Use of simultaneous absorbance-transmittance and excitation-emission matrix (A-TEEM) spectroscopy to monitor source water contamination for waterworks

Conventional oil-in-water analyzers used by waterworks have hydrocarbon detection limits at mg/L levels and do not identify the type of oil compounds. The objectives of this study were to evaluate a more sensitive optical instrument and the analysis method to (1) determine the signature excitation and emission matrixs of each type of oil (such as diesel, heavy oil, gasoline and kerosene) or their indicator organic compounds and enter them into the instrument's software library and (2) test out the effectiveness of the instrument in detecting the above-mentioned oil in local waterworks’ source and treated water. The patented simultaneous absorbance-transmittance excitation-emission matrix (A-TEEM) instrument method was used to identify and quantify low levels of organic contaminants present in a much higher background of other dissolved organic matter components in raw and treated water. Multivariate regression and machine learning techniques were applied and shown to have potential for alerting plant operators to organic contamination events.

Reducing central line-associated bloodstream infection in contaminated central venous catheters: case studies of a pediatric contamination guideline

Healthcare organizations have prioritized patient safety and quality improvement efforts to reduce central line-associated bloodstream infections (CLABSIs). Implementation of central venous catheter (CVC) insertion and maintenance bundles have significantly reduced infection rates. Nevertheless, CLABSIs continue to be a significant cause of mortality and morbidity in hospitals, and further efforts are necessary to improve CVC care practices. A hospital-wide committee at a tertiary care pediatric hospital identified gaps in our CVC maintenance practices resulting from CVC contamination events from a patient's body fluids. A lack of published literature on the topic resulted in the need to create an institutional clinical practice guideline (CPG) to develop guidance to mitigate potential CLASBIs from CVC contamination. Utilization of the CVC CPG in all inpatient units and other reduction strategies resulted in a steady decline in our CLABSI rates, particularly in those related to CVC contamination events. Case reports illustrate the effectiveness of the CPG.

Comparative Analysis of Hydrogen Fluoride Exposed Patients Based on Major Burn Criteria After the 2012 Gumi City Chemical Leak Disaster

This study conducted to analyze and compare the epidemiological and clinical characteristics of hydrogen fluoride exposed patients based on major burn criteria for the appropriate emergency department (ED) response to a mass casualty chemical spill. This retrospective cross-sectional study included the records of patients (n = 199) who visited the ED of Gumi City University Hospital from September 27, 2012, to October 20, 2012. Subjects were included in the major burn group (MBG) if they presented with wounds that required referral to a burn center according to the American Burn Association guidelines or in the non-major burn group (NMBG) if not. Males were predominant in both the MBG (n = 55, 48 males) and NMBG (n = 144, 84 males; p < 0.05). The most prevalent timeline for visiting the ED was the phase which included 9-32 hours post-leak of HF, including 45 patients (81.8%) in the MBG and 122 patients (84.7%) in the NMBG (p < 0.001). The respiratory tract was the site of greatest damage in patients in both the MBG and NMBG (n=47, 85.5% versus n=142, 98.6%, p < 0.001). Regarding dispositions, all patients in the NMBG were discharged (n=144, 100%); however, 8 patients (14.5%) in the MBG underwent other dispositions (discharge againt medical advice, 5 patients; admission, 1; death, 2, p < 0.05). Patient outcomes after major chemical contamination events should be characterized in future studies to maximize the quality of patient care.

Application of Whole Genome Sequencing to Understand Diversity and Presence of Genes Associated with Sanitizer Tolerance in Listeria monocytogenes from Produce Handling Sources

Recent listeriosis outbreaks linked to fresh produce suggest the need to better understand and mitigate L. monocytogenes contamination in packing and processing environments. Using whole genome sequencing (WGS) and phenotype screening assays for sanitizer tolerance, we characterized 48 L. monocytogenes isolates previously recovered from environmental samples in five produce handling facilities. Within the studied population there were 10 sequence types (STs) and 16 cgMLST types (CTs). Pairwise single nucleotide polymorphisms (SNPs) ranged from 0 to 3047 SNPs within a CT, revealing closely and distantly related isolates indicative of both sporadic and continuous contamination events within the facility. Within Facility 1, we identified a closely related cluster (0–2 SNPs) of isolates belonging to clonal complex 37 (CC37; CT9492), with isolates recovered during sampling events 1-year apart and in various locations inside and outside the facility. The accessory genome of these CC37 isolates varied from 94 to 210 genes. Notable genetic elements and mutations amongst the isolates included the bcrABC cassette (2/48), associated with QAC tolerance; mutations in the actA gene on the Listeria pathogenicity island (LIPI) 1 (20/48); presence of LIPI-3 (21/48) and LIPI-4 (23/48). This work highlights the potential use of WGS in tracing the pathogen within a facility and understanding properties of L. monocytogenes in produce settings.

A Review of Probabilistic Genotyping Systems: EuroForMix, DNAStatistX and STRmix™

Probabilistic genotyping has become widespread. EuroForMix and DNAStatistX are both based upon maximum likelihood estimation using a γ model, whereas STRmix™ is a Bayesian approach that specifies prior distributions on the unknown model parameters. A general overview is provided of the historical development of probabilistic genotyping. Some general principles of interpretation are described, including: the application to investigative vs. evaluative reporting; detection of contamination events; inter and intra laboratory studies; numbers of contributors; proposition setting and validation of software and its performance. This is followed by details of the evolution, utility, practice and adoption of the software discussed.

