The global spread of drug-resistant bacterial infections poses an urgent need for the development of novel antibacterial materials. To address the risk of multidrug-resistant (MDR) bacterial infections, peptide-based nanomaterials have emerged as a cutting-edge research focus in antibacterial field. This advancement is underpinned by their intrinsic capabilities such as self-assembly, drug delivery, high stability, and multivalent binding effects. However, there is still a multi-dimensional knowledge gap in rational design of materials from the perspective of antibacterial strategy, and there is a lack of summary on the specific structural modules on which peptide-based nanomaterials depend on antibacterial mechanism. This review comprehensively outlines the antibacterial strategies employed by peptide-based nanomaterials, with an emphasis on the molecular mechanisms through which they exert bactericidal effects via multiple pathways, and proposes a “three-tiered lethality model”. Furthermore, we also discuss dynamically regulated assembly modules under microenvironment-responsive conditions and future AI-driven development pathways for nanomaterials. Grounded in sterilization mechanisms, this review aims to foster a paradigm shift from empirical optimization to rational design in peptide-based nanomaterials, thereby accelerating the development of intelligent systems with broad-spectrum activity and precisely controllable functions.

Historically, bioactive flavonoids from plant foods have been important components of the human diet and play key roles in shaping gut microbiota composition and host metabolism. Licochalcone A (LCA), a chalcone-type flavonoid derived from licorice (Glycyrrhiza spp.), has gained attention for its potential interactions with gut microbial communities. In the present study, an in vitro fecal batch fermentation system using samples from six healthy volunteers was used to characterize LCA-induced changes in microbial composition and metabolism. LCA was rapidly metabolized by the intestinal microbiota within 48 h, with pronounced interindividual variability among donors, indicating active microbial transformation. LCA treatment altered microbial activity by modifying short-chain fatty acid profiles, including acetate, propionate, and butyrate. LCA significantly increased the relative abundance of beneficial bacteria, including Prevotella, Segatella, and Bacteroides, while decreasing the abundance of taxa such as Fusobacterium and Escherichia. Untargeted metabolomics of the fermented broth revealed that LCA reshaped the gut metabolome, enriching metabolites involved in tryptophan metabolism and pantothenate and coenzyme A biosynthesis. Several metabolites, including Romucosine, Mosin C, and lucidone B, were altered, suggesting changes in microbial metabolic activity. Overall, these findings demonstrate that LCA can reshape gut microbial composition and metabolism, providing a basis for future development of functional foods.

Campylobacteriosis is a major foodborne diseases, with an estimated 96 million cases worldwide annually. Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli) are major causes of human gastroenteritis, and poultry products are the main transmission source. An increasing incidence of antimicrobial resistance (AMR) among Campylobacter strains further complicates the control of these pathogens in the food chain. Although various approaches have been explored, phage biocontrol, particularly with Campylobacter group II phages, has shown promise in controlled preharvest and postharvest studies. Group II phages are highly specific and lyse C. jejuni and C. coli with potential to reduce Campylobacter colonization in poultry. These phages offer a selective, eco-compatible alternative to conventional antimicrobial treatments that selectively kill pathogenic bacteria without significantly affecting gut microbiota. Applying phage therapy during poultry processing, such as spraying or dipping, has reduced Campylobacter loads on chicken skin and meat, as well as on the surfaces of poultry equipment, thereby diminishing the risk of food chain contamination. Moreover, consistent performance under commercial poultry conditions requires further large-scale validation and process-specific optimization (formulation stability, delivery logistics, and integration with existing biosecurity and processing hurdles). This review discusses antimicrobial resistance trends in Campylobacter, poultry as a key transmission route, and the use of group II phages to reduce Campylobacter contamination. It also highlights challenges and opportunities, including optimization of phage preparations for scale-up; rigorous genomic screening and safety evaluation; evaluation of effects on microbial communities and countering antibiotic-resistant bacteria; and exploration of transposase-associated functions for future phage engineering.

