scholarly journals Nanomaterials for Biosensing Lipopolysaccharide

Biosensors ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Palak Sondhi ◽  
Md Helal Uddin Maruf ◽  
Keith J. Stine
Keyword(s):  
Septic Shock ◽  
Surface Modification ◽  
Pathogen Detection ◽  
Low Cost ◽  
Fast Response ◽  
Magnetic Nanomaterials ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Recent Developments ◽  
Metal Nanomaterials

Lipopolysaccharides (LPS) are endotoxins, hazardous and toxic inflammatory stimulators released from the outer membrane of Gram-negative bacteria, and are the major cause of septic shock giving rise to millions of fatal illnesses worldwide. There is an urgent need to identify and detect these molecules selectively and rapidly. Pathogen detection has been done by traditional as well as biosensor-based methods. Nanomaterial based biosensors can assist in achieving these goals and have tremendous potential. The biosensing techniques developed are low-cost, easy to operate, and give a fast response. Due to extremely small size, large surface area, and scope for surface modification, nanomaterials have been used to target various biomolecules, including LPS. The sensing mechanism can be quite complex and involves the transformation of chemical interactions into amplified physical signals. Many different sorts of nanomaterials such as metal nanomaterials, magnetic nanomaterials, quantum dots, and others have been used for biosensing of LPS and have shown attractive results. This review considers the recent developments in the application of nanomaterials in sensing of LPS with emphasis given mainly to electrochemical and optical sensing.

scholarly journals Interaction of Antimicrobial Peptide Temporin L with Lipopolysaccharide In Vitro and in Experimental Rat Models of Septic Shock Caused by Gram-Negative Bacteria

2006 ◽  
Vol 50 (7) ◽  
pp. 2478-2486 ◽  
Author(s):  
Andrea Giacometti ◽  
Oscar Cirioni ◽  
Roberto Ghiselli ◽  
Federico Mocchegiani ◽  
Fiorenza Orlando ◽  
...  
Keyword(s):  
Septic Shock ◽  
Antimicrobial Peptide ◽  
Gram Negative Bacteria ◽  
Amphibian Skin ◽  
Necrosis Factor Alpha ◽  
Gram Negative ◽  
Rat Models ◽  
E Coli ◽  
Tnf Α

ABSTRACT Sepsis remains a major cause of morbidity and mortality in hospitalized patients, despite intense efforts to improve survival. The primary lead for septic shock results from activation of host effector cells by endotoxin, the lipopolysaccharide (LPS) associated with cell membranes of gram-negative bacteria. For these reasons, the quest for compounds with antiendotoxin properties is actively pursued. We investigated the efficacy of the amphibian skin antimicrobial peptide temporin L in binding Escherichia coli LPS in vitro and counteracting its effects in vivo. Temporin L strongly bound to purified E. coli LPS and lipid A in vitro, as proven by fluorescent displacement assay, and readily penetrated into E. coli LPS monolayers. Furthermore, the killing activity of temporin L against E. coli was progressively inhibited by increasing concentrations of LPS added to the medium, further confirming the peptide's affinity for endotoxin. Antimicrobial assays showed that temporin L interacted synergistically with the clinically used β-lactam antibiotics piperacillin and imipenem. Therefore, we characterized the activity of temporin L when combined with imipenem and piperacillin in the prevention of lethality in two rat models of septic shock, measuring bacterial growth in blood and intra-abdominal fluid, endotoxin and tumor necrosis factor alpha (TNF-α) concentrations in plasma, and lethality. With respect to controls and single-drug treatments, the simultaneous administration of temporin L and β-lactams produced the highest antimicrobial activities and the strongest reduction in plasma endotoxin and TNF-α levels, resulting in the highest survival rates.

