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ObjectiveTo investigate the serotype distribution and antimicrobial resistance characteristics of Salmonella isolated from retail chicken in Beijing City.MethodsA total of 135 Salmonella strains were isolated from retail chicken meat collected from three large wholesale markets in Fengtai District in Beijing City from 2014 to 2015. The serotype of these Salmonella strains was identified using both a Luminex serotyping kit and a traditional serum agglutination method. Multilocus sequence typing was performed according to the recommended conditions of the Enterobase database. Antimicrobial susceptibility testing plates were used to determine the susceptibility of the isolates against 12 classes of drugs representing 25 antimicrobial agents. PCR was used to detect the prevalence of the 10 mobile colistin resistance genes （mcr） and three NDM-type carbapenemases genes （blaNDM）.ResultsAmong the 135 Salmonella strains， 6 serogroups were detected， with D1 and B being the main serogroups； 20 serotypes were detected， in which Enteritidis， Indiana， and Thompson were the dominant ones with percentages of 50.4%， 15.6%， and 8.1%， respectively； 21 ST types were obtained， and a good correspondence was observed between serotypes and ST types. 91.9% of all tested isolates showed resistance to the tested drugs and showed the highest resistance to nalidixic acid， ampicillin， ampicillin-sulbactam， tetracycline. Multi-drug resistant strains accounted for 71.1% of all strains and were resistant to as many as 18 kinds of antimicrobial compounds belonging to 10 categories. Among the 17 strains co-resistant to 8 or more classes of drugs， 16 were of the Indiana serotype. The proportion of strains with high multi-drug resistance was different in different packaging methods， different seasons， and different wholesale markets. All strains were negative for the mcr and blaNDM genes.ConclusionThe serotypes of Salmonella isolates from chicken meat in wholesale markets in Beijing City from 2014 to 2015 were complex， with the dominant serotype of Salmonella Enterititis， and the overall antimicrobial resistance level of all isolates was high. To assess the possible food safety risks， continuous monitoring for Salmonella Indiana with high levels of antimicrobial resistance must be carried out and their drug resistance and transmission mechanisms must be studied to help develop first-line and ultimate drugs for clinical treatment of Salmonella diseases.

The microbial control in broiler chicken slaughtering and processing is essential in ensuring food safety and human health. Scalding， washing， and cooling are crucial stages for controlling microbial contamination during broiler chicken processing， and a combined use of multiple measures can effectively reduce microbial load on broiler chicken carcasses. Among these antimicrobial agents， sodium hypochlorite， cetylpyridinium chloride， and acidified sodium chlorite are effective in reducing contamination by pathogens such as Salmonella， Escherichia coli， and Campylobacter on broiler chicken carcasses. However， the effectiveness of reducing microbes depends on the stages of microbial control and the amount and duration of antimicrobial agent application. This article provides an overview of the control measures for microbial contamination at various stages of broiler chicken slaughtering and processing. Additionally， this study systematically elucidates the microbial reduction effects of various antimicrobial agents in these process stages. This review aims to provide data references for preventing and controlling microbial contamination during broiler chicken slaughtering and processing in domestic industries， thereby promoting the healthy development of the broiler production industry and safeguarding consumer health.

The lithology and hardness of the coal seam roof are directly related to the stability and water permeability of the roadway and the safe production of the coal mine. It has become a common method to predict gas content based on AVO inversion, but the conventional AVO inversion formula is a simplified approximation of Zoeppritz equation in different degrees under certain conditions, which affects the inversion accuracy to some extent. On the basis of petrophysical analysis of the roof, the pre-stack inversion of quasi-linear Zoeppritz equation with the smallest overall angle error was employed to lithology and hardness prediction of coal seam roof in Yangquan Mining Area, Shanxi Province. The results show that the expression of quasi-linear Zoeppritz equation is simple, and through the AVO characteristic analysis of different Zoeppritz approximate formulas, found that the precision of quasi-linear Zoeppritz equation is the highest, second only to that of accurate Zoeppritz equation. The analysis of rock mechanics characteristics shows that Young’s modulus multiplied by density is the most sensitive to hardness, and pseudo-gamma P-wave velocity can effectively reflect roof lithology. The lithology and hardness characterization parameters obtained from inversion are combined with the parameter well data and geological data to comprehensively evaluate the roof stability, provide geological evidence for roadway excavation and reduce the coal mine production risk.