Escherichia coli (E. coli) is a major foodborne pathogen that affects 2.8 million people globally. The widespread use of antibiotics and disinfectants in livestock production has contributed to the emergence of multidrug-resistant strains, underscoring the need for resistance surveillance and the development of alternative control strategies, such as ozone nano water (ONW). ONW has emerged as a promising disinfectant, particularly for controlling microbial contamination in food safety and medical applications. In this study, we evaluated the bactericidal activity of ONW against four E. coli strains, including three clinical isolates with multidrug-resistant (MDR) phenotypes, and assessed potential short-term effects on antimicrobial susceptibility. ONW was physicochemically characterized (nano bubble size distribution, zeta potential, and stability under varied conditions). ONW caused rapid inactivation of all strains and markedly suppressed biofilm formation. Flow cytometry and microscopy (SEM and TEM) demonstrated that ONW induced significant cell membrane damage, resulting in bacterial death. Confocal Raman microspectroscopy revealed decreases in spectral features associated with membranes, cell walls, nucleic acids, and ATP, supporting a multi-target oxidative injury mechanism. Interestingly, ONW did not significantly alter the antimicrobial sensitivity of E. coli strains across three consecutive generations, suggesting its potential as a sustainable disinfectant without promoting resistance. These results indicate that ONW is an effective and potentially sustainable disinfectant against E. coli, including MDR strains, with applicability to medical and agricultural settings while minimizing concerns about resistance selection. 1. Ozone nano water (ONW) exhibits bactericidal effects on multidrug-resistant E. coli. 2. ONW with concentrations of 4.14 and 8.48 mg/L achieves 100

Matrine, an alkaline polysaccharide, is the main bioactive component of Sophora flavescens and has been shown to possess pharmacological activities. In our previous research, we found that matrine exerted significant antibacterial activity in vitro and enhanced the efficacy of antibiotics and mitigated bacterial resistance. Nevertheless, the mechanisms by which matrine influences intestinal health are not well understood. Thus, we explored how matrine influences the intestinal well-being of yellow-feathered chickens and the mechanisms involved. Our current findings reveal that matrine supplementation can boost goblet cell quantity in the intestine, enhance intestinal barrier function, and strengthen immune response. Furthermore, we found that matrine treatment modulated the abundance of specific intestinal bacteria. Transcriptomic profiles further confirmed that dietary matrine altered the gene expression profile. Examining the DEGs revealed unique signaling pathways involved in regulating immune responses, lipid metabolism, and neural conduction. Adding matrine to the diet can improve the intestinal mucosal barrier integrity and strengthen immune function.

Antimicrobial peptides as a promising therapeutic drug against multidrug-resistant pathogens, have attracted great interest because of their excellent antibacterial properties and low tendency to induce drug resistance. Nevertheless, the structural instability of peptide chains and their vulnerability to enzymatic breakdown considerably diminish their bioactivity, consequently restricting their antibacterial effectiveness and clinical applicability. To address this fundamental limitation, we engineered highly stable self-assembling peptides by combining de novo sequence design with strategic control over non-covalent interactions. This nanostructure incorporates three distinct functional domains, adopting a protease-resistant beta-sheet conformation that demonstrates robust stability when exposed to proteolytic enzymes, serum components, and ionic environments. The system concurrently displays potent antimicrobial performance and effective biofilm elimination capacity. Moreover, the SAP exhibits excellent biocompatibility and demonstrates promising therapeutic outcomes in vivo. This multi-noncovalent interaction-driven self-assembly approach establishes a framework for developing stable peptide nanomaterials and advances the clinical translation of peptide-based antimicrobial therapeutics.

Campylobacter is a major foodborne pathogen, commonly transmitted through poultry. The emergence of multidrug-resistant strains due to antibiotic overuse in poultry farming highlights the need for monitoring resistance patterns and exploring alternative control strategies, such as bacteriophage application. This study examined the antimicrobial resistance patterns in Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli). Additionally, a novel lytic Campylobacter phage CC_R7 was isolated, characterized, and subjected to complete genomic analysis. The phage CC_R7 application was evaluated for biofilm removal under slaughterhouse conditions and as a biocontrol agent in chicken meat. The results showed that the resistance rate in C. coli was higher than in C. jejuni. The phage CC_R7 has a genome size of 180,566 bp, and no virulent gene was found. It has a broad host range, killing 60 % of C. coli and 27.2 % of C. jejuni tested strains with excellent adsorption, a short latent period of 40 min, and a high burst size of 119 virions. The phage remained stable across temperatures (4 °C-50 °C) and pH levels (4-10). Moreover, phage CC_R7 has the potential to inhibit biofilm formation and reduce Campylobacter contamination in chicken meat by 1.2 log/g. Therefore, Campylobacter phage CC_R7 has unique characteristics to combat multidrug-resistant Campylobacter strains and can be used as a feed additive for biocontrol in food.

