Clostridium difficile infection in an Iranian hospital

<p>Abstract</p> <p>Background</p> <p><it>Clostridium difficile</it> infection (CDI) is an important cause of morbidity and mortality internationally, yet there are important regional differences in the epidemiology and microbiology of disease. Most reports have come from North America and Europe, with limited information from other regions, including the Middle East. Given the changes in the epidemiology of CDI in developed countries, particularly associated with the dissemination of hypervirulent epidemic clones, an understanding of the epidemiology and microbiology of CDI in diverse regions is warranted. This study involved collection of stool samples from individuals with diarrhea at the Isfahan University of Medical Sciences Teaching Hospital, Isfahan, Iran, between October 2010 and March 2011. Selective enrichment culture for <it>C. difficile</it> was performed and isolates were characterised using ribotyping, PCR for the detection of <it>tcdA, tcdB</it> and <it>cdtB</it> genes, and <it>tcdC</it> sequence analysis.</p> <p>Findings</p> <p><it>Clostridium difficile</it> was isolated from 19/89 (21%) stool samples of 17/86 (20%) patients. 13/17 (77%) cases of CDI were hospital-associated. Patients with CDI were significantly older (43 ± 28y) than those with non-CDI diarrhea (24, ± 26y)(<it>P</it> = 0.018). All isolates were toxigenic, and possessed genes encoding for toxins A and B. Six (32%) of 19 isolates also possessed <it>cdtB</it>. Twelve ribotypes were identified. Ribotype 078/toxinotype V was most common, accounting for 4 (21%) of isolates. A single isolate of a different toxinotype V ribotype was identified, as was a toxinotype XXIV isolate. The remaining isolates consisted of 9 different toxinotype 0 ribotypes.</p> <p>Conclusions</p> <p>CDI is an important cause of diarrhea in patients in this hospital. The diversity of ribotypes was striking, and the number of different types suggests the presence of a broad range of strains in the community, the hospital or both. The predominance of toxinotype V strains, which have been associated with community-associated disease and food animals, was unexpected and possible sources of this type require further investigation.</p

Developments in nanoparticles for use in biosensors to assess food safety and quality

The following will provide an overview on how advances in nanoparticle technology have contributed towards developing biosensors to screen for safety and quality markers associated with foods. The novel properties of nanoparticles will be described and how such characteristics have been exploited in sensor design will be provided. All the biosensor formats were initially developed for the health care sector to meet the demand for point-of-care diagnostics. As a consequence, research has been directed towards miniaturization thereby reducing the sample volume to nanolitres. However, the needs of the food sector are very different which may ultimately limit commercial application of nanoparticle based nanosensors

Protein detection using hydrogel-based molecularly imprinted polymers integrated with dual polarisation interferometry

A polyacrylamide-based molecularly imprinted polymer (MIP) was prepared for bovine haemoglobin (BHb). A 3 mg/ml solution of BHb was injected over a dual polarisation interferometer (DPI) sensor to form a physisorbed layer typically of 3.5 ± 0.5 nm thickness. Onto the pre-adsorbed protein layer, MIP and NIP (non-imprinted polymer) were separately injected to monitor the interaction of BHb MIP or NIP particles under different loading conditions with the pre-adsorbed protein layer. In the case of NIP flowing of the protein layer, there was negligible surface stripping of the pre-adsorbed protein. When a protein-eluted sample of MIP particles was flowed over a pre-adsorbed protein layer on the sensor chip, the sensor detected significant decreases in both layer thickness and mass, suggestive that protein was being selectively bound to MIP after being stripped-off from the sensor surface. We also integrated thin-film MIPS for BHb and BSA onto the DPI sensor surface and were able to show that whereas BHb bound selectively and strongly to the BHb MIP thin film (resulting in a sustained increase in thickness and mass), the BHb protein only demonstrated transient and reversible binding on the BSA MIP. MIPs were also tested after biofouling with plasma or serum at various dilutions. We found that serum at 1/100 dilution allowed the MIP to still function selectively. This is the first demonstration of MIPs being integrated with DPI in the development of synthetic receptor-based optical protein sensors. © 2012 Elsevier B.V. All rights reserved

Developments in nanoparticles for use in biosensors to assess food safety and quality

