Wireless Data Acquisition of Transient Signals for Mobile Spectrometry Applications.

Wireless data acquisition using smartphones or handhelds offers increased mobility, it provides reduced size and weight, it has low electrical power requirements, and (in some cases) it has an ability to access the internet. Thus, it is well suited for mobile spectrometry applications using miniaturized, field-portable spectrometers, or detectors for chemical analysis in the field (i.e.

Evaluation of rapid screening techniques for detection of Salmonella spp. from produce samples after pre-enrichment according to FDA BAM and a short secondary enrichment.

Unlabelled: Conventional detection of Salmonella from foods involves enrichment and isolation on selective media which can significantly lengthen time to result. The objective of this study was to evaluate the utility of an accelerated plating procedure and the use of rapid screening devices for Salmonella detection. Fresh produce was inoculated with Salmonella at ~2·5, ~7·5 and ~25 CFU sample(-1) .

Detection and isolation of low levels of E. coli O157:H7 in cilantro by real-time PCR, immunomagnetic separation, and cultural methods with and without an acid treatment.

Unlabelled: Leafy greens such as cilantro, contaminated with Escherichia coli O157:H7, have been implicated in cases of human illnesses. High levels of microflora in fresh cilantro make recovery of low numbers of E. coli O157:H7 difficult.

Recovery of E. coli O157 strains after exposure to acidification at pH 2.

Aims: Rapid detection and selective isolation of E. coli O157:H7 strains have been difficult owing to the potential interference from background microflora present in high background food matrices. To help selectively isolate E.

Efficacy of a post enrichment acid treatment for isolation of Escherichia coli O157:H7 from alfalfa sprouts.

The enrichment, detection and isolation procedure in the current US FDA BAM have been shown effective for Escherichia coli O157:H7 in a wide variety of foods. Recently reported modifications to the enrichment protocol, including post-enrichment immunomagnetic separation (IMS) procedures have improved sensitivity of the method for alfalfa sprouts. However, cultural isolation on selective agar plates still presents a challenge in this food matrix.

Battery-operated, argon-hydrogen microplasma on hybrid, postage stamp-sized plastic-quartz chips for elemental analysis of liquid microsamples using a portable optical emission spectrometer.

A battery-operated, atmospheric pressure, self-igniting, planar geometry Ar-H(2) microplasma for elemental analysis of liquid microsamples is described. The inexpensive microplasma device (MPD) fabricated for this work was a hybrid plastic-quartz structure that was formed on chips with an area (roughly) equal to that of a small-sized postage stamp (MPD footprint, 12.5-mm width by 38-mm length).

Optimization and evaluation of a modified enrichment procedure combined with immunomagnetic separation for detection of E. coli O157:H7 from artificially contaminated alfalfa sprouts.

Escherichia coli O157:H7 has been linked to foodborne disease outbreaks with alfalfa sprouts. Detection of the organism in sprouts by standard cultural methods can be difficult due to the high background microflora. The objective of this study was to develop and optimize an enrichment protocol with and without post-enrichment immunomagnetic separation (IMS) for the rapid detection by real-time PCR (RTiPCR) and cultural recovery of E.

Detection of E. coli O157:H7 in raw ground beef by Pathatrix™ immunomagnetic-separation, real-time PCR and cultural methods.

Detection of Escherichia coli O157:H7 by conventional cultural methods can be difficult in food matrices with a high background flora such as raw ground beef. Raw ground beef samples, artificially contaminated separately with five strains of E. coli O157:H7 at low (~0.

Helium-hydrogen microplasma device (MPD) on postage-stamp-size plastic-quartz chips.

A new design of a miniaturized, atmospheric-pressure, low-power (e.g., battery-operated), self-igniting, planar-geometry microplasma device (MPD) for use with liquid microsamples is described.

A new chromogenic agar medium for detection of potentially virulent Yersinia enterocolitica.