Mastitis caused by methicillin-resistant Staphylococcus aureus (MRSA) is a common issue in dairy farming, with sequence types (STs) related to cows mainly including ST9 and ST97. ST59, the predominant community-acquired clone, is still less reported in dairy cows. This study investigated the antimicrobial resistance patterns and molecular characteristics of 77 Staphylococcus aureus isolates obtained from eight dairy farms in the mid-east of China during 2019-2020, focusing particularly on the bovine mastitis-related livestock-associated MRSA (LA-MRSA) clone ST59. Among the 77 isolates, 14 isolates were identified as MRSA. A total of 20 STs were identified, with ST59 being the most prevalent among MRSA isolates (35.7%). All MRSA isolates possessed various Staphylococcal cassette chromosome mec (SCCmec) types, including XII (n = 5), IV.a (n = 4), IV.c (n = 2), IV.g (n = 2), and V (n = 1). Three MRSA lineages were identified: MRSA-ST59-t437-SCCmec IV.a/IV.g (n = 5), MRSA-ST9-t899-SCCmec XII (n = 4), and MRSA-ST88-t3622-SCCmec IV.c (n = 2). Approximately 44.2% of isolates demonstrated multidrug resistance. MRSA isolates showed a higher prevalence of antimicrobial resistance compared to methicillin-sensitive Staphylococcus aureus (MSSA) isolates. Virulence factor assays revealed that all MRSA isolates carried at least hemolysin genes and enterotoxin genes. ST59-MRSA strains showed the closest genetic relationship with human-derived strains, indicating a potential public health risk due to transmission of Staphylococcus aureus between livestock and humans. This study highlights the significant prevalence of the bovine mastitis-related LA-MRSA clone ST59 in the mid-east of China. Therefore, reinforcing monitoring and implementing preventive measures are essential to combat LA-MRSA. IMPORTANCE:Obtained the prevalence and molecular characteristics of Staphylococcus aureus in dairy farms in the mid-east of China from 2019 to 2020. Recently identified livestock-associated methicillin-resistant S. aureus (LA-MRSA) clones in cattle, including ST59-MRSA, may have originated from human sources, suggesting a potential risk for interspecies transmission.

BACKGROUND:Berberine (BBR), a widely used monomer in traditional Chinese medicine, well-known for its extensive pharmacological activities against tumors, neurological disorders, and cardiovascular disease. These effects are mediated through the regulation of multiple molecular targets and signaling pathways, including the MAPK, TLR4/NF-κB, PI3K/AKT, and AMPK/mTOR. In addition, BBR demonstrate potent antimicrobial activity by reducing pathogen invasiveness, disrupting biofilms integrity, preventing the formation of macromolecules, and interfering with metabolic processes. More, BBR can modulate the gut microbiome and exhibit an effective treatment for metabolic disorders such as diabetes mellitus. PURPOSE:The goal of this review is to present a current summary of the molecular processes that underlie BBR's action, discussing BBR interactions with novel factors, examining current knowledge on BBR side effect and nano-carrier applications, offering new perspective on expanding its therapeutic use. Further is required to identify novel targets of berberine and to investigate its potential for new therapeutic applications. METHODS:The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data were organized into tabular and narrative formats. Structural formulae of compounds were created using ChemDraw Professional 22.0 software, while botanical information was sourced from the Flora of China (www.iplant.cn). The keyword "Berberine" was used to search databases, including ScienceDirect, PubMed, CNKI, and Web of Science, covering publications from 1970 to 2024. To ensure comprehensive data collection, additional searches were conducted using Connected Papers, Springer Search, Baidu Scholar, Google Scholar, and other databases. Keywords such as "toxicology," "traditional uses," "molecular mechanism," "pharmacology," and "chemical compounds" were applied to further refine and analyze the collected information. RESULTS:Berberine exerts potent antibacterial, anti-inflammatory, and therapeutic effects in cardiovascular, neurological, metabolic, and tumor-related conditions by modulating key intracellular signaling pathways (e.g., AMPK/mTOR, PI3K/AKT, TLR4/NF-κB). It also impacts gut flora, offering new treatment avenues for gastrointestinal diseases, diabetes, and related renal disorders. Despite its clinical efficacy, berberine's low oral bioavailability and the complexity of its mechanisms and safety profile highlight the need for further research to fully unlock its therapeutic potential. CONCLUSION:This study summarises the methods by which berberine heals a number of prevalent conditions and elaborates on the relationship between berberine and illnesses. Furthermore, it discusses the application of berberine nanofomulations in treating diseases. Future research on berberine should explore its potential in treating rare diseases, mental health disorders, immune conditions, neurodegenerative diseases, metabolic disorders, and cancer, while enhancing drug delivery systems and investigating its epigenetic effects.

