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13 pages, 2072 KiB

Open AccessArticle

Antibacterial and Cytocompatible pH-Responsive Peptide Hydrogel

by Dona Imanga Upamadi Edirisinghe, Areetha D’Souza, Maryam Ramezani, Robert J. Carroll, Quenten Chicón, Cheyene L. Muenzel, Jonathan Soule, Mary Beth Browning Monroe, Alison E. Patteson and Olga V. Makhlynets

Molecules 2023, 28(11), 4390; https://doi.org/10.3390/molecules28114390 - 27 May 2023

Cited by 7 | Viewed by 2427

Abstract

A short peptide, FHHF-11, was designed to change stiffness as a function of pH due to changing degree of protonation of histidines. As pH changes in the physiologically relevant range, G′ was measured at 0 Pa (pH 6) and 50,000 Pa (pH 8). [...] Read more.

A short peptide, FHHF-11, was designed to change stiffness as a function of pH due to changing degree of protonation of histidines. As pH changes in the physiologically relevant range, G′ was measured at 0 Pa (pH 6) and 50,000 Pa (pH 8). This peptide-based hydrogel is antimicrobial and cytocompatible with skin cells (fibroblasts). It was demonstrated that the incorporation of unnatural AzAla tryptophan analog residue improves the antimicrobial properties of the hydrogel. The material developed can have a practical application and be a paradigm shift in the approach to wound treatment, and it will improve healing outcomes for millions of patients each year. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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12 pages, 2355 KiB

Open AccessArticle

One-Step Construction of Tryptophan-Derived Small Molecule Hydrogels for Antibacterial Materials

by Xianwen Song, Shunmei He, Jun Zheng, Shutong Yang, Qiang Li and Yi Zhang

Molecules 2023, 28(8), 3334; https://doi.org/10.3390/molecules28083334 - 10 Apr 2023

Cited by 3 | Viewed by 1818

Abstract

Amino acid-based hydrogels have received widespread attention because of their wide range of sources, biodegradability, and biocompatibility. Despite considerable progress, the development of such hydrogels has been limited by critical problems such as bacterial infection and complex preparation. Herein, by using the non-toxic [...] Read more.

Amino acid-based hydrogels have received widespread attention because of their wide range of sources, biodegradability, and biocompatibility. Despite considerable progress, the development of such hydrogels has been limited by critical problems such as bacterial infection and complex preparation. Herein, by using the non-toxic gluconolactone (GDL) to adjust the pH of the solution to induce the rapid self-assembly of N-[(benzyloxy)carbonyl]-L-tryptophan (ZW) to form a three-dimensional (3D) gel network, we developed a stable and effective self-assembled small-molecule hydrogel. Characterization assays and molecular dynamics studies indicate that π–π stacking and hydrogen bonding are the main drivers of self-assembly between ZW molecules. In vitro experiments further confirmed this material’s sustained release properties, low cytotoxicity, and excellent antibacterial activity, particularly against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. This study provides a different and innovative perspective for the further development of antibacterial materials based on amino acid derivatives. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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11 pages, 2273 KiB

Open AccessArticle

Preparation, Characterization and Antibacterial Property Analysis of Cellulose Nanocrystals (CNC) and Chitosan Nanoparticles Fine-Tuned Starch Film

by Zilong Deng, Zixuan Wu, Xiao Tan, Fangkun Deng, Yaobang Chen, Yanping Chen and Hongcai Zhang

Molecules 2022, 27(23), 8542; https://doi.org/10.3390/molecules27238542 - 4 Dec 2022

Cited by 18 | Viewed by 2328

Abstract

To improve the mechanical and antibacterial properties of traditional starch-based film, herein, cellulose nanocrystals (CNCs) and chitosan nanoparticles (CS NPs) were introduced to potato starch (PS, film-forming matrix) for the preparation of nanocomposite film without incorporation of additional antibacterial agents. CNCs with varied [...] Read more.