The following will provide an overview on how advances in nanoparticle technology have contributed towards developing biosensors to screen for safety and quality markers associated with foods. The novel properties of nanoparticles will be described and how such characteristics have been exploited in sensor design will be provided. All the biosensor formats were initially developed for the health care sector to meet the demand for point-of-care diagnostics. As a consequence, research has been directed towards miniaturization thereby reducing the sample volume to nanolitres. However, the needs of the food sector are very different which may ultimately limit commercial application of nanoparticle based nanosensors. © 2014 Elsevier Ltd

The rise and fall of attitudes : longitudinal comparisons with economic motive using data from a field experiment

Littering, giving blood, conserving energy, voter registration and wearing seatbelts serve as examples of public behaviours which governments have attempted to alter. Whether it be for purposes of controlling costs, helping other citizens, or protecting the environment, altering behavioural patterns which operate against the general well-being of society has become big business. A plethora of techniques have been employed in efforts to sway the activity patterns of people. While various approaches have been undertaken, the research focuses upon two traditions. First, an economic or behavioural approach is employed where behavioural changes are believed to be influenced most effectively by material rewards. Second, cognitive or attitudinal approaches stress that attitudes play an operative role in effecting behavioural change. Using shifts in daily patterns of energy use as an example of social behaviour, the research reported here contrasts cognitive and economic models. While the two approaches can be complementary, it also may be that under certain conditions one or the other model is most successful. Where the two models do contrast is in the predictions made about what behavioural change will result after the removal of economic incentives. Data from a large field-experiment using a multi-stage probability sample of nearly 700 Wisconsin households is analysed to examine the influence of cognitive and behavioural models of time-of-day energy usage. The objective of the experiment was to determine whether economic stimuli could be used to reduce peoples' use of peak-time energy consumption. Behavioural change in energy consumption patterns was measured by in-house meters which recorded all usage for a year prior to the introduction of special time-of-day rates; for three years while the rates were in effect; and for a sub-sample of households, the summer after the rates ended. In addition, three waves of survey data from mailed questionnaires administered prior to, during, and following the experiment allow monitoring of the development and change in attitude toward time-of-day pricing of electricity, and its influence on behaviour. In contrast to earlier published work, this analysis suggests only a minimal, independent impact of attitude on behavioural change under time-of-day electricity rates. At the conclusion of the experiment, and in the absence of any further financial rewards, households, by and large, returned to former consumption levels. Concomitant changes in attitudinal commitment occurred as well. Nevertheless, a subset of households, constituting some twenty percent of the original sample, remained highly committed to peak electricity reductions and, to a degree, maintained their prior conserving behaviours without further financial reward. Several analyses were performed in an attempt to reconcile the contradictory nature of the current findings with those of earlier research. It is argued that the apparent influence of attitude in affecting behaviour at the time the pricing incentive was in effect was exaggerated by householders substituting an attitudinal for a financial motive. Further, the influence of price on attitude formation may have been underestimated due to the curvilinear relation of price with behaviour. Evidence in support of each of these hypotheses is provided. It is concluded that, in combination with price, attitude is important to maintaining behavioural change, but that its independent influence, in this instance, is minor. At the same time, the effect of price appears less based on the size of the pricing incentive, than serving as an informational source signalling appropriate action, irrespective of the absolute financial reward. Finally, the thesis concludes with some speculations on the lessons from this experiment for other attempts to alter behavioural patterns.Arts, Faculty ofSociology, Department ofGraduat

Development and Evaluation of Silver Zeolite Antifouling Coatings on Stainless Steel for Food Contact Surfaces

The majority of foodborne illness outbreaks can be linked to cross-contamination events through contact with contaminated surfaces. Consequently, there is a sustained interest in developing antimicrobial coatings such as silver zeolite to reduce contamination levels. In this study, we examined the efficacy of silver zeolite for preventing biofilm formation by common foodborne pathogens such as Listeria innocua Seeliger and Escherichia coli O157:H7. Biofilm formation was assessed by cresyl violet assay, quantification of colony-forming units and scanning electron microscopy, and atomic force microscopy. For silver zeolite suspended in growth media, concentrations of 0.3% w/v were effective at reducing bacterial growth of L. innocua after 8 h. For E. coli incubated with silver zeolite, there was a dose-dependent reduction in bacteria after 4 h. When coated stainless steel coupons were incubated with Listeria and E. coli, significant reductions in bacterial growth were achieved. Coating stainless steel food processing surfaces with silver zeolite may provide a means of reducing cross-contamination events of pathogens and spoilage microbes. The ability of the surface to resist the attachment of biofilms provides a complementary approach to chemical sanitation. Practical Applications: Antimicrobial coatings are gaining importance for the food manufacturing and food processing industries for food safety applications. The results of this study demonstrate that the silver zeolite could inhibit foodborne pathogenic biofilm formation and could potentially serve as an effective antimicrobial coating for food contact surfaces. The methodology for impregnating the silver zeolite in polymers followed by coating on stainless steel surface provides detailed procedure for preparing the antimicrobial surfaces

