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Pre-cut fresh fruits and vegetables are highly appealing to consumers for their convenience, however, as they are highly susceptible to microbial contamination in processing, the potential risks of foodborne illnesses to public health are not negligible. This study aimed to assess the prevalence, antibiotic susceptibility and molecular characteristics of major foodborne pathogens (Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella) isolated from fresh-cut fruits and vegetables in Beijing, China. 86 stains were isolated from 326 samples, with S. aureus being the highest prevalence (15.38 %), followed by E. coli (9.23 %) and L. monocytogenes (1.85 %), while no Salmonella was detected. The prevalence by type of food indicated that fruit trays and mixed vegetables were more susceptible to contamination by pathogens. 98 % of S. aureus were resistant to at least of one antibiotic, and showed a high resistance rate to benzylpenicillin (90 %) and oxacillin (48 %). Among 25 E. coli isolates, 57.67 % of which exhibited multi-drug resistance, with common resist to trimethoprim/sulfamethoxazole (66.67 %) and ampicillin (63.33 %). A total of 9 sequence types (STs) and 8 spa types were identified in 35 S. aureus isolates, with ST398-t34 being the predominant type (42.86 %). Additionally, analysis of 25 E. coli isolates demonstrated significant heterogeneity, characterized by 22 serotypes and 18 STs. Genomic analysis revealed that 5 and 44 distinct antibiotic resistance genes (ARGs) in S. aureus and E. coli, respectively. Seven quinolone resistance-determining regions (QRDRs) mutations were identified in E. coli isolates, of which GyrA (S83L) was the most frequently detected. All the S. aureus and E. coli isolates harbored virulence genes. ARGs in S. aureus and E. coli showed a significant positive correlation with plasmids. Furthermore, one L. monocytogenes isolate, which was ST101 and serogroupIIc from watermelon sample, harbored virulence genes (inlA and inlB) and LIPI-1 pathogenic islands (prfA, plcA, hly and actA), which posed potential risks for consumer's health. This study focused on the potential microbial risk of fresh-cut fruits and vegetables associated with foodborne diseases, improving the scientific understanding towards risk assessment related to ready-to-eat foods., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Anthropogenic environments such as those created by intensive farming of livestock, have been proposed to provide ideal selection pressure for the emergence of antimicrobial-resistant Escherichia coli bacteria and antimicrobial resistance genes (ARGs) and spread to humans. Here, we performed a longitudinal study in a large-scale commercial poultry farm in China, collecting E. coli isolates from both farm and slaughterhouse; targeting animals, carcasses, workers and their households and environment. By using whole-genome phylogenetic analysis and network analysis based on single nucleotide polymorphisms (SNPs), we found highly interrelated non-pathogenic and pathogenic E. coli strains with phylogenetic intermixing, and a high prevalence of shared multidrug resistance profiles amongst livestock, human and environment. Through an original data processing pipeline which combines omics, machine learning, gene sharing network and mobile genetic elements analysis, we investigated the resistance to 26 different antimicrobials and identified 361 genes associated to antimicrobial resistance (AMR) phenotypes; 58 of these were known AMR-associated genes and 35 were associated to multidrug resistance. We uncovered an extensive network of genes, correlated to AMR phenotypes, shared among livestock, humans, farm and slaughterhouse environments. We also found several human, livestock and environmental isolates sharing closely related mobile genetic elements carrying ARGs across host species and environments. In a scenario where no consensus exists on how antibiotic use in the livestock may affect antibiotic resistance in the human population, our findings provide novel insights into the broader epidemiology of antimicrobial resistance in livestock farming. Moreover, our original data analysis method has the potential to uncover AMR transmission pathways when applied to the study of other pathogens active in other anthropogenic environments characterised by complex interconnections between host species., Competing Interests: The authors have declared that no competing interests exist.

An Escherichia coli bioreporter harboring the phenol-inducible mphK promoter (P(mphK)) from Acinetobacter calcoaceticus PHEA-2 fused to a beta-galactosidase gene (lacZ) and the regulator gene (mopR) of A. calcoaceticus NCIB8250 was constructed to detect phenol. P(mphK) containing three inverted repeats (IR1, IR2 and IR3) upstream of mphK was activated by the regulator MopR in the presence of phenol. Deletion analysis of P(mphK) revealed that IR2 and IR3 were essential for promoter activity, while IR1 was involved in transcriptional repression. The sensitivity of the bioreporter for the detection of phenol (0.1-5 microM) was improved by about 100% through deletion of IR1 in P(mphK).

ObjectiveTo understand the antimicrobial resistance of Escherichia coli recovered from breeding and slaughtering of broiler chickens, and to explore the impact of disinfectant use on resistance during COVID-19 pandemic.MethodsA total of 722 strains of Echerichia coli, isolated from broiler farms and slaughterhouses in Henan, Shandong and Liaoning provinces, were tested for resistance of 27 kinds of antimicrobial compouds belonging to 12 categories using broth dilution method, and the changes of antimicrobial resistance of strains from Shandong province before and after the outbreak of COVID-19 were analyzed.ResultsAn overall high level antimicrobial resistance was found among 722 Escherichia coli isolates, 96% of which were drug resistant strains. The resistance rate of 9 drugs in 6 categories, including AMP, was higher than 75% with the highest one of 88.1%, eight drugs got the intermediary rate of over 10%, and multiple drug resistant strains accounted for 94.7% of all resistant strains; a total of 517 drug resistance profiles were found. The strains resistant to 10 and 9 drugs ranked the top, and 118 strains were resistant to 11 kinds of antimicrobial compounds at the same time, with 2 of which were resistant to 24 drugs. Resistance of Escherichia coli isolates in Shandong province to DOX, PB and AMS/AMC increased significantly after COVID-19 pandemic.ConclusionThe overall antimicrobial resistance of Escherichia coli isolates recovered from broiler farms and slaughterhouses in China is at a very high level, and the multi-drug resistance is serious, which may be related to the long-term widespread use of related drugs in the upstream of the food chain. During the COVID-19 outbreaks, the disinfection measures in broiler breeding and slaughter processing might be related to the enhancement of the Escherichia coli antimicrobial resistance to some drugs. Continuous active surveillance from a preventive perspective should be carried out to fully assess the upside risk to antimicrobial resistance of the pathogens recovered from the food chain by the use of disinfectants.