scholarly journals Regulation of Plant Mineral Nutrition by Signal Molecules

2021 ◽  
Vol 9 (4) ◽  
pp. 774
Author(s):  
Vipin Chandra Kalia ◽  
Chunjie Gong ◽  
Sanjay K. S. Patel ◽  
Jung-Kul Lee
Keyword(s):  
Signal Molecules ◽  
Gram Negative Bacteria ◽  
Human Beings ◽  
High Cell ◽  
Specific Chemical ◽  
Gram Negative ◽  
Plant Mineral Nutrition ◽  
Recent Developments ◽  
Cell Densities ◽  
Metabolic Activities

Microbes operate their metabolic activities at a unicellular level. However, it has been revealed that a few metabolic activities only prove beneficial to microbes if operated at high cell densities. These cell density-dependent activities termed quorum sensing (QS) operate through specific chemical signals. In Gram-negative bacteria, the most widely reported QS signals are acylhomoserine lactones. In contrast, a novel QS-like system has been elucidated, regulating communication between microbes and plants through strigolactones. These systems regulate bioprocesses, which affect the health of plants, animals, and human beings. This mini-review presents recent developments in the QS and QS-like signal molecules in promoting plant health.

scholarly journals Clinical pharmacokinetics of 3-h extended infusion of meropenem in adult patients with severe sepsis and septic shock: implications for empirical therapy against Gram-negative bacteria

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Amol T. Kothekar ◽  
Jigeeshu Vasishtha Divatia ◽  
Sheila Nainan Myatra ◽  
Anand Patil ◽  
Manjunath Nookala Krishnamurthy ◽  
...  
Keyword(s):  
Septic Shock ◽  
Severe Sepsis ◽  
Modeling And Simulation ◽  
Empirical Therapy ◽  
Gram Negative Bacteria ◽  
Clinical Pharmacokinetics ◽  
Gram Negative ◽  
Arterial Blood ◽  
Days Of Therapy ◽  
Extended Infusion

Abstract Background Optimal anti-bacterial activity of meropenem requires maintenance of its plasma concentration (Cp) above the minimum inhibitory concentration (MIC) of the pathogen for at least 40% of the dosing interval (fT > MIC > 40). We aimed to determine whether a 3-h extended infusion (EI) of meropenem achieves fT > MIC > 40 on the first and third days of therapy in patients with severe sepsis or septic shock. We also simulated the performance of the EI with respect to other pharmacokinetic (PK) targets such as fT > 4 × MIC > 40, fT > MIC = 100, and fT > 4 × MIC = 100. Methods Arterial blood samples of 25 adults with severe sepsis or septic shock receiving meropenem 1000 mg as a 3-h EI eight hourly (Q8H) were obtained at various intervals during and after the first and seventh doses. Plasma meropenem concentrations were determined using a reverse-phase high-performance liquid chromatography assay, followed by modeling and simulation of PK data. European Committee on Antimicrobial Susceptibility Testing (EUCAST) definitions of MIC breakpoints for sensitive and resistant Gram-negative bacteria were used. Results A 3-h EI of meropenem 1000 mg Q8H achieved fT > 2 µg/mL > 40 on the first and third days, providing activity against sensitive strains of Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii. However, it failed to achieve fT > 4 µg/mL > 40 to provide activity against strains susceptible to increased exposure in 33.3 and 39.1% patients on the first and the third days, respectively. Modeling and simulation showed that a bolus dose of 500 mg followed by 3-h EI of meropenem 1500 mg Q8H will achieve this target. A bolus of 500 mg followed by an infusion of 2000 mg would be required to achieve fT > 8 µg > 40. Targets of fT > 4 µg/mL = 100 and fT > 8 µg/mL = 100 may be achievable in two-thirds of patients by increasing the frequency of dosing to six hourly (Q6H). Conclusions In patients with severe sepsis or septic shock, EI of 1000 mg of meropenem over 3 h administered Q8H is inadequate to provide activity (fT > 4 µg/mL > 40) against strains susceptible to increased exposure, which requires a bolus of 500 mg followed by EI of 1500 mg Q8H. While fT > 8 µg/mL > 40 require escalation of EI dose, fT > 4 µg/mL = 100 and fT > 8 µg/mL = 100 require escalation of both EI dose and frequency.

