Research

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9 pages, 4268 KiB

Open AccessArticle

The Glucocorticoid PYED-1 Disrupts Mature Biofilms of Candida spp. and Inhibits Hyphal Development in Candida albicans

by Anna Esposito, Antonella Migliaccio, Vita Dora Iula, Raffaele Zarrilli, Annalisa Guaragna and Eliana De Gregorio

Antibiotics 2021, 10(11), 1396; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10111396 - 13 Nov 2021

Viewed by 1611

Abstract

Invasive Candida infections have become a global public health problem due to the increase of Candida species resistant against antifungal therapeutics. The glucocorticoid PYED-1 (pregnadiene-11-hydroxy-16α,17α-epoxy-3,20-dione-1) has antimicrobial activity against various bacterial taxa. Consequently, it might be considered for the treatment of Candida infections. [...] Read more.

Invasive Candida infections have become a global public health problem due to the increase of Candida species resistant against antifungal therapeutics. The glucocorticoid PYED-1 (pregnadiene-11-hydroxy-16α,17α-epoxy-3,20-dione-1) has antimicrobial activity against various bacterial taxa. Consequently, it might be considered for the treatment of Candida infections. The antifungal activity of PYED-1 was evaluated against several fungal strains that were representative of the five species that causes the majority of Candida infections—namely, Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis and Candida krusei. PYED-1 exhibited a weak antifungal activity and a fungistatic effect on all five Candida species. On the other hand, PYED-1 exhibited a good anti-biofilm activity, and was able to eradicate the preformed biofilms of all Candida species analyzed. Moreover, PYED-1 inhibited germ tube and hyphae formation of C. albicans and reduced adhesion of C. albicans to abiotic surfaces by up to 30%. Full article

(This article belongs to the Special Issue Antibacterial, Antibiofilm and Anti-virulence Activity Research of Both Natural and Synthetic Products)

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16 pages, 7529 KiB

Open AccessArticle

Interaction of Temporin-L Analogues with the E. coli FtsZ Protein

by Angela Di Somma, Carolina Canè, Antonio Moretta and Angela Duilio

Antibiotics 2021, 10(6), 704; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10060704 - 11 Jun 2021

Cited by 7 | Viewed by 2311

Abstract

The research of new therapeutic agents to fight bacterial infections has recently focused on the investigation of antimicrobial peptides (AMPs), the most common weapon that all organisms produce to prevent invasion by external pathogens. Among AMPs, the amphibian Temporins constitute a well-known family [...] Read more.

The research of new therapeutic agents to fight bacterial infections has recently focused on the investigation of antimicrobial peptides (AMPs), the most common weapon that all organisms produce to prevent invasion by external pathogens. Among AMPs, the amphibian Temporins constitute a well-known family with high antibacterial properties against Gram-positive and Gram-negative bacteria. In particular, Temporin-L was shown to affect bacterial cell division by inhibiting FtsZ, a tubulin-like protein involved in the crucial step of Z-ring formation at the beginning of the division process. As FtsZ represents a leading target for new antibacterial compounds, in this paper we investigated in detail the interaction of Temporin L with Escherichia coli FtsZ and designed two TL analogues in an attempt to increase peptide-protein interactions and to better understand the structural determinants leading to FtsZ inhibition. The results demonstrated that the TL analogues improved their binding to FtsZ, originating stable protein-peptide complexes. Functional studies showed that both peptides were endowed with a high capability of inhibiting both the enzymatic and polymerization activities of the protein. Moreover, the TL analogues were able to inhibit bacterial growth at low micromolar concentrations. These observations may open up the way to the development of novel peptide or peptidomimetic drugs tailored to bind FtsZ, hampering a crucial process of bacterial life that might be proposed for future pharmaceutical applications. Full article

(This article belongs to the Special Issue Antibacterial, Antibiofilm and Anti-virulence Activity Research of Both Natural and Synthetic Products)

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14 pages, 8364 KiB

Open AccessArticle

Sub-Inhibitory Concentrations of Ciprofloxacin Alone and Combinations with Plant-Derived Compounds against P. aeruginosa Biofilms and Their Effects on the Metabolomic Profile of P. aeruginosa Biofilms

by Didem Kart, Tuba Reçber, Emirhan Nemutlu and Meral Sagiroglu

Antibiotics 2021, 10(4), 414; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10040414 - 09 Apr 2021

Cited by 11 | Viewed by 2788

Abstract

Introduction: Alternative anti-biofilm agents are needed to combat Pseudomonas aeruginosa infections. The mechanisms behind these new agents also need to be revealed at a molecular level. Materials and methods: The anti-biofilm effects of 10 plant-derived compounds on P. aeruginosa biofilms were investigated using [...] Read more.