Contaminants and Where to Find Them: Microbiological Quality Control in Axenic Animal Facilities

The use of axenic animal models in experimental research has exponentially grown in the past few years and the most reliable way for confirming their axenic status remains unclear. It is especially the case when using individual ventilated positive-pressure cages such as the Isocage. This type of cage are at a greater risk of contamination and expose animals to a longer handling process leading to more potential stress when opened compared to isolators. The aim of this study was to propose simple ways to detect microbial contaminants with Isocages type isolator resulting by developing, validating and optimizing three different methods (culture, microscopy, and molecular). These three approaches were also tested in situ by spiking 21 axenic mice with different microorganisms. Our results suggest that the culture method can be used for feces and surface station (IBS) swabs exclusively (in Brain Heart Infusion for 7 days at 25°C and 37°C in aerobic conditions, and at 30°C in anaerobic conditions), while microscopy (wet mounts) and molecular method (quantitative PCR) were only suitable for fecal matter analyses. In situ results suggests that the culture and molecular methods can detect up to 100% of bacterial contamination events while the microscopy approach generates many erroneous results when not performed by a skilled microscopist. In situ results also suggest that when an axenic mouse is contaminated by a microbial agent, the microorganism will colonize the mouse to such an extent that detection is obvious in 4 days, in average. This report validates simple but complimentary tests that can be used for optimal detection of contaminants in axenic animal facilities using Isocage type isolators.

Introducing the Rapid Alert Supply Network Extractor (RASNEX) tool to mine supply chain information from food and feed contamination notifications in Europe

Background During food or feed contamination events, it is of utmost importance to ensure their rapid resolution to minimize impact on human health, animal health and finances. The existing Rapid Alert System for Food and Feed (RASFF) is used by the European Commission, national competent authorities of member countries and the European Food Safety Authority to report information on any direct or indirect human health risk arising from food or feed, or serious risks to animal health or the environment in relation to feed. Nevertheless, no methods exist to to collectively evaluate this vast source of supply chain information. Methods To aid in the extraction, evaluation and visualization of the data in RASFF notifications, we present the Rapid Alert Supply Network Extractor (RASNEX) open-source tool available from https://doi.org/10.5281/zenodo.4322555 freely. Among RASNEX’s functions is the graphical mapping of food and feed supply chain operators implicated in contamination events. RASNEX can be used during ongoing events as a support tool for risk analysis using RASFF notifications as input. Results In a first use case, we showcase the functionality of RASNEX with the RASFF notification on a 2017/2018 contamination event in eggs caused by the illegal use of fipronil. The information in this RASFF notification is used to visualize nine different flows of main and related food products. In a second use case, we combine RASFF notifications from different types of food safety hazards (Salmonella spp., fipronil and others) to obtain wider coverage of the visualized egg supply network compared to the first use case. Actors in the egg supply chain were identified mainly for Italy, Poland and Benelux. Other countries (although involved in the egg supply chain) were underrepresented. Conclusions We hypothesize that biases may be caused by inconsistent RASFF reporting behaviors by its members. These inconsistencies may be counteracted by implementing standardized decision-making tools to harmonize decisions whether to launch a RASFF notification, in turn resulting in a more uniform future coverage across European food and feed supply chains with RASNEX.

A Collaborative Experience: Implementation of an Optimised Tc-99m Generator Assembly Process

Technetium-99m (Tc-99m) has a six-hour half-life making customer transportation times a challenge. ANSTO (Australia's Nuclear Science and Technology Organisation) Health Products group has overcome this by delivering the parent isotope Molybdenum-99 (Mo-99), which has a half-life of sixty-six hours, in shielded GENTECH™ generators. As part of ANSTO's questioning attitude, an augmented risk assessment was undertaken to identify any potential exposure risks of the GENTECH™ assembly process. The evaluation identified potential areas of improvement in contamination control for the manual handling of the generator leads. Upon further analysis, contamination events from the generator leads had the potential for skin doses above the threshold for skin tissue reactions. Additional substitution and administrative controls were designed to mitigate the risks identified. The effectiveness of the new controls was assessed for efficiency in the manufacturing process through mock trials and fitness for use in a pharmaceutical cleanroom environment. The implemented controls were monitored, and data from each run was gathered. This data included; changes in radiological conditions and dosimetry results. Upon implementation, there was an observable decrease in glove contamination. The decrease verified that there was a reduction in the risk of skin contamination events. The data analysis was used to model the dose averted, which revealed a reduction in potential extremity dose to production workers. This paper aims to show the optimisation within an approved process through the implementation of engineering and administrative controls, resulting in a dose reduction to workers.

Optimal Water Quality Sensor Placement by Accounting for Possible Contamination Events in Water Distribution Networks

Contamination in water distribution networks (WDNs) can occur at any time and location. One protection measure in WDNs is the placement of water quality sensors (WQSs) to detect contamination and provide information for locating the potential contamination source. The placement of WQSs in WDNs must be optimally planned. Therefore, a robust sensor-placement strategy (SPS) is vital. The SPS should have clear objectives regarding what needs to be achieved by the sensor configuration. Here, the objectives of the SPS were set to cover the contamination event stages of detection, consumption, and source localization. As contamination events occur in any form of intrusion, at any location and time, the objectives had to be tested against many possible scenarios, and they needed to reach a fair value considering all scenarios. In this study, the particle swarm optimization (PSO) algorithm was selected as the optimizer. The SPS was further reinforced using a databasing method to improve its computational efficiency. The performance of the proposed method was examined by comparing it with a benchmark SPS example and applying it to DMA-sized, real WDNs. The proposed optimization approach improved the overall fitness of the configuration by 23.1% and showed a stable placement behavior with the increase in sensors.