Antimicrobial Polymers: The Potential Replacement of Existing Antibiotics?

Antimicrobial resistance is now considered a major global challenge; compromising medical advancements and our ability to treat infectious disease. Increased antimicrobial resistance has resulted in increased morbidity and mortality due to infectious diseases worldwide. The lack of discovery of novel compounds from natural products or new classes of antimicrobials, encouraged us to recycle discontinued antimicrobials that were previously removed from routine use due to their toxicity, e.g., colistin. Since the discovery of new classes of compounds is extremely expensive and has very little success, one strategy to overcome this issue could be the application of synthetic compounds that possess antimicrobial activities. Polymers with innate antimicrobial properties or that have the ability to be conjugated with other antimicrobial compounds create the possibility for replacement of antimicrobials either for the direct application as medicine or implanted on medical devices to control infection. Here, we provide the latest update on research related to antimicrobial polymers in the context of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens. We summarise polymer subgroups: compounds containing natural peptides, halogens, phosphor and sulfo derivatives and phenol and benzoic derivatives, organometalic polymers, metal nanoparticles incorporated into polymeric carriers, dendrimers and polymer-based guanidine. We intend to enhance understanding in the field and promote further work on the development of polymer based antimicrobial compounds.

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Air Ambulance: Antimicrobial Power of Bacterial Volatiles

Antibiotics ◽

10.3390/antibiotics11010109 ◽

2022 ◽

Vol 11 (1) ◽

pp. 109

Author(s):

Alexander Lammers ◽

Michael Lalk ◽

Paolina Garbeva

Keyword(s):

Antimicrobial Resistance ◽

Antimicrobial Activities ◽

Chemical Diversity ◽

Antimicrobial Compounds ◽

Interspecies Interactions ◽

Human Pathogens ◽

Innovative Solutions ◽

Exciting Source ◽

Antimicrobial Volatiles ◽

Bacterial Volatiles

We are currently facing an antimicrobial resistance crisis, which means that a lot of bacterial pathogens have developed resistance to common antibiotics. Hence, novel and innovative solutions are urgently needed to combat resistant human pathogens. A new source of antimicrobial compounds could be bacterial volatiles. Volatiles are ubiquitous produced, chemically divers and playing essential roles in intra- and interspecies interactions like communication and antimicrobial defense. In the last years, an increasing number of studies showed bioactivities of bacterial volatiles, including antibacterial, antifungal and anti-oomycete activities, indicating bacterial volatiles as an exciting source for novel antimicrobial compounds. In this review we introduce the chemical diversity of bacterial volatiles, their antimicrobial activities and methods for testing this activity. Concluding, we discuss the possibility of using antimicrobial volatiles to antagonize the antimicrobial resistance crisis.

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Antibiotics resistance - a stumbling block to antibiotics research

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v10i3.1410 ◽

2019 ◽

Vol 10 (3) ◽

pp. 2008-2013

Author(s):

Sivasankari Marimuthu ◽

Arul Jayanthi Antonisamy ◽

Sankar Malayandi ◽

Karthikeyan Rajendran

Keyword(s):

Antimicrobial Properties ◽

Structural Features ◽

Antibiotics Resistance ◽

Antimicrobial Compounds ◽

Resistance Development ◽

Synthetic Compounds ◽

Development Of Resistance ◽

Serious Infections ◽

New Antibiotics ◽

Antibiotic Discovery

Antibiotics are natural or synthetic substances that inhibit the growth of infectious microorganisms and prevent from them, causing serious infections. Though the discovery of penicillin was claimed to be accidental, later on, systematic procedures for antibiotic discovery was introduced by Waksman through his streptomycin discovery. Adopting Waksman's platform, many researchers are exploring natural sources in search of antibiotics. On the other hand, the development of resistance to antibiotics is growing at a rate faster than the discovery of new antibiotics. While a number of semi synthetic and synthetic compounds with antimicrobial properties are emerging to combat the above problem, the microorganisms are in no way working inferior to resist the actions of such substances. In fact, the development of resistance by microorganisms to above said alternatives are observed at an even faster rate than the natural antimicrobial compounds obtained from microbes. The reason behind such a faster resistance development is due to the similar structural features of semi-synthetic and synthetic compounds to natural antibiotics from microbes. The treatment of infectious diseases becomes a big task and requires a greater concern nowadays to avoid increased rates of mortality. This is an alarming condition demanding for the discovery and development of new antimicrobial compounds that would end up as a better solution for the existing problem and avoid the development of resistance. This review presents the background of antibiotics discovery and resistance development and also provides an insight into the available strategies to combat the problem.

