Microbial enrichment and multiplexed microfiltration for accelerated detection of Salmonella in spinach

Effect of flux and shear rate on E. coli recovery in tangential flow filtration through a single hollow fiber

Pathogenic bacteria which enter a viable but non-culturable (VBNC) state impede efforts to reach detectable concentrations required for PCR methods. This motivated a strategy for tangential flow filtration to concentrate bacteria in aqueous samples while maintaining the bacteria in a viable state, maximizing their recovery and achieving high fluxes through a single hollow fiber membrane. Filtrations were carried out for green fluorescent protein (GFP) E. coli at high shear rates (up to 27,000 sec-1) through 0.2 μm cut-off polyethersulfone (PES) microfilter membranes or 50 kDa polysulfone (PS) ultrafilter membranes. High shear minimized bacterial attachment on membrane surfaces, which would otherwise occur due to forced convection of the particles to the membrane surface at high flux conditions. Single fiber filter modules were constructed to facilitate concentration of Escherichia coli at fluxes ranging from 55 to 4500 L m-2 h-1. The effect of high shear rates on bacterial viability was found to be minimal with bacterial losses during filtration caused principally by their accumulation on the membrane surface. Recoveries of 90% were achievable at high shear rates when the average flux was ≤300 L m-2 h-1. This corresponded to a 3-h filtration time for a 225 mL sample through a single hollow fiber. Detectable bacteria concentrations of 1800 colony-forming unit (CFU)/mL were achieved for starting concentrations of 140 CFU/mL.

Advancing medical technology innovation and clinical translation via a model of industry-enabled technical and educational support: Indiana Clinical and Translational Sciences Institute's Medical Technology Advance Program

The success rate for translation of newly engineered medical technologies into clinical practice is low. Traversing the "translational valleys of death" requires a high level of knowledge of the complex landscape of technical, ethical, regulatory, and commercialization challenges along a multi-agency path of approvals. The Indiana Clinical and Translational Sciences Institute developed a program targeted at increasing that success rate through comprehensive training, education, and resourcing. The Medical Technology Advance Program (MTAP) provides technical, educational, and consultative assistance to investigators that leverages partnerships with experts in the health products industry to speed progress toward clinical implementation. The training, resourcing, and guidance are integrated through the entire journey of medical technology translation. Investigators are supported through a set of courses that cover bioethics, ethical engineering, preclinical and clinical study design, regulatory submissions, entrepreneurship, and commercialization. In addition to the integrated technical and educational resources, program experts provide direct consultation for planning each phase along the life cycle of translation. Since 2008, nearly 200 investigators have gained assistance from MTAP resulting in over 100 publications and patents. This support via medicine-engineering-industry partnership provides a unique and novel opportunity to expedite new medical technologies into clinical and product implementation.

Rapid and sensitive detection of E. coli O157:H7 and S. Typhimurium in iceberg lettuce and cabbage using filtration, DNA concentration, and qPCR without enrichment

The outbreaks due to the low number of foodborne pathogens present in ready-to-eat products can be prevented by rapid and sensitive detection method. However, as a conventional detection method, it is impossible to monitor foodborne bacteria existing which is less than 50 cfu/25 g in a food. This study was designed to investigate the possibility of detecting 1 cfu in the short-term through filtration, DNA concentration, and qPCR. As a result of the filtration + DNA concentration method, the recovery concentrations of Escherichia coli O157:H7 and Salmonella Typhimurium was not significantly different from initial inoculation (>7 cfu/25 g). In iceberg lettuce and cabbage, this method was able to detect 7 and 7 cfu/25 g of E. coli and 68 and 5 cfu/25 g of S. Typhimurium. We demonstrated the potential of the filtration + DNA concentration method as a shorter time alternative to conventional enrichment-based rapid detection in vegetables.