Virulence
·
2025
·
IF 5.4
Hao-Jie Shen,Jun-Feng Wang,Zheng-Jie Xue,Jia-Qi Shi,Bing Chen,Dong-Min Chen,Ni-Pi Chen,Yu-Dong Li,Chao-Dong Qian
Antimicrobial resistance is one of the greatest threats to global health. A thorough comprehension of the underlying processes through which bacteria evolve the ability to withstand diverse stressors is vital for the development of efficacious strategies to address this challenge. This study aimed to elucidate the mechanisms underlying the adaptation of an acrB-deficient strain of Escherichia coli ATCC 35218 (35218m) to sanguinarine (SAN), the main component of phytobiotic derived from Macleaya cordata. Analysis of the in vitro-selected SAN-resistant clones of strain 35218m led to the identification of a functionally uncharacterized TetR regulator, EefR. The regulator represses its own expression and that of four neighboring genes forming the eefRABCD operon, encoding components of a tripartite RND-efflux pump (EefABC) and a putative MFS-type exporter (EefD). Overexpression of these pumps reduces the susceptibility of acrB-deficient E. coli to SAN and structurally diverse antibiotics. The eefR-eefABC-eefD cluster, widely distributed across Enterobacteriaceae genomes, is also found on plasmids in several E. coli isolates, indicating a significant risk for the rapid spread of this multidrug resistance mechanism.
研究领域:
微生物学
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分子生物学
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耐药机制
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细菌遗传学
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抗生素耐药性
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DOI
PubMed
高影响因子
Emerging Microbes & Infections
·
2018
·
IF 6.032
Jin-xin Zheng,Zhi-wei Lin,Xiang Sun,Wei-hong Lin,Zhong Chen,Yang Wu,Guo-bin Qi,Qi-wen Deng,Di Qu,Zhi-jian Yu
This study investigated the characteristics and mechanisms of eravacycline resistance and heteroresistance in clinical Klebsiella pneumoniae isolates. A total of 393 clinical K. pneumoniae isolates were collected and subjected to eravacycline and tigecycline MIC determinations using the agar dilution method. Eravacycline heteroresistance was assessed by a population analysis profile (PAP). The expression levels of efflux pumps and their regulators were determined by quantitative reverse-transcription PCR (qRT-PCR). This study identified 67 eravacycline-nonsusceptible isolates; among the extended-spectrum β-lactamase (ESBL)-positive isolates, eravacycline-nonsusceptible isolates were detected more frequently than tigecycline-nonsusceptible isolates (21.7% vs. 9.4%, p = 0.001). The study sample was observed to include 20 K. pneumoniae isolates with eravacycline heteroresistance. Compared to the reference strain, oqxA or oqxB overexpression was observed in nine eravacycline-nonsusceptible isolates (range, 35.64–309.02-fold) and 13 eravacycline-heteroresistant isolates (8.42–296.34-fold). The overexpression of macA or macB was detected in 12 eravacycline-heteroresistant isolates (3.23–28.35-fold). Overexpression of the efflux pump regulator gene ramA was observed in 11 eravacycline-nonsusceptible isolates (3.33–94.05-fold) and 18 eravacycline-heteroresistant isolates (3.89–571.70-fold). The eravacycline MICs were increased by one–fourfold by overexpression of oqxAB or macAB in three eravacycline-sensitive isolates. In conclusion, the overexpression of OqxAB and MacAB efflux pumps and the transcriptional regulator RamA were suggested to be involved in K. pneumoniae eravacycline resistance and heteroresistance.
研究领域:
微生物学
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医学
·
药理学
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产品关联
DOI
PubMed
高影响因子
STRUCTURE
·
2025
·
IF 4.3
Zhenlin Ouyang,Wenbo He,Di Wu,Hao An,Lei Duan,Min Jiao,Xiaoyu He,Qinyue Yu,Jiaxin Zhang,Qian Qin,Ruochen Wang,Fang Zheng,Peter M. Hwang,Xiaoting Hua,Li Zhu,Yurong Wen
Multidrug-resistant Acinetobacter baumannii has emerged as one of the most antibiotic-resistant bacterial pathogens associated with nosocomial infection, with its resistance highly depending on multiple multidrug efflux pumps. Here, we report the cryoelectron microscopy (cryo-EM) structure of Acinetobacter drug efflux G (AdeG), the inner membrane component of one of three important resistance-nodulation-cell division (RND) pump family members in A. baumannii , which is involved in drug resistance to chloramphenicol, trimethoprim, ciprofloxacin, and clindamycin. We systematically compare the structures and substrate binding specificities of AdeG, AdeB, and AdeJ multidrug efflux pumps via molecular docking, revealing potential determinants for drug binding. Knockout experiments demonstrate a functional complementarity between AdeABC, AdeFGH, and AdeIJK. Our study provides a structural understanding of A. baumannii multidrug efflux pump AdeG and reveals complementary drug efflux activity between AdeG and other RND efflux pumps, which may promote further rational drug discovery efforts targeting multidrug efflux pumps.
