scholarly journals Bactericidal Activity of Mammalian Cathelicidin-Derived Peptides

2000 ◽  
Vol 68 (5) ◽  
pp. 2748-2755 ◽  
Author(s):  
Sue M. Travis ◽  
Norma N. Anderson ◽  
William R. Forsyth ◽  
Cesar Espiritu ◽  
Barbara D. Conway ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Peptides ◽  
Bactericidal Activity ◽  
Bacterial Infections ◽  
Therapeutic Potential ◽  
Solid Phase ◽  
Antimicrobial Properties ◽  
Helical Structure ◽  
Peptide Backbone ◽  
Parent Molecule

ABSTRACT Endogenous antimicrobial peptides of the cathelicidin family contribute to innate immunity. The emergence of widespread antibiotic resistance in many commonly encountered bacteria requires the search for new bactericidal agents with therapeutic potential. Solid-phase synthesis was employed to prepare linear antimicrobial peptides found in cathelicidins of five mammals: human (FALL39/LL37), rabbit (CAP18), mouse (mCRAMP), rat (rCRAMP), and sheep (SMAP29 and SMAP34). These peptides were tested at ionic strengths of 25 and 175 mM against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus. Each peptide manifested activity against P. aeruginosa irrespective of the NaCl concentration. CAP18 and SMAP29 were the most effective peptides of the group against all test organisms under both low- and high-salt conditions. Select peptides of 15 to 21 residues, modeled on CAP18 (37 residues), retained activity against the gram-negative bacteria and methicillin-sensitive S. aureus, although the bactericidal activity was reduced compared to that of the parent peptide. In accordance with the behavior of the parent molecule, the truncated peptides adopted an α-helical structure in the presence of trifluoroethanol or lipopolysaccharide. The relationship between the bactericidal activity and several physiochemical properties of the cathelicidins was examined. The activities of the full-length peptides correlated positively with a predicted gradient of hydrophobicity along the peptide backbone and with net positive charge; they correlated inversely with relative abundance of anionic residues. The salt-resistant, antimicrobial properties of CAP18 and SMAP29 suggest that these peptides or congeneric structures have potential for the treatment of bacterial infections in normal and immunocompromised persons and individuals with cystic fibrosis.

scholarly journals Bactericidal activites of selected macrofungi extracts against Staphylococcus aureus

2017 ◽  
pp. 193-200
Author(s):  
Daniela Nikolovska-Nedelkoska ◽  
Natalija Atanasova-Pancevska ◽  
Mitko Karadelev ◽  
Dzoko Kungulovski
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Activity ◽  
Minimum Bactericidal Concentration ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Specific Response ◽  
Hostile Environment ◽  
Microdilution Method ◽  
Polypore Fungi ◽  
Potential Use

The increasing of the antibiotic resistance exhibited by pathogenic microorganisms has resulted in research directed toward evaluation of novel sources of antimicrobial compounds. Previous studies have indicated that macrofungi, as a specific response to the natural hostile environment, produce secondary metabolites with antimicrobial properties. In this study, antimicrobial activities of the extracts from six wild mushrooms: Amanita echinocephala, Russula medulata, Cerena unicolor, Hericium erinaceus, Ishnoderma benzoinum and Laetiporus sulphureus were evaluated against Grampositive bacterium Staphylococcus aureus. The antimicrobial potential of the methanolic mushroom extracts was investigated by the microdilution method. Antimicrobial activity was observed in all species included in the study. All the extracts that demonstrated inhibitory activities were further tested for bactericidal activity and minimum bactericidal concentration (MBC) values were determined. The tested microorganism was most sensitive to the examined extracts from the polypore fungi C. unicolor and H. erinaceus. The highest bactericidal activity was obtained in the extracts from the species C. unicolor (MBC=1.563 mg/mL). The experimental results revealed that the methanolic extract of C. unicolor possessed significant bactericidal activity. The findings suggest the potential use of this wild mushroom as antimicrobial agent.

scholarly journals Synthesis and Antibacterial Evaluation of New Pyrazolo[3,4-d]pyrimidines Kinase Inhibitors

