The increasing incidence and emergence of polymyxin-resistant Acinetobacter baumannii pose a significant threat to global public health. The presence of sub-minimal inhibitory concentration (sub-MIC) antibiotics during clinical treatment is inevitable and may drive the development of antibiotic resistance. Therefore, understanding the fitness costs and underlying mechanisms of resistance evolution under sub-MIC polymyxin B (PMB) is crucial for controlling the spread of PMB-resistant strains. In this study, PMB resistance evolved rapidly within 1-2 days in different A. baumannii strains and acquisition of PMB resistance altered the bacterial susceptibility to other antibiotics. All evolved strains suffered varying degrees of fitness costs, manifesting as a reduced growth rate, in vitro competitiveness, motility ability, biofilm formation, and adhesion and invasion to host cells. Proteomic and qRT-PCR analyses revealed upregulation of efflux pumps, two-component systems and outer membrane proteins in resistant strains, along with downregulation of genes involved in lipid A biosynthesis, motility and biofilm formation. Notably, the increasing PMB resistance was attenuated upon co-treatment with efflux pump inhibitor CCCP. This study indicates that evolution of PMB resistance incurs substantial fitness costs in A. baumannii, and the loss of LPS production and overexpression of efflux pumps may represent the key mechanisms underlying this evolutionary process.

Two-component regulatory systems (TCSs) are ubiquitous signal transduction pathways in bacteria, enabling adaptive responses to environmental changes via phosphoryl signaling. In Vibrio parahaemolyticus, a globally significant enteropathogen, TCSs orchestrate survival strategies and pathogenicity. This review synthesizes current knowledge on the composition, signaling mechanisms, and functional roles of key TCSs in V. parahaemolyticus. Systems such as VbrK/VbrR, which senses β-lactams and nitrite to modulate β-lactamase production and suppresses type III secretion system 1 (T3SS1), and ArcB/ArcA, which integrates oxygen-dependent signals into quorum sensing and virulence regulation, highlight the adaptability of this pathogen. Other systems, including BarA/UvrY, PhoB/PhoR, and TtrS/TtrR, further illustrate the regulatory complexity governing metabolism, motility, and host colonization. Despite advances, significant gaps remain in understanding ligand specificity, cross-system interactions, and mechanistic details of transcriptional regulation, particularly for newly identified regulatory targets and auxiliary TCS interactions.

BACKGROUND:Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are becoming increasingly difficult to treat because of the resistance of this pathogen to multiple drugs and its ability to form biofilms. Therefore, the development of new antimicrobial agents to combat MRSA infections is urgently needed. METHODS:We designed and synthesized a series of structurally novel pyridine-fused quinolinones via a one-pot method, and compound PQ-L5 which exhibited excellent antibacterial activity against gram-positive bacteria, especially MRSA strains was selected for further study. The bactericidal activity, synergistic antibacterial effect and antibiofilm activity of PQ-L5 were investigated, and then its in vitro cytotoxicity and in vivo anti-MRSA efficacy were evaluated. RESULTS:PQ-L5 displayed rapid bactericidal activity without inducing resistance even after continuous passage. The mechanistic study revealed that PQ-L5 inhibited peptidoglycan biosynthesis by binding to PBP2a, disrupting the bacterial cell wall and ultimately resulting in bacterial death. Furthermore, PQ-L5 restored the susceptibility of MRSA to β-lactam antibiotics and could inhibit the biofilm formation of different MRSA strains at sub-MIC concentrations both alone and in combination with oxacillin. In addition, PQ-L5 had low hemolytic activity and cytotoxicity in vitro, and in a mouse skin tissue infection model, PQ-L5 alone or in combination with oxacillin at a low dose reduced the MRSA load in wounds and enhanced the process of wound healing. CONCLUSIONS:PQ-L5 might be a promising antimicrobial agent against MRSA infections and that the synergistic effect of PQ-L5 combined with β-lactams reduces the required dosages of these drugs and thus minimizes potential toxic side effects.

