Microbial Risk Analysis最新文献

In this study, the heat resistance of S. aureus in goats’ raw milk subjected to thermisation temperatures was characterised through tests at various temperatures and modelling the survival curves using the Weibull model, through a two-step and an omnibus approach, which can model a full dataset covering all experimental conditions in one step. The fitting capacity of the secondary models obtained from the two-step approach was reasonable (adj. R² > 0.639) and both demonstrated the negative linear effects of temperature on $\sqrt{\chi }$ (p = 0.0004) and $\sqrt{\beta }$ (p = 0.017). The fitting capacity of the omnibus model was more satisfactory (adj. R² = 0.996) and also hinted at the negative linear effect of temperature on $\sqrt{\chi }$ (p < 0.0001), with the added advantage that, in this model, random effects can be used to account for the variability in the parameters. Our study estimated the significant inactivation parameters and established a model capable of predicting S. aureus behaviour at various temperatures. This information is useful to create time-temperature tables to reach target log reductions of S. aureus in goats’ raw milk to be used by artisanal cheesemakers; hence providing an opportunity to increase the microbiological safety of cheeses made from unpasteurised milk.

Aflatoxin B1 (AFB1), is among the most carcinogenic and genotoxic food and feed contaminants and there is no acceptable level of their intake. An analysis of the top 10 countries of origin notifications on aflatoxins (AFs) involved in the EU RASFF database over the last 26 years was undertaken. A risk assessment was estimated for simulating the worst-case scenario for the serious notifications of the mostly notified products as well. Out of 12,400 notifications on AFs over the period between 1997 and 2022, of which 10,340 (83.39 %) concerned Iran which was the most frequently notified country (21.56 %), followed by Turkey (20.48), China (9.99 %), India (7.88 %), the USA (7.74 %), Argentina (5.82 %), Egypt (3.94 %), Brazil (3.05 %), Pakistan (1.52 %), and Nigeria (1.41 %). Germany was the most notifying country, followed by the Netherlands. Among all notifications, 53.3 % have been border rejected. Nuts, nuts products, and seeds were the highest notified product category followed by fruits and vegetables. The highest serious risk decision in terms of notification number was taken for contaminated dried fig from Turkey, followed by pistachio from Iran. The estimated margin of exposure (MOE) values for the mostly notified products i.e., pistachio, dried fig, and peanut were <10,000 which is not safe and represents a health concern.

Objectives

In this research, we aimed to find potential factors which are rapidly obtained for the risk of the coming new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), when their genetic substitutions were detected in late 2022.

Methods

We first performed molecular docking simulation analyses of the spike proteins with human angiotensin-converting enzyme 2 (ACE2) by using ZDOCK program to determine the binding affinities to human cells of three new variants of SARS-CoV-2: Omicron BQ.1, XBB, and XBB.1.5. We then investigated the three variants to determine the relative evolutionary distance of the spike protein gene (S gene) from the Wuhan, Omicron BA.1, and Omicron BA.4/5 variants.

Results

The results indicated that Omicron BQ.1. had a highest binding affinity but had the shortest evolutionary distance from BA.4/5. The XBB variant had a lower binding affinity and long evolutionary distances from all the three variants. However, the XBB.1.5 variant had the highest binding affinity of the spike protein with ACE2 and the longest evolutionary distance of the S gene.

Conclusion

This result suggested that in silico binding affinity of the spike protein with ACE2 and the relative evolutionary distance of S gene may be potential factors for the risk of SARS-CoV-2 variants based on the comparison of infectivity of BQ.1, XBB, and XBB.1.5.

