Epidemiological Evaluation of Bacillus cereus-Induced Foodborne Outbreaks - China, 2010-2020.

Introduction: Bacillus cereus (B. cereus) is a common gram-positive bacterium that contaminates starch-rich food and can cause outbreaks of foodborne diseases. This study describes the characteristics of outbreaks caused by B. cereus in China during 2010-2020 and explore the possible reasons for changes in the number of outbreaks over time. Results of this analysis can efficiently help guide and allocate public resources to prevent B. cereus-caused foodborne diseases. Methods: Descriptive statistical methods were used to analyze the data on B. cereus outbreaks in China during this period. The data were identified and reported at all levels in China through National Foodborne Disease Outbreak Surveillance System. Results: From 2010 to 2020, a total of 419 foodborne outbreaks prompted by B. cereus were reported in China, leading to 7,892 cases, 2,786 hospital admissions, and 5 fatalities. The bulk of the outbreaks were recorded in the summer, primarily between May and September. The most recurrent food vehicle was linked with rice or flour-based products, notably those made with rice or fried rice. School canteens bore the brunt of the B. cereus outbreaks. In multifactor outbreaks, food contamination was identified as the most common culprit; while in instances where only one factor contributed, improper storage was most frequently implicated. Conclusion: The prevalence of B. cereus outbreaks remained relatively consistent throughout the studied period. Understanding the types of foods, causative factors, and contributing elements leading to B. cereus outbreaks can help inform prevention strategies for foodborne illnesses. The majority of outbreaks were associated with rice- or flour-based foods in school canteens, suggesting contamination and improper storage during food preparation. Consequently, it is essential to prioritize continuous education for canteen staff on food safety, efficacious management, and proper practices. The implementation of comprehensive guidelines, encompassing multiple critical aspects, can potentially reduce the occurrence of B. cereus outbreaks.

Epidemiological Features of Foodborne Disease Outbreaks in Catering Service Facilities - China, 2010-2020.

Introduction: In terms of food preparation settings, catering service facilities have been identified as locations with the highest incidence of foodborne disease outbreaks in China. Since 2010, the China National Center for Food Safety Risk Assessment has established the Foodborne Disease Outbreak Surveillance System (FDOSS) to monitor foodborne disease outbreaks. Consequently, data from the FDOSS has provided a more accurate depiction of the epidemic characteristics of outbreaks within these facilities. Methods: From 2010 to 2020, the FDOSS gathered data related to the prevalence of outbreaks, cases, hospitalizations, and deaths linked to foodborne disease outbreaks in catering service facilities. This study examined the temporal and geographical distribution, pathogenic factors, and contributing variables of these outbreaks over the course of the decade. Results: From 2010 to 2020, China's catering service facilities reported 18,331 outbreaks, which resulted in 206,718 illnesses, 68,561 hospitalizations, and 201 deaths. The second and third quarters of the year accounted for 76.12% of the outbreaks and 72.93% of the cases. The primary pathogenic factors were pathogenic organisms, which caused 4,883 (26.64%) outbreaks, 94,047 (45.50%) cases, 32,170 (46.92%) hospitalizations, and 21 (10.45%) deaths. There were 5,607 (30.59%) outbreaks in restaurants, 2,876 (15.69%) outbreaks from street vendors, and 2,560 (13.97%) outbreaks in employee canteens in China. Conclusions: The implementation of relevant control methods, including health education and promotion, is critical for addressing foodborne diseases in catering service facilities. Regular food safety training sessions for restaurant personnel and managers are essential to ensuring the effective management of these health risks.

Effectiveness of inactivated COVID-19 vaccines among older adults in Shanghai: retrospective cohort study.

We conducted a matched retrospective cohort study of two cohorts to estimate inactivated vaccine effectiveness (VE) and its comparative effectiveness of booster dose among older people in Shanghai. Cohort 1 consisted of a vaccinated group (≥1 dose) and an unvaccinated group (3,317,475 pairs), and cohort 2 consisted of a booster vaccinated group and a fully vaccinated group (2,084,721 pairs). The Kaplan-Meier method and Cox regression models were used to estimate risk and hazard ratios (HRs) study outcomes. For cohort 1, the overall estimated VEs of ≥1 dose of inactivated vaccine against SARS-CoV-2 infection, severe/critical Covid-19, and Covid-19 related death were 24.7% (95%CI 23.7%-25.7%), 86.6% (83.1%-89.4%), and 93.2% (88.0%-96.1%), respectively. Subset analysis showed that the booster vaccination provided greatest protection. For cohort 2, compared with full vaccination, relative VEs of booster dose against corresponding outcome were 16.3% (14.4%-17.9%), 60.5% (37.8%-74.9%), and 81.7% (17.5%-95.9%). Here we show, although under the scenario of persistent dynamic zero-Covid policy and non-pharmaceutical interventions, promoting high uptake of the full vaccination series and booster dose among older adults is critically important. Timely vaccination with the booster dose provided effective protection against Covid-19 outcomes.

Effectiveness of inactivated and Ad5-nCoV COVID-19 vaccines against SARS-CoV-2 Omicron BA. 2 variant infection, severe illness, and death.