Introduction: Alternative anti-biofilm agents are needed to combat Pseudomonas aeruginosa infections. The mechanisms behind these new agents also need to be revealed at a molecular level. Materials and methods: The anti-biofilm effects of 10 plant-derived compounds on P. aeruginosa biofilms were investigated using minimum biofilm eradication concentration (MBEC) and virulence assays. The effects of ciprofloxacin and compound combinations on P. aeruginosa in mono and triple biofilms were compared. A metabolomic approach and qRT-PCR were applied to the biofilms treated with ciprofloxacin in combination with baicalein, esculin hydrate, curcumin, and cinnamaldehyde at sub-minimal biofilm inhibitory concentration (MBIC) concentrations to highlight the specific metabolic shifts between the biofilms and to determine the quorum sensing gene expressions, respectively. Results: The combinations of ciprofloxacin with curcumin, baicalein, esculetin, and cinnamaldehyde showed more reduced MBICs than ciprofloxacin alone. The quorum sensing genes were downregulated in the presence of curcumin and cinnamaldehyde, while upregulated in the presence of baicalein and esculin hydrate rather than for ciprofloxacin alone. The combinations exhibited different killing effects on P. aeruginosa in mono and triple biofilms without affecting its virulence. The findings of the decreased metabolite levels related to pyrimidine and lipopolysaccharide synthesis and to down-regulated alginate and lasI expressions strongly indicate the role of multifactorial mechanisms for curcumin-mediated P. aeruginosa growth inhibition. Conclusions: The use of curcumin, baicalein, esculetin, and cinnamaldehyde with ciprofloxacin will help fight against P. aeruginosa biofilms. To the best of our knowledge, this is the first study of its kind to define the effect of plant-based compounds as possible anti-biofilm agents with low MBICs for the treatment of P. aeruginosa biofilms through metabolomic pathways. Full article

(This article belongs to the Special Issue Antibacterial, Antibiofilm and Anti-virulence Activity Research of Both Natural and Synthetic Products)

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16 pages, 4254 KiB

Open AccessArticle

Indole Derivatives Obtained from Egyptian Enterobacter sp. Soil Isolates Exhibit Antivirulence Activities against Uropathogenic Proteus mirabilis

by Mai A. Amer, Reham Wasfi, Ahmed S. Attia and Mohamed A. Ramadan

Antibiotics 2021, 10(4), 363; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10040363 - 29 Mar 2021

Cited by 11 | Viewed by 3463

Abstract

Proteus mirabilis is a frequent cause of catheter associated urinary tract infections (CAUTIs). Several virulence factors contribute to its pathogenesis, but swarming motility, biofilm formation, and urease activity are considered the hallmarks. The increased prevalence in antibiotic resistance among uropathogens is alarming and [...] Read more.

Proteus mirabilis is a frequent cause of catheter associated urinary tract infections (CAUTIs). Several virulence factors contribute to its pathogenesis, but swarming motility, biofilm formation, and urease activity are considered the hallmarks. The increased prevalence in antibiotic resistance among uropathogens is alarming and requires searching for new treatment alternatives. With this in mind, our study aims to investigate antivirulence activity of indole derivatives against multidrug resistant P. mirabilis isolates. Ethyl acetate (EtOAc) extracts from Enterobacter sp. (rhizobacterium), isolated from Egyptian soil samples were tested for their ability to antagonize the virulence capacity and biofilm activity of P. mirabilis uropathogens. Extracts of two Enterobacter sp. isolates (coded Zch127 and Cbg70) showed the highest antivirulence activities against P. mirabilis. The two promising rhizobacteria Zch127 and Cbg70 were isolated from soil surrounding: Cucurbita pepo (Zucchini) and Brassica oleracea var. capitata L. (Cabbage), respectively. Sub-minimum inhibitory concentrations (Sub-MICs) of the two extracts showed potent antibiofilm activity with significant biofilm reduction of ten P. mirabilis clinical isolates (p-value < 0.05) in a dose-dependent manner. Interestingly, the Zch127 extract showed anti-urease, anti-swarming and anti-swimming activity against the tested strains. Indole derivatives identified represented key components of indole pyruvate, indole acetamide pathways; involved in the synthesis of indole acetic acid. Additional compounds for indole acetonitrile pathway were detected in the Zch127 extract which showed higher antivirulence activity. Accordingly, the findings of the current study model the feasibility of using these extracts as promising antivirulence agent against the P. mirabilis uropathogens and as potential therapy for treatment of urinary tract infections (UTIs). Full article

(This article belongs to the Special Issue Antibacterial, Antibiofilm and Anti-virulence Activity Research of Both Natural and Synthetic Products)

