Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for the proteomic based identification of Aggregatibacter actinomycetemcomitans isolated from orodental infections.

Aim: Aggregatibacter actinomycetemcomitans is a fastidious gram negative cocco bacilli responsible for aggressive and chronic periodontitis as well as other systemic infections. In this study the usefulness of MALDITOF MS a proteomic based study was evaluated for the identification of A. actinomycetemcomitans isolates from orodental infections. Materials and methods: Fifty clinical isolates of A. actinomycetemcomitans obtained from orodental infections were subjected for identification with conventional as well as MALDITOF MS analysis. Results: All the isolates tested were accurately identified by the MALDITOF MS analysis. Among the 50 isolates 35 were identified at secure and probable species level and another 15 were identified at highly probable species level. Conclusion: MALDITOF MS is reliable, cost effective and rapid test for the identification of slow growing fastidious bacteria like A. actinomycetemcomitans compared with conventional methods

Identificación rápida de microorganismos de frascos de hemocultivos por espectrometría de masas: Comparación de 2 procedimientos diagnósticos / Rapid identification of microorganisms by mass spectrometry in a blood culture system: Comparison of two procedures

La identificación rápida de microorganismos es crítica, en especial en pacientes sépticos hospitalizados. La espectrometría de masas conocida como matrix-assisted laser desorption/ionization time-of- flight mass spectrometry (MALDI-TOF MS) permite la identificación directa desde botellas de hemocultivos positivos en forma rápida y sencilla. Este estudio evaluó el desempeño del procedimiento basado en el sistema MALDI Biotyper que utiliza el kit comercial MALDI Sepsityper de Bruker Daltonics (en adelante, MS) frente a uno artesanal (en adelante, HF). Se procesaron 840 botellas de hemocultivos positivos con HF y 542 de estas fueron evaluadas también con MS. Se logró la identificación de los microorganismos en 670 (79,76 %) y 391 (72,14 %) botellas, respectivamente (p = 0,0013). Se demostró la efectividad de ambos procedimientos para la identificación de microorganismos desde frascos de hemocultivos positivos. Sin embargo, el procedimiento HF fue superior al MS, en especial frente a bacterias gram positivas.

Rapid identification of microorganisms is critical in hospitalized infected patients. Blood culture is currently the gold standard for detecting and identifying microorganisms causing bacteremia or sepsis. The introduction of mass spectrometry by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF MS) in microbiology laboratories, especially in microorganisms growing in blood culture bottles, provides rapid identification. This study evaluates the performance of the Maldi Sepsityper Biotyper procedure (hereinafter, MS) compared to that of an in-home method (hereinafter, HF). Eight hundred and forty (840) positive blood culture bottles were processed using the HF procedure, 542 of which were also processed using MS. The organisms were identified in 670 (79. 76 %) and 391 (72. 14 %) bottles respectively (p = 0,0013). This study demonstrates the effectiveness of both procedures for identifying microorganisms directly from positive blood culture bottles. However, the HF procedure proved to be more effective than MS, especially in the presence of Gram positive organisms.

Insights into the protein profiles of stress tolerant and mesophilic yeast by proteomics approach: a comparative study.

Proteins of the stress tolerant and mesophilic yeast were extracted using optimized protein extraction method and estimated by Bradford method. Immobilized pH gradient (IPG) strips were rehydrated with known concentrations of protein samples. Rehydrated IPG strips were run in isoelectric focusing (IEF) to separate the proteins on the basis of their pH gradient. 2DE gels were run, stained and image of the stress tolerant yeast was compared with the gel image of mesophilic yeast. The image analysis using the image master software resulted in the identification of differentially expressed spots in stress tolerant yeast. Among the differentially expressed spots, six were selected and characterized by MALDI-TOF as Enolase, Fructose bisphosphate aldolase, Alcohol dehydrogenase, 30KDa HSP, HSP70 and HSP90.

Proteomic Analysis of Differently Expressed Proteins in a Mouse Model for Allergic Asthma

Allergic asthma is associated with persistent functional and structural changes in the airways and involves many different cell types. Many proteins involved in allergic asthma have been identified individually, but complete protein profiles (proteome) have not yet been reported. Here we have used a differential proteome mapping strategy to identify tissue proteins that are differentially expressed in mice with allergic asthma and in normal mice. Mouse lung tissue proteins were separated using two-dimensional gel electrophoresis over a pH range between 4 and 7, digested, and then analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MS). The proteins were identified using automated MS data acquisition. The resulting data were searched against a protein database using an internal Mascot search routine. This approach identified 15 proteins that were differentially expressed in the lungs of mice with allergic asthma and normal mice. All 15 proteins were identified by MS, and 9 could be linked to asthma-related symptoms, oxidation, or tissue remodeling. Our data suggest that these proteins may prove useful as surrogate biomarkers for quantitatively monitoring disease state progression or response to therapy.