Efflux of TolC protein to different antimicrobials can be replaced by other outer membrane proteins with similar ß-barrel structures in extraintestinal pathogenic Escherichia coli.

AIM: As a major efflux pump system in Gram-negative bacteria, AcrAB-TolC plays a key role in the transport of multiple drug substrates and is considered a potential target for the development of novel antimicrobials. Our previous study found that TolC inactivation compromised the resistance to different antimicrobials in porcine extraintestinal pathogenic Escherichia coli (ExPEC) strain PPECC042 (WT). This study was designed to investigate the functional substitution of TolC by other outer membrane proteins (OMPs) with similar ß-barrel structures in pumping out different antimicrobials. METHODS AND RESULTS: In this study, we found that over-expression of several OMPs with similar ß-barrel structures, OmpX, OmpC, OmpN, OmpW, and PhoE, in the ΔtolC strain restored the resistance to macrolides, quinolones, or tetracyclines to the level of WT strain. However, the introduction of any one of the five OMPs did not affect the resistance of the strains ΔacrA, ΔacrB, and ΔacrAΔtolC. Further study revealed that the efflux activity was significantly reduced in the ΔtolC strain, but not in the WT strain and the ΔtolC strains over-expressing various OMPs. Additionally, Nile red dye test and ciprofloxacin accumulation test confirmed that the lost efflux activity and drug accumulation in bacterial periplasm by TolC inactivation was restored by the over-expression of each OMP, depending on the presence of genes acrA and acrB. CONCLUSION: All five OMPs can replace the TolC protein to play the efflux role in pumping out the drugs from the periplasm to the extracellular space with the help of proteins AcrA and AcrB.

A Prospective Self-controlled Clinical Trial of Nonactivated Low Leukocyte PRP in Female Pattern Hair Loss Patients of Childbearing Age.

BACKGROUND: Alopecia significantly affects the mental health and social relationship of women since childbearing age, highlighting the need for a safe, effective, and convenient treatment. METHODS: The authors have conducted a prospective self-controlled trial involving 15 female patients at childbearing age with alopecia. These patients received a subcutaneous scalp injection of platelet-rich plasma once every 4 weeks for 3 treatments in total. Outcome measurements were included below: changes in hair density (hair/cm 2 ), hair follicle density (hair follicle/cm 2 ), and overall photographic assessment (improved or not) at 4, 12, and 24 weeks right after the first treatment. RESULTS: Comparing the photographs taken before and after the intervention, 67% of patients' hair density increased from 151 ± 39.82 hairs/cm 2 (preintervention) to 170.96 ± 37.14 hairs/cm 2 (at 24-week follow-up), representing an approximate increase of 19 hairs/cm 2 . Meanwhile, hair follicle density increased by approximately 15 follicles/cm 2 after 24 weeks since the first treatment, rising from 151.04 ± 41.99 follicles/cm 2 to 166.72 ± 37.13 follicles/cm 2 . The primary adverse reactions observed were local swelling and pain due to injections. CONCLUSION: Local injection of nonactivated platelet-rich plasma with low leukocytes concentration could be an effective strategy to alleviate alopecia symptoms in female patients.

A Novel Cost Calculation Method for Manipulator Trajectory Planning.

It is worthwhile to calculate the execution cost of a manipulator for selecting a planning algorithm to generate trajectories, especially for an agricultural robot. Although there are various off-the-shelf trajectory planning methods, such as pursuing the shortest stroke or the smallest time cost, they often do not consider factors synthetically. This paper uses the state-of-the-art Python version of the Robotics Toolbox for manipulator trajectory planning instead of the traditional D-H method. We propose a cost function with mass, iteration, and residual to assess the effort of a manipulator. We realized three inverse kinematics methods (NR, GN, and LM with variants) and verified our cost function's feasibility and effectiveness. Furthermore, we compared it with state-of-the-art methods such as Double A* and MoveIt. Results show that our method is valid and stable. Moreover, we applied LM (Chan λ = 0.1) in mobile operation on our agricultural robot platform.

A Redactable Blockchain-Based Data Management Scheme for Agricultural Product Traceability.