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Wide-Spectrum Biomimetic Antimicrobial Systems

ScienceOpen Research ◽

10.14293/s2199-1006.1.sor-life.cmgpsn.v1 ◽

2016 ◽

Author(s):

Heidi Weinkauf ◽

Byron Brehm-Stecher

Keyword(s):

Time Course ◽

Wide Spectrum ◽

Test Organism ◽

Antimicrobial Activities ◽

Antimicrobial Polymers ◽

Gram Positive Bacteria ◽

Effective Components ◽

Transmission Electron ◽

Natural Peptides ◽

D Value

Antimicrobial peptides (AMPs) are effective components of the host immune response and are widely distributed throughout nature. Recently, nontoxic antimicrobial polymers that mimic the structures of naturally occurring AMPs have been designed and are under development commercially as novel therapeutics. These compounds have several potential advantages over natural AMPs, including greater stability and reduced immunogenicity compared to natural peptides, relatively simple and scalable syntheses and the ability to tailor or “fine tune” their activities through combinatorial approaches. In previous work, we demonstrated the utility of certain generally regarded as safe (GRAS) flavorant and aroma compounds as enhancers of uptake and activity of clinically important antibiotics (Brehm-Stecher and Johnson, 2003). Here, we have extended this approach to include enhancement of biomimetic antimicrobial polymers. Three low molecular weight (<1,000D), broad-spectrum arylamide polymers (PolyMedix, Inc., Radnor, PA) were examined for their antimicrobial activities against gram-negative bacteria, gram-positive bacteria, yeast and filamentous fungi, both alone and when co-administered with sesquiterpenoid enhancers. Assay formats included disk diffusion, automated turbidimetry, time course (kinetic) plating of antimicrobial-treated cell suspensions, outer membrane assays with 1 -N-phenylnaphthyl-amine (NPN) and transmission electron microscopy (TEM). Although results differed according to the polymer and test organism used, treatments containing sesquiterpenoids were marked either by increased ZOIs, decreased MICs or more rapid inactivation when compared with polymer-only treatments. Antimicrobial activity, expressed as decimal reduction times (D-value) showed that after 5 min the combination of sesquiterpenoid and polymer were significantly different from the controls (p<0.05) with a D-value of 3.92 min when incubated with Escherichia coli ATCC 25922.  Collectively, our results indicate that the combination of sesquiterpenoid enhancing agents with biomimetic antimicrobial polymers shows promise for the development of new, faster-acting and more broadly effective antimicrobial therapies.

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Selected Fungal Natural Products with Antimicrobial Properties

Molecules ◽

10.3390/molecules25040911 ◽

2020 ◽

Vol 25 (4) ◽

pp. 911 ◽

Cited By ~ 6

Author(s):

Dorota Jakubczyk ◽

Francois Dussart

Keyword(s):

Antimicrobial Activity ◽

Natural Products ◽

Antimicrobial Resistance ◽

Middle Ages ◽

Ergot Alkaloids ◽

Antimicrobial Properties ◽

Antimicrobial Drugs ◽

Global Challenge ◽

Fungal Natural Products ◽

Negative Reputation

Fungal natural products and their effects have been known to humankind for hundreds of years. For example, toxic ergot alkaloids produced by filamentous fungi growing on rye poisoned thousands of people and livestock throughout the Middle Ages. However, their later medicinal applications, followed by the discovery of the first class of antibiotics, penicillins and other drugs of fungal origin, such as peptidic natural products, terpenoids or polyketides, have altered the historically negative reputation of fungal “toxins”. The development of new antimicrobial drugs is currently a major global challenge, mainly due to antimicrobial resistance phenomena. Therefore, the structures, biosynthesis and antimicrobial activity of selected fungal natural products are described here.

