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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]

Sharing of genetic elements among different pathogens and commensals inhabiting same hosts and environments has significant implications for antimicrobial resistance (AMR), especially in settings with high antimicrobial exposure. We analysed 661 Escherichia coli and Salmonella enterica isolates collected within and across hosts and environments, in 10 Chinese chicken farms over 2.5 years using data-mining methods. Most isolates within same hosts possessed the same clinically relevant AMR-carrying mobile genetic elements (plasmids: 70.6%, transposons: 78%), which also showed recent common evolution. Supervised machine learning classifiers revealed known and novel AMR-associated mutations and genes underlying resistance to 28 antimicrobials, primarily associated with resistance in E. coli and susceptibility in S. enterica. Many were essential and affected same metabolic processes in both species, albeit with varying degrees of phylogenetic penetration. Multi-modal strategies are crucial to investigate the interplay of mobilome, resistance and metabolism in cohabiting bacteria, especially in ecological settings where community-driven resistance selection occurs. Bacteria in the same environment can share genetic material but the extent to which this influences development of antimicrobial resistance is unclear. Here, the authors investigate the evidence for co-evolution of antimicrobial resistance in bacteria found coexisting in animals and the environment in chicken farms and slaughterhouses in China. [ABSTRACT FROM AUTHOR]

Objective: The objective of the present study was to determine the prevalence, antimicrobial resistance, virulence profiles, and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) obtained from ready-to-eat (RTE) foods in China. Methods: Two hundred seventy-six RTE food-associated S. aureus isolates were collected from 25 provinces across China in 2018, then characterized by antimicrobial susceptibility testing, virulence factors detecting, multilocus sequence typing (MLST), spa typing, SCCmec typing and pulsed-field gel electrophoresis (PFGE). Results: Two hundred fifty isolates (90.6%) were resistant to at least one antimicrobial agent; 73 (26.4%) isolates were multi-drug resistant (MDR). Thirty MRSA isolates were identified, among which nine toxin genes (sea, seb, sec, sed, seh, selk, sell, selq, and tsst-1) were detected. Sixty percent (18/30) of the MRSA isolates harbored multiple toxin genes. Four virulence gene patterns were identified, with seb-selk-selq (30/30) being the most common pattern. Thirteen sequence types, as well as 13 spa and 4 SCCmec types were found among 30 MRSA isolates. The most prevalent MRSA lineages were CC59-t437-SCCmecIV/V (23.3% [7/30]), CC398-t011-SCCmecV (23.3% [7/30]), and CC1-t114-SCCmecIV (16.7% [5/30]). Conclusions: Our findings highlight the importance for the identification of prevalent clones, assessment of drug-resistance and virulence, and formulation of food safety measures for public health. [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]

The mcr-1 gene mediating mobile colistin resistance in Escherichia coli was first reported in China in 2016 followed by reports among different species worldwide, especially in E. coli and Klebsiella. However, data on its transmission in Salmonella are still lacking. This study analyzed the antimicrobial resistance (AMR) profiles and the mcr-1 gene presence in 755 foodborne Salmonella from 26 provinces of mainland, China in 2016. Genomic features of two mcr-1- carrying isolates, genome sequencing, serotypes and further resistance profiles were studied. Among the 755 Salmonella tested, 72.6% were found to be resistant to at least one antimicrobial agent and 10% were defined as multi-drug resistant (MDR). Salmonella Derby CFSA231 and Salmonella Typhimurium CFSA629 were mcr-1 -harboring isolates. Both expressed an MDR phenotype and included a single circular chromosome and one plasmid. Among the 22 AMR genes identified in S. Derby CFSA231, only the mcr-1 gene was localized on the IncX4 type plasmid pCFSA231 while 20 chromosomal AMR genes, including four plasmid-mediated quinolone resistance (PMQR) genes, were mapped within a 64 kb Salmonella genomic island (SGI) like region. S. Typhimurium CFSA629 possessed 11 resistance genes including an mcr-1.19 variant and two ESBL genes. Two IS 26 -flanked composite-like transposons were identified. Additionally, 153 and 152 virulence factors were separately identified in these two isolates with secretion system and fimbrial adherence determinants as the dominant virulence classes. Our study extends our concern on mcr-1 -carrying Salmonella in regards to antimicrobial resistance and virulence factors, and highlight the importance of surveillance to mitigate dissemination of mcr -encoding genes among foodborne Salmonella. [ABSTRACT FROM AUTHOR]