BACKGROUND: Limited data are available on the effectiveness of inactivated and Ad5-nCoV COVID-19 vaccines in real-world use-especially against Omicron variants in SARS-CoV-2 infection-naïve population. METHODS: A matched case-control study was conducted among people aged ≥ 3 years between 2 December 2021 and 13 May 2022. Cases were SARS-CoV-2-infected individuals, individuals with severe/critical COVID-19, or COVID-19-related deaths. Controls were selected from consecutively test-negative individuals at the same time as cases were diagnosed and were exact-matched on year-of-age, gender, birthplace, illness onset date, and residential district in ratios of 1:1 with infected individuals and 4:1 with severe/critical COVID-19 and COVID-19-related death. Additionally, two subsets were constructed to analyze separate vaccine effectiveness (VE) of inactivated vaccines (subset 1) and Ad5-vectored vaccine (subset 2) against each of the three outcomes. RESULTS: Our study included 612,597 documented SARS-CoV-2 infections, among which 1485 progressed to severe or critical illness and 568 died. Administering COVID-19 vaccines provided limited protection against SARS-CoV-2 infection across all age groups (overall VE: 16.0%, 95% CI: 15.1-17.0%) but high protection against severe/critical illness (88.6%, 85.8-90.8%) and COVID-19-related death (91.6%, 86.8-94.6%). In subset 1, inactivated vaccine showed 16.3% (15.4-17.2%) effective against infection, 88.6% (85.8-90.9%) effective against severe/critical COVIID-19, and 91.7% (86.9-94.7%) against COVID-19 death. Booster vaccination with inactivated vaccines enhanced protection against severe COVID-19 (92.7%, 90.1-94.6%) and COVID-19 death (95.9%, 91.4-98.1%). Inactivated VE against infection began to wane 12 weeks after the last dose, but two and three doses sustained high protection levels (> 80%) against severe/critical illness and death, while subset 2 showed Ad5-vectored vaccine was 13.2% (10.9-15.5%) effective against infection and 77.9% (15.6-94.2%) effective against severe/critical COVIID-19. CONCLUSIONS: Our real-world study found high and durable two- and three-dose inactivated VE against Omicron-associated severe/critical illness and death across all age groups, but lower effectiveness against Omicron infection, which reinforces the critical importance of full-series vaccination and timely booster dose administration for all eligible individuals.

Variable selection from a feature representing protein sequences: a case of classification on bacterial type IV secreted effectors.

BACKGROUND: Classification of certain proteins with specific functions is momentous for biological research. Encoding approaches of protein sequences for feature extraction play an important role in protein classification. Many computational methods (namely classifiers) are used for classification on protein sequences according to various encoding approaches. Commonly, protein sequences keep certain labels corresponding to different categories of biological functions (e.g., bacterial type IV secreted effectors or not), which makes protein prediction a fantasy. As to protein prediction, a kernel set of protein sequences keeping certain labels certified by biological experiments should be existent in advance. However, it has been hardly ever seen in prevailing researches. Therefore, unsupervised learning rather than supervised learning (e.g. classification) should be considered. As to protein classification, various classifiers may help to evaluate the effectiveness of different encoding approaches. Besides, variable selection from an encoded feature representing protein sequences is an important issue that also needs to be considered. RESULTS: Focusing on the latter problem, we propose a new method for variable selection from an encoded feature representing protein sequences. Taking a benchmark dataset containing 1947 protein sequences as a case, experiments are made to identify bacterial type IV secreted effectors (T4SE) from protein sequences, which are composed of 399 T4SE and 1548 non-T4SE. Comparable and quantified results are obtained only using certain components of the encoded feature, i.e., position-specific scoring matix, and that indicates the effectiveness of our method. CONCLUSIONS: Certain variables other than an encoded feature they belong to do work for discrimination between different types of proteins. In addition, ensemble classifiers with an automatic assignment of different base classifiers do achieve a better classification result.

Simultaneous roxarsone photocatalytic degradation and arsenic adsorption removal by TiO2/FeOOH hybrid.

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid) is an extensively used organoarsenic feed additive. The effective removal of arsenic from roxarsone degradation before discharging is of great importance for controlling artificial arsenic pollution in aquatic environment. In this study, a bifunctional TiO2/ferrihydrite (TiO2/FeOOH) hybrid was synthesized by a hydrothermal method for the simultaneously photocatalytic degradation of roxarsone and adsorption removal of released arsenic. The analysis of the prepared TiO2/FeOOH by field-emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), Raman spectra, X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS) confirmed the successful formation of the hybrid of crystalline TiO2 and no crystalline FeOOH. TiO2/FeOOH hybrid had better adsorption capacity for As(V) than roxarsone. Compared to TiO2, the TiO2/FeOOH hybrid exhibited much superior UV-driven photocatalytic activities for roxarsone degradation. After 12 h irradiation, more than 96% of roxarsone was degraded by 1:1 TiO2/FeOOH hybrid, and the released As(V) was simultaneously removed from the solution. The residual As(V) concentration was lower than 0.02 mg L-1. The reusability test indicated that TiO2/FeOOH hybrid had excellent stability and reliability. The possible mechanism of roxarsone degradation and released inorganic arsenics removal by this hybrid was also proposed. These results clearly indicated that the TiO2/FeOOH hybrid could be used for the removal of roxarsone and its degradation product.

Adsorption and photocatalytic decomposition of roxarsone by TiO2 and its mechanism.

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid) has been widely used as organic arsenic additive in animal industry. In this study, the adsorption of roxarsone on TiO2 under dark conditions, the photocatalytic decomposition of roxarsone under UV/TiO2, and the possible photocatalytic pathway were investigated. At the initial concentration of 5-35 mg/L, the adsorption of roxarsone fitted well with the pseudo-second-order kinetics. The isotherms analysis showed that the Langmuir model was better than the Freundlich and Dubinin­Radushkevich models for describing the adsorption process. After 7 h of photocatalytic decomposition, a complete disappearance of roxarsone was achieved. The pH value has a significant effect on both adsorption and photocatalytic decomposition of roxarsone. The results of high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS) and gas chromatography-mass spectrometry (GC/MS) analyses proved the cleavage of the As-C bond during the photocatalytic decomposition process by TiO2 and the intermediates of the decomposition. Based on the results, a possible photocatalytic decomposition pathway was proposed.