To improve the mechanical and antibacterial properties of traditional starch-based film, herein, cellulose nanocrystals (CNCs) and chitosan nanoparticles (CS NPs) were introduced to potato starch (PS, film-forming matrix) for the preparation of nanocomposite film without incorporation of additional antibacterial agents. CNCs with varied concentrations were added to PS and CS NPs composite system to evaluate the optimal film performance. The results showed that tensile strength (TS) of nanocomposite film with 0, 0.01, 0.05, and 0.1% (w/w) CNCs incorporation were 41, 46, 47 and 41 MPa, respectively. The elongation at break (EAB) reached 12.5, 10.2, 7.1 and 13.3%, respectively. Due to the reinforcing effect of CNCs, surface morphology and structural properties of nanocomposite film were altered. TGA analysis confirmed the existence of hydrogen bondings and electrostatic attractions between components in the film-forming matrix. The prepared nanocomposite films showed good antibacterial properties against both E. coli and S. aureus. The nanocomposite film, consist of three most abundant biodegradable polymers, could potentially serve as antibacterial packaging films with strong mechanical properties for food and allied industries. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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13 pages, 5918 KiB

Open AccessArticle

AgCu NP Formation by the Ag NP Catalysis of Cu Ions at Room Temperature and Their Antibacterial Efficacy: A Kinetic Study

by Yujie Tao, Fang Zhou, Kaixin Wang, Dequan Yang and Edward Sacher

Molecules 2022, 27(20), 6951; https://doi.org/10.3390/molecules27206951 - 17 Oct 2022

Cited by 9 | Viewed by 2016

Abstract

Although a facile route to prepare AgCu nanoalloys (NAs) with enhanced antibacterial efficacy using Ag NP catalysis of Cu ions at elevated temperatures was previously developed, its detailed reaction process is still unclear due to the fast reaction process at higher temperatures. This [...] Read more.

Although a facile route to prepare AgCu nanoalloys (NAs) with enhanced antibacterial efficacy using Ag NP catalysis of Cu ions at elevated temperatures was previously developed, its detailed reaction process is still unclear due to the fast reaction process at higher temperatures. This work found that AgCu NAs can also be synthesized by the same process but at room temperature. AgCu NAs formation kinetics have been studied using UV–Visible spectra and Transmission Electron Microscopy (TEM), where formation includes Cu²⁺ deposition onto the Ag NP surface and Ag⁺ release, reduction, and agglomeration to form new Ag NPs; this is followed by a redistribution of the NA components and coalescence to form larger AgCu NPs. It is found that SPR absorption is linear with time early in the reaction, as expected for both pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetics; neither model is followed subsequently due to contributions from newly formed Ag NPs and AgCu NAs. The antibacterial efficacy of the AgCu NAs thus formed was estimated, with a continuous increase over the whole alloying process, demonstrating the correlation of antibacterial efficacy with the extent of AgCu NA formation and Ag⁺ release. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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12 pages, 1698 KiB

Open AccessArticle

Molecular Characterization of Bacterial Isolates from Soil Samples and Evaluation of their Antibacterial Potential against MDRS

by Shahida Sadiqi, Muhammad Hamza, Farooq Ali, Sadia Alam, Qismat Shakeela, Shehzad Ahmed, Asma Ayaz, Sajid Ali, Saddam Saqib, Fazal Ullah and Wajid Zaman

Molecules 2022, 27(19), 6281; https://doi.org/10.3390/molecules27196281 - 23 Sep 2022

Cited by 19 | Viewed by 3714

Abstract

Some soil microbes, with their diverse inhabitance, biologically active metabolites, and endospore formation, gave them characteristic predominance and recognition among other microbial communities. The present study collected ten soil samples from green land, agricultural and marshy soil sites of Khyber Pakhtunkhwa, Pakistan. After [...] Read more.