With the development of agricultural information technology, the Internet of Things and blockchain have become important in the traceability of agricultural products. Sensors collect real-time data in agricultural production and a blockchain provides a secure and transparent storage medium for these data, which improves the transparency and credibility of agricultural product traceability. However, existing agricultural product traceability solutions are limited by the immutability of the blockchain, making it difficult to delete erroneous data and modify the scope of data sharing. This damages the credibility of traceability data and is not conducive to the exchange and sharing of information among enterprises. In this article, we propose an agricultural product traceability data management scheme based on a redactable blockchain. This scheme allows agricultural enterprises to encrypt data to protect privacy. In order to facilitate the maintenance and sharing of data, we introduce a chameleon hash function to provide data modification capabilities. Enterprises can fix erroneous data and update the access permissions of the data. To improve the efficiency of block editing, our scheme adopts a distributed block editing method. This method supports threshold editing operations, avoiding single-point-of-failure issues. We save records of data modifications on the blockchain and establish accountability mechanisms to identify malicious entities. Finally, in this paper we provide a security analysis of our proposed solution and verify its effectiveness through experiments. Compared with the existing scheme, the block generating speed is improved by 42% and the block editing speed is improved by 29.3% at 125 nodes.

Boosting the Reversible, High-Rate Na+ Storage Capability of the Hard Carbon Anode Via the Synergistic Structural Tailoring and Controlled Presodiation.

Hard carbons (HCs) are extensively investigated as the potential anodes for commercialization of sodium-ion batteries (SIBs). However, the practical deployment of HC anode suffers from the retarded Na+ diffusion at the high-rate or low-temperature operation scenarios. Herein, a multiscale modification strategy by tuning HC microstructure on the particle level as well as replenishing extra Na+ reservoir for the electrode through a homogeneous presodiation therapy is presented. Consequently, the coulombic efficiency of HC anode can be precisely controlled till the close-to-unit value. Detailed kinetics analysis observes that the Na+ diffusivity can be drastically enhanced by two orders of magnitude at the low potential region (< 0.1 V vs. Na+ /Na), which accelerates the rate-limiting step. As pairing the presodiated HC anode (≈5.0 ± 0.2 mg cm-2 ) with the NaVPO4 F cathode (≈10.3 mg cm-2 ) in the 200 mAh pouch cell, the optimal balance of the cyclability (83% over 1000 cycles), low-temperature behavior till -40 °C as well as the maximized power output of 1500 W kg-1 can be simultaneously achieved. This synergistic modification strategy opens a new avenue to exploit the reversible, ultrafast Na+ storage kinetics of HC anodes, which thus constitutes a quantum leap forward toward high-rate SIB prototyping.

Cotransfer of resistance to cephalosporins, colistin, and fosfomycin mediated by an IncHI2/pSH16G4928-like plasmid in ESBL-producing monophasic Salmonella Typhimurium strains of pig origin.

AIMS: To assess the co-transmission risk of phenotypic and genetic resistance to cephalosporins, colistin, and fosfomycin in Salmonella strains collected along the whole pork production chain. METHODS AND RESULTS: From a total of 107 Salmonella isolates from samples collected in pig slaughterhouses and markets, 15 ESBL-producing Salmonella strains resistant to cefotaxime were identified by broth microdilution method and clavulanic acid inhibition test, including 14 monophasic Salmonella Typhimurium strains and one Salmonella Derby strain. Whole genome sequence analysis showed that nine monophasic S. Typhimurium strains coresistant to colistin and fosfomycin carried the resistance genes blaCTX-M-14, mcr-1, and fosA3. Conjugational transfer tests demonstrated that the phenotypic and genetic resistance to cephalosporins, colistin, and fosfomycin could cotransfer back and forth between Salmonella and Escherichia coli via an IncHI2/pSH16G4928-like plasmid. CONCLUSIONS: This study reports the cotransmission of phenotypic and genetic resistance to cephalosporins, colistin, and fosfomycin via an IncHI2/pSH16G4928-like plasmid in Salmonella strains of animal origin, giving an alarm for the prevention of the development and spread of bacterial multidrug resistance.

Enteropathogenic Escherichia coli is a predominant pathotype in healthy pigs in Hubei Province of China.

AIM: This study aims to investigate the prevalence of intestinal pathogenic Escherichia coli (InPEC) in healthy pig-related samples and evaluate the potential virulence of the InPEC strains. METHODS AND RESULTS: A multiplex PCR method was established to identify different pathotypes of InPEC. A total of 800 rectal swab samples and 296 pork samples were collected from pig farms and slaughterhouses in Hubei province, China. From these samples, a total of 21 InPEC strains were isolated, including 19 enteropathogenic E. coli (EPEC) and 2 shiga toxin-producing E. coli (STEC) strains. By whole-genome sequencing and in silico typing, it was shown that the sequence types and serotypes were diverse among the strains. Antimicrobial susceptibility assays showed that 90.48% of the strains were multi-drug resistant. The virulence of the strains was first evaluated using the Galleria mellonella larvae model, which showed that most of the strains possessed medium to high pathogenicity. A moderately virulent EPEC isolate was further selected to characterize its pathogenicity using a mouse model, which suggested that it could cause significant diarrhea. Bioluminescence imaging (BLI) was then used to investigate the colonization dynamics of this EPEC isolate, which showed that the EPEC strain could colonize the mouse cecum for up to 5 days.