研究领域:
微生物学
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结构生物学
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药理学
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产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2025
·
IF 9
Jian Gao,Jingyu Wu,Yuancai Chen
This study found that bio-Pd 0 nanoparticles could launch proton motive force (PMF)-mediated antibiotics efflux pump (AEP) to confer the detoxification capability on Citrobacter freundii , as evidenced by the highest sulfamethoxazole (SMX) specific degradation rate (81.7 μg L −1 mg −1 protein d −1 ) at high PMF (pH 6). The batch experiment and RT-qPCR results indicated that bio-Pd 0 activated the AcrB efflux pump through upregulating the AEP transcriptional regulation factor ramA (2.7–3.1 times), which benefited the intra/extracellular respiration and ATP production/utilization. Path analysis revealed that the prosperity of metabolic activity and extracellular electron output capacity enabled SMX biodegradation, mainly through the electron redistribution and energy optimization with the formate dehydrogenase/hydrogenase based Short-chain (FDH/Hase-S-chain). The upregulation of hypE (2.7–8.6 times) and atpD (1.9–2.3 times) genes encoding the Hase respiratory chain and the F-type ATP synthase, respectively, further supports this mechanism. These novel findings provided a new strategy to improve the biodegradation efficiency of antibiotics wastewater.
研究领域:
微生物学
·
环境科学
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产品关联
DOI
PubMed
高影响因子
INFECTION GENETICS AND EVOLUTION
·
2021
·
IF 3.342
Dongmei Jia,Wenping Sun
Objectives A frequent emergence of drug resistance has been observed and posed great threat to global public health recently. This work aimed to investigate the potential synergistic effect and the underlying mechanisms of AgNPs-fluconazole combination more extensively through 2 clinically isolated fluconazole-resistant Candida albicans ( C. albicans ) strains. Methods Antifungal properties of AgNPs and fluconazole alone or together against planktonic cells and biofilms were tested. Cellular and molecular targets associated with fluconazole resistance were monitored after AgNPs treatment. Antifungal potential of AgNPs-fluconazole combination was also explored in vivo using a mouse model of disseminated candidiasis. Tissue burden and survival rate were analyzed. Results The results indicated that AgNPs worked synergistically with fluconazole against both planktonic cells of fluconazole-resistant C. albicans and biofilms formed <12 h. AgNPs treatment down-regulated ERG1 , ERG11 , ERG25 , and CDR2 , decreased membrane ergosterol levels and membrane fluidity, reduced membrane content of Cdr1p, Cdr2p, and thus efflux bump activity. The elevated ROS production was also a likely cause of the synergistic effect. In vivo , AgNPs and fluconazole combination significantly decreased the fungal burden and improved the survival rate of infected mice. Conclusion In conclusion, these results further confirm that AgNPs-fluconazole combination is a hopeful strategy for the treatment of fluconazole-resistant fungal infections.