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5354
Author(s):  
Chiara Greco ◽  
Rosa Catania ◽  
Dario Leonardo Balacco ◽  
Vincenzo Taresco ◽  
Francesca Musumeci ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Protein Kinases ◽  
Heterocyclic Compounds ◽  
Bacterial Infections ◽  
Kinase Inhibitors ◽  
Antimicrobial Properties ◽  
Important Class ◽  
Prevention And Treatment ◽  
Antibacterial Evaluation

Pyrazolo[3,4-d]pyrimidines represent an important class of heterocyclic compounds well-known for their anticancer activity exerted by the inhibition of eukaryotic protein kinases. Recently, pyrazolo[3,4-d]pyrimidines have become increasingly attractive for their potential antimicrobial properties. Here, we explored the activity of a library of in-house pyrazolo[3,4-d]pyrimidines, targeting human protein kinases, against Staphylococcus aureus and Escherichia coli and their interaction with ampicillin and kanamycin, representing important classes of clinically used antibiotics. Our results represent a first step towards the potential application of dual active pyrazolo[3,4-d]pyrimidine kinase inhibitors in the prevention and treatment of bacterial infections in cancer patients.

scholarly journals Cathelicidin Antimicrobial Peptides with Reduced Activation of Toll-Like Receptor Signaling Have Potent Bactericidal Activity against Colistin-Resistant Bacteria

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Cheng Kao ◽  
Xiaoyan Lin ◽  
Guanghui Yi ◽  
Yunliang Zhang ◽  
Dean A. Rowe-Magnus ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Bactericidal Activity ◽  
Bacterial Infections ◽  
Inflammatory Responses ◽  
Human Cells ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Human Red Blood Cells ◽  
Minor Injuries

ABSTRACT The world is at the precipice of a postantibiotic era in which medical procedures and minor injuries can result in bacterial infections that are no longer effectively treated by antibiotics. Cathelicidins are peptides produced by animals to combat bacterial infections and to regulate innate immune responses. However, cathelicidins are potent activators of the inflammatory response. Cathelicidins with reduced proinflammatory activity and potent bactericidal activity in the low micromolar range against Gram-negative bacteria have been identified. Motifs in cathelicidins that impact bactericidal activity and cytotoxicity to human cells have been elucidated and used to generate peptides that have reduced activation of proinflammatory cytokine production and reduced cytotoxicity to human cells. The resultant peptides have bactericidal activities comparable to that of colistin and can kill colistin-resistant bacteria. IMPORTANCE Cathelicidins are antimicrobial peptides that can also increase inflammatory responses. This combination of activities can cause complications in the treatment of bacterial infections despite the pressing need for new antimicrobials. We have identified cathelicidins with decreased activation of inflammatory responses. The peptides kill Gram-negative bacteria at low micromolar concentrations by binding to and perturbing the integrity of the bacterial membrane. The peptides were also engineered to further decrease lysis of human red blood cells. The peptides have activities comparable to those of the polymyxins, a class of antibiotics to which plasmid-borne resistance is rapidly spreading and can kill colistin-resistant bacteria. These peptides are promising candidates for the development of novel antibacterial agents.

scholarly journals Insulin Treatment Directly Restores Neutrophil Phagocytosis and Bactericidal Activity in Diabetic Mice and Thereby Improves Surgical Site Staphylococcus aureus Infection

2012 ◽  
Vol 80 (12) ◽  
pp. 4409-4416 ◽  
Author(s):  
Hidekazu Yano ◽  
Manabu Kinoshita ◽  
Keiichi Fujino ◽  
Masahiro Nakashima ◽  
Yoritsuna Yamamoto ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Activity ◽  
Bacterial Infections ◽  
Insulin Treatment ◽  
Ex Vivo ◽  
Surgical Site Infections ◽  
Superoxide Production ◽  
Diabetic Patients ◽  
Diabetic Mice ◽  
Content Type