Some soil microbes, with their diverse inhabitance, biologically active metabolites, and endospore formation, gave them characteristic predominance and recognition among other microbial communities. The present study collected ten soil samples from green land, agricultural and marshy soil sites of Khyber Pakhtunkhwa, Pakistan. After culturing on described media, the bacterial isolates were identified through phenotypic, biochemical and phylogenetic analysis. Our phylogenetic analysis revealed three bacterial isolates, A6S7, A1S6, and A1S10, showing 99% nucleotides sequence similarity with Brevibacillus formosus, Bacillus Subtilis and Paenibacillus dendritiformis. The crude extract was prepared from bacterial isolates to assess the anti-bacterial potential against various targeted multidrug-resistant strains (MDRS), including Acinetobacter baumannii (ATCC 19606), Methicillin-resistant Staphylococcus aureus (MRSA) (BAA-1683), Klebsiella pneumoniae (ATCC 13883), Pseudomonas aeruginosa (BAA-2108), Staphylococcus aureus (ATCC 292013), Escherichia coli (ATCC25922) and Salmonella typhi (ATCC 14028). Our analysis revealed that all bacterial extracts possess activity against Gram-negative and Gram-positive bacteria at a concentration of 5 mg/mL, efficiently restricting the growth of E. coli compared with positive control ciprofloxacin. The study concluded that the identified species have the potential to produce antimicrobial compounds which can be used to control different microbial infections, especially MDRS. Moreover, the analysis of the bacterial extracts through GC-MS indicated the presence of different antimicrobial compounds such as propanoic acid, oxalic acid, phenol and hexadecanoic acid. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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16 pages, 1579 KiB

Open AccessArticle

Extraction of Bioactive Compounds for Antioxidant, Antimicrobial, and Antidiabetic Applications

by Fatimah Saeed Aldughaylibi, Muhammad Asam Raza, Sumaira Naeem, Humera Rafi, Mir Waqas Alam, Basma Souayeh, Mohd Farhan, Muhammad Aamir, Noushi Zaidi and Tanveer Ahmad Mir

Molecules 2022, 27(18), 5935; https://doi.org/10.3390/molecules27185935 - 13 Sep 2022

Cited by 12 | Viewed by 2539

Abstract

This study was designed to check the potential of secondary metabolites of the selected plants; Citrullus colocynthis, Solanum nigrum, Solanum surattense, Calotropis procera, Agave americana, and Anagallis arvensis for antioxidant, antibacterial, antifungal, and antidiabetic agents. Plant material was [...] Read more.

This study was designed to check the potential of secondary metabolites of the selected plants; Citrullus colocynthis, Solanum nigrum, Solanum surattense, Calotropis procera, Agave americana, and Anagallis arvensis for antioxidant, antibacterial, antifungal, and antidiabetic agents. Plant material was soaked in ethanol/methanol to get the crude extract, which was further partitioned via solvent extraction technique. GCMS and FTIR analytical techniques were applied to check the compounds responsible for causing antioxidant, antimicrobial, and antidiabetic activities. It was concluded that about 80% of studied extracts/fractions were active against α-amylase, ranging from 43 to 96%. The highest activity (96.63%) was exhibited by butanol fractions of A. arvensis while the least response (43.65%) was shown by the aqueous fraction of C. colocynthis and the methanol fraction of fruit of S. surattense. The highest antioxidant activity was shown by the ethyl acetate fraction of Anagallis arvensis (78.1%), while aqueous as well as n-hexane fractions are the least active throughout the assay. Results showed that all tested plants can be an excellent source of natural products with potential antimicrobial, antioxidant, and antidiabetic potential. The biological response of these species is depicted as a good therapeutic agent, and, in the future, it can be encapsulated for drug discovery. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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14 pages, 4536 KiB

Open AccessArticle

A g-Type Lysozyme from Deep-Sea Hydrothermal Vent Shrimp Kills Selectively Gram-Negative Bacteria

by Jing-Chang Luo, Jian Zhang and Li Sun

Molecules 2021, 26(24), 7624; https://doi.org/10.3390/molecules26247624 - 16 Dec 2021

Cited by 7 | Viewed by 2691

Abstract

Lysozyme is a key effector molecule of the innate immune system in both vertebrate and invertebrate. It is classified into six types, one of which is the goose-type (g-type). To date, no study on g-type lysozyme in crustacean has been documented. Here, we [...] Read more.

