, and in 26 isolates (54.2%) at genus level. The eight isolates for which MALDI-TOF MS did not manage to identify, or the identification obtained was rejected by sequencing, belonged to species that are still not added to the BioTyper II data library. CONCLUSIONS: Results obtained in this study show that, overall, MALDI-TOF MS identification of anaerobic bacteria is more reliable than identification obtained by conventional biochemical methods (24% more correct identifications at species level). The number of major errors (incorrect identification at the genus level) is also 2.5-times lower. Moreover, all the major errors obtained by MALDI-TOF MS were due to the absence of some species in the data library. Thus, when data libraries are more complete, reliability differences between both methods will probably be even higher.

[Proteomic applications in the Clinical Microbiology laboratory]. / Aplicaciones de la proteómica en el laboratorio de Microbiología Clínica.

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is rapidly becoming a new routine resource in Clinical Microbiology laboratories. Its usefulness for bacterial identification is now generally accepted, although there is still some reluctance as regards specific bacterial groups and some other microorganisms, such as moulds. There are other potential applications of this technology in Clinical Microbiology, which are beginning to be developed. A review is presented on the current data on the identification of microorganisms, including the most problematic groups, such as mycobacteria, anaerobic bacteria and moulds. We also analyse its applications for direct sample identification, its impact on pathogenic characteristics of microorganisms, and its potential epidemiological applications. Finally, we review the studies published on its applications for determining antimicrobial susceptibility, and its applications on amplicons, instead of microorganism protein extracts.

Identification of Brucella by MALDI-TOF mass spectrometry. Fast and reliable identification from agar plates and blood cultures.

BACKGROUND: MALDI-TOF mass spectrometry (MS) is a reliable method for bacteria identification. Some databases used for this purpose lack reference profiles for Brucella species, which is still an important pathogen in wide areas around the world. We report the creation of profiles for MALDI-TOF Biotyper 2.0 database (Bruker Daltonics, Germany) and their usefulness for identifying brucellae from culture plates and blood cultures. METHODOLOGY/PRINCIPAL FINDINGS: We created MALDI Biotyper 2.0 profiles for type strains belonging to B. melitensis biotypes 1, 2 and 3; B. abortus biotypes 1, 2, 5 and 9; B. suis, B. canis, B ceti and B. pinnipedialis. Then, 131 clinical isolates grown on plate cultures were used in triplicate to check identification. Identification at genus level was always correct, although in most cases the three replicates reported different identification at species level. Simulated blood cultures were performed with type strains belonging to the main human pathogenic species (B. melitensis, B. abortus, B. suis and B. canis), and studied by MALDI-TOF MS in triplicate. Identification at genus level was always correct. CONCLUSIONS/SIGNIFICANCE: MALDI-TOF MS is reliable for Brucella identification to the genus level from culture plates and directly from blood culture bottles.