ABSTRACTBacterial infections, including surgical site infections (SSI), are a common and serious complication of diabetes.Staphylococcus aureus, which is eliminated mainly by neutrophils, is a major cause of SSI in diabetic patients. However, the precise mechanisms by which diabetes predisposes to staphylococcal infection are not fully elucidated. The effect of insulin on this infection is also not well understood. We therefore investigated the effect of insulin treatment on SSI and neutrophil function in diabetic mice.S. aureuswas inoculated into the abdominal muscle in diabeticdb/dband high-fat-diet (HFD)-fed mice with or without insulin treatment. Although the diabeticdb/dbmice developed SSI, insulin treatment ameliorated the infection.db/dbmice had neutrophil dysfunction, such as decreased phagocytosis, superoxide production, and killing activity ofS. aureus; however, insulin treatment restored these functions.Ex vivotreatment (coincubation) of neutrophils with insulin and euglycemic control by phlorizin suggest that insulin may directly activate neutrophil phagocytic and bactericidal activity independently of its euglycemic effect. However, insulin may indirectly restore superoxide production by neutrophils through its euglycemic effect. HFD-fed mice with mild hyperglycemia also developed more severe SSI byS. aureusthan control mice and had impaired neutrophil phagocytic and bactericidal activity, which was improved by insulin treatment. Unlikedb/dbmice, in HFD mice, superoxide production was increased in neutrophils and subsequently suppressed by insulin treatment. Glycemic control by insulin also normalized the neutrophil superoxide-producing capability in HFD mice. Thus, insulin may restore neutrophil phagocytosis and bactericidal activity, thereby ameliorating SSI.

scholarly journals Lipidation of Temporin-1CEb Derivatives as a Tool for Activity Improvement, Pros and Cons of the Approach

2021 ◽  
Vol 22 (13) ◽  
pp. 6679
Author(s):  
Paulina Kosikowska-Adamus ◽  
Emilia Sikorska ◽  
Dariusz Wyrzykowski ◽  
Aleksandra Walewska ◽  
Anna Golda ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Peptides ◽  
Antimicrobial Properties ◽  
Carbon Chain ◽  
Microbial Pathogens ◽  
Multi Drug Resistance ◽  
Aggregation State ◽  
Conventional Antibiotics ◽  
Biofilm Development

The alarming raise of multi-drug resistance among human microbial pathogens makes the development of novel therapeutics a priority task. In contrast to conventional antibiotics, antimicrobial peptides (AMPs), besides evoking a broad spectrum of activity against microorganisms, could offer additional benefits, such as the ability to neutralize toxins, modulate inflammatory response, eradicate bacterial and fungal biofilms or prevent their development. The latter properties are of special interest, as most antibiotics available on the market have limited ability to diffuse through rigid structures of biofilms. Lipidation of AMPs is considered as an effective approach for enhancement of their antimicrobial potential and in vivo stability; however, it could also have undesired impact on selectivity, solubility or the aggregation state of the modified peptides. In the present work, we describe the results of structural modifications of compounds designed based on cationic antimicrobial peptides DK5 and CAR-PEG-DK5, derivatized at their N-terminal part with fatty acids with different lengths of carbon chain. The proposed modifications substantially improved antimicrobial properties of the final compounds and their effectiveness in inhibition of biofilm development as well as eradication of pre-formed 24 h old biofilms of Candida albicans and Staphylococcus aureus. The most active compounds (C5-DK5, C12-DK5 and C12-CAR-PEG-DK5) were also potent against multi-drug resistant Staphylococcus aureus USA300 strain and clinical isolates of Pseudomonas aeruginosa. Both experimental and in silico methods revealed strong correlation between the length of fatty acid attached to the peptides and their final membranolytic properties, tendency to self-assemble and cytotoxicity.

scholarly journals Antioxidant Property and Bactericidal Activity of Linum usitatissimum Seed Essential Oil Nanoemulsion (LSEO-NE) on Staphylococcus aureus

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Roghaye Keykhasalar ◽  
Masoud Homayouni Tabrizi ◽  
Pouran Ardalan
Keyword(s):  
Staphylococcus Aureus ◽  
Antioxidant Activity ◽  
Essential Oil ◽  
Bactericidal Activity ◽  
Linum Usitatissimum ◽  
Bacterial Infections ◽  
Antioxidant Property ◽  
In Vivo Studies ◽  
Force Microscopy