Lysozyme is a key effector molecule of the innate immune system in both vertebrate and invertebrate. It is classified into six types, one of which is the goose-type (g-type). To date, no study on g-type lysozyme in crustacean has been documented. Here, we report the identification and characterization of a g-type lysozyme (named LysG1) from the shrimp inhabiting a deep-sea hydrothermal vent in Manus Basin. LysG1 possesses conserved structural features of g-type lysozymes. The recombinant LysG1 (rLysG1) exhibited no muramidase activity and killed selectively Gram-negative bacteria in a manner that depended on temperature, pH, and metal ions. rLysG1 bound target bacteria via interaction with bacterial cell wall components, notably lipopolysaccharide (LPS), and induced cellular membrane permeabilization, which eventually caused cell lysis. The endotoxin-binding capacity enabled rLysG1 to alleviate the inflammatory response induced by LPS. Mutation analysis showed that the bacterial binding and killing activities of rLysG1 required the integrity of the conserved α3 and 4 helixes of the protein. Together, these results provide the first insight into the activity and working mechanism of g-type lysozyme in crustacean and deep-sea organisms. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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19 pages, 36342 KiB

Open AccessArticle

Antibacterial Polysiloxane Polymers and Coatings for Cochlear Implants

by Vlad Cozma, Irina Rosca, Luminita Radulescu, Cristian Martu, Valentin Nastasa, Cristian-Dragos Varganici, Elena-Laura Ursu, Florica Doroftei, Mariana Pinteala and Carmen Racles

Molecules 2021, 26(16), 4892; https://doi.org/10.3390/molecules26164892 - 12 Aug 2021

Cited by 12 | Viewed by 2482

Abstract

Within this study, new materials were synthesized and characterized based on polysiloxane modified with different ratios of N-acetyl-l-cysteine (NAC) and crosslinked via UV-assisted thiol-ene addition, in order to obtain efficient membranes able to resist bacterial adherence and biofilm formation. These [...] Read more.

Within this study, new materials were synthesized and characterized based on polysiloxane modified with different ratios of N-acetyl-l-cysteine (NAC) and crosslinked via UV-assisted thiol-ene addition, in order to obtain efficient membranes able to resist bacterial adherence and biofilm formation. These membranes were subjected to in vitro testing for microbial adherence against S. pneumoniae using standardized tests. WISTAR rats were implanted for 4 weeks with crosslinked siloxane samples without and with NAC. A set of physical characterization methods was employed to assess the chemical structure and morphological aspects of the new synthetized materials before and after contact with the microbiological medium. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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10 pages, 1294 KiB

Open AccessArticle

Peptoids with Antibiofilm Activity against the Gram Negative Obligate Anaerobe, Fusobacterium nucleatum

by Jamie Toole, Hannah L. Bolt, John J. Marley, Sheila Patrick, Steven L. Cobb and Fionnuala T. Lundy

Molecules 2021, 26(16), 4741; https://doi.org/10.3390/molecules26164741 - 5 Aug 2021

Cited by 2 | Viewed by 2034

Abstract

Peptoids (oligo N-substituted glycines) are peptide analogues, which can be designed to mimic host antimicrobial peptides, with the advantage that they are resistant to proteolytic degradation. Few studies on the antimicrobial efficacy of peptoids have focused on Gram negative anaerobic microbes associated [...] Read more.

Peptoids (oligo N-substituted glycines) are peptide analogues, which can be designed to mimic host antimicrobial peptides, with the advantage that they are resistant to proteolytic degradation. Few studies on the antimicrobial efficacy of peptoids have focused on Gram negative anaerobic microbes associated with clinical infections, which are commonly recalcitrant to antibiotic treatment. We therefore studied the cytotoxicity and antibiofilm activity of a family of peptoids against the Gram negative obligate anaerobe Fusobacterium nucleatum, which is associated with infections in the oral cavity. Two peptoids, peptoid 4 (NaeNpheNphe)4 and peptoid 9 (NahNspeNspe)₃ were shown to be efficacious against F. nucleatum biofilms at a concentration of 1 μM. At this concentration, peptoids 4 and 9 were not cytotoxic to human erythrocytes or primary human gingival fibroblast cells. Peptoids 4 and 9 therefore have merit as future therapeutics for the treatment of oral infections. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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15 pages, 2738 KiB