Linezolid (LZD) is used to treat infectious diseases caused by Gram-positive bacteria, but thrombocytopenia is one of the main adverse reactions to LZD administration. Early prediction of linezolid-induced thrombocytopenia (LI-TP) is of great importance to improve the clinical outcomes and prognoses. The aim of this study was to develop and validate a prediction model for LI-TP. A retrospective cohort of hospitalized adults receiving LZD therapy (January 2014–June 2022) was analyzed. Independent risk factors for LI-TP were identified via logistic regression in the training set (n = 757). A nomogram model for LI-TP were developed based on independent risk factors, and verified in validation set (n = 123). The incidence of LI-TP was 13.5

BACKGROUND:Thrombocytopenia is a common adverse side effects of Linezolid (LZD) but the underlying mechanism remains unclear. This study aimed to analyze the mechanism of LZD induced thrombocytopenia for LZD induced thrombocytopenia. METHODS:Cells proliferation, proplatelet formation assay and platelet production were evaluated in human megakaryoblastic leukemia cell line MEG-01 or C57BL/6 mice following LZD administration. The metabolic profiles and gene expression of MEG-01 cells was subsequently analyzed using molecular and bioinformatics techniques. RESULTS:LZD induced a dose- and time-dependent decrease in cells proliferation and inhibited proplatelet formation. It alters metabolic pathways including central carbon metabolism as indicated by a decrease in pyruvate, ATP and GTP levels (P < 0.01). Expression of genes related to energy production and conversion and the cytoskeleton were altered, such as SLC25A21, HBB, PRR5, MYL4 and RHoE (P < 0.01). Pyruvate supplementation rescued reduced metabolites induced by LZD, increased proplatelet formation of MEG-01 cells and length of pseudopod (P < 0.05). Furthermore, pyruvate rescued the counts of megakaryocytes in bone marrow and peripheral platelets in LZD treated mice (P < 0.05). CONCLUSION:LZD inhibits mitochondrial energy metabolism, resulting in proplatelet formation reduction. Pyruvate reverses LZD induced thrombocytopenia, which provide a basis for mechanistic insights of LZD induced thrombocytopenia.

Objective: This study aimed to investigate the effects of polymyxin B (PMB) in combination with other antibiotics on delaying resistance in Klebsiella pneumoniae and to explore the mechanisms underlying PMB-induced resistance. Methods: In vitro continuous induction experiments were performed to observe changes in drug susceptibility with PMB alone vs. in combination. RNA-seq, quantitative reverse transcription PCR, and proteomic analyses were utilized to evaluate differential gene and protein expression between induced-resistant strains and those exhibiting delayed resistance. Then, gene knockout experiments were performed to validate the functional roles of relevant genes. Results: These findings indicated that PMB alone could induce resistance within 1–2 d, whereas the combination with amikacin (AMK) or tigecycline delayed the onset of resistance by 6 d. RNA-seq, quantitative reverse transcription PCR, and proteomic analyses revealed significant upregulation of nlpE, two-component systems, and AcrAB-TolC efflux pump-associated genes in PMB-induced resistant strains, whereas these genes were downregulated in the delayed resistant strains of PMB combined with AMK. Deletion and complementation experiments demonstrated that the expression levels of two-component systems and efflux pump-related genes were downregulated in nlpE knockout strains. Furthermore, PMB induction experiments revealed a significant upregulation of PmrA, PhoP, PhoQ, PagP, and AcrB proteins associated with cationic antimicrobial peptide pathways in the wild-type and nlpE complemented strains, whereas no differential change was observed in the nlpE knockout strain. Conclusions: nlpE contributes to PMB resistance by modulating the AcrAB-TolC efflux pump and the PhoP/Q and PmrA/B two-component systems. The combined use of PMB with AMK effectively delays the development of resistance in K. pneumoniae through the regulation of nlpE and its associated signalling pathways.

The emergence of multidrug-resistant Klebsiella pneumoniae, including carbapenem-resistant K. pneumoniae (CRKP), as one of the most common and notable superbugs, has long been a major threat to public health. As natural predators of bacteria, bacteriophages (or phages) can induce the lysis of bacterial cells. Herein, we report the isolation and characterization of two phages and their efficacy in the control of CRKP. Using the sequence type 11 (ST11) CRKP strain THR60 and its related strain THR60r as the host bacteria, phages GZ7 and GZ9 were isolated from hospital sewage, respectively. GZ7 is a myovirus with a head of 64 nm in diameter and a tail of 97 nm in length, and GZ9 is a siphovirus with a head of 67 nm in diameter and a tail of 175 nm in length. The host spectrum of a phage cocktail consisting of phages GZ7 and GZ9 was 82.4% (42/51 strains). An in vitro antibacterial activity assay demonstrated that the phage cocktail consisting of GZ7 and GZ9 effectively inhibited bacterial growth and suppressed the production of phage-resistant bacteria. In vivo experiment revealed that phage-treated mice exhibited lower K. pneumoniae burdens in the lungs compared to untreated control mice. Additionally, phage-treated mice experienced less body weight loss and had reduced levels of inflammatory cytokines in their lungs. Lung lesion conditions were significantly improved by phage therapy. Notably, the therapeutic effects of the GZ7 + GZ9 cocktail and GZ7 alone on mouse pulmonary infections were nearly equivalent. Therefore, phages GZ7 and GZ9 showed potential as alternatives to antibiotics for treating pneumonia caused by multidrug-resistant K. pneumoniae.

