Antimicrobial Resistance and Antimicrobial Activity of Bioactive Compounds in Drug Formulations

A special issue of Pharmaceutics (ISSN 1999-4923). This special issue belongs to the section "Physical Pharmacy and Formulation".

Deadline for manuscript submissions: 31 July 2025 | Viewed by 6945

Special Issue Editors


E-Mail Website
Guest Editor
Department of Infectious Microbiology, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria
Interests: pathogenic bacteria; food-borne zoonozes; virulence factors; bacteria–host relationships; infectious immunology; molecular biology; ecology of pathogens; new antibacterial agents; antimicrobial resistance
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Department of Infectious Microbiology, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
Interests: antimicrobial agents; antimicrobial resistance; quorum sensing; gene expression; virulence factors

Special Issue Information

Dear Colleagues,

Antimicrobial resistance (AMR) to clinically approved antibiotics and chemotherapeutics in human and veterinary medicine has been a global challenge for over 60 years. It has been reported that deaths caused by AMR could increase from 700,000 in 2014 to 10 million by 2050. 

Most antibiotics and chemotherapeutics actively damage cells, and therefore, they cannot completely destroy bacterial cells in biofilms. Biofilm formation is associated with the adhesion, motility, resistance to antibiotics, DNA transfer, autolysis, metabolic activity, etc., abilities of bacteria. These factors are regulated by the expression of genes united in a system called quorum sensing. Inhibitors of this system, respective of gene expression, can be bioactive molecules that do not affect bacterial growth or mimic the action of signaling molecules. This is why the search for and identification of new biologically active molecules of which the action is enhanced by their inclusion in drug formulations are of public health importance. Such carriers can be solid lipid nanoparticles, nanocapsules, liposomes, microemulsion drug delivery systems, etc.

This Special Issue aims to introduce new natural compounds with microbiological activities to conventional delivery systems for the prevention and treatment of infectious diseases in human and veterinary medicine. In this Special Issue, original research articles and reviews are welcome. Research areas may include the isolation of bioactive compounds and their loading into drug delivery systems; evaluation of their antimicrobial in vitro or/and in vivo activity, according to the Ethics and Animal Care Committee; their role in quorum sensing system; and determining their stability for practical use.

I look forward to receiving your contributions.

Prof. Dr. Hristo Najdenski
Dr. Lyudmila Dimitrova
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Pharmaceutics is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • new biologically active agents
  • drug delivery systems
  • antibiotic resistance
  • gene expression
  • biofilms
  • quorum sensing
  • in vitro and in vivo models

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (7 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

16 pages, 1431 KiB  
Article
Cenostigma bracteosum Hydroethanolic Extract: Chemical Profile, Antibacterial Activity, Cytotoxicity, and Gel Formulation Development
by Addison R. Almeida, Francisco A. S. D. Pinheiro, Marília G. M. Fideles, Roberto B. L. Cunha, Vitor P. P. Confessor, Kátia N. Matsui, Weslley S. Paiva, Hugo A. O. Rocha, Gislene Ganade, Laila S. Espindola, Waldenice A. Morais and Leandro S. Ferreira
Pharmaceutics 2025, 17(6), 780; https://doi.org/10.3390/pharmaceutics17060780 - 14 Jun 2025
Viewed by 303
Abstract
Background:Cenostigma bracteosum (Tul.) Gagnon & G.P. Lewis (Fabaceae), popularly known as “catingueira”, is a plant widely distributed in the Caatinga biome, which comprises 11% of the Brazilian territory. While this species is of interest given local knowledge, formal reports are lacking in [...] Read more.
Background:Cenostigma bracteosum (Tul.) Gagnon & G.P. Lewis (Fabaceae), popularly known as “catingueira”, is a plant widely distributed in the Caatinga biome, which comprises 11% of the Brazilian territory. While this species is of interest given local knowledge, formal reports are lacking in the literature, warranting targeted investigation. This study aimed to prepare and characterize a hydroethanolic extract of C. bracteosum leaves, prepare carbopol gels containing the extract, and evaluate their cytotoxicity and antibacterial activity against Staphylococcus aureus and Escherichia coli. Methods: The initial extract was prepared in an ultrasonic bath using ethanol/water (70:30, v/v). The extract (1 mg/mL) was analyzed by liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS). Carbopol-based gels containing 1% and 3% of C. bracteosum extract were prepared and characterized in terms of pH, conductivity, spreadability, and rheology. The cytotoxicity was determined by the MTT method using MC3T3-E1 pre-osteoblast cells and L929-CCL1 fibroblast cells. The antibacterial activity of the extract and gels was evaluated using the agar diffusion method against S. aureus and E. coli. Results: The C. bracteosum leaves extract demonstrated antibacterial activity against S. aureus and E. coli, were not cytotoxic for the assessed cells at concentrations up to 100 μg/mL, and its analysis by UHPLC-MS/MS allowed the annotation of 18 metabolites, mainly of the phenolic acid and flavonoids glycoside classes, together with a biflavonoid. The prepared gels remained stable over the 30-day post-production analysis period. Conclusions: These findings provide a better understanding of the chemical diversity of the secondary metabolites of a common Caatinga biome species—C. bracteosum—specifically present in leaves hydroethanolic extract and gel formulation adapted for skin application with activity against S. aureus. Full article
Show Figures