Multidrug-resistant Staphylococcus aureus (MDR-SA) poses a critical challenge in both clinical and livestock settings, where conventional antibiotics are increasingly ineffective. To explore alternative strategies, we screened 223 compounds and identified ziyuglycoside II as a promising candidate. Its antibacterial and synergistic effects were evaluated using minimum inhibitory concentration (MIC) and checkerboard assays, biofilm inhibition and clearance tests, and mechanistic analyses of membrane integrity, reactive oxygen species (ROS) generation, membrane potential, and ATP synthesis. Biosafety was assessed through hemolysis and mammalian cytotoxicity assays, and therapeutic potential was examined in Galleria mellonella and mouse endometritis models. Ziyuglycoside II exhibited moderate activity (MIC =32 µg/mL) but showed strong synergy with tetracycline (fractional inhibitory concentration index 0.25-0.375), effectively suppressing resistant and susceptible strains. Time-kill assays revealed a reduction of up to 5 log₁₀ in bacterial counts with the combination. The pairing also inhibited biofilm formation, eradicated mature biofilms, and produced markedly thinner, fragmented biofilm structures under confocal microscopy. Mechanistic studies have demonstrated that ziyuglycoside II potentiates tetracycline by disrupting membrane integrity, inducing ROS accumulation, depolarizing the membrane potential, and impairing ATP synthesis. Importantly, no hemolytic or cytotoxic effects were observed at active concentrations. In vivo, the combination outperformed monotherapy by improving host survival, reducing uterine bacterial burden, and alleviating inflammatory responses. Together, these findings establish ziyuglycoside II as a safe and effective tetracycline potentiator, providing a promising strategy to combat MDR S. aureus infections.

Aditoprim (ADP) is a novel dihydrofolate reductase inhibitor. It has potent antibacterial activity, low toxicity, and no mutagenicity. These characteristics position it as a promising candidate for further research in clinical veterinary medicine and its effect on humans. Therefore, this research aimed to investigate the impact of ADP on human microbiota. ADP (0, 1, 16, and 128 mg/L) was added to chemostats containing human intestinal flora. Microflora communities, short-chain fatty acids (SCFAs), and the rate of antibiotic resistance were monitored at different time points before and after the administration of ADP. Salmonella Typhimurium inoculation was used to assess the gut microbiota's colonization barrier over a period of three days. The results indicate long-term exposure to higher levels of ADP (16 and 128 mg/L) disrupted the colonization barrier of intestinal flora and increased the proportion of resistant bacteria. 16S rRNA sequencing data indicate that high levels of ADP caused significant changes in gut microbiota, especially Bacteroides fragilis and Bacteroides uniformis. This study assessed the microbiological safety of ADP in vitro for the first time by simulating the human gut microbiota environment. The findings showed that 1 mg/L was the no observable adverse effect concentration, and the microbiological acceptable daily intake was determined to be 91.67 µg/kg.BW/day.

Multidrug-resistant Campylobacter jejuni (MDR C. jejuni), the leading cause of food-borne gastroenteritis worldwide, poses a significant threat to public health and food safety. The intestinal microbiota prevents MDR C. jejuni colonization, but the specific mechanisms remain poorly understood. In this study, we performed a multi-omics analysis of the gut microbiota in C57BL/6 mice, combined with in vitro experiments, to investigate the role of gut microbiota in C. jejuni colonization. Treatment with tylvalosin, a new macrolide, altered the gut microbiota composition, reducing Bifidobacterium longum communities and decreasing levels of short-chain fatty acids (acetic acid, propionic acid, n-butyric acid, i-butyric acid, and i-valeric acid). This disruption of intestinal homeostasis facilitated C. jejuni colonization. Through metagenomic sequencing, we identified and isolated Lactobacillus murinus (L. murinus) from the mice’s intestinal flora, which exhibited inhibitory activity against C. jejuni in vitro. Metabolomic analysis and in vitro validation further revealed the significance of L. murinus-derived metabolites. Our results indicate that L. murinus inhibits and kills C. jejuni in a co-culture system by secreting acids that synergistically induce apoptosis, leading to cell membrane disruption and the release of cellular contents.