OBJECTIVES:This study investigated the mechanisms underlying polymyxin B (PMB)-induced resistance and examined the role of PMB in combination with amikacin (AMK) in delaying the development of resistance. METHODS:In vitro continuous induction of three Klebsiella pneumoniae strains was performed using PMB alone or in combination with AMK, and variations in the minimum inhibitory concentration (MIC) were determined via the microdilution method. The Kp81 strain, which presented the most significant delay in resistance development, was selected for analysis of the expression of relevant genes via qRT-PCR. Homologous recombination techniques were employed to construct nlpE and cpxR gene knockout and complemented Kp81 strains, and the expression levels of these genes, as well as changes in the MIC following continuous induction, were assessed. Additionally, the biofilm-forming abilities of the strains were analyzed via crystal violet staining and confocal laser scanning microscopy. RESULTS:The results indicate that the combination of PMB and AMK can delay the development of resistance to PMB in K. pneumoniae. qRT-PCR analysis demonstrated a significant increase in the expression of phoP, nlpE, cpxR, and acrA in the resistant strain Kp81·R, whereas these genes were significantly downregulated in the resistant delay strain Kp81·DR. Notably, after 20 h of PMB treatment, the expression of nlpE was markedly elevated in the nlpE knockout strain. cpxR exhibited synchronized dynamic changes with nlpE in both the nlpE knockout and complemented strains, whereas acrA showed a similar expression pattern in the cpxR knockout and complemented strains. Additionally, the absence of nlpE or cpxR was found to delay PMB resistance. Furthermore, biofilm formation was significantly increased in both the resistant strains and those treated with PMB, while the combination of PMB with AMK inhibited biofilm formation. CONCLUSIONS:The combination of PMB and AMK can delay the development of resistance in K. pneumoniae to PMB. The nlpE gene, as a key regulatory factor, can influence PMB resistance by modulating the CpxA/R two-component system and biofilm formation.

Background: Rheumatoid arthritis (RA) tends to occur in symmetrical joints and is always accompanied by synovial hyperplasia and cartilage damage. Triptolide (TP), an extract from Tripterygium, has anti-inflammatory and immunomodulatory properties and could be used in the treatment of RA. However, its poor water solubility and the multi-system lesions caused by the use of this substance limit its clinical application. Therefore, it would be of great significance to assemble a composite nanoparticle hydrogel and apply it to a collagen-induced arthritis (CIA) mouse model to investigate the therapeutic effect and biosafety of this compound. Method: TP@HSA nanoparticles (TP@HSA NPs) were fabricated with a self-assembly method; a thermosensitive hydrogel loaded with the TP@HSA NPs (TP@HSA NP hydrogel) was prepared by using chitosan and beta- glycerophosphate (β-GP) and was then intra-articularly injected into CIA mice. The changes in joint swelling were measured with a digital caliper, and inflammation and cartilage damage were evaluated by using hematoxylin and eosin (H&E) and safranin O–fast green (SO&FG) staining, respectively. Results: TP@HSA NPs with an average diameter of 112 ± 2 nm were successfully assembled, and their encapsulation efficiency and drug loading efficiency were 47.6 ± 1.5% and 10.6 ± 3.3%, respectively. The TP@HSA NP hydrogel had a gelation temperature of 30.5 ± 0.2 °C, which allows for its injection at low temperatures and its sol–gel transformation under physiological conditions within 2 min, making it a suitable drug depot. The TP@HSA NP hydrogel was intra-articularly injected into CIA mice; it released TP locally and exerted anti-inflammatory and immunomodulatory effects, alleviating synovial inflammation and cartilage damage effectively. Conclusions: We successfully fabricated a TP@HSA NP-loaded thermosensitive hydrogel with good biosafety, which can release TP slowly for the treatment of RA. Our study provides a basis for the development of TP-based innovative preparations and has good application prospects.