Graphical abstract

19 pages, 2624 KiB  
Article
Production of Myco-Nanomaterial Products from Pleurotus ostreatus (Agaricomycetes) Mushroom via Pyrolysis
by Gréta Törős, Áron Béni, Andrea Kovács Balláné, Dávid Semsey, Aya Ferroudj and József Prokisch
Pharmaceutics 2025, 17(5), 591; https://doi.org/10.3390/pharmaceutics17050591 - 30 Apr 2025
Cited by 1 | Viewed by 331
Abstract
Background: The study aimed to develop a sustainable method for producing myco-nanomaterials, particularly fluorescent carbon nanodots (CNDs), from freeze-dried Pleurotus ostreatus (Agaricomycetes) mushroom powder via pyrolysis. The goal was to investigate how pyrolysis conditions affect CND characteristics and their potential antimicrobial properties. Mushroom [...] Read more.
Background: The study aimed to develop a sustainable method for producing myco-nanomaterials, particularly fluorescent carbon nanodots (CNDs), from freeze-dried Pleurotus ostreatus (Agaricomycetes) mushroom powder via pyrolysis. The goal was to investigate how pyrolysis conditions affect CND characteristics and their potential antimicrobial properties. Mushroom powder was pyrolyzed at temperatures ranging from 150 to 240 °C. The resulting products were analyzed for yield, molecular weight, fluorescence intensity, and estimated CND concentration in relation to the carbon-to-nitrogen (C/N) ratio. Antibacterial activity was tested against Escherichia coli and Staphylococcus epidermidis. Product yield decreased from 13.20% at 150 °C to 0.80% at 240 °C. Molecular weight peaked at 200 °C (623.20 kDa), while maximum fluorescence intensity (739.40 A.U.) was observed at 210 °C. A strong positive correlation (R2 = 0.72) was found between the C/N ratio and estimated CND concentration. Antimicrobial testing revealed notable inhibition of E. coli, associated with higher fluorescence intensity and CND content. Pyrolyzed P. ostreatus mushroom powder offers a promising, eco-friendly platform for producing luminescent, carbonaceous nanomaterials with antibacterial potential. These non-purified, myco-derived nanomaterials may contribute to green nanotechnology development and antimicrobial strategies. Full article
Show Figures

Figure 1

14 pages, 1171 KiB  
Article
Antimycobacterial Activity of Essential Oils from Bulgarian Rosa Species Against Phylogenomically Different Mycobacterium tuberculosis Strains
by Violeta Valcheva, Milka Mileva, Marine Dogonadze, Ana Dobreva and Igor Mokrousov
Pharmaceutics 2024, 16(11), 1393; https://doi.org/10.3390/pharmaceutics16111393 - 29 Oct 2024
Viewed by 1312
Abstract
In this study, we aimed to assess the activity of the essential oils from four Bulgarian oil-bearing roses Rosa damascena Mill., R. alba L., R. centifolia L., and R. gallica L., on the reference strain Mycobacterium tuberculosis H37Rv and clinical M. tuberculosis strains [...] Read more.
In this study, we aimed to assess the activity of the essential oils from four Bulgarian oil-bearing roses Rosa damascena Mill., R. alba L., R. centifolia L., and R. gallica L., on the reference strain Mycobacterium tuberculosis H37Rv and clinical M. tuberculosis strains of the Beijing and Latin-American Mediterraneum genotypes. The chemical composition of the essential oils was determined by gas chromatography (GC-FID/MS). Minimal inhibitory concentrations (MIC) were determined using the resazurin method. R. alba oil showed the highest inhibitory activity when tested on all strains of different phylogenetic origins with MIC in the range of 0.16–0.31 mg/mL, while R. gallica oil was the least active (MIC 0.62–1.25 mg/mL). The obtained results show heterogeneity of rose oil action on different mycobacterial strains and we hypothesize that the combined level of geraniol and nerol is a key factor that underlies the antimycobacterial action of the rose oils. Strain Beijing 396 was relatively more susceptible to the rose oils probably due to multiple and likely deleterious mutations in its efflux pump genes. Two clinical MDR strains have likely developed during their previous adaptation to anti-TB drugs certain drug tolerance mechanisms that also permitted them to demonstrate intrinsic tolerance to the essential oils. Further research should investigate a possible synergistic action of the new-generation anti-TB drugs and the most promising rose oil extracts on the large panel of different strains. Full article
Show Figures