In 2018, China implemented the Veterinary Antimicrobial Use Reduction Action to curb the rapid development of antibiotic resistance (AR). However, the AR-related pollutions in animal farms after the reduction policy has been poorly investigated. Here, we performed a comprehensive investigation combining UPLC-MS/MS, metagenomic, and bacterial genomic analyses in eight representative large-scale chicken farms in Guangdong, China. Our results showed that antibiotics and ARGs contaminations were more severe in broiler farms than in layer farms. Notably, diverse tet(X) variants were prevalent in the chicken farms. These tet(X)s was carried by diverse E. coli lineages and obviously correlated with ISCR2 and IS1B transposases. The resistomes in chicken farms was significantly correlated with microbial community, and multiple factor analyses indicated that the joint effect of antibiotics-microbial community-MGEs was the most dominant driver of ARGs. Host tracking identified a variety of ARG bacterial hosts and the co-occurrence of ARGs-MRGs-MGEs. Source tracking indicated that the inherent component represented the main feature of resistomes in different hosts, while ARG transfer between the chicken gut and farm environments were frequent. A multiperspective evaluation of AR risk revealed that the early effect of antibiotic reduction was exhibited by the mitigation of maximum level of risky ARGs, prevalence of environmental AR pathogens, and HGT potential of ARGs mediated by phage structures. Overall, our findings provide insights into the antibiotic and ARG profiles in large-scale chicken farms with different rearing strategies and demonstrate a preliminary view of the performance of antibiotic reduction actions in China.

The widespread utilization of antibiotic growth promoters (AGPs) boosts the growth rate of food animals and enhances human living standards. Nevertheless, it is accompanied by escalating antibiotic resistance. Consequently, there is an urgent demand to develop novel alternatives to growth promoters. The objective of this study was to develop a non-antibiotic growth promoter (NAGP) for augmenting the growth rate of food animals. The growth-promoting effect of plant-derived NAGPs was assessed in mice and broiler chickens, and its growth-promoting mechanism was initially investigated. The results reveal that a combination of hawthorn (also known as shanzha) and astragalus (also known as huangqi) extracts (SQ) enhanced the growth rate of mice both in vivo and in vitro, attributed to their significant capacity to promote muscle growth and improve immunity (p < 0.05). The composite super energy extract M (CSEE-M), further optimized on the basis of SQ, significantly improved growth performance and feed conversion ratio, and elevated the activity of intestinal digestive enzymes (p < 0.05) in both mice and broilers and reshaped the gut microbiota of broilers. The addition of 0.5% CSEE-M to broiler drinking water significantly increased muscle content and improved carcass quality (p < 0.05). In conclusion, both SQ and CSEE-M hold great promise as NAGPs and serve as effective substitutes to AGPs. This research not only furnishes new solutions for the misuse of antibiotics but presents a fresh perspective for the development of growth promoters.

Diethylstilbestrol (DES), a synthetic non-steroid estrogen, it has been prohibited from being added to animal feed for any purposes. Herein, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on a specific monoclonal antibody (mAb) was developed for the rapid screening of DES. Primarily, conjugates of mono-O-3-carboxypropyl diethylstilbestrol with keyhole limpet hemocyanin were used to raise a specific mAb, 1B7, which had IC50 value for DES of 213.0 ng L-1. The limits of detection and limits of quantification value for DES in animal-derived foods ranged from 68.1 to 103.1 ng L-1 and 100.8-192.7 ng L-1, respectively. The DES recovery ranged from 70.1 % to 103.1 %, with coefficients of variation below 13.9 %. A positive correlation (R2 = 0.997) was observed between the results of ic-ELISA and HPLC-MS/MS for milk. In order to inspect its detection effect, milk and animal-derived foods were chosen as the testing object. The results showed that this ic-ELISA method (specific mAb, 1B7) can effectively examine for DES residues.

