AFRICAN JOURNAL OF BIOTECHNOLOGY
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2018
·Vol. 17
·期 8
·232-238
·
IF 0
Renata Albuquerque Costa,Theodora Thays Arruda Cavalcante,Carla Thiciane Vasconcelos de Melo,Domingos Lucas Araújo Barroso,Hider Machado Melo,Mário Geraldo de Carvalho,Francisco Eduardo Aragão Catunda Júnior
Chemical composition, in vitro antioxidant and antibacterial activities of essential oil of Lippia sidoides (EOLS) and its major constituent was investigated. Chemical composition was analyzed in a gas chromatograph coupled to a mass spectrometer (GC/MS). Antioxidant activity (AA) was obtained using 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging assay. Antimicrobial activity was tested using disk-diffusion test against Staphylococcus aureus ATCC 25923 and nine S. aureus strains resistant to beta-lactams, tetracycline and quinolone. EOLS chemical composition revealed the presence of 15 components identified as monoterpenes hydrocarbon (1.56%), oxygenated monoterpenes (94.31%) and sesquiterpenes hydrocarbon (4.11%), and the major components were thymol (79.70%). All OELS concentrations analyzed showed AA varying from 19.09 ± 2.088% (100 µg/mL) to 74.32 ± 1.61% (3.200 µg/mL). For thymol, the most efficient AA (70.11 ± 3.43%) was found with higher concentration (6.400 µg/mL). All S. aureus strains (n = 10) were sensitive to OELS and thymol. When OELS was used, the halo size of the ATCC strain was 74.4 mm and for the resistant-strains, it ranged from 29 to 60.4 mm. Thymol bioactive was lower when compared with OELS: the ATCC strain showed a halo of 24.5 mm and a variation of 17.5 to 45 mm was observed between the halo sizes in resistant strains. The results suggest that OELS as compared to thymol has better potential for use as an antimicrobial and antioxidant agent.
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DOI
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 12
·1-8
·
IF 5.479
Yang Guotai,Huang Min,Wang Yutong,Chen Guanhua,Zhao Yu,Xu Hengyi
A lectin magnetic separation (LMS) method for Staphylococcus aureus ( S. aureus ) was developed with the aim to improve the efficiency of magnetic nanoparticles and to expand the scope of bacterial recognition. Poly(ethylene glycol) (PEG)-mediated magnetic nanoparticles modified with streptavidin (MNP-PEG-SA) were synthesized and then applied to a two-step LMS based on the use of wheat germ agglutinin (WGA). Three specific methods for S. aureus detection (suitable for different requirements including detection time and sensitivity) were designed. The new LMS has improved anchoring efficiency (compared to two-step LMS methods) and requires a reduced number of magnetic particles. The Baird–Parker (B-P) method can detect S. aureus with a detection limit of 3 × 10 0 CFU·mL −1 within 15 h; the polymerase chain reaction (PCR) method can be finished within 4 h, with the lowest detection limit (LOD) of 3 × 10 2 CFU·mL −1 . The LOD of HRP-pig IgG-based colorimetric method is 3 × 10 5 CFU·mL −1 , and the method only lasts for 2 h. If combined with specific detection methods, it meets different needs for rapid detection of S. aureus .
Schematic representation of lectin magnetic separation (LMS) based on biotin-wheat germ agglutinin (WGA) and poly (ethylene glycol) (PEG)-mediated streptavidin-modified magnetic nanoparticles (MNP-PEG-SA) and three different quantification strategies (including B-P culture assay, PCR assay, and colorimetric assay) for S. aureus .
研究领域:
微生物学
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纳米技术
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分析化学
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分子生物学
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DOI
PubMed
高影响因子
RSC Advances
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2021
·Vol. 11
·期 30
·18252-18258
·
IF 3.361
Wenjin Wu,Yuping Yang,Lan Wang,Tingting Xu,Rui Wang
Staphylococcus aureus (S. aureus) is one of the most commonly isolated foodborne pathogens, and is considered as a major cause of foodborne illnesses worldwide. However, the development of smart and accurate analytical methods for the simultaneous detection and elimination of S. aureus in matrices of food or drinks remains challenging. In the present work, a mussel-inspired material, ε-poly-L-lysine-3,4-dihydroxy benzaldehyde (EPD), was designed and fabricated based on its Schiff base structure. Owing to the robust ability of the material to adhere onto wet electrode surfaces and the pH-responsive properties of EPD, the prepared immunosensor exhibited an excellent detection limit and linear range with on-demand antibacterial activity. In real milk samples, the average values obtained from the immunosensor were approximate to the standard results obtained from the plate count method, and the relative standard deviation was 3.16–6.54%, suggesting the good accuracy of the developed method. Moreover, it exhibited good selectivity, reproducibility, and stability, thus demonstrating the potential significant applications of the electrochemical immunosensor in drinks safety monitoring.