Open AccessArticle

Functional Characterization of Porcine NK-Lysin: A Novel Immunomodulator That Regulates Intestinal Inflammatory Response

by Qian Lin, Qingqing Fu, Daiwen Chen, Bing Yu, Yuheng Luo, Zhiqing Huang, Ping Zheng, Xiangbing Mao, Jie Yu, Junqiu Luo, Hui Yan and Jun He

Molecules 2021, 26(14), 4242; https://doi.org/10.3390/molecules26144242 - 13 Jul 2021

Cited by 9 | Viewed by 2777

Abstract

Porcine NK-Lysine (PNKL) is a new antimicrobial peptide (AMP) identified in the small intestine. In this study, PNKL protein was obtained through heterologous expression in Escherichia coli and was estimated by SDS-PAGE at 33 kDa. The antibacterial activities of PNKL were determined using [...] Read more.

Porcine NK-Lysine (PNKL) is a new antimicrobial peptide (AMP) identified in the small intestine. In this study, PNKL protein was obtained through heterologous expression in Escherichia coli and was estimated by SDS-PAGE at 33 kDa. The antibacterial activities of PNKL were determined using various bacterial strains and showed broad-spectrum antimicrobial activity against Gram-negative and Gram-positive bacteria. Furthermore, E. coli K88-challenged IPEC-J2 cells were used to determine PNKL influences on inflammatory responses. Hemolytic assays showed that PNKL had no detrimental impact on cell viability. Interestingly, PNKL elevated the viability of IPEC-J2 cells exposure to E. coli K88. PNKL significantly decreased the cell apoptosis rate, and improved the distribution and abundance of tight junction protein ZO-1 in IPEC-J2 cells upon E. coli K88-challenge. Importantly, PNKL not only down regulated the expressions of inflammatory cytokines such as the IL-6 and TNF-α, but also down regulated the expressions of NF-κB, Caspase3, and Caspase9 in the E. coli K88-challenged cells. These results suggest a novel function of natural killer (NK)-lysin, and the anti-bacterial and anti-inflammatory properties of PNKL may allow it a potential substitute for conventionally used antibiotics or drugs. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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Review

Jump to: Research

16 pages, 6432 KiB

Open AccessReview

Glycopolymers for Antibacterial and Antiviral Applications

by Ruoyao Mei, Xingyu Heng, Xiaoli Liu and Gaojian Chen

Molecules 2023, 28(3), 985; https://doi.org/10.3390/molecules28030985 - 18 Jan 2023

Cited by 8 | Viewed by 2286

Abstract

Diseases induced by bacterial and viral infections are common occurrences in our daily life, and the main prevention and treatment strategies are vaccination and taking antibacterial/antiviral drugs. However, vaccines can only be used for specific viral infections, and the abuse of antibacterial/antiviral drugs [...] Read more.

Diseases induced by bacterial and viral infections are common occurrences in our daily life, and the main prevention and treatment strategies are vaccination and taking antibacterial/antiviral drugs. However, vaccines can only be used for specific viral infections, and the abuse of antibacterial/antiviral drugs will create multi−drug−resistant bacteria and viruses. Therefore, it is necessary to develop more targeted prevention and treatment methods against bacteria and viruses. Proteins on the surface of bacteria and viruses can specifically bind to sugar, so glycopolymers can be used as potential antibacterial and antiviral drugs. In this review, the research of glycopolymers for bacterial/viral detection/inhibition and antibacterial/antiviral applications in recent years are summarized. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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18 pages, 2202 KiB

Open AccessReview

Lysozyme and Its Application as Antibacterial Agent in Food Industry

by Nida Nawaz, Sai Wen, Fenghuan Wang, Shiza Nawaz, Junaid Raza, Maryam Iftikhar and Muhammad Usman

Molecules 2022, 27(19), 6305; https://doi.org/10.3390/molecules27196305 - 24 Sep 2022

Cited by 58 | Viewed by 8820

Abstract

Lysozymes are hydrolytic enzymes characterized by their ability to cleave the β-(1,4)-glycosidic bonds in peptidoglycan, a major structural component of the bacterial cell wall. This hydrolysis action compromises the integrity of the cell wall, causing the lysis of bacteria. For more than 80 [...] Read more.

