Frontiers in Microbiology
·
2025
·
IF 4.5
Zhibo Xu,Haonan Ma,Xinmiao Jiang,Quzhen Baima,Yuqi Zhen,Shipeng Yang,Xiuping Meng
Calcium hydroxide (Ca(OH)2) is commonly used as a root canal disinfectant, but its effectiveness against Enterococcus faecalis is limited, likely due to the bacterium’s ability to tolerate it. This study aimed to investigate the underlying mechanism of E. faecalis tolerance to repeated exposure to Ca(OH)2. Initially, E. faecalis was exposed to Ca(OH)2 for 10 successive passages. The survival rate of the bacteria increased progressively, suggesting the development of tolerance to Ca(OH)2. Crystal violet staining revealed that calcium hydroxide-tolerant strains formed more robust biofilms compared to standard strains. To delve into the mechanisms of Ca(OH)2 tolerance in E. faecalis, RNA sequencing was employed for a preliminary investigation. Transcriptome sequencing identified 683 differentially expressed genes (DEGs) in the calcium hydroxide-tolerant strain, with 368 genes upregulated and 315 downregulated compared to the standard strain. Bioinformatics analysis revealed that the upregulated genes were associated with carbohydrate transport and metabolism, starch and sucrose metabolism, quorum sensing, aminoacyl-tRNA biosynthesis, and two-component systems signaling pathways. In contrast, the downregulated genes were primarily linked to lipoic acid metabolism, degradation of valine, leucine, and isoleucine, and the citric acid cycle (tricarboxylic acid cycle) signaling pathways. The findings suggest that prolonged exposure to Ca(OH)2 induces tolerance in E. faecalis. RNA sequencing further revealed that this tolerance involves multiple interconnected signaling pathways, providing a critical foundation for future research into therapeutic strategies for E. faecalis infections.
研究领域:
微生物学
·
口腔医学
·
基因组学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Jiaying Cui,Nengwu Zhu,Naixin Kang,Chitam Ha,Chaohong Shi,Pingxiao Wu
In this study, the biorecovery mechanism of palladium ions (Pd(II)) as palladium nanoparticles by Enterococcus faecalis ( E. faecalis ), a typical Gram-positive bacterium, was explored from acting force, participated substance and reaction process. The XRD and TEM analysis showed that the deposit locations of Pd-NPs depended on the transfer of Pd(II) in biosorption, and the process was invested by effect factors and theory models of isotherm, thermodynamics, and kinetics, which was a spontaneous endothermic process fitted well by Langmuir isotherm and pseudo-second order kinetics. In addition, the surface characteristic changes of E. faecalis during biorecovery of Pd(II) were compared by FTIR and XPS, and it found that carboxyl groups, hydroxyl groups and amine groups were the main participated functional groups in biorecovery. Furthermore, the contrary pH change between biosorption and bioreduction combined with above results proved that electrostatic interaction, complex formation of Pd(II) on the cell and intracellular uptake were the acting forces for biosorption, and the bioreduction of adsorbed Pd(II) was via the hydrolysis and oxidation of sodium formate to deliver electron. Therefore, the biorecovery mechanism of Pd(II) can be divided into the biosorption from solution to cells, and then the bioreduction and crystallization in situ by the electron donor and the link frame of E. faecalis .