Figure 1

Review

Jump to: Research

23 pages, 2060 KiB  
Review
Phage Therapy in Managing Multidrug-Resistant (MDR) Infections in Cancer Therapy: Innovations, Complications, and Future Directions
by Alice N. Mafe and Dietrich Büsselberg
Pharmaceutics 2025, 17(7), 820; https://doi.org/10.3390/pharmaceutics17070820 - 24 Jun 2025
Abstract
Multidrug-resistant (MDR) bacterial infections present a major challenge in cancer therapy, particularly for immunocompromised patients undergoing chemotherapy, radiation, or surgery. These infections often arise from prolonged antibiotic use, hospital-acquired pathogens, and weakened immune defenses, leading to increased morbidity and mortality. As conventional antibiotics [...] Read more.
Multidrug-resistant (MDR) bacterial infections present a major challenge in cancer therapy, particularly for immunocompromised patients undergoing chemotherapy, radiation, or surgery. These infections often arise from prolonged antibiotic use, hospital-acquired pathogens, and weakened immune defenses, leading to increased morbidity and mortality. As conventional antibiotics become less effective against MDR strains, there is an urgent need for alternative treatment options. This review highlights phage therapy as a promising approach to managing MDR bacterial infections in cancer patients. Once widely used, phage therapy has recently regained attention as a targeted antimicrobial strategy that can specifically eliminate harmful bacteria while preserving the beneficial microbiota. Phages work by directly lysing bacteria, disrupting biofilms, and synergizing with antibiotics to restore bacterial susceptibility. These mechanisms make phage therapy especially appealing for treating infections that complicate cancer treatments. However, the clinical application of phage therapy faces challenges such as variability in phage–host interactions, regulatory hurdles, and immune responses in patients. This review identifies gaps in current research regarding the use of phage therapy for MDR infections in cancer patients. By examining recent innovations, therapeutic mechanisms, and associated limitations, we provide valuable insights into the potential of phage therapy for improving infection management in oncology. Future research should focus on refining phage delivery methods, assessing long-term safety, and exploring combination therapies to maximize clinical efficacy. Overcoming these challenges could position phage therapy as a valuable complement to existing antimicrobial strategies in cancer care. Full article
Show Figures

Figure 1

26 pages, 803 KiB  
Review
Bioactive Plant Compounds as Alternatives Against Antifungal Resistance in the Candida Strains
by Thainá dos Santos Dantas, Janaina Carla Barbosa Machado, Magda Rhayanny Assunção Ferreira and Luiz Alberto Lira Soares
Pharmaceutics 2025, 17(6), 687; https://doi.org/10.3390/pharmaceutics17060687 - 23 May 2025
Viewed by 402
Abstract
The pathogenicity of Candida spp. poses a persistent challenge, particularly in hospital environments where these species proliferate and cause opportunistic infections. Many strains have developed resistance to commonly used antifungal agents, including azoles, polyenes, and echinocandins, complicating treatment, especially in immuno-compromised patients. Understanding [...] Read more.
The pathogenicity of Candida spp. poses a persistent challenge, particularly in hospital environments where these species proliferate and cause opportunistic infections. Many strains have developed resistance to commonly used antifungal agents, including azoles, polyenes, and echinocandins, complicating treatment, especially in immuno-compromised patients. Understanding the mechanisms underlying antifungal resistance, such as mutations in genes involved in ergosterol biosynthesis, efflux pump activity, and enzymatic pathways, is crucial for developing targeted interventions. Given the challenges associated with discovering new antifungal agents, medicinal plants have emerged as a promising source of bioactive compounds with anti-Candida activity. Secondary metabolites, including terpenoids, alkaloids, flavonoids, and tannins, exhibit various mechanisms of action, such as biofilm inhibition, membrane disruption, and oxidative stress induction. However, challenges such as extract standardization, and the lack of clinical studies continue to limit their therapeutic application. This review underscores the potential of medicinal plants as complementary or alternative strategies to conventional antifungal therapies, emphasizing the need for multidisciplinary research to overcome these hurdles and harness the therapeutic potential of natural products. Full article
Show Figures