Migraine, a neurological disorder with a significant female predilection, is the leading cause of disability-adjusted life years (DALYs) in women of childbearing age (WCBA). There is currently a lack of comprehensive literature analysis on the overall global burden and changing trends of migraines in WCBA. This study extracted three main indicators, including prevalence, incidence, and DALYs, related to migraine in WCBA from the Global Burden of Disease(GBD) database from 1990 to 2021. Our study presented point estimates with 95

OBJECTIVES:To investigate the factors influencing imipenem/cilastatin (IMI) and meropenem (MEM) concentrations in critically ill adult patients and the role of these concentrations in the clinical outcome. METHODS:Plasma trough concentrations of IMI and MEM were detected by high-performance liquid chromatography. A target value of 100%-time above MIC was used for the drugs. RESULTS:A total of 186 patients were included, with 87 receiving IMI and 99 receiving MEM. The percentages of patients reaching the target IMI and MEM concentrations were 44.8% and 38.4%, respectively. The proportions of patients infected with drug-resistant bacteria were 57.5% and 69.7% in the IMI group and MEM group, respectively. In the multivariate analysis, the risk factors for an IMI concentration that did not reach the target were infection with drug-resistant bacteria, and those for MEM were infection with drug-resistant bacteria, estimated glomerular filtration rate, and diabetes mellitus. A total of 47.1% of patients had good outcomes in the IMI cohort, and 38.1% of patients had good outcomes in the MEM cohort. The duration of mechanical ventilation and IMI concentration were associated with ICU stay in patients in the IMI cohort, while MEM concentration and severe pneumonia affected the clinical outcome of patients in the MEM cohort. CONCLUSION:Infection with drug-resistant bacteria is an important factor influencing whether IMI and MEM concentrations reach the target. Furthermore, IMI and MEM concentrations are associated with the clinical outcome, and elevated doses of IMI and MEM should be given to patients who are infected with drug-resistant bacteria.

Purpose:We aimed to assess the burden of Fungal Skin Diseases (FSD) in 2021 and explore the changing trends from 1990 to 2021 across different age groups and time periods. Methods:This study extracted three key indicators of the burden of FSD from the Global Burden of Disease (GBD) 2021 study: prevalence, incidence, and disability-adjusted life years (DALYs). The results were presented using point estimates and Uncertainty Intervals (UIs), and secondary analysis was conducted on these data to assess the changing trends in the burden of FSD using percentage change. Results:In 2021, the global cases of prevalence, incidence, and DALYs of FSD were reported at 616.5 million, 1,729.2 million, and 3,429.5 thousand, respectively, an increase of approximately 68% since 1990. The age-standardized rates per 100,000 population for prevalence, incidence, and DALYs were 7,789.6, 21,668.4, and 43.4, respectively. These rates represent percentage increases of 6.21%, 3.74%, and 6.56% since 1990. In terms of age distribution, the ages for FSD-related prevalence, incidence, and DALYs peak cases globally were in the 5-9 age group, with distinct age groups observed in low and low-middle, middle, high-middle and high SDI regions at 5-9 years, 45-49 years, and 70-74 years, respectively. Conclusion:Over the past 32 years, there has been a significant increase in the global burden of FSD. With improvements in the Socio-Demographic Index (SDI), the age groups for FSD-related peak cases are gradually shifting towards older age groups. This indicates the need to allocate healthcare resources rationally to address the challenges arising from the significant differences in geographic distribution, gender, and among different populations.

Radiation-induced colitis is a serious clinical problem worldwide. However, the current treatment options for this condition have limited efficacy and can cause side effects. To address this issue, colon-targeted fullerenol@pectin@chitosan gel microspheres (FPCGMs) are developed, which can aggregate on colon tissue for a long time, scavenge free radicals generated in the process of radiation, and regulate intestinal flora to mitigate damage to colonic tissue. First, FPCGMs exhibit acid resistance and colon-targeted release properties, which reduce gastrointestinal exposure and extend the local colonic drug residence time. Second, fullerenol, which has a superior scavenging ability and chemical stability, reduces oxidative stress in colonic epithelial cells. Based on this, it is found that FPCGMs significantly reduce inflammation in colonic tissue, mitigated damage to tight junctions of colonic epithelial cells, and significantly relieved radiation-induced colitis in mice. Moreover, 16S ribosomal DNA (16S rDNA) sequencing results show that the composition of the intestinal flora is optimized after FPCGMs are utilized, indicating that the relative abundance of probiotics increases while harmful bacteria are inhibited. These findings suggest that it is a promising candidate for treating radiation-induced colitis.