研究领域:
微生物学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Chitam Ha,Nengwu Zhu,Ru Shang,Chaohong Shi,Jiaying Cui,Ihsanullah Sohoo,Pingxiao Wu,Yanlan Cao
Precious metal Palladium (Pd) is a scarce natural resource with increasing industrial demand. The use of microorganisms for biorecovery of Pd is a promising approach because it mimics natural biogeochemical cycles. In this study, we investigated the biorecovery of Pd 0 nanoparticles (Pd 0 -NPs) by Enterococcus faecalis ( E. faecalis ) with sodium formate as electron donor. X-ray diffraction analyses exhibited that the process could successfully reduce Pd 2+ and generate Pd 0 -NPs. Transmission electron microscope observation showed that the Pd 0 -NPs were associated at the membrane and inside of the cell. Under the optimum conditions of temperature (40 °C), sodium formate concentration (25 mM), biomass (1.2 g L −1 ), and 210 mg L −1 Pd 2+ (pH 3.0–3.5) were completely reduced within 48 h. The percentage of the Pd 0 -NPs with an average size lower than 10 nm increased from 91.5% to 99.6% as the biomass increased from 1.2 to 3.6 g L −1 , respectively. The catalytic property of the Pd 0 -NPs treated by ultrasonication was higher than chemically prepared Pd 0 . It showed that 6.3 mg Pd 0 -NPs could catalyze the complete reduction of 5.0 μmol Cr 6+ in 12 h. All of these findings suggest that it is potentially feasible to recover Pd 0 -NPs with catalytic activity from industrial wastes using E. faecalis .
研究领域:
微生物学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers in Microbiology
·
2025
·
IF 4.5
Yuqi Zhen,Quzhen Baima,Shipeng Yang,Yu Cao,XiuPing Meng
Enterococcus faecalis (E. faecalis) is commonly associated with persistent periapical infections. Even after multiple courses of root canal therapy, the infection is difficult to eradicate due to its drug resistance and adaptability. However, root canal treatment will remove nutrients from the root canal and make the remaining E. faecalis near starvation. Iron is an essential element for the growth and metabolism of E. faecalis, but previous studies were mostly based on bacterial nutrient sufficient conditions. Therefore, in this study, the starvation state was used as the breakthrough point to explore the mechanism of iron on the biofilm formation of E. faecalis, so as to be more suitable for clinical practice. In this study, we first constructed a starving E. faecalis model. Subsequently, we found that iron supply promoted biofilm formation in starved E. faecalis, with more eDNA in the biofilm. Iron starvation induced by the iron competitive inhibitor gallium nitrate reduced biofilm formation but increased the proportion of eDNA. In contrast, high iron levels in the environment counteracted this inhibition of biofilm formation. Following DNase I treatment, both the eDNA content and viable bacteria within the biofilm of the iron-supply group exhibited a statistically significant reduction. These results suggest that iron supply may regulate the proliferation of active bacteria by regulating eDNA release, thereby promoting biofilm formation of starved E. faecalis and providing a new perspective on its survival strategy under stress.
研究领域:
微生物学
·
口腔医学
·
感染病学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PHOTOCHEMISTRY AND PHOTOBIOLOGY
·
2022
·Vol. 99
·期 1
·68-77
·
IF 3.521
Xianhu Wei,Qihui Gu,Ying Feng,Youxiong Zhang,Ying Li,Shuhong Zhang,Jumei Zhang,Shi Wu,Xiaojuan Yang,Qinghua Ye,Yu Ding,Juan Wang,Moutong Chen,Qingping Wu
A new, simple-to-synthesize and sensitive turn-on fluorogenic substrate ( CFMU-Glu ) for β-glucosidase activity was developed. This probe was based on a 7-hydroxycoumarin derivative ( CFMU ) that could emit green fluorescence and had the low p K a value of 5.61 ± 0.01. CFMU-Glu could be used for sensitive monitoring of the almond βGLU and Enterococcus faecalis ( E. faecalis ) at the optimal pHs of 6.50 and 7.00, respectively. Moreover, a new sensitive and selective fluorogenic broth (PBF-B) for E. faecalis , utilizing CFMU-Glu and polymyxin B, was also developed. Polymyxin B was discovered to can significantly improve the detection selectivity and signal intensity. The proposed 4-four method using PBF-B and a microcentrifuge tube could provide fluorogenic detection limits of 5.01 × 10 4 and 1.0 × 10 5 CFU mL −1 by fluorescence microplate reader and naked eye, respectively; it could also provide a turn-on chromogenic detection limit of 1.0 × 10 6 CFU mL −1 by naked eye. The proposed method could detect 8 CFU mL −1 of E. faecalis in drinking water, Liangcha (herbal tea) and milk samples within 10 h, without pre-enrichment.