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15 pages, 2384 KiB

Open AccessArticle

Comparative Investigation of Composition, Antifungal, and Anti-Inflammatory Effects of the Essential Oil from Three Industrial Hemp Varieties from Italian Cultivation

by Giustino Orlando, Sabrina Adorisio, Domenico Delfino, Annalisa Chiavaroli, Luigi Brunetti, Lucia Recinella, Sheila Leone, Marianna D’Antonio, Gokhan Zengin, Alessandra Acquaviva, Mirko Antico, Paola Angelini, Giancarlo Angeles Flores, Roberto Venanzoni, Massimo Tacchini, Simonetta Cristina Di Simone, Luigi Menghini and Claudio Ferrante

Antibiotics 2021, 10(3), 334; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10030334 - 22 Mar 2021

Cited by 20 | Viewed by 3960

Abstract

Industrial hemp is characterized by a huge amount of by-products, such as inflorescences, that may represent high-quality sources of biomolecules with pharmaceutical interest. In the present study, we have evaluated the phytochemical profile, including terpene and terpenophenolic compounds, of the essential oils (EOs) [...] Read more.

Industrial hemp is characterized by a huge amount of by-products, such as inflorescences, that may represent high-quality sources of biomolecules with pharmaceutical interest. In the present study, we have evaluated the phytochemical profile, including terpene and terpenophenolic compounds, of the essential oils (EOs) of Futura 75, Carmagnola selezionata and Eletta campana hemp varieties. The EOs were also tested for antifungal properties toward Trichophyton mentagrophytes, Trichophyton rubrum, Arthroderma crocatum, Arthroderma quadrifidum, Arthroderma gypseum, Arthroderma curreyi, and Arthroderma insingulare. In parallel, we investigated the inhibitory effects of the EOs against tyrosinase, and the production of prostaglandin E₂ in isolated mouse skin exposed to hydrogen peroxide. In human H1299 lung adenocarcinoma cells, we also evaluated the influence of the EOs on the gene expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2), which are involved in SARS-CoV-2 entry in human host. E-caryophyllene and α-pinene were the prominent terpenes in the EOs, whereas the cannabidiolic acid was the terpenophenol present at higher concentration. The EOs inhibited the growth of all tested dermatophytes species. In isolated skin specimens, EOs prevented the hydrogen-peroxide-induced synthesis of prostaglandin E₂, consistent with the intrinsic antityrosinase activity. Finally, in H1299 cells, all tested EOs reduced the gene expression of ACE-2 and TMPRSS2, as well. Therefore, the present findings highlight the rationale for the use of the present EOs against infectious diseases. Full article

(This article belongs to the Special Issue Antibacterial, Antibiofilm and Anti-virulence Activity Research of Both Natural and Synthetic Products)

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19 pages, 1843 KiB

Open AccessArticle

Pharmacological Potential and Chemical Characterization of Bridelia ferruginea Benth.—A Native Tropical African Medicinal Plant

by Mohamad Fawzi Mahomoodally, Sharmeen Jugreet, Kouadio Ibrahime Sinan, Gokhan Zengin, Gunes Ak, Ramazan Ceylan, József Jekő, Zoltán Cziáky, Paola Angelini, Giancarlo Angeles Flores, Roberto Venanzoni, Simonetta Cristina Di Simone, Luigi Menghini, Giustino Orlando, Claudio Ferrante, Ouattara Katinan Etienne and Massimo Tacchini

Antibiotics 2021, 10(2), 223; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10020223 - 23 Feb 2021

Cited by 19 | Viewed by 3268

Abstract

To avail the possible pharmacological actions of Brideliaferruginea Benth., the present investigation was designed to quantitatively analyze the total flavonoid and phenolic contents and assess the various antioxidant and enzyme inhibition properties of leaf and stem bark extracts (ethyl acetate, water and [...] Read more.

To avail the possible pharmacological actions of Brideliaferruginea Benth., the present investigation was designed to quantitatively analyze the total flavonoid and phenolic contents and assess the various antioxidant and enzyme inhibition properties of leaf and stem bark extracts (ethyl acetate, water and methanolic) of B. ferruginea. Anti-proliferative effect was also investigated against human colon cancer cells (HCT116) as well as the antimicrobial potential against multiple bacterial and fungal (yeasts and dermatophytes) strains. The methanolic and water extracts of the stem bark demonstrated the highest phenolic content (193.58 ± 0.98 and 187.84 ± 1.88 mg/g, respectively), while the leaf extracts showed comparatively higher flavonoid contents (24.37–42.31 mg/g). Overall, the methanolic extracts were found to possess the most significant antioxidant potency. Compared to the other extracts, methanolic extracts of the B. ferruginea were revealed to be most potent inhibitors of acetyl- and butyryl-cholinesterases, tyrosinase α-amylase, except α-glucosidase. Only the ethyl acetate extracts were found to inhibit glucosidase. Additionally, the stem bark methanolic extract also showed potent inhibitory activity against E. coli and gram-positive bacteria (MIC (minimum inhibitory concentration): 2.48–62.99 µg/mL), as well as all the tested fungi (MIC: 4.96–62.99 µg/mL). In conclusion, B. ferruginea can be regarded as a promising source of bioactive compounds displaying multifunctional pharmacological activities and thus is a potential candidate for further investigations in the endeavor to develop botanical formulations for pharmaceutical and cosmeceutical industries. Full article