Background: Voriconazole (VCZ) metabolism is influenced by many factors. Identifying independent influencing factors helps optimize VCZ dosing regimens and maintain its trough concentration (C 0 ) in the therapeutic window. Methods: We conducted a prospective study investigating independent factors influencing VCZ C 0 and the VCZ C 0 to VCZ N-oxide concentration ratio (C 0 /C N ) in younger adults and elderly patients. A stepwise multivariate linear regression model, including the IL-6 inflammatory marker, was used. The receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive effect of the indicator. Results: A total of 463 VCZ C 0 were analyzed from 304 patients. In younger adult patients, the independent factors that influenced VCZ C 0 were the levels of total bile acid (TBA) and glutamic-pyruvic transaminase (ALT) and the use of proton-pump inhibitors. The independent factors influencing VCZ C 0 /C N were IL-6, age, direct bilirubin, and TBA. The TBA level was positively associated with VCZ C 0 ( ρ = 0.176, p = 0.019). VCZ C 0 increased significantly when the TBA levels were higher than 10 μmol/L ( p = 0.027). ROC curve analysis indicated that when the TBA level ≥4.05 μmol/L, the incidence of a VCZ C 0 greater than 5 μg/ml (95% CI = 0.54–0.74) ( p = 0.007) increased. In elderly patients, the influencing factors of VCZ C 0 were DBIL, albumin, and estimated glomerular filtration rate (eGFR). The independent factors that affected VCZ C 0 /C N were eGFR, ALT, γ-glutamyl transferase, TBA, and platelet count. TBA levels showed a positive association with VCZ C 0 ( ρ = 0.204, p = 0.006) and C 0 /C N ( ρ = 0.342, p < 0.001). VCZ C 0 /C N increased significantly when TBA levels were greater than 10 μmol/L ( p = 0.025). ROC curve analysis indicated that when the TBA level ≥14.55 μmol/L, the incidence of a VCZ C 0 greater than 5 μg/ml (95% CI = 0.52–0.71) ( p = 0.048) increased. Conclusion: TBA level may serve as a novel marker for VCZ metabolism. eGFR and platelet count should also be considered when using VCZ, especially in elderly patients.

Objective: Plasma trough concentration of voriconazole (VCZ) was associated with its toxicity and efficacy. However, the nonlinear pharmacokinetic characteristics of VCZ make it difficult to determine the relationship between clinical characteristics and its concentration. We intended to present a machine learning (ML)-based method to predict toxic plasma trough concentration of VCZ (>5 & mu;g/mL).Methods: A single center retrospective study was conducted. Three ML algorithms were used to estimate the concentration in adult patients, including random forest (RF), gradient boosting (GB), and extreme gradient boosting (XGBoost). The importance of variables was recognized by the SHapley Additive exPlanations (SHAP) method. In addition, an external validation set was used to validate the robustness of models.Results: A total of 1318 VCZ plasma concentration were included, with 33 variables enrolled in the model. Nine classification models were developed using the RF, GB, and XGBoost algorithms. Most models performed well for both the training set and test set, with an average balanced accuracy (BA) of 0.704 and an average accuracy (ACC) of 0.788. In addition, the average Matthews correlation coefficient value reached 0.484, which indicated the predicted values are meaningful. Based on the average BA and ACC values, the predictive ability of the models can be ranked from best to worst as follows: younger adult models > mixed models > elderly models, and XGBoost models > GBT models > RF models. The SHAP results showed that the top five influencing factors in younger adult patients (<60 years) were albumin, total bile acid (TBA), platelets count, age, and inflammation, while the top five influencing factors in elderly patients were albumin, TBA, aspartate aminotransferase, creatinine, and alanine aminotransferase. Furthermore, the prediction of external validation set for VCZ concentrations verified the high reliability of the models, for the ACC value of 0.822 by the best model.Conclusions: The ML models can be reliable tools for predicting toxic concentration exposure of VCZ. The SHAP results may provide useful guidelines for dosage adjustment of VCZ.