Background: Linum usitatissimum Seed Essential Oil (LSEO) as an efficient antimicrobial compound contains various types of phytochemicals, such as lignans and phenols. Objectives: In the current study, we produced LSEO nanoemulsion (LSEO-NE) to study its antioxidant capacity and bactericidal activity against Staphylococcus aureus. Methods: The LSEO-NE was produced using the ultrasonication method and characterized by Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), and Scanning Electron Microscopy (SEM). Then, we measured its antioxidant activity utilizing both ABTS and DPPH tests at four different LSEO-NE concentrations (200, 600, 800, and 1000 µg/mL) compared to glutathione. Finally, we evaluated its bactericidal activity on S. aureus by studying Antibiotic Susceptibility Testing (AST) using LSEO-NE-smeared discs compared to non-smeared and kanamycin discs. Results: The 67.3 nm droplets of LSEO-NE with PDI of 0.452 exhibited strong antioxidant activity, similar to glutathione, in both ABTS (IC50 = 350 µg/mL) and DPPH (IC50 = 235 µg/mL) tests. Moreover, the AST results revealed the significant sensitivity of S. aureus to LSEO-NE-smeared discs when compared to non-smeared and kanamycin discs. Conclusions: According to the results, LSEO-NE can be applied as a safe, natural, and effective antibiotic for bacterial infections caused by S. aureus in most organs, such as the respiratory system and skin. However, further in vivo studies are required to evaluate the LSEO-NE antibacterial efficiency against other pathogenic S. aureus strains.

scholarly journals Enhancement of Immune Response and Anti-Infection of Mice by Porcine Antimicrobial Peptides and Interleukin-4/6 Fusion Gene Encapsulated in Chitosan Nanoparticles

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 552
Author(s):  
Junjie Peng ◽  
Yongle Xiao ◽  
Xiaoping Wan ◽  
Qian Chen ◽  
Huan Wang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Response ◽  
Antimicrobial Peptides ◽  
Bacterial Infections ◽  
Fusion Gene ◽  
Chitosan Nanoparticles ◽  
Eukaryotic Expression ◽  
Interleukin 4 ◽  
Post Inoculation ◽  
E Coli

In order to develop a novel and effective immunoregulator to enhance both the immune response and antimicrobial function, a recombinant eukaryotic expression plasmid-pVAX1 co-expressing fusion cathelicidin antimicrobial peptides (CAMPs) and fusion porcine interleukin-4/6 gene (IL-4/6) was constructed and encapsulated in chitosan nanoparticles (CS-VAP4/6), prepared by the ionotropic gelation method. Four-week-old female Kunming mice were divided into three groups and intramuscularly injected, respectively, with CS-VAP, CS-VAP4/6, and CS-pVAX1. On 28 days post-inoculation, the mice were challenged by intraperitoneal injection with Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922); IgG, IgG1 and IgG2a, CD4+, and CD8+ T cells increased significantly in the VAP- and VAP4/6- treated mice, detected by ELISA and flow cytometry, correspondingly (p < 0.05). As analyzed by qPCR, expression levels of Toll-like receptor (TLR) 1, TLR4, TLR6, TLR9, IL-1, IL-2, IL-4, IL-6, IL-7, IL-12, IL-15, IL-23, Tumor Necrosis Factor (TNF)-α, and Interferon-gamma (IFN-γ) genes were also significantly up-regulated in comparison with those of the control mice (p < 0.05). Their immunological markers were elevated significantly to different degrees in CS-VAP4/6-treated mice compared with CS-VAP in different days post-inoculation (p < 0.05). After challenge with E. coli and Staphylococcus aureus, most of the VAP- and VAP4/6- treated mice survived, and no symptoms of bacterial infection were observed. In contrast, 80% of control mice died of infection. Among the treated groups, VAP4/6 had a stronger resistance against challenge with E. coli infection. These results demonstrated that the fusion gene of antimicrobial peptide and interleukin-4/6 has the promising potential as a safe and effective immunomodulator for the control of bacterial infections.

scholarly journals A New Era of Antibiotics: The Clinical Potential of Antimicrobial Peptides