Purpose: The present study aims to validate possible stage migration of lymph node metastasis related to the insufficient examined lymph node (ELN) count in pN3a gastric cancer (GC) patients. Methods: 1976 pN3 patients who underwent the R0 surgery in three high-capacity institutions in China were enrolled to explore the stage migration of nodal involvement, and 3146 pN3 cases from the Surveillance, Epidemiology, and End Results (SEER) Program Registry were used as an external validation cohort. Results: After the propensity score matching of the Chinese cohort, the ELN count, as an independent predictor for GC outcome, was confirmed to be associated with the stage migration of lymph node metastasis in pN3a patients based on the univariate and multivariate survival analyses. Logistic regress was adopted to elucidate that the ELN count was an independent factor related to the long-term survival status of GC patients after curative surgery. Likelihood ratio test showed that the ELN count had the smallest Bayesian information criterion value among the clinicopathologic variables, corresponding to an efficient model to predict outcomes. Subsequently, stage migration of lymph node metastasis was predominantly detected in pN3a patient sub-group with insufficient (less than 16) ELN count, who presented with similar prognosis as the pN3b patients (P = 0.463) as per the stratum analysis with Kaplan–Meier. These methods were further validated using data from the SEER cohort, and the similar promising results were obtained. Conclusion: pN3a patients with insufficient ELN count should be considered as pN3b cases to achieve accurate prognostic evaluation after curative gastrectomy. [ABSTRACT FROM AUTHOR]

Prevalent in marine, estuarine and coastal environments, Vibrio parahaemolyticus is one of the major foodborne pathogens which can cause acute gastroenteritis through consumption of contaminated food. This study encompassed antimicrobial resistance, molecular characteristics and phylogenetic relationships of 163 V. parahaemolyticus isolated from aquatic foods across 15 provinces in China. The isolates showed high resistance rates against ampicillin (90.80 %, 148/163) and cefazolin (72.39 %, 118/163). Only 5 isolates demonstrated multi-drug resistance (MDR) phenotypes. A total of 37 different antibiotic resistance genes (ARGs) in correlation with seven antimicrobial categories were identified. tet (34) and tet (35) were present in all 163 isolates. Other most prevalent ARGs were those conferring resistance to β-lactams, with prevalence rate around 18.40 % (30/163). The virulence genes tdh and trh were found in 17 (10.43 %) and 9 (5.52 %) isolates, respectively. Totally 121 sequence types (STs) were identified through whole genome analysis, among which 60 were novel. The most prevalent sequence type was ST3 (9.20 %, 15/163), which shared the same genotype profile of trh _ , tdh + and bla CARB-22 +. Most of the tdh + V. parahaemolyticus isolates was clustered into a distinctive clade by the phylogenetic analysis. Our study showed that the antimicrobial resistance of V. parahaemolyticus in aquatic foods in China was moderate. However, the emerging of MDR isolates implicate strengthened monitoring is needed for the better treatment of human V. parahaemolyticus infections. High genetic diversity and virulence potential of the isolates analyzed in this study help better understanding and evaluating the risk of V. parahaemolyticus posed to public health. • MDR V. parahaemolyticus isolates appeared in a specific region of China. • One trh + MDR V. parahaemolyticus was found. • The most prevalent sequence type ST3 all harbored tdh and bla CARB. • The majority of the tdh + isolates were clustered into a distinctive clade. [ABSTRACT FROM AUTHOR]