研究领域:
食品科学
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分析化学
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生物技术
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微生物学
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DOI
PubMed
高影响因子
Foods
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2021
·Vol. 10
·期 12
·2976
·
IF 4.35
Jianying Zhao,Jing Qian,Hong Zhuang,Ji Luo,Mingming Huang,Wenjing Yan,Jianhao Zhang
This study aimed to investigate effects of plasma-activated solution (PAS) on the cell biology ofStaphylococcus aureusand qualities of fresh lettuce leaves. PAS was prepared by dielectric barrier discharge plasma and incubated withS. aureusfor 10–30 min or with lettuces for 10 min. Effects on cell biology were evaluated with microscopic images, cell integrity, and chemical modification of cellular components. Effects on lettuce quality were estimated with the viable microbial counts, color, contents of vitamin C and chlorophyll, and surface integrity. PAS reducedS. aureuspopulation by 4.95-log and resulted in increased cell membrane leakage. It also resulted in increased contents of reactive oxygen species in cells, C=O bonds in peptidoglycan, and 8-hydroxydeoxyguanosine content in cellular DNA, and reduced ratios of unsaturated/saturated fatty acids in the cell membrane. PAS treatment reduced bacterial load on fresh lettuce and had no negative effects on the quality. Data suggest that PAS can be used for the disinfection of ready-to-eat fresh vegetables.Keywords:reactive oxygen species;peptidoglycan;cell membrane;DNA;lettuces
研究领域:
食品科学
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微生物学
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DOI
PubMed
高影响因子
Nature Communications
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2019
·Vol. 10
·期 1
·1-15
·
IF 11.878
Li Jun,Liu Xiangmei,Tan Lei,Cui Zhenduo,Yang Xianjin,Liang Yanqin,Li Zhaoyang,Zhu Shengli,Zheng Yufeng,Yeung Kelvin Wai Kwok,Wang Xianbao,Wu Shuilin
The application of photothermal therapy to treat bacterial infections remains a challenge, as the high temperatures required for bacterial elimination can damage healthy tissues. Here, we develop an exogenous antibacterial agent consisting of zinc-doped Prussian blue (ZnPB) that kills methicillin-resistant Staphylococcus aureus in vitro and in a rat model of cutaneous wound infection. Local heat triggered by the photothermal effect accelerates the release and penetration of ions into the bacteria, resulting in alteration of intracellular metabolic pathways and bacterial killing without systemic toxicity. ZnPB treatment leads to the upregulation of genes involved in tissue remodeling, promotes collagen deposition and enhances wound repair. The efficient photothermal conversion of ZnPB allows the use of relatively few doses and low laser flux, making the platform a potential alternative to current antibiotic therapies against bacterial wound infections.