(This article belongs to the Special Issue Antibacterial, Antibiofilm and Anti-virulence Activity Research of Both Natural and Synthetic Products)

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13 pages, 4091 KiB

Open AccessArticle

Baicalein Inhibits Streptococcus mutans Biofilms and Dental Caries-Related Virulence Phenotypes

by Aparna Vijayakumar, Hema Bhagavathi Sarveswari, Sahana Vasudevan, Karthi Shanmugam, Adline Princy Solomon and Prasanna Neelakantan

Antibiotics 2021, 10(2), 215; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10020215 - 21 Feb 2021

Cited by 21 | Viewed by 3489

Abstract

Dental caries, the most common oral disease, is a major public healthcare burden and affects more than three billion people worldwide. The contemporary understanding of the need for a healthy microbiome and the emergence of antimicrobial resistance has resulted in an urgent need [...] Read more.

Dental caries, the most common oral disease, is a major public healthcare burden and affects more than three billion people worldwide. The contemporary understanding of the need for a healthy microbiome and the emergence of antimicrobial resistance has resulted in an urgent need to identify compounds that curb the virulence of pathobionts without microbial killing. Through this study, we have demonstrated for the first time that 5,6,7-trihydroxyflavone (Baicalein) significantly downregulates crucial caries-related virulence phenotypes in Streptococcus mutans. Baicalein significantly inhibited biofilm formation by Streptococcus mutans UA159 (MBIC₅₀ = 200 μM), without significant growth inhibition. Notably, these concentrations of baicalein did not affect the commensal S. gordonii. Strikingly, baicalein significantly reduced cell surface hydrophobicity, autoaggregation and acid production by S. mutans. Mechanistic studies (qRT-PCR) showed downregulation of various genes regulating biofilm formation, surface attachment, quorum sensing, acid production and competence. Finally, we demonstrate the potential translational value of baicalein by reporting synergistic interaction with fluoride against S. mutans biofilms. Full article

(This article belongs to the Special Issue Antibacterial, Antibiofilm and Anti-virulence Activity Research of Both Natural and Synthetic Products)

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Review

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32 pages, 15897 KiB

Open AccessEditor’s ChoiceReview

Efflux Pump Mediated Antimicrobial Resistance by Staphylococci in Health-Related Environments: Challenges and the Quest for Inhibition

by Abolfazl Dashtbani-Roozbehani and Melissa H. Brown

Antibiotics 2021, 10(12), 1502; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10121502 - 07 Dec 2021

Cited by 40 | Viewed by 6520

Abstract

The increasing emergence of antimicrobial resistance in staphylococcal bacteria is a major health threat worldwide due to significant morbidity and mortality resulting from their associated hospital- or community-acquired infections. Dramatic decrease in the discovery of new antibiotics from the pharmaceutical industry coupled with [...] Read more.

The increasing emergence of antimicrobial resistance in staphylococcal bacteria is a major health threat worldwide due to significant morbidity and mortality resulting from their associated hospital- or community-acquired infections. Dramatic decrease in the discovery of new antibiotics from the pharmaceutical industry coupled with increased use of sanitisers and disinfectants due to the ongoing COVID-19 pandemic can further aggravate the problem of antimicrobial resistance. Staphylococci utilise multiple mechanisms to circumvent the effects of antimicrobials. One of these resistance mechanisms is the export of antimicrobial agents through the activity of membrane-embedded multidrug efflux pump proteins. The use of efflux pump inhibitors in combination with currently approved antimicrobials is a promising strategy to potentiate their clinical efficacy against resistant strains of staphylococci, and simultaneously reduce the selection of resistant mutants. This review presents an overview of the current knowledge of staphylococcal efflux pumps, discusses their clinical impact, and summarises compounds found in the last decade from plant and synthetic origin that have the potential to be used as adjuvants to antibiotic therapy against multidrug resistant staphylococci. Critically, future high-resolution structures of staphylococcal efflux pumps could aid in design and development of safer, more target-specific and highly potent efflux pump inhibitors to progress into clinical use. Full article

(This article belongs to the Special Issue Antibacterial, Antibiofilm and Anti-virulence Activity Research of Both Natural and Synthetic Products)

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