Antimicrobial resistance (AMR) can potentially harm global public health. Horizontal gene transfer (HGT), which speeds up the emergence of AMR and increases the burden of drug resistance in mobile genetic elements (MGEs), is the primary method by which AMR genes are transferred across bacterial pathogens. New approaches are urgently needed to halt the spread of bacterial diseases and antibiotic resistance. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), an RNA-guided adaptive immune system, protects prokaryotes from foreign DNA like plasmids and phages. This approach may be essential in limiting horizontal gene transfer and halting the spread of antibiotic resistance. The CRISPR-Cas system has been crucial in identifying and understanding resistance mechanisms and developing novel therapeutic approaches. This review article investigates the CRISPR-Cas system's potential as a tool to combat bacterial AMR. Antibiotic-resistant bacteria can be targeted and eliminated by the CRISPR-Cas system. It has been proven to be an efficient method for removing carbapenem-resistant plasmids and regaining antibiotic susceptibility. The CRISPR-Cas system has enormous potential as a weapon against bacterial AMR. It precisely targets and eliminates antibiotic-resistant bacteria, facilitates resistance mechanism identification, and offers new possibilities in diagnostics and therapeutics.

In this study, a highly sensitive monoclonal antibody (mAb) was developed for the detection of aflatoxin B-1 (AFB(1)) in maize and feed. Additionally, indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and time-resolved fluorescence immunoassay assay (TRFICA) were established. Firstly, the hapten AFB(1)-CMO was synthesized and conjugated with carrier proteins to prepare the immunogen for mouse immunization. Subsequently, mAb was generated using the classical hybridoma technique. The lowest half-maximal inhibitory concentration (IC50) of ic-ELISA was 38.6 ng/kg with a linear range of 6.25-100 ng/kg. The limits of detections (LODs) were 6.58 ng/kg and 5.54 ng/kg in maize and feed, respectively, with the recoveries ranging from 72% to 94%. The TRFICA was developed with a significantly reduced detection time of only 21 min, from sample processing to reading. Additionally, the limits of detection (LODs) for maize and feed were determined to be 62.7 ng/kg and 121 ng/kg, respectively. The linear ranges were 100-4000 ng/kg, with the recoveries ranging from 90% to 98%. In conclusion, the development of AFB(1) mAb and the establishment of ic-ELISA for high-throughput sample detection, as well as TRFICA for rapid detection presented robust tools for versatile AFB(1) detection in different scenarios.

ABSTRACTThe prevalence and dissemination of the plasmid-mediated fluoroquinolone (FQ) resistance gene qnr in Salmonella are considered serious public health concerns worldwide. So far, no comprehensive large-scale studies have focused on the prevalence and genetic characteristics of the qnr gene in Salmonella isolated from chickens. Herein, this study aimed to investigate the prevalence, antimicrobial resistance (AMR) patterns, and molecular characteristics of chicken-originated qnr-positive Salmonella strains from chicken farms, slaughterhouses, and markets in 12 provinces of China in 2020–2021. The overall prevalence of the qnr gene was 21.13% (56/265), with the highest prevalence in markets (36.11%, 26/72), followed in farms (17.95%, 21/117), and slaughterhouses (10.53%, 9/76). Only the qnrS and qnrB genes were detected, and the prevalence rate of the qnrS gene (19.25%, 51/265) was higher than that of the qnrB gene (1.89%, 5/265). Whole genome sequencing identified 37 distinct AMR genes and 15 plasmid replicons, and the most frequent mutation in quinolone resistance determining regions was parC (T57S; 91.49%, 43/47). Meanwhile, four different qnrS and two qnrB genetic environments were discovered among 47 qnr-positive Salmonella strains. In total, 21.28% (10/47) of the strains were capable of conjugative transfer, and all were qnrS1-positive strains, with the majority of transferable plasmids being IncHI2 types (n = 4). Overall, the prevalence of qnr-positive Salmonella strains from chickens in China and their carriage of multiple resistance and virulence genes and transferable plasmids is a major concern, which calls for continuous surveillance of qnr-positive Salmonella and the development of measures to control its prevalence and transmission.IMPORTANCESalmonella is a common foodborne pathogen responsible for 155,000 deaths annually worldwide. Fluoroquinolones (FQs) are used as first-line drugs for the treatment of Salmonella infections in several countries and regions. However, the emergence and increasing prevalence of the FQ-resistant gene qnr in Salmonella isolated from chickens have been widely reported. Gaining insight into the genetic mechanisms of AMR genes in chicken could lead to the development of preventive measures to control and reduce the risk of drug resistance. In this study, we identified qnr-positive Salmonellae isolated from chickens in different regions of China and their AMR patterns and genome-wide characteristics, providing a theoretical basis for further control of their prevalence and transmission.