ObjectiveA dual real-time polymerase chain reaction (PCR) method for simultaneous detection of two virulence genes tdh and trh of Vibrio parahaemolyticus was established, and the virulence genes carried by 2 771 strains of foodborne Vibrio parahaemolyticus in China were comprehensively detected.MethodsAccording to the tdh and trh virulence genes of Vibrio parahaemolyticus, PCR primers and fluorescent probes were designed respectively, the real-time PCR reaction system and reaction procedure were optimized, and a dual real-time PCR detection method which can detect the two virulence genes at the same time was established. The virulence genes carried by 2 771 strains of foodborne Vibrio parahaemolyticus isolated in 2015 and 2016 were detected by the established method, and compared with the result of PCR method to evaluate the sensitivity, accuracy and specificity of the method.ResultsThe established dual fluorescence PCR method could detect both tdh and trh virulence genes at the same time, and its sensitivity was 1.5×10-4 ng/μL. The accuracy and specificity were 100%. In 2015, the carrying rates of tdh and trh genes in foodborne Vibrio parahaemolyticus in China were 0.26% (3/1 137) and 1.67%(19/1 137) respectively, and were 0.24%(4/1 634) and 0.43%(7/1 634) in 2016 respectively.ConclusionIn this study, a dual real-time PCR method for simultaneous detection of tdh and trh virulence genes of Vibrio parahaemolyticus was established, which could quickly and accurately screen the virulence genes of Vibrio parahaemolyticus. The carrying rate of tdh and trh virulence genes of Vibrio parahaemolyticus isolated from food in China was low. The dual real-time PCR method can be applied to the study of the pathogenicity of Vibrio parahaemolyticus in food, and provide scientific data for the risk assessment of dietary exposure to Vibrio parahaemolyticus in China.

ObjectiveWhole genome sequencing and analysis was conducted on a Burkholderia gladiolus pv. cocovenenans strain, isolated from raw corn flour sample which caused family agglutinative bongkrekic acid poisoning. The genetic characteristics of its virulence and pathogenicity were analyzed as well.MethodsGenomic DNA was extracted from DBJ isolate, the whole genome sequencing was carried out. Bioinformatics method were used to mine and analyze the data obtained from sequencing.ResultsTwo independent chromosomes (G1 and G2) and one plasmid (P) were found in DBJ isolate. The lengths of the chromosomes and plasmid were about 4 Mb and 300 kb respectively. The GC content of the two chromosomes was both around 68.0%, and that of the plasmid was slightly lower at 63.0%. The bon gene cluster was found on chromosome G2. The phylogenetic analysis showed that DBJ isolate and UCD-UG_CHAPALOTE stain which was isolated from corn sample in Canada were in the same clade. Among 255 strains, 31 carrying bon gene cluster and they had obvious genetic evolutionary tendency.ConclusionThe bon gene cluster was located on the chromosome of Burkholderia gladiolus pv. cocovenenans DBJ, and it was the main pathogenic gene causing food poisoning in human.

Objective Campylobacter species are the main causes of foodborne illness worldwide, posing significant threats to public health. This study aimed to investigate the antibiotic resistance and genomic characterization of C. jejuni/C.coli from retail chickens in Beijing. Methods Antimicrobial susceptibility testing was conducted on 126 C. jejuni/C. coli isolated from retail chickens in Beijing, following CLSI protocols. Whole genomes of all isolates were sequenced using the Illumina platform. Results More C. coli (83.82%) showed multi-drug resistance than C. jejuni (8.62%). Genomic analysis demonstrated 42 sequence types (STs) and 12 clonal complexes (CCs), from which CC828 and CC52 were dominant. cdtA, cdtB and cdtC encoding cytotoxic protein were present spontaneously in most C. jejuni but not found in any C. coli isolates. The abundances of antibiotic resistance genes (ARGs) and virulence genes (VGs) in C. jejuni and C. coli were significantly different, with ARGs numbered in C. coli and VGs in C. jejuni. Conclusions High prevalence of multi-drug resistance C. coli and C. jejuni isolated from Beijing chickens were challenging clinical antibiotic usages in the treatment of Campylobacter infection. The surveillance of particular C. jejuni and C. coli STs correlated with higher resistance and virulence needs to be strengthened in the future. [ABSTRACT FROM AUTHOR]