After the first introduction of African swine fever (ASF) in the European Union in 2014, the ASF virus (ASFV) has steadily spread in the European Union. The virus has occasionally been transmitted over unexpectedly large distances that are believed to be related to human-mediated spread. Hunting tourism has been mentioned as a potential contributor to these long-distance jumps, although evidence is lacking. In this study, the possible role of hunters carrying ASFV-contaminated wild boar products (WBP) from hunting trips in affected countries was evaluated. A quantitative risk model was developed to estimate the expected annual number of ASF exposures of wild boar and domestic pigs in the Netherlands via this introduction route. Main input data into the model were the ASF prevalence in hunted wild boar, the number and destination of hunting trips of Dutch hunters, and the probabilities that hunters take WBP home and dispose leftovers such that wild boar or domestic pigs have access. The model indicated that the total expected annual number of exposures (wild boar and domestic pigs together) in the Netherlands is 0.048 (95% uncertainty interval 7.5 × 10⁻³ – 0.15). Model results were most sensitive to uncertainty on leftovers fed to domestic pigs (swill feeding), which is an illegal practice. Uncertainties on the ASF prevalence of hunted wild boar and the probabilities that hunters take WBP home also impacted model results. Default model results were based on the 2019 situation. Alternative scenarios were run with the model to account for the change of ASF status of Belgium (recovery of ASF-free status) and Germany (ASF-infected) in 2020. Results indicated that especially the presence of ASF in Germany increased the incursion risk. However, this increase might be counteracted by a change in travel behavior of hunters.

Background

We aimed to determine risk factors associated with rates of contaminated blood cultures in the emergency department (ED).

Methods

This single-center, cohort study of 1098 consecutive patients ≥ 20 years of age was performed in the ED of university hospital over a 26-month period.

Results

We analyzed 2096 pairs of blood cultures. Potential contamination was identified in 172 (8.2%) of the 2096 pairs of blood cultures. Multivariate analysis revealed more frequent contamination when puncture sites were disinfected with povidone-iodine (PVI) than with alcohol/chlorhexidine gluconate (adjusted odds ratio, 7.13; 95% confidence interval [CI], 4.8–10.7; P < 0.001). Femoral and central venous catheters showed more frequent contamination than peripheral venous sites. Blood collection by first- or second-year residents did not show an increase in contaminated blood cultures.

Conclusions

Rates of contaminated blood cultures were significantly associated with PVI and specific sites, but were not significantly associated with blood collection by residents.

From the perspectives of molecular biology, genetics and biothermodynamics, SARS-CoV-2 is the among the best characterized viruses. Research on SARS-CoV-2 has shed a new light onto driving forces and molecular mechanisms of viral evolution. This paper reports results on empirical formulas, biosynthesis reactions and thermodynamic properties of biosynthesis (multiplication) for the Zeta P.2, Eta B.1.525, Theta P.3, Kappa B.1.617.1, Iota B.1.526, Lambda C.37 and Mu B.1.621 variants of SARS-CoV-2. Thermodynamic analysis has shown that the physical driving forces for evolution of SARS-CoV-2 are Gibbs energy of biosynthesis and Gibbs energy of binding. The driving forces have led SARS-CoV-2 through the evolution process from the original Hu-1 to the newest variants in accordance with the expectations of the evolution theory.

SARS-CoV-2 has during the last 3 years mutated several dozen times. Most mutations in the newly formed variants have been chemically and thermodynamically characterized. New variants have been declared as variants under monitoring. The European Centre for Disease Prevention and Control has suggested the hypothesis that the new BN.1, CH.1.1 and XBC variants could have properties similar to those of VOC. Thermodynamic properties of new variants have been reported in this manuscript for the first time. Gibbs energy of biosynthesis, as the driving force for viral multiplication, is less negative for the new variants than for the earlier variants. This indicates that the virus has evolved towards decrease in pathogenicity, which leads to less severe forms of COVID-19.

