scholarly journals Thanatin: An Emerging Host Defense Antimicrobial Peptide with Multiple Modes of Action

2021 ◽  
Vol 22 (4) ◽  
pp. 1522
Author(s):  
Rachita Dash ◽  
Surajit Bhattacharjya
Keyword(s):  
Therapeutic Potential ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Multiple Modes ◽  
Modes Of Action ◽  
Drug Resistant Bacteria ◽  
Low Concentrations ◽  
Spectrum Activity ◽  
Bacteria And Fungi

Antimicrobial peptides (AMPs) possess great potential for combating drug-resistant bacteria. Thanatin is a pathogen-inducible single-disulfide-bond-containing β-hairpin AMP which was first isolated from the insect Podisus maculiventris. The 21-residue-long thanatin displays broad-spectrum activity against both Gram-negative and Gram-positive bacteria as well as against various species of fungi. Remarkably, thanatin was found to be highly potent in inhibiting the growth of bacteria and fungi at considerably low concentrations. Although thanatin was isolated around 25 years ago, only recently has there been a pronounced interest in understanding its mode of action and activity against drug-resistant bacteria. In this review, multiple modes of action of thanatin in killing bacteria and in vivo activity, therapeutic potential are discussed. This promising AMP requires further research for the development of novel molecules for the treatment of infections caused by drug resistant pathogens.

scholarly journals Silver i-motifs and their antibacterial activity

2021 ◽  
Author(s):  
Jessica Bratt
Keyword(s):  
Antibacterial Activity ◽  
Therapeutic Potential ◽  
Bacterial Load ◽  
Therapeutic Benefit ◽  
In Vivo Studies ◽  
Resistant Bacteria ◽  
Drug Resistant Bacteria ◽  
Low Concentrations

<p>The spread of antibiotic resistance and the emergence of multi-drug resistant bacteria is a major threat to public health. This study investigated a unique cytosine rich DNA structure, the i-Motif to deliver soluble Ag+ as a novel antimicrobial agent (AgiMs). AgiMs were evaluated in vitro against P. aeruginosa and A. baumannii strains. AgiMs displayed significant antibacterial activity against both P. aeruginosa and A. baumannii (median MIC: 0.875 µM and 0.75 µM, respectively) by rapid, bactericidal and concentration-dependent effect. Low concentrations of AgiMs showed efficacy against PAO1 20-h biofilms, resulting in 57% reduction in biomass (5 x MIC). A single dose of AgiMs extended survival of G. Mellonella larvae, with the therapeutic benefit paralleled in the reduction of internal bacterial load. Synergistic interactions were observed with the combination of AgiMs and tobramycin, a common antibiotic used to treat P. aeruginosa infections; indicating the potential for AgiMs to reinstate the potency of current antibiotics. This silver-based agent might be an alternative to the failing antibiotic regimes for MDR resistant infections. Further in vitro and in vivo studies are warranted to confirm the therapeutic potential. </p>

scholarly journals Silver i-motifs and their antibacterial activity

2021 ◽  
Author(s):  
Jessica Bratt
Keyword(s):  
Antibacterial Activity ◽  
Therapeutic Potential ◽  
Bacterial Load ◽  
Therapeutic Benefit ◽  
In Vivo Studies ◽  
Resistant Bacteria ◽  
Drug Resistant Bacteria ◽  
Low Concentrations

<p>The spread of antibiotic resistance and the emergence of multi-drug resistant bacteria is a major threat to public health. This study investigated a unique cytosine rich DNA structure, the i-Motif to deliver soluble Ag+ as a novel antimicrobial agent (AgiMs). AgiMs were evaluated in vitro against P. aeruginosa and A. baumannii strains. AgiMs displayed significant antibacterial activity against both P. aeruginosa and A. baumannii (median MIC: 0.875 µM and 0.75 µM, respectively) by rapid, bactericidal and concentration-dependent effect. Low concentrations of AgiMs showed efficacy against PAO1 20-h biofilms, resulting in 57% reduction in biomass (5 x MIC). A single dose of AgiMs extended survival of G. Mellonella larvae, with the therapeutic benefit paralleled in the reduction of internal bacterial load. Synergistic interactions were observed with the combination of AgiMs and tobramycin, a common antibiotic used to treat P. aeruginosa infections; indicating the potential for AgiMs to reinstate the potency of current antibiotics. This silver-based agent might be an alternative to the failing antibiotic regimes for MDR resistant infections. Further in vitro and in vivo studies are warranted to confirm the therapeutic potential. </p>

scholarly journals Quorum Sensing Inhibition in Chromobacterium violaceum, Antibacterial Activity and GC-MS Analysis of Centaurea praecox (Oliv. & Hiern) Extracts