Shiga toxin-producing Escherichia coli (STEC) O157 is an important foodborne pathogen. The aims of this study were to determine genetic relatedness of STEC O157 isolated from foods in China. STEC O157 isolates from food were characterized by virulence gene typing, antibiotyping, Multi-locus sequence typing (MLST), pulsed-field gel electrophoresis analysis (PFGE), Multi-locus variable number tandem repeat analysis (MLVA), and the single nucleotide polymorphism (SNP) clade typing. Of the 30 STEC O157 isolates analyzed, all isolates harbored eae , exhA , stx1 and/or stx2 genes with stx2c subtype predominating. By MLST, they were relatively homogenous with only 4 STs. PFGE and MLVA generated 22 pulsotyples and 23 patterns, respectively, which showed considerable diversity. Only one clade 8 isolate was detected. These results indicate that STEC O157 isolates from foods in China were heterogeneous. There was no correlation between genotypic characteristics and sources of isolates. Since different subtyping methods often give different discriminatory powers, the use of more than one subtyping approach is necessary in providing a more accurate picture of the genetic diversity of STEC O157. Four isolates were from ready-to-eat meat or salads, underscores the risk of infections. There is a need for surveillance of STEC O157 in foods and clinically and implementation of prevention strategies to prevent outbreaks of STEC O157 infections in China. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to characterize the genomic features of a Salmonella enterica serovar Typhimurium ST34 isolate, CFSA629, which carried a novel mcr-1 variant, designated as mcr-1.19, mapped to an ESBL-encoding IncHI2 plasmid., Methods: Antimicrobial susceptibility assays as well as WGS were carried out on isolate CFSA629. The complete closed genome was obtained and then explored to obtain genomic features. Plasmid sequence comparison was performed for pCFSA629 with similar plasmids and the mcr-1 genetic environment was analysed., Results: S. Typhimurium ST34 CFSA629 expressed an MDR phenotype to six classes of compound and consisted of a single circular chromosome and one plasmid. It possessed 11 resistance genes including 2 ESBL genes that mapped to the chromosome and the plasmid; an IS26-flanked composite-like transposon was identified. A novel mcr-1 variant (mcr-1.19) was identified, which had a unique SNP (G1534A) that gave rise to a novel MCR-1 protein containing a Val512Ile amino acid substitution. Plasmid pCFSA629 possessed a conjugative plasmid transfer gene cluster as well as an antimicrobial resistance-encoding gene cluster-containing region that contained two IS26 composite-like transposonal modules, but was devoid of any plasmid-mediated quinolone resistance genes. The background of mcr-1.19 consisted of an ISApl1-mcr-1-PAP2-ter module., Conclusions: We report on an MDR S. Typhimurium ST34 CFSA629 isolate cultured from egg in China, harbouring an mcr-1.19 variant mapped to an IncHI2 plasmid. This highlights the importance of surveillance to mitigate dissemination of mcr-encoding genes among foodborne Salmonella. Improved surveillance is important for tackling the dissemination of mcr genes among foodborne Salmonella around the world., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: Our aim was to determine the antimicrobial susceptibilities of 2862 Listeria monocytogenes cultured from various foods in China and to use WGS to characterize the antimicrobial resistance and virulence genotypes of those expressing a resistance phenotype., Methods: The susceptibilities of 2862 L. monocytogenes were determined by broth microdilution. Twenty-eight L. monocytogenes were found to be resistant to one to four antibiotics. All 28 resistant isolates were subsequently sequenced using short-read high accuracy protocols. The corresponding genomes were assembled and further analysis was carried out using appropriate bioinformatics pipelines., Results: All 28 resistant L. monocytogenes were classified into five STs (ST3, ST8, ST9, ST155 and ST515). Both ST9 and ST155 were dominant and their genotypes correlated with their resistance phenotypes. All ST9 isolates were MDR and could be phylogenetically classified into two clusters. One was relatively close to clinical origins and one to food. Downstream analysis of the genetic contexts in which these resistance genotypes were found suggested that these may have been acquired from other bacteria by horizontal transfer or insertion into the chromosome. All isolates harboured Listeria pathogenicity island (LIPI)-1 and LIPI-2, and only two harboured LIPI-3., Conclusions: This study reported on the antimicrobial susceptibilities of 2862 foodborne L. monocytogenes along with the genomic characterization of 28 resistant isolates, 11 of which expressed an MDR phenotype. These data showed that this bacterium can acquire resistance by horizontal gene transfer in and between species. This study may necessitate a re-evaluation of risk to public health, associated with this bacterial species., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To carry out isolation and the viable plate count of probiotics from yoghourt. To investigate the antimicrobial susceptibility of strains to penicillin, gentamicin, ampicillin, vancomycin, clindamycin and erythromycin., Methods: Probiotics were recovered and counted from yoghourt by plate count method. The recovered isolates were characterized by Gram's stain, biochemical test, antimicrobial susceptibility test., Results: MRS medium and (36 +/- 1) degrees C were the optimum condition of culture. In total, 52 probiotic isolates were recovered from 31 yoghourt products, 12 (38.7%) products showed a lower probiotic quantity than 1 x 10(6) cfu/ml of the national stantard, and 19 (61.3%) products were higher than 1 x 10(6) cfu/ml. Gram's stain showed that 37 isolates were gram positive bacilli and 15 isolates were positive coccus. These 52 isolates were grouped into six species by biochemical method, including L. bulgaricus, S. thermophilus, L. acidophilus, L. casei, L. delbrueckii and L. fermentum. All 52 isolates were susceptible to penicillin and ampicillin, one isolate was resistant to both clindamycin and erythromycin, four isolates were resistant to vancomycin., Conclusion: Most of yoghourt products contained sufficient viable probiotics as required by the national standard. A small quantity of isolates were resistant to some antimicrobials and multi -drug resistant isolates were also found.