scholarly journals Polymyxin B Hemoperfusion in Pneumonic Septic Shock Caused by Gram-Negative Bacteria

2015 ◽  
Vol 30 (3) ◽  
pp. 171-175
Author(s):  
Jung-Wan Yoo ◽  
Su Yeon Park ◽  
Jin Jeon ◽  
Jin Won Huh ◽  
Chae-Man Lim ◽  
...  
Keyword(s):  
Septic Shock ◽  
Polymyxin B ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Polymyxin B Hemoperfusion

scholarly journals LPS-binding protein protects mice from septic shock caused by LPS or gram-negative bacteria.

1998 ◽  
Vol 101 (10) ◽  
pp. 2065-2071 ◽  
Author(s):  
N Lamping ◽  
R Dettmer ◽  
N W Schröder ◽  
D Pfeil ◽  
W Hallatschek ◽  
...  
Keyword(s):  
Septic Shock ◽  
Binding Protein ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Lps Binding

The Development of New Small-Molecule Inhibitors Targeting Bacterial Metallo-β-lactamases

2018 ◽  
Vol 18 (10) ◽  
pp. 834-843 ◽  
Author(s):  
Ping Wang ◽  
Jing Cheng ◽  
Cong-Cong Liu ◽  
Kai Tang ◽  
Feng Xu ◽  
...  
Keyword(s):  
Small Molecule ◽  
Horizontal Transfer ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Major Threat ◽  
Extensively Drug Resistant ◽  
Genes Encoding ◽  
Recent Developments ◽  
Almost All

Metallo-β-lactamases (MBLs) are a family of Zn(II)-dependent enzymes that can hydrolyze almost all β-lactam antibiotics. Horizontal transfer of the genes encoding MBLs among Gram-negative bacteria pathogens has led to the emergence of extensively drug-resistant pathogens, which now represent a major threat to human health. As there is not to date yet a clinically available MBL inhibitor, the discovery of new MBL inhibitors has great urgency. This review highlights the recent developments in the discovery of small-molecule MBL inhibitors.

scholarly journals Comparison Between Phenotypic Confirmatory Test & Double Disc Synergy Test in Detection of Extended Spectrum b-Lactamases Producers Among Gram-Negative Bacilli

2017 ◽  
Vol 15 (2) ◽  
pp. 3-8
Author(s):  
Abu Hena Md Saiful Karim Chowdhury ◽  
Sukumar Nandi ◽  
Mahbubur Rahman ◽  
ASM Ashanul Karim ◽  
Syeda Shanoor Hasina Mamtaz ◽  
...  
Keyword(s):  
Predictive Value ◽  
Low Cost ◽  
Standard Procedure ◽  
Confirmatory Test ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Extended Spectrum ◽  
Major Interest ◽  
Synergy Test

Background: Extended-Spectrum b-Lactamases (ESBLs) producing bacteria are increasing in number and causing more severe infections because of their continuous mutation and multidrug resistance property which make its treatment difficult. Thus reliable, sensitive and low cost method to detect ESBLs producers, therefore, is of major interest. The present study was undertaken to compare the sensitivity between double disc synergy test & phenotypic confirmatory test to detect ESBLs producing bacteria.Methods: All the isolates were identified by standard procedure of identification & isolated gram-negative bacteria initially screened by Minimum Inhibitory Concentration (MIC) ESBLs breakpoints. Then suspected ESBLs producers are confirmed by double disc synergy test & phenotypic confirmatory test.Results: In the present study, total 176(74.89%) bacterial strains were isolated from 235 samples of wound swab & pus, and urine. Among the isolates, 150(85.23%) were gram-negative and 26(14.77%) were gram-positive bacteria. The gram-negative bacteria were screened for suspected ESBLs & then subjected to confirmatory test where Phenotypic Confirmatory Test (PCT) detected 89(62.68%) and Double Disc Synergy Test (DDST) detected 74(52.11%) ESBL producers. So 15(10.57%) isolates were missed by double disc synergy test. In this study, we determined sensitivity, specificity, positive predictive value & negative predictive value of Phenotypic Confirmatory Test (PCT) were 100%, 77.9%, 83.1% & 100% respectively and those of Double Disc Synergy Test (DDST) were 83.1%, 100%, 100%, and 77.9% respectively.Conclusion: Between these two tests, phenotypic confirmatory test found to be more sensitive procedure than double disc synergy test for the detection of ESBLs producing organisms.Chatt Maa Shi Hosp Med Coll J; Vol.15 (2); Jul 2016; Page 3-8

