Detection of extended-spectrum β-lactamase and carbapenemase activity in Gram-negative bacilli using liquid chromatography - tandem mass spectrometry

PURPOSE: Several mass spectrometry-based methods for antimicrobial sensitivity testing have been described in recent years. They offer an alternative to commercially available testing systems which were considered to have disadvantages in terms of cost- and time-efficiency. The aim of this study was to develop a LC-MS/MS-based antibiotic hydrolysis assay for evaluating antimicrobial resistance of Gram-negative bacteria. METHODS: Four species of Gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Providencia stuartii and Acinetobacter baumannii) were tested against six antibiotics from three different classes: ampicillin, meropenem, imipenem, ceftazidime, ceftriaxone and cefepime. Bacterial suspensions from each species were incubated with a mixture of the six antibiotics. Any remaining antibiotic following incubation were measured using LC-MS/MS. The results were interpreted using measurements obtained for an E. coli strain sensitive to all antibiotics and expressed as percentage of hydrolyzed antibiotic. These were subsequently compared to commercially-available system for the bacteria identification and susceptibility testing. RESULTS: Overall, LC-MS/MS assay and commercial antimicrobial susceptibility platform results showed good agreement in terms of an organism being resistant/sensitive to an antibiotic. The time required to complete the LC-MS/MS-based hydrolysis test was under 5 h, significantly shorter that commercially available susceptibility testing platforms. CONCLUSION: By using a sensitive strain for results interpretation and simultaneous use of multiple antibiotics, the proposed protocol offers improved robustness and multiplexing over previously described methods for antibiotic sensitivity testing. Nevertheless, further research is needed before routine assimilation of the method, especially for strains with intermediate resistance

Biosurfactant production in sub-oxic conditions detected in hydrocarbon-degrading isolates from marine and estuarine sediments

Hydrocarbon bioremediation in anoxic sediment layers is still challenging not only because it involves metabolic pathways with lower energy yields but also because the production of biosurfactants that contribute to the dispersion of the pollutant is limited by oxygen availability. This work aims at screening populations of culturable hydrocarbonoclastic and biosurfactant (BSF) producing bacteria from deep sub-seafloor sediments (mud volcanos from Gulf of Cadiz) and estuarine sub-surface sediments (Ria de Aveiro) for strains with potential to operate in sub-oxic conditions. Isolates were retrieved from anaerobic selective cultures in which crude oil was provided as sole carbon source and different supplements were provided as electron acceptors. Twelve representative isolates were obtained from selective cultures with deep-sea and estuary sediments, six from each. These were identified by sequencing of 16S rRNA gene fragments belonging to Pseudomonas, Bacillus, Ochrobactrum, Brevundimonas, Psychrobacter, Staphylococcus, Marinobacter and Curtobacterium genera. BSF production by the isolates was tested by atomized oil assay, surface tension measurement and determination of the emulsification index. All isolates were able to produce BSFs under aerobic and anaerobic conditions, except for isolate DS27 which only produced BSF under aerobic conditions. These isolates presented potential to be applied in bioremediation or microbial enhanced oil recovery strategies under conditions of oxygen limitation. For the first time, members of Ochrobactrum, Brevundimonas, Psychrobacter, Staphylococcus, Marinobacter and Curtobacterium genera are described as anaerobic producers of BSFs.publishe

Sistemi di dono-reciprocità nel sistema economico capitalista: utopia o coesistenza feconda? Il caso dell’Economia di Comunione nella libertà

This article analyzes the Economy of Communion in Freedom (EoC), an economic phenomenon that was born in 1991 in Brazil and is nowadays widespread worldwide , with some 860 companies informing their actions towards the primary objective to create a society without poverty, in order to achieve a more general aim: “make humankind one family”. Hypothesis of this article is that the EoC, due to his embeddedness in a particular cultural practice, inserts into capitalist system typical  elements from a gift-reciprocity system, similar to the one observed by anthropologists in archaic and traditional societies,  able to create “reciprocity” and “properly social bonds” beside the instrumental and powerfull relationships. To investigate this hypothesis the EoC is seen as a process, paying attention to the forms of exchange implemented, and as a sociological  place focusing the analysis on the actions and relations system, targeting in particular three groups of actors: 1. entrepreneurs, 2. poors that are aid recipents, and 3. management committees that are centrally or locally responsible of the distribution of such aid. The research has been informed by data collected through an on-the-field observation period in Brazil, with qualitative techniques and tools (documents and interviews) and having as theoretical perspective the Paradigm of gift of the M.A.U.S.S. (Mouvement Anti-utilitariste dans les Sciences Sociales)