研究领域:
微生物学
·
分析化学
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Jove-Journal of Visualized Experiments
·
2022
·
IF 1.424
Yuhao Ma,Zahariah Hasan,Jia Huang,Jun Chen,Chun Loong Ho
As microbes that thrive in the host body primarily have adaptive abilities that facilitate their survival, methods for classifying and identifying their nature would be beneficial in facilitating their characterization. Currently, most studies focus only on one specific characterization method; however, the isolation and identification of microorganisms from the host is a continuous process and usually requires several combinatorial characterization methods. Herein, we describe methods of identifying the microbial biofilm-forming ability, the microbial respiration state, and their chemotaxis behavior. The methods are used to identify five microbes, three of which were isolated from the bone tissue of Sprague-Dawley (SD) rats (Corynebacterium stationis, Staphylococcus cohnii subsp. urealyticus, and Enterococcus faecalis) and two from the American Type Culture Collection (ATCC)-Staphylococcus aureus ATCC 25923 and Enterococcus faecalis V583. The microbes isolated from the SD rat bone tissue include the gram-positive microbes. These microbes have adapted to thrive under stressful and nutrient-limiting environments within the bone matrix. This article aims to provide the readers with the specific know-how of determining the nature and behavior of the isolated microbes within a laboratory setting.
研究领域:
微生物学
·
分子生物学
·
传染病学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
mBio
·
2026
·
IF 5.4
Minghan Guan,Xiaoyu Guo,Mengzhen Kong,Yang Qin,Hua Xu,Xiaomin Su,Pan Wang,Xiaobing Wang
The development of various cancers is intricately linked with the human microbiome. Recent studies have highlighted a substantial association between pancreatic cancer and gut microbiota. However, the specific roles and underlying regulatory mechanisms of individual gut microbial species in pancreatic cancer progression remain poorly understood. Enterococcus faecalis, a common member of the human commensal microbiota, has been found to be enriched in the tumor tissues of pancreatic cancer patients. However, its functional contribution has not been clearly defined. In this study, we established a co-culture system involving E. faecalis and pancreatic cancer cells. Our results show that E. faecalis promoted the proliferation, migration, and invasion of pancreatic cancer cells. Following pre-treatment with E. faecalis, the phosphorylation level of epidermal growth factor receptor (EGFR) was markedly elevated. Inhibition of EGFR effectively suppressed the pro-proliferative effects induced by E. faecalis. Further investigation revealed that E. faecalis stimulated the production of reactive oxygen species (ROS) in pancreatic cancer cells. This ROS production might be sensed by Toll-like receptors (TLRs), leading to the activation of the EGFR signaling pathway. When cells were incubated with TLR inhibitors or ROS scavengers, both EGFR expression and its downstream pro-proliferative effects were significantly attenuated. Collectively, this study provides mechanistic insights into how E. faecalis contributes to pancreatic cancer progression and offers new perspectives for the development of diagnostic and therapeutic strategies targeting this microbial signaling pathway.
✓ 已验证
DOI
PubMed
高影响因子
AIP Advances
·
2024
·Vol. 14
·期 11
·
IF 1.4
Liu Xiao-Bin,Dai Xiao-Hua,Li Li,Shen Jing,Li Wei,Li Chang-Yi
Enterococcus faecalis ( E. faecalis ) is one of the dominant bacteria in infected root canals, and it is tolerant to commonly used root canal disinfectants. Ag + has a certain antibacterial effect on E. faecalis , but the instability and potential toxicity of Ag + limit its application. Metal azolate framework-7 (MAF-7) is a typical metal–organic framework that has been used for drug delivery due to its high encapsulation efficiency, tunable release profile, and low cytotoxicity. In this study, we used a simple method for the synthesis of Ag + /MAF-7 nanocomposites. After characterization via several techniques, the antibacterial activity of this nanocomposite against E. faecalis was investigated. Ag + was found to be uniformly bound to MAF-7, and the resulting Ag + /MAF-7 nanocomposite showed significant antibacterial activity against E. faecalis . This study demonstrates the potential application of nanocomposite antibacterial materials in treating infected root canals.