Background: The fruit of Terminalia chebula has been widely used for a thousand years for treating diarrhea, ulcers, and arthritic diseases in Asian countries. However, the active components of this Traditional Chinese medicine and their mechanisms remain unclear, necessitating further investigation. Objectives: To perform simultaneous quantitative analysis of five polyphenols in T. chebula and evaluate their anti-arthritic effects including antioxidant and anti-inflammatory activity in vitro. Materials and methods: Water, 50% water-ethanol, and pure ethanol were used as extract solvents. Quantitative analysis of gallic acid, corilagin, chebulanin, chebulagic acid, and ellagic acid in the three extracts was performed using high-performance liquid chromatography (HPLC). Antioxidant activity was assessed by the 2,2-diphenylpicrylhydrazyl (DPPH) radical-scavenging assay, and anti-inflammatory activity was evaluated by detecting interleukin (IL)-6 and IL-8 expression in IL-1β-stimulated MH7A cells. Results: The 50% water-ethanol solvent was the optimal solvent yielding the highest total polyphenol content, and the concentrations of chebulanin and chebulagic acid were much higher than those of gallic acid, corilagin, and ellagic acid in the extracts. The DPPH radical-scavenging assay showed that gallic acid and ellagic acid were the strongest antioxidative components, while the other three components showed comparable antioxidative activity. As for the anti-inflammatory effect, chebulanin and chebulagic acid significantly inhibited IL-6 and IL-8 expression at all three concentrations; corilagin and ellagic acid significantly inhibited IL-6 and IL-8 expression at high concentration; and gallic acid could not inhibit IL-8 expression and showed weak inhibition of IL-6 expression in IL-1β-stimulated MH7A cells. Principal component analysis indicated that chebulanin and chebulagic acid were the main components responsible for the anti-arthritic effects of T. chebula. Conclusion: Our findings highlight the potential anti-arthritic role of chebulanin and chebulagic acid from T. chebula.

Vibrio parahaemolyticus, a Gram-negative, halophilic bacterium, is a leading cause of acute gastroenteritis in humans. AphA and OpaR are the master quorum sensing (QS) regulators operating at low cell density (LCD) and high cell density (HCD), respectively. QsvR is an AraC-type protein that integrates into the QS system to control gene expression by directly controlling the transcription of aphA and opaR. However, the regulation of QsvR itself remains unclear to date. In this study, we show that vpa0607 and qsvR are transcribed as an operon, vpa0607-qsvR. AphA indirectly activates the transcription of vpa0607 at LCD, whereas OpaR and QsvR directly repress vpa0607 transcription at HCD, leading to the highest expression levels of vpa0607 occurs at LCD. Moreover, VPA0607 acts as an active RNase II-type protein in V. parahaemolyticus and feedback inhibits the expression of QsvR at the post-transcriptional level. Taken together, this work deepens our understanding of the regulation of QsvR and enriches the integration mechanisms of QsvR with the QS system in V. parahaemolyticus.

Introduction:Colistin is regarded as one of the last-resort antibiotics against severe infections caused by carbapenem-resistant Enterobacteriaceae. Strains with cooccurrence of mcr-9 and carbapenemase genes are of particular concern. This study aimed to investigate the genetic characteristics of a bla KPC-2-carrying plasmid, bla NDM-1-carrying plasmid and mcr-9-carrying plasmid coexisting in a carbapenem-resistant Enterobacter hormaechei isolate.Methods:E. hormaechei strain E1532 was subjected to whole-genome sequencing, and the complete nucleotide sequences of three resistance plasmids identified in the strain were compared with related plasmid sequences. The resistance phenotypes mediated by these plasmids were analyzed by plasmid transfer, carbapenemase activity and antimicrobial susceptibility testing.Results:Whole-genome sequencing revealed that strain E1532 carries three different resistance plasmids, pE1532-KPC, pE1532-NDM and pE1532-MCR. pE1532-KPC harboring bla KPC-2 and pE1532-NDM harboring bla NDM-1 are highly identical to the IncR plasmid pHN84KPC and IncX3 plasmid pNDM-HN380, respectively. The mcr-9-carrying plasmid pE1532-MCR possesses a backbone highly similar to that of the IncHI2 plasmids R478 and p505108-MDR, though their accessory modules differ. These three coexisting plasmids carry a large number of resistance genes and contribute to high resistance to almost all antibiotics tested, except for amikacin, trimethoprim/sulfamethoxazole, tigecycline and polymyxin B. Most of the plasmid-mediated resistance genes are located in or flanked by various mobile genetic elements, facilitating horizontal transfer of antibiotic resistance genes.Discussion:This is the first report of a single E. hormaechei isolate with coexistence of three resistance plasmids carrying mcr-9 and the two most common carbapenemase genes, bla KPC-2 and bla NDM-1. The prevalence and genetic features of these coexisting plasmids should be monitored to facilitate the establishment of effective strategies to control their further spread.