Graphical abstract

18 pages, 2224 KiB  
Review
Combining Advanced Therapies with Alternative Treatments: A New Approach to Managing Antimicrobial Resistance?
by Greta Kaspute, Arunas Zebrauskas, Akvile Streckyte, Tatjana Ivaskiene and Urte Prentice
Pharmaceutics 2025, 17(5), 648; https://doi.org/10.3390/pharmaceutics17050648 - 15 May 2025
Cited by 1 | Viewed by 702
Abstract
Bacterial antimicrobial resistance (AMR) represents a critical public health threat, with increasing resistance compromising the effectiveness of treatments worldwide. Resistance trends, such as fluctuating benzylpenicillin resistance in Staphylococcus aureus, highlight the growing urgency, with projections indicating a rise in resistance to various [...] Read more.
Bacterial antimicrobial resistance (AMR) represents a critical public health threat, with increasing resistance compromising the effectiveness of treatments worldwide. Resistance trends, such as fluctuating benzylpenicillin resistance in Staphylococcus aureus, highlight the growing urgency, with projections indicating a rise in resistance to various antibiotics, including complete resistance to gentamicin and tetracycline by 2027. Despite substantial efforts to develop new antibiotics and drug delivery systems, these approaches must undergo rigorous clinical evaluation to ensure their safety and efficacy. In parallel, alternative therapies, such as phytotherapy and apitherapy, have garnered attention for their potential in combating infections. Natural substances like tea tree essential oils and propolis, which exhibit antimicrobial properties, are being increasingly incorporated into novel drug delivery systems. However, much of the research on these materials is not new, with several studies already exploring their effectiveness. To address the escalating AMR crisis, combining advanced therapies with alternative medicine could offer a promising solution. Advanced therapy products could target bacterial genomes and enhance the effectiveness of antibiotics and natural substances. This integrated approach remains underexplored in pre-clinical and clinical trials, presenting future research opportunities to develop more effective strategies in combating AMR. Given the rapid spread of resistant infections, there is an urgent need for innovative antimicrobial agents to overcome emerging resistance mechanisms and improve diagnoses and treatments. Full article
Show Figures

Figure 1

41 pages, 2709 KiB  
Review
Advancing Antibiotic-Resistant Microbe Combat: Nanocarrier-Based Systems in Combination Therapy Targeting Quorum Sensing
by Sanchaita Rajkhowa, Safrina Zeenat Hussain, Manisha Agarwal, Alaiha Zaheen, Sami A. Al-Hussain and Magdi E. A. Zaki
Pharmaceutics 2024, 16(9), 1160; https://doi.org/10.3390/pharmaceutics16091160 - 3 Sep 2024
Cited by 3 | Viewed by 2685
Abstract
The increase in antibiotic-resistant bacteria presents a significant risk to worldwide public health, emphasizing the necessity of novel approaches to address infections. Quorum sensing, an essential method of communication among bacteria, controls activities like the formation of biofilms, the production of virulence factors, [...] Read more.
The increase in antibiotic-resistant bacteria presents a significant risk to worldwide public health, emphasizing the necessity of novel approaches to address infections. Quorum sensing, an essential method of communication among bacteria, controls activities like the formation of biofilms, the production of virulence factors, and the synthesis of secondary metabolites according to the number of individuals in the population. Quorum quenching, which interferes with these processes, emerges as a vital approach to diminish bacterial virulence and prevent biofilm formation. Nanocarriers, characterized by their small size, high surface-area-to-volume ratio, and modifiable surface chemistry, offer a versatile platform for the disruption of bacterial communication by targeting various stages within the quorum sensing pathway. These features allow nanocarriers to infiltrate biofilms, disrupt cell membranes, and inhibit bacterial proliferation, presenting a promising alternative to traditional antibiotics. Integrating nanocarrier-based systems into combination therapies provides a multi-pronged approach to infection control, enhancing both the efficacy and specificity of treatment regimens. Nonetheless, challenges related to the stability, safety, and clinical effectiveness of nanomaterial-based antimicrobial treatments remain. Continued research and development are essential to overcoming these obstacles and fully harnessing the potential of nano-antimicrobial therapies. This review emphasizes the importance of quorum sensing in bacterial behavior and highlights the transformative potential of nanotechnology in advancing antimicrobial treatments, offering innovative solutions to combat antibiotic-resistant pathogens. Full article
Show Figures

Graphical abstract

Back to TopTop