研究领域:
微生物学
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药理学
·
感染性疾病
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产品关联
DOI
PubMed
高影响因子
Microbiology Spectrum
·
2025
·
IF 3.8
Heng Zhang,Yizheng Zhou,Hanmo Yang,Xinyi Tao,Yinping Chen,Fuqiang Dong,Yi Sun
The growing resistance of Aspergillus to azoles poses a significant challenge in treating invasive fungal infections. This study aimed to investigate the synergistic effect of berbamine hydrochloride (BBM) combined with azoles in treating Aspergillus fumigatus and explore the role of efflux pump inhibition in this synergy. The efficacy of combining BBM with itraconazole (ITC), voriconazole (VOR), and posaconazole (POS) was tested against 69 A. fumigatus strains that had been identified using the M38-A3 broth microdilution method. quantitative reverse transcription PCR (RT-qPCR) was used to measure gene expression related to synergy, while flow cytometry was employed to assess mitochondrial reactive oxygen species (ROS) levels, and Rhodamine 6G exocytosis assays were performed to quantify efflux pump activity. BBM alone showed no significant antifungal activity. BBM combined with POS exhibited synergy against 66 strains (95.7%), while two clinical isolates (Af05/Af08) and one defective strain (Δcdr1B) showed no synergy. Synergy with ITC was observed in three strains (4.3%), but not with VOR. In the non-synergistic Af05 and Af08 strains, the expression of the cdr1B gene was significantly lower compared to wild-type (WT) strains. ROS levels increased significantly in WT with POS and BBM combination therapy, but not in the defective strains. Glucose uptake was also reduced in the POS-BBM combination. BBM enhances azole sensitivity in A. fumigatus primarily by inhibiting the cdr1B-mediated efflux pump, supported by reduced Rhodamine 6G exocytosis and synergy loss in cdr1B-deficient strains. ROS accumulation and metabolic disruption may further contribute to this synergy. Targeting efflux pumps with BBM provides a novel strategy to combat azole resistance.
研究领域:
医学
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微生物学
·
药理学
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产品关联
DOI
PubMed
高影响因子
AQUACULTURE
·
2025
·
IF 3.9
Keda Ying,Xinru Ren,Meiru Tong,Siyu Ye,Yuhong Shi,Qianjin Zhou,Jiong Chen
Multidrug-resistant (MDR) pathogens are a significant threat to aquaculture due to their resistance to most conventional drugs. AcrAB-TolC is a known MDR efflux pump that increases antibiotic resistance. Inhibiting such pumps is a promising strategy in drug discovery. In this study, phytocompounds derived from Commelina communis (Asiatic dayflower) have been identified as candidate inhibitors for AcrB of Aeromonas hydrophila through virtual screening, encompassing molecular docking and molecular dynamics (MD) simulation. Consequently, five phytocompounds from the Asiatic dayflower met the criteria as suggested by the TCMSP database. Among them, flavocommelin, luteolin, and delphin_qt, exhibiting values higher than or equal to the control PAβN, emerged as candidate inhibitors of AcrB protein according to molecular docking analysis. Luteolin, which adhered to Lipinski's rule of five, was stable in binding to AcrB in a 50 ns molecular dynamics simulation. Luteolin also attenuated the reduction in Nile Red fluorescence in a dose-dependent manner, indicating the actual inhibition of the AcrAB-TolC efflux pump of the MDR A. hydrophila Y-1. The checkerboard synergy analysis revealed that luteolin exerted a positive impact on the six tested antibiotics, with fractional inhibitory concentration (FIC) indexes ranging from 0.125 to 0.375. Luteolin and florfenicol were recognized for having the best synergistic activity. When Ctenopharyngodon idella (grass carp) and Plecoglossus altivelis (ayu) were infected by A. hydrophila Y-1, the combination of luteolin and florfenicol markedly enhanced the survival rate and declined the bacterial load, as compared to either luteolin or florfenicol alone. Thus, luteolin is an effective efflux pump inhibitor for AcrAB-TolC of A. hydrophila , enhancing antibiotic sensitivity and exhibiting synergistic effects with antibiotics.
研究领域:
微生物学
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药理学
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分子生物学
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产品关联
DOI
高影响因子
ENVIRONMENT INTERNATIONAL
·
2019
·
IF 7.943
Qing-Lin Chen,Dong Zhu,Xin-Li An,Jing Ding,Yong-Guan Zhu,Li Cui
Growing evidences have demonstrated that heavy metal contamination can promote the proliferation of antibiotic resistance genes (ARGs) via co-selection. However, effects of nano-metal-materials on the occurrence and level of ARGs in the soil and plant, have not been fully explored. To gain insights into this impact, we conducted a pot experiment by adding nano‑silver particles (AgNPs) as a stimuli and Ag ion (AgNO 3 ) and tetracycline as a comparison. By using high throughput quantitative PCR, our results indicated that application of AgNPs (~20 nm and ~50 nm) at a concentration of 100 ppm resulted in no significant changes in the abundance of ARGs in either soil or phyllosphere ( P > 0.05). Nevertheless, the overall pattern of resistome, especially in soil, was shifted following AgNPs application, with a significance increase in the relative abundance of efflux pumps genes, which is an important mechanism for co-selection of ARGs by heavy metals. By comparison, Ag ion at an equivalent Ag mass of AgNPs markedly increased ARGs abundance and shifted ARGs profile in soil, indicating that free Ag ion had a stronger impact on ARGs than AgNPs. These findings provide new insights in assessing the risks of manufactured nanomaterials accumulated in the environment.
