Recent Advances in Biotechnological Applications of Microbial Surfactants

A special issue of Pharmaceutics (ISSN 1999-4923). This special issue belongs to the section "Drug Targeting and Design".

Deadline for manuscript submissions: closed (10 November 2023) | Viewed by 6474

Special Issue Editors

Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
Interests: biosurfactants; antimicrobial resistance; natural products; antiviral assay; bacterial biofilm; antibacterial assay
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The current state of emergency, driven by the spread of emerging and resistant pathogens, such as the coronavirus, has prompted the development of new strategies to combat viral, bacterial, fungal and/or parasitic infections. Microbial biosurfactants (BSs) play an important role in such efforts. BSs are surface-active compounds characterized by a hydrophilic head and a hydrophobic tail, with a huge range of biological activities, including antimicrobial, antiviral, anticancer and antioxidant properties, among others. They are utilized as ingredients in various pharmaceutical formulations, such as drugs, adjuvants for therapeutic and as an alternative to common disinfectants.

This Special Issue aims to collect original and review contributions that delve into the latest results on the benefits and applications of biosurfactants in different fields. We look forward to receiving your contributions.

Dr. Carla Zannella
Dr. Rosa Giugliano
Guest Editors

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Keywords

  • biosurfactants
  • antiviral
  • antimicrobial
  • microbial infections
  • pharmaceutical applications
  • natural products 

Published Papers (4 papers)