2020 ◽  
Vol 9 (4) ◽  
pp. 1569-1577
Keyword(s):  
Antibacterial Activity ◽  
Quorum Sensing ◽  
Research Strategy ◽  
Chromobacterium Violaceum ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Control Drug ◽  
Ms Analysis ◽  
Drug Resistant Bacteria

The quorum sensing (QS) mechanism has become a viable research strategy for the discovery of plant-derived anti-virulent agents to control drug-resistant bacteria. The increasing incidences of drug-resistant bacteria and the effort to curb it necessitate this study. We investigated the QS inhibitory potential of Centaurea praecox extracts on Chromobacterium violaceum (CV), antibacterial activity, and determination of chemical composition using GC-MS. C. praecox was subjected to sequential extraction using hexane (HEX), dichloromethane (DCM), ethyl acetate (EA), ethanol (ET), and aqueous (AQ) solvents. The extracts were subsequently evaluated for antibacterial activity using disc diffusion and QS violacein inhibition using spectrophotometry. The antibacterial effects of the extracts were moderate on gram-positive bacteria at 4 mg/mL in the order: HEX >EA >DCM >ET =AQ. However, the DCM extract demonstrated the most effective violacein inhibition of ≥80% at 0.3 mg/mL. QS violacein inhibitions were generally found to be concentration-dependent in the order: DCM >EA >HEX >ET =AQ with efficacies of ≥ 90% inhibition at ≥ 0.6 mg/mL. GC-MS analysis on the most potent DCM extract revealed N-vinylmethanimine, N-ethyl formamide, and propanamide among components identified. We concluded that C. praecox DCM extract contains bioactive chemicals as QS inhibitors and potential anti-virulent agents capable of combating the pathogenicity of drug-resistant bacteria in vivo.

scholarly journals Nanoparticles Enable Efficient Delivery of Antimicrobial Peptides for the Treatment of Deep Infections

2021 ◽  
Author(s):  
Yingxue Deng ◽  
Rui Huang ◽  
Songyin Huang ◽  
Menghua Xiong
Keyword(s):  
Antimicrobial Peptides ◽  
Broad Spectrum ◽  
Antimicrobial Properties ◽  
Therapeutic Index ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Drug Resistant Bacteria ◽  
Efficient Delivery ◽  
Delivery Vehicles

Antimicrobial peptides (AMPs) have emerged as promising alternatives of traditional antibiotics against drug-resistant bacteria owing to their broad-spectrum antimicrobial properties and low tendency to drugresistance. However, their therapeutic efficacy in vivo, especially for infections in deep organs, is limited owing to their systemic toxicity and low bioavailability. Nanoparticles-based delivery systems offer a strategy to increase the therapeutic index of AMPs by preventing proteolysis, increasing the accumulation at infection sites, and reducing toxicity. Herein, we will discuss the current progress of using nanoparticles as delivery vehicles for AMPs for the treatment of deep infections.

Venom of Viperidae: A perspective of its antibacterial and antitumor potential

2021 ◽  
Vol 22 ◽  
Author(s):  
André Silva ◽  
Fernando Gonçalves ◽  
Helena Oliveira ◽  
Sérgio Marques
Keyword(s):  
Therapeutic Potential ◽  
Modern Medicine ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Cytotoxic Effects ◽  
Venomous Snake ◽  
Drug Resistant Bacteria ◽  
Antitumor Potential ◽  
Biological Compounds ◽  
Considerable Damage