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Essential Oils as Antimicrobial Agents—Myth or Real Alternative?

Molecules ◽

10.3390/molecules24112130 ◽

2019 ◽

Vol 24 (11) ◽

pp. 2130 ◽

Cited By ~ 46

Author(s):

Katarzyna Wińska ◽

Wanda Mączka ◽

Jacek Łyczko ◽

Małgorzata Grabarczyk ◽

Anna Czubaszek ◽

...

Keyword(s):

Essential Oils ◽

Antimicrobial Agents ◽

Antimicrobial Properties ◽

Antimicrobial Activities ◽

Biological Properties ◽

Pathogenic Microorganisms ◽

Human History ◽

Antitumor Activities ◽

Synthetic Compounds ◽

Potential Alternative

Herbs and the essential oils derived from them have been used from the beginning of human history for different purposes. Their beneficial properties have been applied to mask unpleasant odors, attract the attention of other people, add flavor and aroma properties to prepared dishes, perfumes, and cosmetics, etc. Herbs and essential oils (EOs) have also been used in medicine because of their biological properties, such as larvicidal action, analgesic and anti-inflammatory properties, antioxidant, fungicide, and antitumor activities, and many more. Many EOs exhibit antimicrobial properties, which is extremely important in fields of science and industry, such as medicine, agriculture, or cosmetology. Among the 250 EOs which are commercially available, about a dozen possess high antimicrobial potential. According to available papers and patents, EOs seem to be a potential alternative to synthetic compounds, especially because of the resistance that has been increasingly developed by pathogenic microorganisms. In this review we summarize the latest research studies about the most-active EOs that are known and used because of their antimicrobial properties. Finally, it is noteworthy that the antimicrobial activities of EOs are not preeminent for all strains. Further investigations should, thus, focus on targeting EOs and microorganisms.

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ANTIMICROBIAL ACTIVITIES OF METHANOL EXTRACT FROM UNIDENTIFIED SPONGE ASSOCIATED BACTERIA IN LEMUKUTAN ISLAND, KALIMANTAN BARAT

Jurnal Ilmu dan Teknologi Kelautan Tropis ◽

10.28930/jitkt.v1i2.7871 ◽

2009 ◽

Vol 1 (2) ◽

Author(s):

Risa Nofiani ◽

Siti Nurbetty ◽

Ajuk Sapar

Keyword(s):

Antimicrobial Activity ◽

Bacillus Subtilis ◽

Pathogenic Bacteria ◽

Methanol Extract ◽

Agar Medium ◽

Antimicrobial Activities ◽

Antimicrobial Compounds ◽

Associated Bacteria ◽

Minimum Inhibitory Concentrations ◽

Sponge Associated Bacteria

The increase of issues on the antibiotics resistant pathogenic bacteria has triggered high exploration for new antimicrobial compounds. One of the potential sources is sponge-associated bacteria. The aim of this study was to get sponge-associated bacteria extract containing antimicrobial activities. On the basis screening of antimicrobial activity using by streaking on agar medium, there were two potential isolates with antimicrobial activities namely LCS1 and LCS2. The two isolates were cultivated,then secondary metabolite product were extracted using methanol as a solvent. Minimum inhibitory concentrations (MICs) of extract LCS 1 were 1,000 μg/well for S. aureus, 950 μg/well for Salmonella sp.and 800 μg/well for Bacillus subtilis. Minimum inhibitory concentrations of extract LCS 2 were 500 μg/well for S. aureus, 1,050 μg/well for Salmonella sp., 750 μg/well for Bacillus subtilis, 350 μg/well for P. aeruginosa, 750 μg/sumur terhadap B. subtilis. Based on the MIC values, the two assay extracts have a relatively low antimicrobial activity. Keywords:Antimicrobial,Sponges associated bacteria,MICs

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Antimicrobial properties of actively purified secondary metabolites isolated from different marine organisms

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200730144536 ◽

2020 ◽

Vol 21 ◽

Author(s):