A New Semantic Segmentation Framework Based on UNet.

This paper discusses a semantic segmentation framework and shows its application in agricultural intelligence, such as providing environmental awareness for agricultural robots to work autonomously and efficiently. We propose an ensemble framework based on the bagging strategy and the UNet network, using RGB and HSV color spaces. We evaluated the framework on our self-built dataset (Maize) and a public dataset (Sugar Beets). Then, we compared it with UNet-based methods (single RGB and single HSV), DeepLab V3+, and SegNet. Experimental results show that our ensemble framework can synthesize the advantages of each color space and obtain the best IoUs (0.8276 and 0.6972) on the datasets (Maize and Sugar Beets), respectively. In addition, including our framework, the UNet-based methods have faster speed and a smaller parameter space than DeepLab V3+ and SegNet, which are more suitable for deployment in resource-constrained environments such as mobile robots.

Molecular Characteristics and Pathogenicity of Staphylococcus aureus Exotoxins.

Staphylococcus aureus stands as one of the most pervasive pathogens given its morbidity and mortality worldwide due to its roles as an infectious agent that causes a wide variety of diseases ranging from moderately severe skin infections to fatal pneumonia and sepsis. S. aureus produces a variety of exotoxins that serve as important virulence factors in S. aureus-related infectious diseases and food poisoning in both humans and animals. For example, staphylococcal enterotoxins (SEs) produced by S. aureus induce staphylococcal foodborne poisoning; toxic shock syndrome toxin-1 (TSST-1), as a typical superantigen, induces toxic shock syndrome; hemolysins induce cell damage in erythrocytes and leukocytes; and exfoliative toxin induces staphylococcal skin scalded syndrome. Recently, Panton-Valentine leucocidin, a cytotoxin produced by community-associated methicillin-resistant S. aureus (CA-MRSA), has been reported, and new types of SEs and staphylococcal enterotoxin-like toxins (SEls) were discovered and reported successively. This review addresses the progress of and novel insights into the molecular structure, biological activities, and pathogenicity of both the classic and the newly identified exotoxins produced by S. aureus.

The Rcs System Contributes to the Motility Defects of the Twin-Arginine Translocation System Mutant of Extraintestinal Pathogenic Escherichia coli.

Flagellum-mediated bacterial motility is important for bacteria to take up nutrients, adapt to environmental changes, and establish infection. The twin-arginine translocation system (Tat) is an important protein export system, playing a critical role in bacterial physiology and pathogenesis. It has been observed for a long time that the Tat system is critical for bacterial motility. However, the underlying mechanism remains unrevealed. In this study, a comparative transcriptomics analysis was performed with extraintestinal pathogenic Escherichia coli (ExPEC), which identified a considerable number of genes differentially expressed when the Tat system was disrupted. Among them, a large proportion of flagellar biosynthesis genes showed downregulation, indicating that transcription regulation plays an important role in mediating the motility defects. We further identified three Tat substrate proteins, MdoD, AmiA, and AmiC, that were responsible for the nonmotile phenotype. The Rcs system was deleted in the Δtat, the ΔmdoD, and the ΔamiAΔamiC strains, which restored the motility of ΔmdoD and partially restored the motility of Δtat and ΔamiAΔamiC. The flagella were also observed in all of the ΔtatΔrcsDB, ΔmdoDΔrcsDB, and ΔamiAΔamiCΔrcsDB strains, but not in the Δtat, ΔmdoD, and ΔamiAΔamiC strains, by using transmission electron microscopy. Quantitative reverse transcription-PCR data revealed that the regulons of the Rcs system displayed differential expression in the tat mutant, indicating that the Rcs signaling was activated. Our results suggest that the Rcs system plays an important role in mediating the motility defects of the tat mutant of ExPEC. IMPORTANCE The Tat system is an important protein export system critical for bacterial physiology and pathogenesis. It has been observed for a long time that the Tat system is critical for bacterial motility. However, the underlying mechanism remains unrevealed. In this study, we combine transcriptomics analysis and bacterial genetics, which reveal that transcription regulation plays an important role in mediating the motility defects of the tat mutant of extraintestinal pathogenic Escherichia coli. The Tat substrate proteins responsible for the motility defects are identified. We further show that the Rcs system contributes to the motility suppression. We for the first time reveal the link between the Tat system and bacterial motility, which is important for understanding the physiological functions of the Tat system.