Impact of a Pretreatment Step on the Acidogenic Fermentation of Spent Coffee Grounds

This work was developed within the scope of the project CICECO-Aveiro Institute of Materials (LA/P/0006/2020), Paulo C. Lemos acknowledges the support by FCT/MCTES for contract IF/01054/2014/CP1224/CT0005.Acidogenic fermentation (AF) is often applied to wastes to produce short-chain organic acids (SCOAs)—molecules with applications in many industries. Spent coffee grounds (SCGs) are a residue from the coffee industry that is rich in carbohydrates, having the potential to be valorized by this process. However, given the recalcitrant nature of this waste, the addition of a pretreatment step can significantly improve AF. In this work, several pretreatment strategies were applied to SCGs (acidic hydrolysis, basic hydrolysis, hydrothermal, microwave, ultrasounds, and supercritical CO2 extraction), evaluated in terms of sugar and inhibitors release, and used in AF. Despite the low yields of sugar extracted, almost all pretreatments increased SCOAs production. Milder extraction conditions also resulted in lower concentrations of inhibitory compounds and, consequently, in a higher concentration of SCOAs. The best results were obtained with acidic hydrolysis of 5%, leading to a production of 1.33 gSCOAs/L, an increase of 185% compared with untreated SCGs.publishersversionpublishe

The Cytotoxic Effects of Betulin-Conjugated Gold Nanoparticles as Stable Formulations in Normal and Melanoma Cells

Gold nanoparticles are currently investigated as theranostics tools in cancer therapy due to their proper biocompatibility and increased efficacy related to the ease to customize the surface properties and to conjugate other molecules. Betulin, [lup-20(29)-ene-3β, 28-diol], is a pentacyclic triterpene that has raised scientific interest due to its antiproliferative effect on several cancer types. Herein we described the synthesis of surface modified betulin-conjugated gold nanoparticles using a slightly modified Turkevich method. Transmission electron microscopy (TEM) imaging, dynamic light scattering (DLS), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used for the characterization of obtained gold nanoparticles. Cytotoxic activity and apoptosis assessment were carried out using the MTT and Annexin V/PI apoptosis assays. The results showed that betulin coated gold nanoparticles presented a dose-dependent cytotoxic effect and induced apoptosis in all tested cell lines

Enzymatic Potential of Filamentous Fungi as a Biological Pretreatment for Acidogenic Fermentation of Coffee Waste

This work was developed within the scope of the project CICECO-Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020), and the Associate Laboratory for Green Chemistry-LAQV (UIDB/50006/2020 and UIDP/50006/2020). It was financed by national funds through the FCT/MCTES (PIDDAC) and, when appropriate, co-financed by FEDER under the PT2020 Partnership Agreement. Paulo C. Lemos acknowledges the support of FCT/MCTES for contract IF/01054/2014/CP1224/CT0005 and Joana Pereira thanks FCT/MCTES for her Ph.D. grant SFRH/BD/130003/2017.Spent coffee grounds (SCGs) are a promising substrate that can be valorized by biotechnological processes, such as for short-chain organic acid (SCOA) production, but their complex structure implies the application of a pretreatment step to increase their biodegradability. Physicochemical pretreatments are widely studied but have multiple drawbacks. An alternative is the application of biological pretreatments that include using fungi Trametes versicolor and Paecilomyces variotii that naturally can degrade complex substrates such as SCGs. This study intended to compare acidic and basic hydrolysis and supercritical CO 2 extraction with the application of these fungi. The highest concentration of SCOAs, 2.52 gCOD/L, was achieved after the acidification of SCGs pretreated with acid hydrolysis, but a very similar result, 2.44 gCOD/L, was obtained after submerged fermentation of SCGs by T. versicolor. This pretreatment also resulted in the best acidification degree, 48%, a very promising result compared to the 13% obtained with the control, untreated SCGs, highlighting the potential of biological pretreatments.publishersversionpublishe