Search

Antimicrobial stewardship practices are critical in preventing the further erosion of treatment options for bacterial infections. Yet, at the same time, determination of an infection's antimicrobial susceptibility requires multiple rounds of culture and expensive lab automation systems. In this work, we report the use of paper-based surface enhanced Raman spectroscopy (SERS) sensors and portable instrumentation to phenotypically discriminate multi-drug resistance with fewer culture steps than conventional clinical microbiology. Specifically, we demonstrate the identification of resistance to varying generations of β -lactam antibiotics by detecting the activity of particular β -lactamase enzymes in a multiplexed assay. The method utilizes molecular reporters that consist of β -lactams with SERS barcodes. Hydrolysis of the β -lactam by β -lactamase enzymes in the sample expels the barcode; the released sulfur-containing barcode is then detected via SERS. Using this approach, we demonstrate the differentiation of E. coli strains with (1) extended spectrum β -lactamase (ESBL), (2) narrow-spectrum β -lactamase, and (3) no resistance, using only a single measurement on a single sample. In addition, we experimentally validate an approach to expand the library of reporters through the simple chemical synthesis of new barcoded β -lactams. Importantly, the reported method determines the susceptibility based on phenotypic β -lactamase activity, which is aligned with current microbiology lab standards. This new method will enable the precise selection of effective β -lactam antibiotics (as opposed to defaulting to drugs of last resort) faster than current methods while using simple steps and low-cost portable instrumentation. Image 1 • We demonstrate phenotypic detection of β-lactamase activity using paper SERS sensors and portable instrumentation. • We show discrimination of β -lactamases with different degrees of resistance in a single sample on a single sensor. • We demonstrate a simple synthesis method to expand the library of SERS-based β -lactamase reporters. • We accomplish β-lactamase discrimination in significantly less time than conventional microbiology. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the prospect of integrating a combined paper&pulp mill with fuel production via biomass gasification was investigated. In the study, three different types of gasifiers (circulating fluidised bed, entrained flow and indirect gasification) and three fuel processes (dimethyl ether, methanol and Fischer-Tropsch wax synthesis) were investigated using computer simulations. The paper reports differences from the stand-alone cases and the integrated cases, using the electricity equivalence efficiency as a measure. Only 6 out of the 18 integrated cases studied displayed a positive result from integration and no obvious fuel selection that stand out as the most beneficial one, however the synthesis of dimethyl ether is, in combination with all gasifiers assessed a rather good choice, with an change in efficiency from integration ranging from −1% to 4%. Dimethyl ether is not the best choice if the electrical equivalence is to be maximised however. In this case the combination of circulating fluidised bed gasification and methanol synthesis should be pursued. The production of Fischer-Tropsch wax should according to the chosen measure not be produced; however there is an added value in the production of a non-oxygenated fuel which has not been taken into account in this particular study. All cases leads to a reduction of 0.4–0.9 kg CO2 per kg of dry biomass used in the process for fuel synthesis and the possibility to export bark is a more significant factor in this respect than which type of fuel is synthesised. [Copyright &y& Elsevier]