研究领域:
环境科学
·
微生物学
·
土壤学
·
植物科学
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DOI
PubMed
高影响因子
Biochimica et Biophysica Acta-Gene Regulatory Mechanisms
·
2023
·
IF 4.7
Xinying Sui,Xinyu Cheng,Zhaodi Li,Yonghong Wang,Zhenpeng Zhang,Ruyue Yan,Lei Chang,Yanchang Li,Ping Xu,Changzhu Duan
Fungal infections and antifungal resistance are the increasing global public health concerns. Mechanisms of fungal resistance include alterations in drug-target interactions, detoxification by high expression of drug efflux transporters, and permeability barriers associated with biofilms. However, the systematic panorama and dynamic changes of the relevant biological processes of fungal drug resistance acquisition remain limited. In this study, we developed a yeast model of resistance to prolonged fluconazole treatment and utilized the isobaric labels TMT (tandem mass tag)-based quantitative proteomics to analyze the proteome composition and changes in native, short-time fluconazole stimulated and drug-resistant strains. The proteome exhibited significant dynamic range at the beginning of treatment but returned to normal condition upon acquisition drug resistance. The sterol pathway responded strongly under a short time of fluconazole treatment, with increased transcript levels of most enzymes facilitating greater protein expression . With the drug resistance acquisition, the sterol pathway returned to normal state, while the expression of efflux pump proteins increased obviously on the transcription level. Finally, multiple efflux pump proteins showed high expression in drug-resistant strain. Thus, families of sterol pathway and efflux pump proteins, which are closely associated with drug resistance mechanisms, may play different roles at different nodes in the process of drug resistance acquisition. Our findings uncover the relatively important role of efflux pump proteins in the acquisition of fluconazole resistance and highlight its potential as the vital antifungal targets.
研究领域:
微生物学
·
药物研发
·
蛋白质组学
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产品关联
DOI
PubMed
高影响因子
Animals
·
2025
·Vol. 15
·期 23
·3491
·
IF 2.7
Yongjie Zhang,Liyang Guo,Shun Wang,Jie Zhang,Xinlei Ren,Rui Li,Jichang Li,Chunli Chen
Simple SummaryPolymyxin E is widely considered the last resort for treating multidrug-resistant Gram-negative bacteria. However, due to the emergence of the plasmid-mediated MCR-1 resistance gene, an increasing number of strains have developed resistance to polymyxin E. Additionally, the prevalence ofEscherichia coliin chickens has imposed a heavy burden on the global food and poultry farming industries. This study aimed to investigate the in vitro and in vivo synergistic effects and mechanisms of quercetin (QUE) combined with polymyxin E against MCR-1-positiveE. coliJD37 from chickens. The in vitro and in vivo synergistic effects of QUE and polymyxin E were confirmed through in vitro drug sensitivity tests, growth curves, time-kill curves, agar diffusion tests, and in vivo chick infection experiments. The results showed that QUE restored the sensitivity of polymyxin E toE. coliJD37 and restored the sensitivity of polymyxin E toE. coliJD37 mainly by increasing the permeability of the cell membrane, elevating the fluidity of the cell membrane, increasing the membrane potential, and reducing the expression of the AcrAB-TolC efflux pump and Lipopolysaccharide (LPS) regulatory-related genes. Molecular docking results revealed the key binding sites of QUE to MCR-1.In animal husbandry and livestock farming, with the spread of the plasmid-mediated MCR-1 gene, polymyxin E, as the last line of defense against drug-resistant Gram-negative bacteria, is facing severe challenges. This study investigated the in vitro and in vivo synergistic effects and mechanisms of QUE combined with polymyxin E against MCR-1-positive chickenE. coliJD37. In vitro experiments showed that QUE could restore the sensitivity ofE. coliJD37 to polymyxin E (FIC = 0.34375) and enhance the bactericidal effect of polymyxin E by increasing cell membrane permeability, fluidity, and membrane potential, downregulating the expression of the AcrAB-TolC efflux pump and LPS-related genes. Molecular docking further identified the key residues for QUE binding to the MCR-1 protein. The in vivo chick infection model confirmed that combination therapy increased survival rates, reduced bacterial load in tissues, alleviated pathological damage, and decreased levels of intestinal inflammatory factors. Our results demonstrate the synergistic bactericidal effect of the QUE-polymyxin E combination against MCR-1-positiveE. coliand elucidate its underlying mechanism.