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Research

27 pages, 6464 KiB  
Article
New Imidazolium Alkaloids with Broad Spectrum of Action from the Marine Bacterium Shewanella aquimarina
by Rosa Giugliano, Gerardo Della Sala, Carmine Buonocore, Carla Zannella, Pietro Tedesco, Fortunato Palma Esposito, Costanza Ragozzino, Annalisa Chianese, Maria Vittoria Morone, Valerio Mazzella, Laura Núñez-Pons, Veronica Folliero, Gianluigi Franci, Anna De Filippis, Massimiliano Galdiero and Donatella de Pascale
Pharmaceutics 2023, 15(8), 2139; https://doi.org/10.3390/pharmaceutics15082139 - 14 Aug 2023
Viewed by 1078
Abstract
The continuous outbreak of drug-resistant bacterial and viral infections imposes the need to search for new drug candidates. Natural products from marine bacteria still inspire the design of pharmaceuticals. Indeed, marine bacteria have unique metabolic flexibility to inhabit each ecological niche, thus expanding [...] Read more.
The continuous outbreak of drug-resistant bacterial and viral infections imposes the need to search for new drug candidates. Natural products from marine bacteria still inspire the design of pharmaceuticals. Indeed, marine bacteria have unique metabolic flexibility to inhabit each ecological niche, thus expanding their biosynthetic ability to assemble unprecedented molecules. The One-Strain-Many-Compounds approach and tandem mass spectrometry allowed the discovery of a Shewanella aquimarina strain as a source of novel imidazolium alkaloids via molecular networking. The alkaloid mixture was shown to exert bioactivities such as: (a) antibacterial activity against antibiotic-resistant Staphylococcus aureus clinical isolates at 100 µg/mL, (b) synergistic effects with tigecycline and linezolid, (c) restoration of MRSA sensitivity to fosfomycin, and (d) interference with the biofilm formation of S. aureus 6538 and MRSA. Moreover, the mixture showed antiviral activity against viruses with and without envelopes. Indeed, it inhibited the entry of coronavirus HcoV-229E and herpes simplex viruses into human cells and inactivated poliovirus PV-1 in post-infection assay at 200 µg/mL. Finally, at the same concentration, the fraction showed anthelminthic activity against Caenorhabditis elegans, causing 99% mortality after 48 h. The broad-spectrum activities of these compounds are partially due to their biosurfactant behavior and make them promising candidates for breaking down drug-resistant infectious diseases. Full article
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19 pages, 6463 KiB  
Article
Limosilactobacillus fermentum KAU0021 Abrogates Mono- and Polymicrobial Biofilms Formed by Candida albicans and Staphylococcus aureus
by Irfan A. Rather, Mohmmad Younus Wani, Majid Rasool Kamli, Jamal S. M. Sabir, Khalid Rehman Hakeem, Ahmad Firoz, Yong Ha Park and Yan Yan Hor
Pharmaceutics 2023, 15(4), 1079; https://doi.org/10.3390/pharmaceutics15041079 - 27 Mar 2023
Cited by 4 | Viewed by 1300
Abstract
Candida albicans and Staphylococcus aureus, representing two different kingdoms, are the most frequently isolated pathogens from invasive infections. Their pathogenic attributes, combined with drug resistance, make them a major threat and a challenge to successful treatments, mainly when involved in polymicrobial biofilm-associated [...] Read more.
Candida albicans and Staphylococcus aureus, representing two different kingdoms, are the most frequently isolated pathogens from invasive infections. Their pathogenic attributes, combined with drug resistance, make them a major threat and a challenge to successful treatments, mainly when involved in polymicrobial biofilm-associated infections. In the present study, we investigated the antimicrobial potential of Lactobacillus metabolite extracts (LMEs) purified from cell-free supernatant of four Lactobacillus strains (KAU007, KAU0010, KAU0021, and Pro-65). Furthermore, LME obtained from the strain KAU0021 (LMEKAU0021), being the most effective, was analyzed for its anti-biofilm property against mono- and polymicrobial biofilms formed by C. albicans and S. aureus. The impact of LMEKAU0021 on membrane integrity in single and mixed culture conditions was also evaluated using propidium iodide. The MIC values recorded for LMEKAU0021 was 406 µg/mL, 203 µg/mL, and 406 µg/mL against planktonic cells of C. albicans SC5314, S. aureus and polymicrobial culture, respectively. The LMEKAU0021 at sub-MIC values potentially abrogates both biofilm formation as well as 24 h mature mono- and polymicrobial biofilms. These results were further validated using different microscopy and viability assays. For insight mechanism, LMEKAU0021 displayed a strong impact on cell membrane integrity of both pathogens in single and mixed conditions. A hemolytic assay using horse blood cells at different concentrations of LMEKAU0021 confirmed the safety of this extract. The results from this study correlate the antimicrobial and anti-biofilm properties of lactobacilli against bacterial and fungal pathogens in different conditions. Further in vitro and in vivo studies determining these effects will support the aim of discovering an alternative strategy for combating serious polymicrobial infections caused by C. albicans and S. aureus. Full article
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19 pages, 4137 KiB  
Article
Evaluation of Antimicrobial Properties and Potential Applications of Pseudomonas gessardii M15 Rhamnolipids towards Multiresistant Staphylococcus aureus
by Carmine Buonocore, Rosa Giugliano, Gerardo Della Sala, Fortunato Palma Esposito, Pietro Tedesco, Veronica Folliero, Massimiliano Galdiero, Gianluigi Franci and Donatella de Pascale
Pharmaceutics 2023, 15(2), 700; https://doi.org/10.3390/pharmaceutics15020700 - 19 Feb 2023
Cited by 3 | Viewed by 1749
Abstract
Staphylococcus aureus is a Gram-positive opportunistic human pathogen responsible for severe infections and thousands of deaths annually, mostly due to its multidrug-resistant (MDR) variants. The cell membrane has emerged as a promising new therapeutic target, and lipophilic molecules, such as biosurfactants, are currently [...] Read more.
Staphylococcus aureus is a Gram-positive opportunistic human pathogen responsible for severe infections and thousands of deaths annually, mostly due to its multidrug-resistant (MDR) variants. The cell membrane has emerged as a promising new therapeutic target, and lipophilic molecules, such as biosurfactants, are currently being utilized. Herein, we evaluated the antimicrobial activity of a rhamnolipids mixture produced by the Antarctic marine bacterium Pseudomonas gessardii M15. We demonstrated that our mixture has bactericidal activity in the range of 12.5–50 µg/mL against a panel of clinical MDR isolates of S. aureus, and that the mixture eradicated the bacterial population in 30 min at MIC value, and in 5 min after doubling the concentration. We also tested abilities of RLs to interfere with biofilm at different stages and determined that RLs can penetrate biofilm and kill the bacteria at sub-MICs values. The mixture was then used to functionalize a cotton swab to evaluate the prevention of S. aureus proliferation. We showed that by using 8 µg of rhamnolipids per swab, the entire bacterial load is eradicated, and just 0.5 µg is sufficient to reduce the growth by 99.99%. Our results strongly indicate the possibility of using this mixture as an additive for wound dressings for chronic wounds. Full article
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15 pages, 5432 KiB  
Article
Assuring the Biofunctionalization of Silicone Covalently Bonded to Rhamnolipids: Antibiofilm Activity and Biocompatibility
by Maïssa Dardouri, Ana Bettencourt, Victor Martin, Filomena A. Carvalho, Bruno Colaço, Adelina Gama, Madeleine Ramstedt, Nuno C. Santos, Maria H. Fernandes, Pedro S. Gomes and Isabel A. C. Ribeiro
Pharmaceutics 2022, 14(9), 1836; https://doi.org/10.3390/pharmaceutics14091836 - 31 Aug 2022
Cited by 4 | Viewed by 1744
Abstract
Silicone-based medical devices composed of polydimethylsiloxane (PDMS) are widely used all over the human body (e.g., urinary stents and catheters, central venous catheters stents) with extreme clinical success. Nevertheless, their abiotic surfaces, being prone to microorganism colonization, are often involved in infection occurrence. [...] Read more.
Silicone-based medical devices composed of polydimethylsiloxane (PDMS) are widely used all over the human body (e.g., urinary stents and catheters, central venous catheters stents) with extreme clinical success. Nevertheless, their abiotic surfaces, being prone to microorganism colonization, are often involved in infection occurrence. Improving PDMS antimicrobial properties by surface functionalization with biosurfactants to prevent related infections has been the goal of different works, but studies that mimic the clinical use of these novel surfaces are missing. This work aims at the biofunctional assessment of PDMS functionalized with rhamnolipids (RLs), using translational tests that more closely mimic the clinical microenvironment. Rhamnolipids were covalently bonded to PDMS, and the obtained surfaces were characterized by contact angle modification assessment, ATR-FTIR analysis and atomic force microscopy imaging. Moreover, a parallel flow chamber was used to assess the Staphylococcus aureus antibiofilm activity of the obtained surfaces under dynamic conditions, and an in vitro characterization with human dermal fibroblast cells in both direct and indirect characterization assays, along with an in vivo subcutaneous implantation assay in the translational rabbit model, was performed. A 1.2 log reduction in S. aureus biofilm was observed after 24 h under flow dynamic conditions. Additionally, functionalized PDMS lessened cell adhesion upon direct contact, while supporting a cytocompatible profile, within an indirect assay. The adequacy of the biological response was further validated upon in vivo subcutaneous tissue implantation. An important step was taken towards biofunctional assessment of RLs-functionalized PDMS, reinforcing their suitability for medical device usage and infection prevention. Full article
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