: The emergence of multi-drug resistant bacteria and limitations on cancer treatment represent two important challenges in modern medicine. Biological compounds have been explored with particular focus on venoms. Although they can be lethal or cause considerable damage to humans, venom is also a source rich in components with high therapeutic potential. Viperidae family is one of the most emblematic venomous snake families and several studies highlighted the antibacterial and antitumor potential of viper toxins. According to the literature, these activities are mainly associated to five protein families – svLAAO, Disintegrins, PLA2, SVMPs and C-type lectins- that act through different mechanisms leading to the inhibition of the growth of bacteria, as well as, cytotoxic effects and inhibition of metastasis process. In this review we provide an overview of the venom toxins produced by species belonging to the Viperidae family, exploring their roles during the envenoming and their pharmacological properties, in order to demonstrate its antibacterial and antitumor potential.

scholarly journals Design, Engineering and Discovery of Novel α-Helical and β-Boomerang Antimicrobial Peptides against Drug Resistant Bacteria

2020 ◽  
Vol 21 (16) ◽  
pp. 5773 ◽  
Author(s):  
Surajit Bhattacharjya ◽  
Suzana K. Straus
Keyword(s):  
Antimicrobial Peptides ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Antibiotic Development ◽  
Extensively Drug Resistant ◽  
Drug Resistant Bacteria ◽  
Drying Up ◽  
Further Development ◽  
Lps Binding

In an era where the pipeline of new antibiotic development is drying up, the continuous rise of multi-drug resistant (MDR) and extensively drug resistant (XDR) bacteria are genuine threats to human health. Although antimicrobial peptides (AMPs) may serve as promising leads against drug resistant bacteria, only a few AMPs are in advanced clinical trials. The limitations of AMPs, namely their low in vivo activity, toxicity, and poor bioavailability, need to be addressed. Here, we review engineering of frog derived short α-helical AMPs (aurein, temporins) and lipopolysaccharide (LPS) binding designed β-boomerang AMPs for further development. The discovery of novel cell selective AMPs from the human proprotein convertase furin is also discussed.

scholarly journals Developing an antibiotic effective against multi-drug resistant bacteria.

2014 ◽  
Vol 70 (a1) ◽  
pp. C714-C714
Author(s):  
Calvin Steussy ◽  
Cynthia Stauffacher ◽  
Mark Lipton ◽  
Mohamed Seleem
Keyword(s):  
Pathogenic Bacteria ◽  
Modern Medicine ◽  
In Vivo Studies ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Lead Compound ◽  
Drug Resistant Bacteria ◽  
Coa Reductase

The emergence of multi-drug resistant pathogenic bacteria is one of the great challenges to modern medicine. The gram positive cocci Methicillin Resistant Staphylococcus aureus (MRSA) and Vancomycin Resistant Enterococcus faecalis (VRE) are two particularly virulent examples. In vivo studies have shown that the eukaryotic like 'mevalonate' isoprenoid pathway used by these pathogenic cocci is essential to their growth and virulence [1]. Our structures of HMG-CoA reductase (HMGR) from P. mevalonii demonstrated that the bacterial enzymes are structurally distinct from the human enzymes allowing for specific antibacterial activity [2]. High throughput in vitro screening against bacterial HMGR at the Southern Research Center, Birmingham, AL uncovered a lead compound with an IC50 of 80 µM with a competitive mode of action. Our x-ray crystal structures of HMGR from E. faecalis complexed with the lead compound and its variations have informed the synthesis of new inhibitors that have improved the IC50 to 5 µM [3]. Studies of this compound show it to be active against both MRSA and VRE in culture, effective against these bacteria in biofilms, and efficacious in a model system of eukaryotic infection. Structures and kinetics of these compounds will be presented and future directions discussed.

scholarly journals Synthesis of 4,4′-(4-Formyl-1H-pyrazole-1,3-diyl)dibenzoic Acid Derivatives as Narrow Spectrum Antibiotics for the Potential Treatment of Acinetobacter Baumannii Infections

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 650 ◽  
Author(s):  
Evan Delancey ◽  
Devin Allison ◽  
Hansa Raj KC ◽  
David F. Gilmore ◽  
Todd Fite ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Inhibitory Concentration ◽  
Organ Injury ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Antimicrobial Studies ◽  
Mammalian Cell Lines ◽  
Drug Resistant Bacteria