研究领域:
牙科学
·
微生物学
·
纳米医学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2024
·
IF 3.7
Chengchun Chen,Duoyun Li,Yongpeng Shang,Zhiwei Lin,Zewen Wen,Peiyu Li,Zhijian Yu,Zhong Chen,Xiaoju Liu
Enterococcus faecalis infections pose a significant clinical challenge due to their multidrug resistance and propensity for biofilm formation. Exploring alternative treatment options, such as repurposing existing drugs, is crucial in addressing this issue. This study investigates the antibacterial activity of candesartan cilexetil against E. faecalis and elucidates its mechanism of action. Candesartan cilexetil exhibited notable antibacterial activity against both E. faecalis and Enterococcus faecium, with minimum inhibitory concentration (MIC) of ≤25 μM. Time-kill curves demonstrated concentration-dependent bactericidal effects. Candesartan cilexetil could significantly inhibited biofilm formation at the concentration of 1/4× MIC and induced alterations in biofilm structure. Permeability assays revealed compromised bacterial membranes, accompanied by the dissipation of membrane potential in E. faecalis cells after treatment with candesartan cilexetil. Checkerboard analysis showed that bacterial membrane phospholipids phosphatidylglycerol and cardiolipin could neutralize the antibacterial activity of candesartan cilexetil in a dose-dependent manner. Biolayer interferometry (BLI) assay indicated specific interactions between candesartan cilexetil and phosphatidylglycerol or cardiolipin. This study demonstrates the promising antibacterial and antibiofilm activities of candesartan cilexetil against multidrug-resistant E. faecalis. The mechanism of action involves disruption of bacterial membranes, possibly by interacting with membrane phospholipids. These findings underscore the potential utility of candesartan cilexetil as an effective therapeutic agent for combating E. faecalis infections, offering a valuable strategy in the battle against antibiotic-resistant pathogens.
研究领域:
微生物学
·
药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MicrobiologyOpen
·
2020
·Vol. 10
·期 1
·e1148
·
IF 3.142
Xianghai Zeng,Pengfei She,Linying Zhou,Shijia Li,Zubair Hussain,Lihua Chen,Yong Wu
Graphical Penfluridol shows effective antimicrobial effects against Enterococcus faecalis in vitro and in vivo. The drug prevents biofilm formation and eliminates mature biofilms. The bacterium Enterococcus faecalis has increasingly attracted global attention as an important opportunistic pathogen due to its ability to form biofilms that are known to increase drug resistance. However, there are still no effective antibiofilm drugs in clinical settings. Here, by drug repurposing, we investigated the antibacterial activity of penfluridol (PF), an oral long-acting antipsychotic approved by the FDA, against E . faecalis type strain and its clinical isolates. It was found that PF inhibited the growth of E . faecalis planktonic cells with the MIC and MBC of 7.81 µg/ml and 15.63 ~ 62.50 µg/ml, respectively. Moreover, PF could significantly prevent the biofilm formation of E . faecalis at the concentration of 1 × MIC. Furthermore, PF significantly eradicated 24 h pre-formed biofilms of E . faecalis in a dose-dependent manner, with a concentration range of 1 × MIC to 8 × MIC. Here, through the checkerboard method with other tested conventional antibiotics, we also determined that gentamycin, penicillin G, and amikacin showed partial synergistic antibacterial effects with PF. Also, PF showed almost no hemolysis on human erythrocytes. In a mouse peritonitis model, a single dose of 20 mg/kg of PF treatment could significantly reduce the bacterial colonization in the liver (~5-fold reduction) and spleen (~3-fold reduction). In conclusion, these findings indicated that after structural optimization, PF has the potential as a new antibacterial agent against E . faecalis .