Lysozymes are hydrolytic enzymes characterized by their ability to cleave the β-(1,4)-glycosidic bonds in peptidoglycan, a major structural component of the bacterial cell wall. This hydrolysis action compromises the integrity of the cell wall, causing the lysis of bacteria. For more than 80 years, its role of antibacterial defense in animals has been renowned, and it is also used as a preservative in foods and pharmaceuticals. In order to improve the antimicrobial efficacy of lysozyme, extensive research has been intended for its modifications. This manuscript reviews the natural antibiotic compound lysozyme with reference to its catalytic and non-catalytic mode of antibacterial action, lysozyme types, susceptibility and resistance of bacteria, modification of lysozyme molecules, and its applications in the food industry. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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30 pages, 11934 KiB

Open AccessEditor’s ChoiceReview

Azobenzene as Antimicrobial Molecules

by Miriam Di Martino, Lucia Sessa, Martina Di Matteo, Barbara Panunzi, Stefano Piotto and Simona Concilio

Molecules 2022, 27(17), 5643; https://doi.org/10.3390/molecules27175643 - 1 Sep 2022

Cited by 27 | Viewed by 4999

Abstract

Azo molecules, characterized by the presence of a -N=N- double bond, are widely used in various fields due to their sensitivity to external stimuli, ch as light. The emergence of bacterial resistance has pushed research towards designing new antimicrobial molecules that are more [...] Read more.

Azo molecules, characterized by the presence of a -N=N- double bond, are widely used in various fields due to their sensitivity to external stimuli, ch as light. The emergence of bacterial resistance has pushed research towards designing new antimicrobial molecules that are more efficient than those currently in use. Many authors have attempted to exploit the antimicrobial activity of azobenzene and to utilize their photoisomerization for selective control of the bioactivities of antimicrobial molecules, which is necessary for antibacterial therapy. This review will provide a systematic and consequential approach to coupling azobenzene moiety with active antimicrobial molecules and drugs, including small and large organic molecules, such as peptides. A selection of significant cutting-edge articles collected in recent years has been discussed, based on the structural pattern and antimicrobial performance, focusing especially on the photoactivity of azobenzene and the design of smart materials as the most targeted and desirable application. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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41 pages, 18837 KiB

Open AccessReview

Recent Developments to Cope the Antibacterial Resistance via β-Lactamase Inhibition

by Zafar Iqbal, Jian Sun, Haikang Yang, Jingwen Ji, Lili He, Lijuan Zhai, Jinbo Ji, Pengjuan Zhou, Dong Tang, Yangxiu Mu, Lin Wang and Zhixiang Yang

Molecules 2022, 27(12), 3832; https://doi.org/10.3390/molecules27123832 - 14 Jun 2022

Cited by 8 | Viewed by 3834

Abstract

Antibacterial resistance towards the β-lactam (BL) drugs is now ubiquitous, and there is a major global health concern associated with the emergence of new β-lactamases (BLAs) as the primary cause of resistance. In addition to the development of new antibacterial drugs, β-lactamase inhibition [...] Read more.

Antibacterial resistance towards the β-lactam (BL) drugs is now ubiquitous, and there is a major global health concern associated with the emergence of new β-lactamases (BLAs) as the primary cause of resistance. In addition to the development of new antibacterial drugs, β-lactamase inhibition is an alternative modality that can be implemented to tackle this resistance channel. This strategy has successfully revitalized the efficacy of a number of otherwise obsolete BLs since the discovery of the first β-lactamase inhibitor (BLI), clavulanic acid. Over the years, β-lactamase inhibition research has grown, leading to the introduction of new synthetic inhibitors, and a few are currently in clinical trials. Of note, the 1, 6-diazabicyclo [3,2,1]octan-7-one (DBO) scaffold gained the attention of researchers around the world, which finally culminated in the approval of two BLIs, avibactam and relebactam, which can successfully inhibit Ambler class A, C, and D β-lactamases. Boronic acids have shown promise in coping with Ambler class B β-lactamases in recent research, in addition to classes A, C, and D with the clinical use of vaborbactam. This review focuses on the further developments in the synthetic strategies using DBO as well as boronic acid derivatives. In addition, various other potential serine- and metallo- β-lactamases inhibitors that have been developed in last few years are discussed briefly as well. Furthermore, binding interactions of the representative inhibitors have been discussed based on the crystal structure data of inhibitor-enzyme complex, published in the literature. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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23 pages, 393 KiB