Acinetobacter baumannii has emerged as one of the most lethal drug-resistant bacteria in recent years. We report the synthesis and antimicrobial studies of 25 new pyrazole-derived hydrazones. Some of these molecules are potent and specific inhibitors of A. baumannii strains with a minimum inhibitory concentration (MIC) value as low as 0.78 µg/mL. These compounds are non-toxic to mammalian cell lines in in vitro studies. Furthermore, one of the potent molecules has been studied for possible in vivo toxicity in the mouse model and found to be non-toxic based on the effect on 14 physiological blood markers of organ injury.

scholarly journals In vitro and in vivo toxicity and antibacterial efficacy of melittin against clinical extensively drug-resistant bacteria

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Parvin Askari ◽  
Mohammad Hasan Namaei ◽  
Kiarash Ghazvini ◽  
Mehran Hosseini
Keyword(s):  
Lethal Dose ◽  
Resistant Bacteria ◽  
Klebsiella Pneumonia ◽  
Antibacterial Efficacy ◽  
Drug Resistant ◽  
Extensively Drug Resistant ◽  
Drug Resistant Bacteria ◽  
Antimicrobial Evaluation

Abstract Background Melittin is one of the most studied antimicrobial peptides, and several in vitro experiments have demonstrated its antibacterial efficacy. However, there is evidence showing melittin has non-promising effects such as cytotoxicity and hemolysis. Therefore, concerns about unwanted collateral toxicity of melittin lie ahead in the path toward its clinical development. With these considerations, the present study aimed to fill the gap between in vitro and in vivo studies. Methods In the first step, in vitro toxicity profile of melittin was assessed using cytotoxicity and hemolysis tests. Next, a maximum intraperitoneal (i.p.) sub-lethal dose was determined using BALB/c mice. Besides toxicity, antimicrobial efficacy of melittin against extensively drug-resistant (XDR) Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus (MRSA), and KPC-producing Klebsiella pneumonia (KPC-KP) pathogens were tested using both in vitro and in vivo methods. Results Melittin showed extensive hemolysis (HD50 = 0.44 µg/mL), and cytotoxicity (IC50 = 6.45 µg/mL) activities with i.p. LD50 value of 4.98 mg/kg in BALB/c mice. In vitro antimicrobial evaluation showed melittin MIC range from 8 to 32 µg/mL for the studied pathogens. Treatment of infected mice with repeated sub-lethal doses of melittin (2.4 mg/kg) displayed no beneficial effect on their survival and peritoneal bacterial loads. Conclusions These results indicate that melittin at its safe dose could not exhibit antimicrobial activity, which hinders its application in clinical practice.

scholarly journals Detection of drug resistant bacteria in different ice creams available in local market of Dhaka city

2017 ◽  
Vol 7 (1) ◽  
pp. 33-35
Author(s):  
Md Musa Howlader ◽  
Tahmina Shammi
Keyword(s):  
Staphylococcus Aureus ◽  
Microbiological Quality ◽  
Ice Cream ◽  
Storage Condition ◽  
Resistant Bacteria ◽  
Local Market ◽  
Drug Resistant ◽  
Drug Resistant Bacteria ◽  
Bacteria And Fungi

Sound microbiological quality of ice cream should be ensured for being a widely popular dairy food in the world. Present study was conducted to determine the microbiological quality of different ice cream samples available in Dhaka, Bangladesh. Total 3 ice cream samples were collected and processed to detect the microbiological quality as well as drug resistant trait of the isolates through several conventional Kirby Bauer method. All the samples were found to be contaminated with the total viable bacteria and fungi within the range of 1.2×104 cfu/ml to 4.3×106 cfu/ml. The presence of E. coli, Staphylococcus aureus was also observed up to 104 cfu/ml. However, the fecal contamination was totally absent in all the samples. Antibiotic profile of two isolates was measured against 8 commonly used antibiotics and both E.coli and Staphylococcus aureus were found to be resistant against more than one antibiotics. Appropriate hygienic and storage condition should be maintained concerning the health safety of consumers. Stamford Journal of Microbiology, Vol.7(1) 2017: 33-35

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