研究领域:
生物医学工程
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微生物学
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伤口愈合
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DOI
PubMed
高影响因子
Pharmaceutics
·
2019
·Vol. 11
·期 10
·524
·
IF 4.773
Kaixiang Zhou,Xiaofang Wang,Dongmei Chen,Yuanyuan Yuan,Shuge Wang,Chao Li,Yuanyuan Yan,Qianying Liu,Liwei Shao,Lingli Huang,Zonghui Yuan,Shuyu Xie
TheStaphylococcus aureus(S. aureus) cow mastitis causes great losses to the cow industry. In order to improve the treatment effect of tilmicosin against cow mastitis, the combination of solid lipid nanoparticle (SLN) technology with in situ hydrogel technology was used to prepare the self-assembly tilmicosin nanogel (TIL-nanogel). The physicochemical characteristics, in vitro release, antibacterial activity and in vivo treatment efficacy of TIL-SLNs and TIL-nanogel were studied, respectively. The results showed the loading capacity (LC), encapsulation efficiency (EE), size, zeta potential and poly dispersion index (PDI) of TIL-nanogel were 23.33 ± 0.77%, 67.89 ± 3.01%, 431.57 ± 12.87 nm, 8.3 ± 0.06 mv and, 0.424 ± 0.032, respectively. The TIL-nanogel showed stronger sustained release in vitro than TIL-SLNs and commercial injection. The cure rate of half dosage and normal dosage of TIL-nanogel was 58.3% and 75.0%, which was higher than that of commercial injection (50.0%) at normal dosage. The results suggest that the treatment dosage of tilmicosin for cow mastitis could be reduced by TIL-nanogel. The novel TIL-nanogel will be beneficial by decreasing the usage of tilmicosin and the treatment costs of cow mastitis.Keywords:tilmicosin;solid lipid nanoparticles;sodium alginate-chitosan nanogel;Staphylococcus aureus;cow mastitis
研究领域:
兽医学
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制药技术
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纳米技术
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微生物学
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DOI
PubMed
高影响因子
FOOD CONTROL
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2020
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IF 4.258
Arakkaveettil Kabeer Farha,Qiong-Qiong Yang,Gowoon Kim,Dan Zhang,Vuyo Mavumengwana,Olivier Habimana,Hua-Bin Li,Harold Corke,Ren-You Gan
Staphylococcus aureus , a foodborne pathogen , poses serious problems to the food industries owing to biofilm formation, and over 25% of the foodborne illnesses in China have been attributed to S. aureus only. Phytochemicals are widely used as anti-biofilm agents with promising efficacy, and most of them are widely available and safe. This study reported the anti-biofilm efficacy of (+)-nootkatone, a sesquiterpene ketone found in a common fruit grapefruit, against multidrug-resistant S. aureus and its potential molecular mechanism. (+)-Nootkatone exhibited bacteriostatic and bactericidal effects at 200 and 400 μg/mL, respectively, against S. aureus SJTUF 20758 and S. aureus ATCC 25923. Crystal violet staining indicated that (+)-nootkatone inhibited S. aureus biofilm formation (p < 0.05) at a sub-MIC of 50 μg/mL and reduced exopolysaccharide production. The thickness of biofilms was significantly reduced by (+)-nootkatone, which was supported by the light microscopy and confocal laser scanning microscopy. Growth curve of bacteria showed that the antibacerial activity of (+)- nootkatone was dose-dependent, and the sub-MIC concentrations did not affect the bacterial growth of planktonic cells. Besides, (+)-nootkatone affected the sliding motility of S. aureus . At 200 μg/mL, (+)-nootkatone led to the reduction of preformed biofilm mass by 50% and bacterial cell death of 79%, accompanied with a reduction of exopolysaccharide. The expression of biofilm-related genes, including sarA, icaA , agrA , RNAIII, and spa , was suppressed by (+)-nootkatone, as revealed by the transcriptional analysis. Additionally, MTT assay revealed that there was no toxicity of (+)-nootkatone to the human foreskin fibroblasts (HFF) cells. Therefore, (+)-nootkatone is a promising phytochemical against S. aureus biofilms, and has the potential to be used in food industry to fight against S. aureus -induced safety issues.
研究领域:
食品科学
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微生物学
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药理学
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分子生物学
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DOI
高影响因子
ACS Applied Materials & Interfaces
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2017
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IF 7.504
Xiangyu Meng,Guotai Yang,Fulai Li,Taobo Liang,Weihua Lai,Hengyi Xu
A novel sandwich strategy was designed to detect Staphylococcus aureus. The strategy is based on an antibacterial agent that captures bacterial cells and a fluorescein-labeled antibody that acts as the signal-output probe. Vancomycin (Van), which exerts a strong antibacterial effect on Gram-positive bacteria, was utilized as a molecular recognition agent to detect pathogenic bacteria. To effectively concentrate S. aureus, we used bovine serum albumin (BSA) as the amplification carrier to modify magnetic beads (MBs), which were then functionalized with Van. To improve the specificity of the method for S. aureus detection, we adopted fluorescein isothiocyanate (FITC)-tagged pig immunoglobulin G (FITC-pig IgG) as the signal probe and the second recognition agent that bound between the Fc fragment of pig IgG and protein A in the surface of S. aureus. To quantify S. aureus, we measured the fluorescence signal by flow cytometry (FCM). The use of multivalent magnetic nanoprobes (Van-BSA-MBs) showed a high concentration efficiency (>98%) at bacterial concentrations of only 33 colony-forming units (CFU)/mL. Furthermore, the sandwich mode (FITC-pig IgG/SA/Van-BSA-MBs) also showed ideal specificity because Van and IgG bound with S. aureus at two distinct sites. The detection limit for S. aureus was 3.3 × 101 CFU/mL and the total detection process could be completed within 120 min. Other Gram-positive bacteria and Gram-negative bacteria, including Listeria monocytogenes, Bacillus cereus, Cronobacter sakazakii, Escherichia coli O157:H7, and Salmonella Enteritidis, negligibly interfered with S. aureus detection. The proposed detection strategy for S. aureus possesses attractive characteristics, such as high sensitivity, simple operation, short testing time, and low cost.