A deep learning approach for orphan gene identification in moso bamboo (Phyllostachys edulis) based on the CNN + Transformer model.

BACKGROUND: Orphan gene play an important role in the environmental stresses of many species and their identification is a critical step to understand biological functions. Moso bamboo has high ecological, economic and cultural value. Studies have shown that the growth of moso bamboo is influenced by various stresses. Several traditional methods are time-consuming and inefficient. Hence, the development of efficient and high-accuracy computational methods for predicting orphan genes is of great significance. RESULTS: In this paper, we propose a novel deep learning model (CNN + Transformer) for identifying orphan genes in moso bamboo. It uses a convolutional neural network in combination with a transformer neural network to capture k-mer amino acids and features between k-mer amino acids in protein sequences. The experimental results show that the average balance accuracy value of CNN + Transformer on moso bamboo dataset can reach 0.875, and the average Matthews Correlation Coefficient (MCC) value can reach 0.471. For the same testing set, the Balance Accuracy (BA), Geometric Mean (GM), Bookmaker Informedness (BM), and MCC values of the recurrent neural network, long short-term memory, gated recurrent unit, and transformer models are all lower than those of CNN + Transformer, which indicated that the model has the extensive ability for OG identification in moso bamboo. CONCLUSIONS: CNN + Transformer model is feasible and obtains the credible predictive results. It may also provide valuable references for other related research. As our knowledge, this is the first model to adopt the deep learning techniques for identifying orphan genes in plants.

Quarter acoustic period pulse compression using stimulated Brillouin scattering in PF-5060.

The pulse duration of the near quarter-acoustic period (τa) is demonstrated in transient stimulated Brillouin scattering (SBS) pulse compression by the suppressing Stokes trailing-edge broadening at high intensities. A theoretical analysis reveals that the difficulty in attaining the transient compression limit is caused by the broadening of the Stokes trailing edge owing to insufficient pump depletion, and this undesirable phenomenon can be significantly suppressed by a high SBS gain coefficient. An average pulse duration of ∼1.05 τa was experimentally achieved in transient compression with a high-energy efficiency of over 30%. Benefiting from energy back conversion, compression below the transient SBS limit (< τa) also occurred when the pump peak power was increased to 150 MW.

Effects of Toxin-Antitoxin System HicAB on Biofilm Formation by Extraintestinal Pathogenic E. coli.

The type II toxin-antitoxin (T-A) HicAB system is abundant in several bacteria and archaea, such as Escherichia coli, Burkholderia Pseudomallei, Yersinia pestis, Pseudomonas aeruginosa, and Streptococcus pneumoniae. This system engages in stress response, virulence, and bacterial persistence. This study showed that the biofilm-forming ability of the hicAB deletion mutant was significantly decreased to moderate ability compared to the extra-intestinal pathogenic Escherichia coli (ExPEC) parent strain and the complemented strain, which are strong biofilm producers. Congo red assay showed that the hicAB mutant maintained the ability to form curli fimbriae. Using RNA-seq and comparative real-time quantitative RT-PCR, we observed the difference in gene expression between the hicAB mutant and the parent strain, which was associated with biofilm formation. Our data indicate that the HicAB type II T-A system has a key role in biofilm formation by ExPEC, which may be associated with outer membrane protein (OMP) gene expression. Collectively, our results indicate that the hicAB type II T-A system is involved in ExPEC biofilm formation.

Public availability of information from officially accredited medical schools in China.