Burkholderia gladioli pv. cocovenenans (B. cocovenenans) and its lethal toxin, bongkrekic acid (BA), have been causing frequent incidents of food poisoning in China, resulting in increased attention. The toxin is produced by B. cocovenenans under appropriate temperature and humidity, and mainly targets the inner mitochondrial membrane to cause toxic effects. At present, there are methods available for detecting BA, but the detoxification mechanism is not perfect. This review summarizes the naming process, biological characteristics, toxin production conditions, and sources of B. cocovenenans, as well as the physical and chemical properties, poisoning mechanism, clinical presentation, detection methods, and detoxification of BA. Additionally, the review provides recommendations for preventing bongkrekic acid poisoning. [ABSTRACT FROM AUTHOR]

Intestinal injuries caused by ionizing radiation (IR) are a major complication of radiotherapy. Ferrostatin-1 (Fer-1) exerts antioxidant and anti-inflammatory effects. We investigated the influence of Fer-1 on IR-induced intestinal damage and explored the possible mechanisms. IEC-6 cells were administrated with Fer-1 for 30 min and subsequently subjected to 9.0 Gy-irradiation. Flow cytometry, qPCR, and WB were used to detect changes. For in vivo experiments, Fer-1 was given intraperitoneally to mice at 1 h before and 24 h after 9.0 Gy total body irradiation (TBI) respectively. Three days after TBI, the small intestines were isolated for analysis. The diversity and composition of the gut microbiota were analyzed by 16S rRNA gene sequencing. In vitro, Fer-1 protected IEC-6 cells from IR injury by reducing the production of ROS and inhibiting both ferroptosis and apoptosis. In vivo, Fer-1 enhanced the survival rates of mice subjected to lethal doses of IR and restored intestinal structure and physiological function. Further investigation showed that Fer-1 protected IEC-6 cells and mice by inhibiting the p53-mediated apoptosis signaling pathway and restoring the gut-microbe balance. This study confirms that Fer-1 protects intestinal injuries through suppressing apoptosis and ferroptosis. [ABSTRACT FROM AUTHOR]

Objective: Non-typhoidal Salmonella (NTS) is a major cause of human salmonellosis globally. Food animals are major NTS reservoirs. An increase in antimicrobial resistance (AMR) in foodborne NTS has led to clinical treatment failures. Here, to examine the prevalence and perform characterization of foodborne NTS with AMR in China, we tested the antimicrobial susceptibility of 1,256 NTS isolates cultured from retail foods in 2020 in China. Methods: The antimicrobial susceptibility of 26 antimicrobial agents representing 12 classes was evaluated with the broth-microdilution method; the presence of ten mcr genes was screened with multi-PCR. The complete closed genomes of mcr-gene-carrying isolates were generated by hybrid assembly through whole genome sequencing on both the PacBio and Illumina platforms. Genomic features and genetic environments of the mcr-1 gene were analysed. Results: The overall drug resistance rate was 92.28%, and the multi-drug resistance (MDR) rate was 76.53%. A total of 341 AMR profiles were determined, and resistance was highest to nalidixic acid (63.38%). Among 887 NTS isolates with MDR, 232 showed co-resistance to cefotaxime and ciprofloxacin, and 25 were resistant to ten classes of antimicrobial agents. The resistance of NTS isolated from different regions varied. Isolates from raw chicken sources most frequently showed resistance. Four NTS carried the mcr-1 gene and represented four different serotypes. Four mcr-1 gene-bearing plasmids from the four Salmonella isolates were classified into two replicon types (IncI2 and IncHI2A). Two mcr-1 genes in IncI2 type plasmids were found to be located between a PAP2 family protein-encoding gene and a relaxaseencoding gene, whereas the other two mcr-1 gene structures in IncHI2A type plasmids showed variations in the presence of insertion sequences. Conclusion: Our data demonstrated severe AMR among foodborne NTS isolated from food in China, thus highlighting the importance of antimicrobial susceptibility surveillance to decrease the spread of AMR, particularly to critical drugs in human medicine. [ABSTRACT FROM AUTHOR]