研究领域:
微生物学
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分析化学
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生物技术
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医学诊断
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DOI
PubMed
高影响因子
VETERINARY MICROBIOLOGY
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2018
·
IF 2.525
Wenyuan Zhou,Xinhui Li,Lei Shi,Hua H. Wang,He Yan
Methicillin-resistant Staphylococcus aureus (MRSA) has been a major public health concern. In this study, a total of 1485 samples from three swine farms, one slaughterhouse and one indoor market in Xiamen, China were collected in 2015, and the prevalence and profiles of MRSA were assessed. All the MRSA isolates were characterized by molecular typing, antibiotic susceptibility, coagulation activity, as well as PCR screening for 38 antibiotic resistance genes, two mobile genetic elements ( lsa (E)-containing multiresistance gene cluster and Tn 558 ), and 36 virulence genes. During the study, 54 of 1485 (3.6%) samples from the swine production, processing and retail chain were found positive for MRSA. A relatively rare SCC mec XII genotype was prevalent in swine farm (84.6%, 11/13) and slaughterhouse isolates (80.6%, 25/31), but absent in the market isolates (0%, 0/10). Notably, all staphylococcal cassette chromosome mec (SCC mec ) type XII MRSA isolates were resistant to at least 6 classes of antibiotics, carried two mobile genetic elements ( lsa (E)-containing multiresistance gene cluster and Tn 558 ) and harbored multiple virulence genes. These multidrug resistant MRSA isolates could also coagulate both bovine and caprine plasma. Our results on the SCC mec XII MRSA isolates, particularly their profiles of related genotypes, antibiotic resistance and virulence determinants, illustrated the evolvement of livestock-associated (LA)-MRSA in the swine production environment and spread along the processing chain. The dominance of the SCC mec XII in MRSA isolates found in this study, differed from previous reports from China, indicated potential contribution associated with the production process.
研究领域:
微生物学
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公共卫生
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兽医学
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分子生物学
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食品安全
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产品关联
DOI
PubMed
高影响因子
ACS Omega
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2018
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IF 0
Zhiyong Song,Huajuan Wang,Yang Wu,Jiangjiang Gu,Shuojun Li,Heyou Han
Combating bacterial pathogens has become a global concern, especially the emergence of drug-resistant bacteria have made conventional antibiotics lose their efficiency. This grim situation suggests the necessity to explore novel antibacterial agents with favorable safety and strong antibacterial activity. Here, we took the advantage of quaternary ammonium compounds and synthesized a long-chain high-molecular organic bis-quaternary ammonium salt (BQAS) with a broad-spectrum bactericidal activity through a facile one-pot reaction. The bactericidal effect of BQAS was evaluated by two bacterial human pathogens: Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive), which are the major cause of diarrheal infections in children and adults. Our experimental results indicate that the bactericidal activity of BQAS is linked to the strong contact between the positively charged quaternary ammonium groups and the bacterial cells, thus leading to a temporary and locally high concentration of reactive oxygen species, which subsequently triggers oxidative stress and membrane damage in the bacteria. This mechanism was further confirmed by several assays, such as the membrane permeabilization assay, fluorescent-based cell live/dead test, scanning electron microscopy, transmission electron microscopy, together with the lactate dehydrogenase release assay, which all indicated that BQAS induced damage to the cytoplasmic membrane and the leakage of intracellular fluid containing essential molecules. The excellent bactericidal activity of BQAS suggests its great application potential as a promising candidate against the rapid emergence of drug-resistant bacterial pathogens.