Several outbreaks of foodborne yersiniosis have been documented and this disease continues to be source of infections transmitted through foods. The selective agars most commonly used to isolate Yersinia enterocolitica in clinical, food and environmental samples, cefsulodin-irgasan-novobiocin (CIN) and MacConkey (MAC) agars, lack the ability to differentiate potentially virulent Y. enterocolitica from other Yersinia that may be present as well as some other bacterial spp.

Detection of Shiga toxin genes stx1, stx2, and the +93 uidA mutation of E. coli O157:H7/H-using SYBR Green I in a real-time multiplex PCR.

Enterohemorrhagic Escherichia coli (EHEC) is a major foodborne pathogen capable of causing diarrhea and vomiting, but more serious complications such as hemorrhagic colitis and hemolytic-uremic syndrome (HUS) can result. A real-time PCR method to detect the presence of Shiga toxin producing E. coli (STEC) and E.

Optimization of a 3'-minor groove binder-DNA probe targeting the uidA gene for rapid identification of Escherichia coli O157:H7 using real-time PCR.

Enterohemorrhagic Escherichia coli are harmful human pathogens capable of causing bloody diarrhea and vomiting. An important serotype commonly associated with human illness is the E. coli O157:H7 serotype.

Multiplex real-time PCR method to identify Shiga toxin genes stx1 and stx2 and Escherichia coli O157:H7/H- serotype.

A multiplex real-time PCR method to simultaneously detect the stx1 and stx2 genes of Shiga toxin-producing Escherichia coli and a unique conserved single-nucleotide polymorphism in the E. coli O157:H7/H- uidA gene has been developed. There is more than 98.

Use of endogenous host plasmids for generation of Escherichia coli O157:H7 and Shigella sonnei strains that stably express the green fluorescent protein.

The gfp gene was manipulated from a commercially available, high copy vector into endogenous plasmids of Escherichia coli O157:H7 and Shigella sonnei to yield stable GFP strains that required neither high copy number for visualization nor antibiotics for stable maintenance of the phenotype. The GFP phenotype of these strains remained stable after repeated passages in media and conditions that enhance plasmid instability and loss from bacterial cells. These results demonstrate the utility of the endogenous plasmids in selectively marking bacteria without altering host cellular function or biochemical properties.

Analysis of environmental Escherichia coli isolates for virulence genes using the TaqMan PCR system.

Aims: To assess the presence of virulence genes in environmental and foodborne Escherichia coli isolates using the TaqMan PCR system.

Methods And Results: Three TaqMan pathogen detection kits called O157:H7, StxI and StxII were used to investigate the presence of virulence genes in Escherichia coli isolates. All 54 foodborne E.

Evaluation of techniques for enrichment and isolation of Escherichia coli O157:H7 from artificially contaminated sprouts.

Because sprouted seed products are kept wet during and after production, have high levels of nutrients, and a neutral pH, they are subject to the outgrowth of pathogens such as Escherichia coli O157:H7. For these same reasons, these products also contain high levels of heterotrophic organisms and in particular coliform bacteria. Recent outbreaks have focused attention on the need to improve methodology for isolating this pathogen from sprouts.

Glutamate decarboxylase genes as a prescreening marker for detection of pathogenic Escherichia coli groups.

The enzyme glutamate decarboxylase (GAD) is prevalent in Escherichia coli but few strains in the various pathogenic E. coli groups have been tested for GAD. Using PCR primers that amplify a 670-bp segment from the gadA and gadB genes encoding GAD, we examined the distribution of the gadAB genes among enteric bacteria.

Genetic analysis for virulence factors in Escherichia coli O104:H21 that was implicated in an outbreak of hemorrhagic colitis.

Isolates of enterohemorrhagic Escherichia coli (EHEC) of serotype O104:H21 implicated in a 1994 outbreak of hemorrhagic colitis in Montana were analyzed for the presence of trait EHEC virulence markers. By using a multiplex PCR that specifically amplifies several genes, the O104:H21 strains were found to carry only the Shiga toxin 2 gene (stx2) and to express Stx2. They did not have the eaeA gene for gamma-intimin, which is typically found in O157:H7, or the alpha- or beta-intimin derivatives, which are common in other EHEC and enteropathogenic E.