Nilushi Indika Bamunu Arachchige ◽

Fazlurrahman Khan ◽

Young-Mog Kim

Keyword(s):

Secondary Metabolites ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Bacterial Species ◽

Antimicrobial Properties ◽

Antimicrobial Effect ◽

Cost Effective ◽

Resistance Mechanisms ◽

Marine Organisms ◽

Antimicrobial Compounds

Background: The treatment of infection caused by pathogenic bacteria becomes one of the serious concerns globally. The failure in the treatment was found due to the exhibition of multiple resistance mechanisms against the antimicrobial agents. Emergence of resistant bacterial species has also been observed due to prolong treatment using conventional antibiotics. To combat these problems, several alternative strategies have been employed using biological and chemically synthesized compounds as antibacterial agents. Marine organisms considered as one of the potential sources for the isolation of bioactive compounds due to the easily available, cost-effective, and eco-friendly. Methods: The online search methodology was adapted for the collection of information related to the antimicrobial properties of marine-derived compounds. These compound has been isolated and purified by different purification techniques, and their structure also characterized. Furthermore, the antibacterial activities have been reported by using broth microdilution as well as disc diffusion assays. Results: The present review paper describes the antimicrobial effect of diverse secondary metabolites which are isolated and purified from the different marine organisms. The structural elucidation of each secondary metabolite has also been done in the present paper, which will help for the in silico designing of the novel and potent antimicrobial compounds. Conclusion: A thorough literature search has been made and summarizes the list of antimicrobial compounds that are isolated from both prokaryotic and eukaryotic marine organisms. The information obtained from the present paper will be helpful for the application of marine compounds as antimicrobial agents against different antibiotic-resistant human pathogenic bacteria.

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Antimicrobial Properties of the Ag, Cu Nanoparticle System

Biology ◽

10.3390/biology10020137 ◽

2021 ◽

Vol 10 (2) ◽

pp. 137

Author(s):

Xinzhen Fan ◽

L’Hocine Yahia ◽

Edward Sacher

Keyword(s):

Reactive Oxygen Species ◽

Biomedical Application ◽

Antimicrobial Properties ◽

Antimicrobial Activities ◽

Oxygen Species ◽

Cu Nanoparticles ◽

Postoperative Infections ◽

Nanoparticle System ◽

Contact Killing ◽

Bacteria And Fungi

Microbes, including bacteria and fungi, easily form stable biofilms on many surfaces. Such biofilms have high resistance to antibiotics, and cause nosocomial and postoperative infections. The antimicrobial and antiviral behaviors of Ag and Cu nanoparticles (NPs) are well known, and possible mechanisms for their actions, such as released ions, reactive oxygen species (ROS), contact killing, the immunostimulatory effect, and others have been proposed. Ag and Cu NPs, and their derivative NPs, have different antimicrobial capacities and cytotoxicities. Factors, such as size, shape and surface treatment, influence their antimicrobial activities. The biomedical application of antimicrobial Ag and Cu NPs involves coating onto substrates, including textiles, polymers, ceramics, and metals. Because Ag and Cu are immiscible, synthetic AgCu nanoalloys have different microstructures, which impact their antimicrobial effects. When mixed, the combination of Ag and Cu NPs act synergistically, offering substantially enhanced antimicrobial behavior. However, when alloyed in Ag–Cu NPs, the antimicrobial behavior is even more enhanced. The reason for this enhancement is unclear. Here, we discuss these results and the possible behavior mechanisms that underlie them.

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A case of neck abscess caused by rare hypervirulent Klebsiella pneumoniae, capsular type K20 and sequence type 420

Annals of Clinical Microbiology and Antimicrobials ◽

10.1186/s12941-021-00453-8 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

John Alexander McHardy ◽

Vathshalan Selvaganeshapillai ◽

Priya Khanna ◽

Ashley Michael Whittington ◽

Jane Turton ◽

...