BACKGROUND: Medical education accreditation in China has been conducted by the Working Committee for the Accreditation of Medical Education (WCAME) and 129 medical schools have completed accreditation by December 2021. Despite studies on the standards, process and effectiveness of accreditation, the actual information transparency of accredited medical schools in China has not been examined. The study investigated the status of publicly available information from WCAME-accredited medical schools in China, and whether public availability of information had significant differences among different types of universities. METHODS: The 129 medical schools' official websites were reviewed for the 21 criteria of the WFME Global Standards for Quality Improvement: Basic Medical Education. Dichotomous method was used to record information as presence or absence. SPSS was utilized for descriptive and ANOVA analyses. RESULTS: The mean of the publicly available information on the 21 criteria was 13.77 ± 3.57, and only 5 (3.9%) accredited medical schools had all relevant information available. Publicly available information on Governance (100%) and Administration (100%) was the most, whereas information on Assessment in support of learning (16.3%) was the least. Public availability of information differed significantly among schools accredited with higher (18.15 ± 2.16), medium (13.69 ± 3.41) and lower results (12.79 ± 3.19) (F = 14.71, p < 0.05). Medical universities and comprehensive universities did not show significant differences in their overall information availability (F = 0.25, p > 0.05). Central government funded universities had a remarkably larger amount of publicly available information than local government funded universities (17.86 ± 1.98 vs. 12.75 ± 2.93, p < 0.05). CONCLUSION: Public availability of information from the accredited medical schools in China needs to be improved to promote transparency and continuous quality improvement, especially with regard to information on curriculum, assessment and quality assurance. Explicit information availability requirements need to be considered to include in medical education standards, and further studies are warranted to explore which information elements should be made publicly available.

PINC: A Tool for Non-Coding RNA Identification in Plants Based on an Automated Machine Learning Framework.

There is evidence that non-coding RNAs play significant roles in the regulation of nutrient homeostasis, development, and stress responses in plants. Accurate identification of ncRNAs is the first step in determining their function. While a number of machine learning tools have been developed for ncRNA identification, no dedicated tool has been developed for ncRNA identification in plants. Here, an automated machine learning tool, PINC is presented to identify ncRNAs in plants using RNA sequences. First, we extracted 91 features from the sequence. Second, we combined the F-test and variance threshold for feature selection to find 10 features. The AutoGluon framework was used to train models for robust identification of non-coding RNAs from datasets constructed for four plant species. Last, these processes were combined into a tool, called PINC, for the identification of plant ncRNAs, which was validated on nine independent test sets, and the accuracy of PINC ranged from 92.74% to 96.42%. As compared with CPC2, CPAT, CPPred, and CNIT, PINC outperformed the other tools in at least five of the eight evaluation indicators. PINC is expected to contribute to identifying and annotating novel ncRNAs in plants.

Identification of bZIP transcription factors and their responses to brown spot in pear.

Basic leucine zipper (bZIP) is a conserved transcription factor (TF) widely present in eukaryotes, and it plays an important role in regulating plant growth and stress responses. To better understand the white pear bZIP gene family, comprehensive bioinformatics analysis of the pear genome was performed. A total of 84 PbbZIP genes were identified, which were divided into 13 subfamilies by phylogenetic analysis. The 84 PbbZIP genes were all located in the nucleus, and 77 of those genes were unevenly distributed across the 17 chromosomes of white pear. The other 7 PbbZIP genes were located on the scaffold. Subsequent expression profile analysis showed that PbbZIP genes in exocarp were significantly upregulated or downregulated in 'Huangguan' pear with brown spot (BS) compared with healthy pear and in response to hormonal treatment with gibberellin A3 (GA3). These results provide helpful insights into the characteristics of PbbZIP genes and their responses to BS in 'Huangguan' pear.

Prevalence and Characterization of Salmonella in Three Typical Commercial Pig Abattoirs in Wuhan, China.

This study was designed to investigate the prevalence and characteristics of Salmonella in three Chinese pig abattoirs (A, B, and C) in Wuhan city in 2016. Four types of pig samples were collected and cultured for Salmonella. Salmonella was detected from 329 samples among the 1440 tested (22.9%). There was no significant difference in the overall prevalence between the first visit and the second visit and among the three abattoirs. Rectal swabs (RS) exhibited a significantly higher prevalence than carcass swabs and pork. A total of 177 isolates were characterized by multilocus sequence typing, serotyping, and antimicrobial susceptibility testing. Among 17 sequence types (STs) and 13 serotypes detected, ST40, ST469, and ST34, corresponding to serovars Derby, Rissen, and Typhimurium, respectively, were predominant. The isolates from different abattoirs exhibited diverse ST distribution. The minimum inhibitory concentrations were determined using the microdilution broth method. Resistance to at least one of the antimicrobials was observed for 96.6% of the strains (171/177), and multidrug resistant (MDR) isolates accounted for 75.7% of the strains (134/177). The highest resistance proportion was for tetracycline (92.7%), and the lowest was for cefotaxime (14.1%). The isolates from abattoir A exhibited a significantly lower MDR proportion than those from other abattoirs (p < 0.05). The isolates recovered from RS and pork samples exhibited significantly higher MDR proportions than those recovered from carcass swab samples. Notably, among three predominant STs of isolates, the ST34 isolates showed the highest MDR proportion. In view of the high Salmonella prevalence and antimicrobial resistance, great attention must be paid to the monitoring and controlling of Salmonella in a full pork production chain.