2020 ◽  
Vol 21 (19) ◽  
pp. 7047 ◽  
Author(s):  
Katrina Browne ◽  
Sudip Chakraborty ◽  
Renxun Chen ◽  
Mark DP Willcox ◽  
David StClair Black ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Innate Immune System ◽  
Therapeutic Potential ◽  
Innate Immune ◽  
Antimicrobial Compound ◽  
Peptide Backbone ◽  
New Era ◽  
Evolutionarily Conserved ◽  
Clinical Potential ◽  
Activity Design

Antimicrobial resistance is a multifaceted crisis, imposing a serious threat to global health. The traditional antibiotic pipeline has been exhausted, prompting research into alternate antimicrobial strategies. Inspired by nature, antimicrobial peptides are rapidly gaining attention for their clinical potential as they present distinct advantages over traditional antibiotics. Antimicrobial peptides are found in all forms of life and demonstrate a pivotal role in the innate immune system. Many antimicrobial peptides are evolutionarily conserved, with limited propensity for resistance. Additionally, chemical modifications to the peptide backbone can be used to improve biological activity and stability and reduce toxicity. This review details the therapeutic potential of peptide-based antimicrobials, as well as the challenges needed to overcome in order for clinical translation. We explore the proposed mechanisms of activity, design of synthetic biomimics, and how this novel class of antimicrobial compound may address the need for effective antibiotics. Finally, we discuss commercially available peptide-based antimicrobials and antimicrobial peptides in clinical trials.

scholarly journals Antimicrobial Activity of a Phage Mixture and a Lactic Acid Bacterium against Staphylococcus aureus from Bovine Mastitis

2020 ◽  
Vol 7 (1) ◽  
pp. 31 ◽  
Author(s):  
Isabel Titze ◽  
Volker Krömker
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Lactic Acid ◽  
Lactic Acid Bacterium ◽  
Incubation Period ◽  
Bacterial Infections ◽  
Bovine Mastitis ◽  
Antimicrobial Properties ◽  
High Antimicrobial Activity

The antimicrobial activity of a phage mixture and a lactic acid bacterium against Staphylococcus aureus isolates from bovine origin was investigated in vitro with regard to possible applications in the therapy of udder inflammation (mastitis) caused by bacterial infections. The S. aureus isolates used for inoculation derived from quarter foremilk samples of mastitis cases. For the examination of the antimicrobial activity, the reduction of the S. aureus germ density was determined [log10 cfu/mL]. The phage mixture consisted of the three obligatory lytic and S. aureus-specific phages STA1.ST29, EB1.ST11 and EB1.ST27 (1:1:1). The selected Lactobacillus plantarum strain with proven antimicrobial properties and the phage mixture were tested against S. aureus in milk, both alone and in combination. The application of the lactic acid bacterium showed only a low reduction ability for a 24 h incubation period. The bacteriophage mixture as well as its combination with the lactic acid bacterium showed high antimicrobial activity against S. aureus for a 24 h incubation period at 37 °C, with only the phage mixture showing significance.

scholarly journals HONEY AS A THERAPEUTIC AGENT, AN INSIGHT INTO ITS ANTIMICROBIAL PROPERTIES.

2020 ◽  
Author(s):  
FOSU ASARE
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Therapeutic Agent ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Close Association ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Medical Practitioners ◽  
Ancient Times ◽  
Insight Into

Traditionally, honey has been used as both food and medicine since ancient times worldwide. Due to its nutritious content and sweet flavor, honey has been in great demand worldwide with China being the leading producer. People apply honey on the wound without having any knowledge of its antibacterial properties. Honey has proven to contain some antibacterial properties such as hydrogen peroxide, acidity, low moisture content, pH, etc. Bacteria are ubiquitous and their life has a close association with humans in their diet, food processing, etc. Some bacteria eg Staphylococcus aureus, consist of the normal flora of humans making them partially harmless but some can be harmful and in turn cause infections. Clinically, antibiotics such as tetracycline, penicillin, amoxicillin lincomycin, etc. have been used in the treatment of bacterial infections but some bacteria eg Methicillin Resistant Staphylococcus aureus have shown resistance to some antibiotics. Medical practitioners have opted for the use of honey in treating bacterial infections due to its antibacterial properties. Researches have proven that honey can kill or inhibit almost every bacteria and is very effective in wound treatment as compared to antibiotics. In light of this most medical practitioners prefer the use of honey in treating bacterial infections.

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