研究领域:
药理学
·
微生物学
·
传染病
·
药物开发
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Frontiers in Microbiology
·
2020
·
IF 4.236
Wen Zewen,Shang Yongpeng,Xu Guangjian,Pu Zhangya,Lin Zhiwei,Bai Bing,Chen Zhong,Zheng Jinxin,Deng Qiwen,Yu Zhijian
Opportunistic infections caused by multidrug-resistant Enterococcus faecalis strains are a significant clinical challenge. Eravacycline (Erava) is a synthetic fluorocycline structurally similar to tigecycline (Tige) that exhibits robust antimicrobial activity against Gram-positive bacteria. This study investigated the in vitro antimicrobial activity and heteroresistance risk of Eravacycline (Erava) in clinical E. faecalis isolates from China along with the mechanism of Erava resistance. A total of 276 non-duplicate E. faecalis isolates were retrospectively collected from a tertiary care hospital in China. Heteroresistance to Erava and the influence of tetracycline (Tet) resistance genes on Erava susceptibility were examined. To clarify the molecular basis for Erava resistance, E. faecalis variants exhibiting Erava-induced resistance were selected under Erava pressure. The relative transcript levels of six candidate genes linked to Erava susceptibility were determined by quantitative reverse-transcription PCR, and their role in Erava resistance and heteroresistance was evaluated by in vitro overexpression experiments. We found that Erava minimum inhibitory concentrations (MICs) against clinical E. faecalis isolates ranged from ≤0.015 to 0.25 mg/l even in strains harboring Tet resistance genes. The detection frequency of Erava heteroresistance in isolates with MICs ≤ 0.06, 0.125, and 0.25 mg/l were 0.43% (1/231), 7.5% (3/40), and 0 (0/5), respectively. No mutations were detected in the 30S ribosomal subunit gene in Erava heteroresistance-derived clones, although mutations in this subunit conferred cross resistance to Tige in Erava-induced resistant E. faecalis. Overexpressing RS00630 (encoding a bone morphogenetic protein family ATP-binding cassette transporter substrate-binding protein) in E. faecalis increased the frequency of Erava and Tige heteroresistance, whereas RS12140, RS06145, and RS06880 overexpression conferred heteroresistance to Tige only. These results indicate that Erava has potent in vitro antimicrobial activity against clinical E. faecalis isolates from China and that Erava heteroresistance can be induced by RS00630 overexpression.
研究领域:
微生物学
·
药理学
·
临床医学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Frontiers in Microbiology
·
2019
·
IF 4.259
Tan Fang,She Pengfei,Zhou Linying,Liu Yiqing,Chen Lihua,Luo Zhen,Wu Yong
Enterococcus faecalis (E. faecalis), a biofilm-forming pathogen, causes nosocomial infections. In recent years, drug resistance by enterococci has become increasingly severe due to widespread antibiotic abuse. Therefore, novel antibacterial agents are urgently needed. In this study, the synthetic retinoid compound CD437 was found to have potent bactericidal effect on E. faecalis. In addition, CD437 exhibited synergistic effects when administered in combination with gentamicin and additive effects when combined with ceftriaxone sodium. CD437 also inhibited biofilm formation by E. faecalis and exerted bactericidal effect on mature biofilm. Moreover, CD437 exhibited antibacterial and anti-biofilm effects against Staphylococcus. No bactericidal action of CD437 was observed against the gram-negative bacillus, but Pseudomonas aeruginosa biofilm extracellular polymeric substances (EPS) matrix formation was reduced. Overall, these findings indicate that CD437 has the potential to be developed as a novel antibacterial drug.
研究领域:
微生物学
·
药理学
·
传染病学
✓ 已验证
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）