Open AccessEditor’s ChoiceReview

The Use of Cerium Compounds as Antimicrobials for Biomedical Applications

by Emilia Barker, Joanna Shepherd and Ilida Ortega Asencio

Molecules 2022, 27(9), 2678; https://doi.org/10.3390/molecules27092678 - 21 Apr 2022

Cited by 47 | Viewed by 4092

Abstract

Cerium and its derivatives have been used as remedies for wounds since the early 20th century. Cerium nitrate has attracted most attention in the treatment of deep burns, followed later by reports of its antimicrobial properties. Its ability to mimic and replace calcium [...] Read more.

Cerium and its derivatives have been used as remedies for wounds since the early 20th century. Cerium nitrate has attracted most attention in the treatment of deep burns, followed later by reports of its antimicrobial properties. Its ability to mimic and replace calcium is presumed to be a major mechanism of its beneficial action. However, despite some encouraging results, the overall data are somewhat confusing with seemingly the same compounds yielding opposing results. Despite this, cerium nitrate is currently used in wound treatment in combination with silver sulfadiazine as Flammacérium. Cerium oxide, especially in nanoparticle form (Nanoceria), has lately captured much interest due to its antibacterial properties mediated via oxidative stress, leading to an increase of published reports. The properties of Nanoceria depend on the synthesis method, their shape and size. Recently, the green synthesis route has gained a lot of interest as an alternative environmentally friendly method, resulting in production of effective antimicrobial and antifungal nanoparticles. Unfortunately, as is the case with antibiotics, emerging bacterial resistance against cerium-derived nanoparticles is a growing concern, especially in the case of bacterial biofilm. However, diverse strategies resulting from better understanding of the biology of cerium are promising. The aim of this paper is to present the progress to date in the use of cerium compounds as antimicrobials in clinical applications (in particular wound healing) and to provide an overview of the mechanisms of action of cerium at both the cellular and molecular level. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

18 pages, 346 KiB

Open AccessReview

The Effects of Natural Products and Environmental Conditions on Antimicrobial Resistance

by Lulu Huang, Saeed Ahmed, Yufeng Gu, Junhong Huang, Boyu An, Cuirong Wu, Yujie Zhou and Guyue Cheng

Molecules 2021, 26(14), 4277; https://doi.org/10.3390/molecules26144277 - 14 Jul 2021

Cited by 23 | Viewed by 3569

Abstract

Due to the extensive application of antibiotics in medical and farming practices, the continued diversification and development of antimicrobial resistance (AMR) has attracted serious public concern. With the emergence of AMR and the failure to treat bacterial infections, it has led to an [...] Read more.

Due to the extensive application of antibiotics in medical and farming practices, the continued diversification and development of antimicrobial resistance (AMR) has attracted serious public concern. With the emergence of AMR and the failure to treat bacterial infections, it has led to an increased interest in searching for novel antibacterial substances such as natural antimicrobial substances, including microbial volatile compounds (MVCs), plant-derived compounds, and antimicrobial peptides. However, increasing observations have revealed that AMR is associated not only with the use of antibacterial substances but also with tolerance to heavy metals existing in nature and being used in agriculture practice. Additionally, bacteria respond to environmental stresses, e.g., nutrients, oxidative stress, envelope stress, by employing various adaptive strategies that contribute to the development of AMR and the survival of bacteria. Therefore, we need to elucidate thoroughly the factors and conditions affecting AMR to take comprehensive measures to control the development of AMR. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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