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yi Xu,Guoxiang You,Shihong Yang,Jie Zhang,Jun Hou
Nano zero-valent iron (nZVI) assisted anaerobic digestion (AD) is considered an effective approach for mediating antibiotic resistance genes (ARGs) dissemination in activated sludge. However, little is known about the mechanisms that drive antibiotic resistomes evolution in relation with their physiological roles distinct from protection of bacteria against antimicrobials. Metagenomic sequencing showed that efflux pumps and rRNA methyltransferase genes were the most prevalent ARGs in anaerobes, being responsible for the variations of antibiotic resistome upon nZVI addition. Particularly, to withstand the oxidative stimuli derived from initially 9 days nZVI exposure, genes involved in the two component systems ( PhoRB , BaeSR , EvgSA ) and global regulator networks ( MarA , SoxS ) were increased, activating the chromosomally encoded intrinsic efflux pumps expression. Furthermore, to benefit for survival, the polyspecific efflux pumps were involved in the microbial physiological adaptations of enhanced siderophores, lipid moieties, and quorum sensing molecules exportation, which induced the adaptative efflux pumps expression. On the other hand, to maintain the protein synthesis under oxidative condition, genes encoding Rsm, Erm, and Rlu family methyltransferases were notably up-regulated via horizontal transfer, inducing the acquired rRNA methylation resistance. Importantly, after prolonged exposure to nZVI for 18 and 27 days, the antibiotic resistomes were measurably decreased, due to the recovered oxidative state and increased membrane rigidity. Overall, these findings provide a deep understanding on the necessity of antibiotic resistome evolution for anaerobes to adapt to nZVI exposure for survival, which can be introduced to improve the ARGs risks analysis.
研究领域:
环境科学
·
微生物学
·
分子生物学
✓ 已验证
DOI
高影响因子
Biomaterials Science
·
2018
·Vol. 6
·期 7
·1923-1935
·
IF 5.831
Xu Chen,Yanan Liu,Ange Lin,Na Huang,Liquan Long,Ye Gang,Jie Liu
Efflux pump system-mediated bacterial multidrug resistance is one of the main causes of antibiotic failure. Therefore, it is necessary to develop a novel nanocarrier that could effectively inhibit drug-resistant bacteria by increasing the intake and retention time of antibiotics. Herein, we constructed a pH-responsive nanocarrier (MSN@FA@CaP@FA) with double folic acid (FA) and calcium phosphate (CaP) covered on the surface of mesoporous silica (MSN) by electrostatic attraction and biomineralization, respectively. Afterward, loading the nanocomposites with ampicillin (Amp) effectively increased the uptake and reduced the efflux effect in Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by the specific targeting of FA. Moreover, Amp-MSN@FA@CaP@FA could specifically transport Amp to the bacterial infection site. Similarly, antibacterial experiments revealed that the Amp-MSN@FA@CaP@FA could significantly enhance the activity of Amp for inhibiting drug-resistant bacteria, without producing drug resistance. Additionally, the Amp-MSN@FA@CaP@FA could reduce the content of protein and inhibit the protein activity in drug-resistant bacteria, so that it destroyed the bacterial membrane and led to the bacteria death. In vivo antibacterial experiments showed that the Amp-MSN@FA@CaP@FA could effectively reduce the mortality of drug-resistant E. coli infection and promote wound healing of drug-resistant S. aureus infection. In summary, Amp-MSN@FA@CaP@FA has a potential for application in sustained-release nanostructures and to inhibit drug-resistant bacteria.
研究领域:
纳米医学
·
微生物学
·
药物递送系统
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）