scholarly journals Chitosan Stabilized Silver Nanoparticles for the Electrochemical Detection of Lipopolysaccharide: A Facile Biosensing Approach for Gram-Negative Bacteria

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 413 ◽  
Author(s):  
Muhammad Imran ◽  
Christopher J. Ehrhardt ◽  
Massimo F. Bertino ◽  
Muhammad R. Shah ◽  
Vamsi K. Yadavalli
Keyword(s):  
Silver Nanoparticles ◽  
Low Cost ◽  
Age Groups ◽  
Single Step ◽  
Indirect Detection ◽  
Detection Methods ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Strong Electrostatic Interaction

Negatively charged lipopolysaccharide (LPS), a major endotoxin and component of the outer membrane of several Gram-negative bacteria, provides a useful biomarker for the indirect detection of these pathogens. For instance, Escherichia coli (E. coli) is a pathogenic bacterium that causes infections in almost all age groups, and has been implicated in food and water contamination. Current diagnostic and detection methods tend to be labor-intensive or expensive, necessitating the need for an easy, sensitive, rapid, and low-cost method. We report on the synthesis and use of positively charged chitosan stabilized silver nanoparticles (Chi-AgNPs) as a sensitive electrochemical nanobiosensor for the detection of LPS. Chi-AgNPs were synthesized through a facile, single step protocol, and characterized for size, charge, and morphology. Glassy carbon electrodes modified with Chi-AgNPs resulted in an enhancement of signal in the presence of both LPS and E. coli. Detection was accomplished over a large concentration range (several orders of magnitude) of 0.001–100 ng/mL and 10–107 CFU/mL. The biosensors can reliably detect LPS and E. coli at very low concentrations. Chi-AgNPs have potential as low cost, sensitive nanobiosensors for Gram-negative bacteria due to strong electrostatic interaction with LPS present in their outer membranes.

scholarly journals Graphene and its Derivatives-Based Optical Sensors

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiao-Guang Gao ◽  
Ling-Xiao Cheng ◽  
Wen-Shuai Jiang ◽  
Xiao-Kuan Li ◽  
Fei Xing
Keyword(s):  
Optical Sensors ◽  
Low Cost ◽  
High Sensitivity ◽  
Fast Response ◽  
Cell Detection ◽  
Single Cell Detection ◽  
Sensing Applications ◽  
Wide Range ◽  
Surface Enhanced Raman ◽  
Recent Developments

Being the first successfully prepared two-dimensional material, graphene has attracted extensive attention from researchers due to its excellent properties and extremely wide range of applications. In particular, graphene and its derivatives have displayed several ideal properties, including broadband light absorption, ability to quench fluorescence, excellent biocompatibility, and strong polarization-dependent effects, thus emerging as one of the most popular platforms for optical sensors. Graphene and its derivatives-based optical sensors have numerous advantages, such as high sensitivity, low-cost, fast response time, and small dimensions. In this review, recent developments in graphene and its derivatives-based optical sensors are summarized, covering aspects related to fluorescence, graphene-based substrates for surface-enhanced Raman scattering (SERS), optical fiber biological sensors, and other kinds of graphene-based optical sensors. Various sensing applications, such as single-cell detection, cancer diagnosis, protein, and DNA sensing, are introduced and discussed systematically. Finally, a summary and roadmap of current and future trends are presented in order to provide a prospect for the development of graphene and its derivatives-based optical sensors.

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