研究领域:
微生物学
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药物化学
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生物医学工程
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DOI
PubMed
Foods
·
2022
·Vol. 11
·期 13
·1852
·
IF 5.561
Yutong Wang,Zhengzheng Wang,Zhongxu Zhan,Leina Yan,Lijun Wang,Hengyi Xu
Staphylococcus aureus(S. aureus) is a common foodborne pathogen that causes fever, vomiting, and other intestinal symptoms, and seriously affects human health and social safety. As a result, a reliable and sensitive detection technique forS. aureusmust be developed. In this work, we proposed a sandwich assay on vancomycin functionalized magnetic beads (Van-MNPs) forS. aureusdetection based on the specific binding between IgG and targets. The Van-MNPs were used as a tool for the separation of target bacteria. The biotin-modified IgG mediates binding between DNA nanoflowers (DNFs) and the target bacteria via interacting with streptavidin. The DNFs prepared by rolling circle amplification (RCA) were employed as a nano-container to enhance the capacity of biotins, and the streptavidin-horseradish peroxidase (SA-HRP) was loaded onto DNFs to catalyze the color change of TMB. Therefore, a colorimetric biosensor based on magnetic separation and rolling circle amplification was developed. The proposed methods forS. aureusdetection showed a limit of detection (LOD) of 3.3 × 103CFU/mL and excellent specificity. The biosensor has a certain reference value for the detection ofS. aureusin juice.Keywords:Staphylococcus aureus;DNA nanoflowers;vancomycin;magnetic separation;juice
研究领域:
生物技术
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食品科学
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分子生物学
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分析化学
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DOI
PubMed
高影响因子
JOURNAL OF NANOBIOTECHNOLOGY
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2021
·Vol. 19
·期 1
·1-19
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IF 10.435
Huang Rong,Cai Guang-Qing,Li Jian,Li Xi-Sheng,Liu Hai-Ting,Shang Xue-Ling,Zhou Jian-Dang,Nie Xin-Min,Gui Rong
Background Due to the intelligent survival strategy and self-preservation of methicillin-resistant Staphylococcus aureus (MRSA), many antibiotics are ineffective in treating MRSA infections. Nano-drug delivery systems have emerged as a new method to overcome this barrier. The aim of this study was to construct a novel nano-drug delivery system for the treatment of MRSA infection, and to evaluate the therapeutic effect and biotoxicity of this system. We prepared a nano silver metal-organic framework using 2-methylimidazole as ligand and silver nitrate as ion provider. Vancomycin (Vanc) was loaded with Ag-MOF, and nano-sized platelet vesicles were prepared to encapsulate Ag-MOF-Vanc, thus forming the novel platelet membrane-camouflaged nanoparticles PLT@Ag-MOF-Vanc.Results The synthesized Ag-MOF particles had uniform size and shape of radiating corona. The mean nanoparticle size and zeta potential of PLT@Ag-MOF-Vanc were 148 nm and − 25.6 mV, respectively. The encapsulation efficiency (EE) and loading efficiency (LE) of vancomycin were 81.0 and 64.7 %, respectively. PLT@Ag-MOF-Vanc was shown to be a pH-responsive nano-drug delivery system with good biocompatibility. Ag-MOF had a good inhibitory effect on the growth of three common clinical strains (Escherichia coli, Pseudomonas aeruginosa, and S. aureus). PLT@Ag-MOF-Vanc showed better antibacterial activity against common clinical strains in vitro than free vancomycin. PLT@Ag-MOF-Vanc killed MRSA through multiple approaches, including interfering with the metabolism of bacteria, catalyzing reactive oxygen species production, destroying the integrity of cell membrane, and inhibiting biofilm formation. Due to the encapsulation of the platelet membrane, PLT@Ag-MOF-Vanc can bind to the surface of the MRSA bacteria and the sites of MRSA infection. PLT@Ag-MOF-Vanc had a good anti-infective effect in mouse MRSA pneumonia model, which was significantly superior to free vancomycin, and has no obvious toxicity.Conclusion sPLT@Ag-MOF-Vanc is a novel effective targeted drug delivery system, which is expected to be used safely in anti-infective therapy of MRSA.Graphic abstract
研究领域:
纳米技术
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药学
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微生物学
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传染病学
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药物递送系统
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DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）