Unified Classification of Bacterial Colonies on Different Agar Media Based on Hyperspectral Imaging and Machine Learning.

A universal method by considering different types of culture media can enable convenient classification of bacterial species. The study combined hyperspectral technology and versatile chemometric algorithms to achieve the rapid and non-destructive classification of three kinds of bacterial colonies (Escherichia coli, Staphylococcus aureus and Salmonella) cultured on three kinds of agar media (Luria-Bertani agar (LA), plate count agar (PA) and tryptone soy agar (TSA)). Based on the extracted spectral data, partial least squares discriminant analysis (PLS-DA) and support vector machine (SVM) were employed to established classification models. The parameters of SVM models were optimized by comparing genetic algorithm (GA), particle swarm optimization (PSO) and grasshopper optimization algorithm (GOA). The best classification model was GOA-SVM, where the overall correct classification rates (OCCRs) for calibration and prediction of the full-wavelength GOA-SVM model were 99.45% and 98.82%, respectively, and the Kappa coefficient for prediction was 0.98. For further investigation, the CARS, SPA and GA wavelength selection methods were used to establish GOA-SVM simplified model, where CARS-GOA-SVM was optimal in model accuracy and stability with the corresponding OCCRs for calibration and prediction and the Kappa coefficients of 99.45%, 98.73% and 0.98, respectively. The above results demonstrated that it was feasible to classify bacterial colonies on different agar media and the unified model provided a continent and accurate way for bacterial classification.

TBC2health: a database of experimentally validated health-beneficial effects of tea bioactive compounds.

Tea is one of the most consumed beverages in the world. Considerable studies show the exceptional health benefits (e.g. antioxidation, cancer prevention) of tea owing to its various bioactive components. However, data from these extensively published papers had not been made available in a central database. To lay a foundation in improving the understanding of healthy tea functions, we established a TBC2health database that currently documents 1338 relationships between 497 tea bioactive compounds and 206 diseases (or phenotypes) manually culled from over 300 published articles. Each entry in TBC2health contains comprehensive information about a bioactive relationship that can be accessed in three aspects: (i) compound information, (ii) disease (or phenotype) information and (iii) evidence and reference. Using the curated bioactive relationships, a bipartite network was reconstructed and the corresponding network (or sub-network) visualization and topological analyses are provided for users. This database has a user-friendly interface for entry browse, search and download. In addition, TBC2health provides a submission page and several useful tools (e.g. BLAST, molecular docking) to facilitate use of the database. Consequently, TBC2health can serve as a valuable bioinformatics platform for the exploration of beneficial effects of tea on human health. TBC2health is freely available at http://camellia.ahau.edu.cn/TBC2health.

Cas9 regulated gene expression and pathogenicity in Riemerella anatipestifer.

Riemerellosis, a Riemerella anatipestifer infection, can cause meningitis, pericarditis, parahepatitis, and airsacculitis in ducks, leading to serious economic losses in the duck meat industry. However, the molecular mechanism of the pathogenesis and virulence factors of this infection are poorly understood. In the present study, we created a mutant strain RA-YMΔCas9 using trans-conjugation. Bacterial virulence tests indicated that the median lethal dose (LD50) of RA-YMΔCas9 was 5.01 × 107 CFU, significantly lower than that of the RA-YM strain, which was 1.58 × 105 CFU. The distribution and blood bacterial load from the infection groups showed no significant difference in the brain between the RA-YMΔCas9 mutant and the wild-type RA-YM strains, however, the number of mutant strains were significantly reduced in the liver, heart, and blood. Animal immunization experiments demonstrated that the intranasal administration of RA-YMΔCas9 in ducklings provided 80% protection after challenge with the wild-type strain, showing potential use as a live mucosal vaccine. RNAseq analysis indicated that Cas9 protein played a regulatory role in gene expression. This study is the first to report on the involvement of Cas9 in the regulation and pathogenesis of R. anatipestifer, and provides a theoretical basis for the development of relevant genetic engineering vaccines.