Development of digoxigenin-labeled PCR amplicon probes for use in the detection and identification of enteropathogenic Yersinia and Shiga toxin-producing Escherichia coli from foods.

By including digoxigenin-11-dUTP in a polymerase chain reaction (PCR), amplification products were produced that contained nonisotopic markers for use as DNA hybridization probes. Because these labeled amplicons encode pathogenic traits for specific foodborne bacteria, they can be used to detect the presence of potentially virulent organisms that may be present in foods. This technology allows the synthesis of a variety of shelf-stable probe reagents for detecting a number of foodborne microbes of public health concern.

Comparison of Template Preparation Methods from Foods for Amplification of Escherichia coli O157 Shiga-Like Toxins Type I and II DNA by Multiplex Polymerase Chain Reaction.

Escherichia coli O157:H7 has been responsible for several recent food-borne outbreaks in the United States. To protect the public health, it is essential that rapid and sensitive methods be developed for detection of this pathogen in foods. Methods were compared for preparation of template DNA for the polymerase chain reaction (PCR) from enrichments of food homogenates seeded with E.

Use of pulsed-field gel electrophoresis for epidemiological study of Escherichia coli O157:H7 during a food-borne outbreak.

Food and patient isolates from an Escherichia coli O157:H7 outbreak associated with undercooked ground beef were characterized by pulsed-field gel electrophoresis and Shiga-like toxin genotype. Pulsed-field gel electrophoresis confirmed the epidemiologically implicated source of the two-state outbreak and differentiated between outbreak and sporadic strains.

An Improved Rapid Technique for Isolation of Escherichia coli O157:H7 from Foods.

A newly revised enrichment and agar-plating system was tested for selectivity and sensitivity in recovery of unstressed and cold-stressed Escherichia coli O157:H7 from foods. Various foods inoculated with known levels of enterohemorrhagic E. coli O157:H7 (EHEC) were tested by enrichment for 6 h at 37°C in modified tryptic soy broth (mTSB) base supplemented with vancomycin, cefsulodin and cefixime, referred to as EHEC enrichment broth (EEB).

Molecular characterization of Yersinia enterocolitica by pulsed-field gel electrophoresis and hybridization of DNA fragments to ail and pYV probes.

Sixty strains of Yersinia enterocolitica from five serogroups (O:3; O:9; O:8; O:5; and O:5,27) and eight non-Y. enterocolitica strains, recovered from diverse sources (humans, animals, food, and the environment) in Europe, Argentina, and the United States, were examined by the pulsed-field gel electrophoresis (PFGE) technique of contour clamped homogeneous electric field electrophoresis (CHEF) by using NotI and XbaI as restriction enzymes. NotI and XbaI generated 36 and 33 restriction endonuclease digestion profiles (REDP), respectively.

Survival of Escherichia coli O157:H7 in Mayonnaise and Mayonnaise-Based Sauces at Room and Refrigerated Temperatures.

Three Escherichia coli Ol57:H7 (EHEC) strains were inoculated separately into portions of commercially prepared mayonnaise held at 25 or 7°C, then examined periodically for survival of detectable EHEC. Four mayonnaise-based sauces including: a) mayonnaise-mustard sauce, b) blue cheese dressing, c) thousand island dressing and d) seafood sauce, were each inoculated with one EHEC strain. Samples of these sauces were held at 5°C, and assayed periodically for survival of detectable EHEC.

Clinical and microbiologic characteristics of cutaneous infection with Yersinia enterocolitica.

The clinical and microbiologic features of primary cutaneous infections by Yersinia enterocolitica are described in three children. Vesiculobullous lesions developed in two patients, and an intense granulation response followed incision and drainage. In the third child, cellulitis and abscess formation developed at the site of minor skin trauma.