Keyword(s):

Public Health ◽

Case Report ◽

Antimicrobial Resistance ◽

Klebsiella Pneumoniae ◽

East Asia ◽

South East Asia ◽

Neck Abscess ◽

Global Challenge ◽

Life Threatening ◽

The Uk

Abstract Background This case report describes a neck abscess caused by a strain of Hypervirulent Klebsiella pneumoniae in a middle aged man with diabetes without a history of travel to East and South East Asia. This case report is of notable significance as Hypervirulent Klebsiella pneumoniae neck abscesses are rarely seen in the UK and are very infrequently documented in individuals who have not first travelled to the high prevalence areas of East and South East Asia. Case presentation This case report describes a 53 year old diabetic man who contracted a Hypervirulent Klebsiella pneumoniae neck abscess which led to the development of sepsis. Klebsiella pneumoniae was cultured from blood cultures and fluid aspirated from the abscess grew the pathogen with same antimicrobial susceptibility. Hypervirulence was demonstrated after the samples were analysed, at the Antimicrobial Resistance and Healthcare Associated Infections Reference Unit Public Health England Colindale, and found to contain the K20 (rmp)A and rmpA2 virulence genes. Discussion Hypervirulent Klebsiella pneumoniae is a Gram-negative, encapsulated, non-motile bacillus notable for its ability to metastatically spread and cause potentially life threatening infections in otherwise healthy adults, but especially in those with diabetes. Genes responsible for the production of hyperviscous mucoid polysaccharide capsules and siderophores, such as those isolated in this case, enable the bacteria to more efficiently evade the hosts immune system and disseminate and invade surrounding and distant tissues. Data from Public Health England shows Hypervirulent Klebsiella pneumoniae are rare in the UK. A review of current literature also showed Hypervirulent Klebsiella pneumoniae almost exclusively occur in those who have traveled to East and South East Asia. Conclusions This case reported a rare Hypervirulent Klebsiella pneumoniae neck abscess outside of, and without travel to, East and South East Asia. This raises concerns about future, potentially life threatening, Hypervirulent Klebsiella pneumoniae infections becoming more widespread without the need for endemic travel. This concern is further exacerbated by the growing global challenge of antimicrobial resistance.

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Development of Advanced Textile Finishes Using Nano-Emulsions from Herbal Extracts for Organic Cotton Fabrics

Coatings ◽

10.3390/coatings11080939 ◽

2021 ◽

Vol 11 (8) ◽

pp. 939

Author(s):

Prabhuraj D. Venkatraman ◽

Usha Sayed ◽

Sneha Parte ◽

Swati Korgaonkar

Keyword(s):

Antimicrobial Resistance ◽

Antimicrobial Properties ◽

Coconut Oil ◽

Cotton Fabrics ◽

Batch Processes ◽

Herbal Extracts ◽

Organic Cotton ◽

Global Pandemic ◽

Nano Emulsion ◽

Sufficient Strength

The development of textile finishing with improved functional properties has been a growing interest among industry and scientists worldwide. The recent global pandemic also enhanced the awareness amongst many toward improved hygiene and the use of antimicrobial textiles. Generally, natural herbal components are known to possess antimicrobial properties which are green and eco-friendly. This research reports a novel and innovative method of developing and optimising nano-emulsions using two combinations of herbal extracts produced from Moringa oleifera, curry leaf, coconut oil (nano-emulsion 1) and other using Aegle marmelos with curry leaf and coconut oil (nano-emulsion 2). Nano-emulsions were optimised for their pH, thermal stability, and particle size, and percentage add-on. Organic cotton fabrics (20 and 60 gsm) were finished with nano-emulsions using continuous and batch processes and characterised for their surface morphology using scanning electron microscopy, energy dispersive X-ray (EDX) analysis and Fourier transform infrared spectroscopy (FTIR) analysis. The finished fabrics were evaluated for their Whiteness Index, assessed for antimicrobial resistance against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) using AATCC 100 and 147 methods. In addition, fabrics were assessed for their antifungal efficacy (AATCC 30), tensile strength and air permeability. Results suggested that finished organic fabrics with nano-emulsions had antimicrobial resistance, antifungal, wash fastness after 20 washing cycles, and sufficient strength. This novel finishing method suggests that organic cotton fabrics treated with nano-emulsions can be used as a durable antimicrobial textile for healthcare and hygiene textiles.

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