Fruit and vegetable wash-water characterization, treatment feasibility study and decision matrices

On average, it is estimated that up to 5 liters of wastewater is generated per kg of produce in post-harvest processing of fruit, leafy greens and root vegetables. The typical wastewater parameters vary in concentration (solids content, COD, BOD, nitrogen, phosphorus) based on the produce being processed. The challenge for producers and regulators is that the selection of the appropriate treatment technology is challenging, so decision matrices were developed to narrow down the treatment selections. Wash-waters for different types of fruit and vegetables from two different operation types, washing only vs. washing and processing. Bench-scale treatments selected for testing included settling, coagulation and flocculation with settling, centrifuge, dissolved air flotation, electrocoagulation, screening, and hydrocyclone. The developed decision matrices summarize the removal effectiveness of the different treatments for typical wastewater parameters and serve as a reference tool in understanding wash-water treatment technologies and their effectiveness in treating various wash-waters.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Decontamination of N95 and surgical masks using a treatment based on a continuous gas phase-Advanced Oxidation Process.

A gas-phase Advanced Oxidation Process (gAOP) was evaluated for decontaminating N95 and surgical masks. The continuous process was based on the generation of hydroxyl-radicals via the UV-C (254 nm) photo-degradation of hydrogen peroxide and ozone. The decontamination efficacy of the gAOP was dependent on the orientation of the N95 mask passing through the gAOP unit with those positioned horizontally enabling greater exposure to hydroxyl-radicals compared to when arranged vertically. The lethality of gAOP was independent of the applied hydrogen peroxide concentration (2-6% v/v) but was significantly (P6 log CFU decrease in Geobacillus stearothermophilus endospores, > 8 log reduction of human coronavirus 229E, and no detection of Escherichia coli K12 on the interior and exterior of masks. There was no negative effect on the N95 mask fitting or particulate efficacy after 20 passes through the gAOP system. No visual changes or hydrogen peroxide residues were detected (6 log CFU reduction of endospores inoculated on the interior or exterior of surgical masks. G. stearothermophilus Apex spore strips could be applied as a biological indicator to verify the performance of gAOP treatment. Also, a chemical indicator based on the oxidative polymerization of pyrrole was found suitable for reporting the generation of hydroxyl-radicals. In conclusion, gAOP is a verifiable treatment that can be applied to decontaminate N95 and surgical masks without any negative effects on functionality

Characterization of antimicrobial efficacy of photocatalytic polymers against food-borne biofilms

Biofouling of food industry equipment and other surfaces that food products contact during processing is a threat to food safety, which results in infectious outbreaks and economic losses due to corrosion, equipment impairment, and reduced heat transfer efficiency. Once firmly attached to a surface, biofilms can be almost impossible to remove using current sanitation procedures. Self-cleaning surfaces with TiO2 coatings that are activated with ultraviolet (UV) light may be effective in preventing bacterial growth or killing or removing adherent organisms but require studies to demonstrate their efficacy and determine optimum conditions for use. Therefore, we examined the efficacy of TiO2-based polymer coatings against key food-borne pathogens namely, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Salmonella typhimurium. Upon photo-catalytic activation of the coatings, the viability of early stage biofilms formed on each coated surface and the relative contribution of reactive oxygen species was evaluated. Results show that the relative antimicrobial activity strength was dependent on the length of UV irradiation; 5-10 min exposure was sufficient to inhibit/kill biofilms of each pathogenic species tested. The results of this study render contact surfaces less attractive for pathogenic biofilms while doubling as an effective mitigation strategy to remove biofilms that form despite coating