Wastewater treatment is essential for preventing infectious diseases and water pollution. To perform this process, workers operate and maintain wastewater treatment plants (WWTPs); thus, they are exposed to the many pathogens in domestic wastewater. Consequently, it is necessary assess occupational exposure to pathogens in WWTPs. Quantitative microbial risk assessment (QMRA) is an approach for estimating the risk posed by a specific pathogen which can be useful for occupational hygiene assessments of biological risk. In this study, we applied QMRA, informed by occupational field surveillance, to estimate the potential risk for WWTP workers. Furthermore, we used simulations to test additional control strategies such as personal protective equipment (PPE). The QMRA was conducted for three WWTPs in Costa Rica with data collected between May 2020 and May 2021. Observation in each workplace showed a need for more consistent application of risk reduction strategies in the work environment, especially in behavior, infrastructure, and use of appropriate PPE. Cryptosporidium sp., Giardia sp., norovirus, and enterovirus genus were measured and detected in the WWTPs, and the treatment performance was unsatisfactory. As a result, the total health disease burden was higher than the benchmark for drinking water recommended by WHO (1.00 × 10⁻⁶ DALY per person per year) by between one and three magnitudes orders in all WWTPs for the three exposure scenarios (operation, maintenance, and visitors). The simulation demonstrated that using PPE could reduce the estimated disease burden by nearly two orders of magnitude. Still, this control measure did not reach a level below the benchmark risk (less than 1.00 × 10⁻⁶ DALY per person per year) for the WWTP workers. This study highlights the importance of using PPE with other control measures, such as automation or barriers, to isolate exposure sources. However, this study employed an uncommon approach in occupational health and hygiene, which combined field inspections, survival analysis, and QMRA, using field surveillance to understand the occupational environment and potential exposure routes, which is crucial for hazard identification and risk assessment. In addition, exposure modeling and QMRA were used to simulate different control scenarios, providing a robust estimate of potential risks associated with occupational exposure.

Background

Few studies have examined the outcomes and predisposing risk factors for anaerobic bloodstream infections (BSIs).

Objective

To determine the survival impact of aerobic versus anaerobic BSI, a prospective cohort study was conducted.

Methods

We prospectively enrolled emergency department patients at a tertiary medical center with BSIs determined by laboratory testing between 2015 and 2016. Anaerobic and aerobic BSIs were compared for demographics, comorbidities, and sources of infection. Several independent risk factors were identified in a multivariable logistic regression model. Using propensity score (PS) matched data, an analysis of survival effects associated with anaerobic BSI has been conducted.

Results

Over a 2-year period, there were 1,166 episodes of BSI, of which 61 (5.2%) occurred as anaerobic episodes. Anaerobic BSIs were strongly associated with intra-abdominal infection (odds ratio [OR] 6.03, 95%CI 2.78–13.09), liver abscess (OR 3.92, 95%CI 1.47–10.45), skin and soft-tissue infection (OR 2.65, 95%CI 1.26–5.62), and metastatic cancer (OR 2.40, 95%CI 1.13–5.08) as the main positive predictors. Negative predictors included diabetes mellitus (OR 0.38, 95%CI 0.18–0.78), thrombocytopenia (OR 0.33, 95%CI 0.18–0.60), and urinary tract infection (OR 0.15, 95%CI 0.04–0.62). Anaerobic BSIs were not associated with worse prognosis after PS-matched analysis (hazard ratio [HR] 1.40, 95%CI 0.44–4.41) in our cohort.

Conclusions

A significant percentage of community-onset BSI was due to anaerobic BSI. Anaerobic BSI can have a detrimental outcome if there are underlying comorbidities, high-risk infection sites, and inappropriate antibiotic choices. The findings of our study may contribute to the prescription of empiric anti-anaerobe antibiotics.

The consumer demand for raw milk from dairy cows has increased and local sales via vending machines have been intensified. Therefore, this study aimed to assess the risk associated with the consumption of unboiled raw milk contaminated with Campylobacter by estimating the number of campylobacteriosis cases. For this a stochastic quantitative microbial risk assessment (QMRA) model was developed that covered the whole supply chain. Information and data for model parametrization were obtained from research publications. Different probability distributions were used to represent the data whenever possible and probabilistic risk estimation was performed using Monte Carlo simulations. Simulations for outbreaks from single vending machines were performed using the developed QMRA baseline model. Further, different risk mitigation scenarios along the supply chain were evaluated to support risk managers in controlling Campylobacter. The analysis suggest a role for Campylobacter infections due to fecal contamination of cows’ udder. The model can easily be adapted and extended when additional data become available as it is provides in the harmonized exchange Food Safety Knowledge Exchange (FSKX) format.