Antibiotics: Conventional Therapy and Natural Compounds with Antibacterial Activity-A Pharmaco-Toxicological Screening

Breaking boundaries: the advancements in transdermal delivery of antibiotics

Transdermal drug delivery systems (TDDS) for antibiotics have seen significant advances in recent years that aimed to improve the efficacy and safety of these drugs. TDDS offer many advantages over other conventional delivery systems such as non-invasiveness, controlled-release pattern, avoidance of first-pass metabolism. The objective of this review is to provide an overview on the recent advances in the TDDS of different groups of antibiotics including β-lactams, tetracyclines, macrolides, and lincosamides, utilized for their effective delivery through the skin and to explore the challenges associated with this field. The majority of antibiotics do not have favorable properties for passive transdermal delivery. Thus, novel strategies have been employed to improve the delivery of antibiotics through the skin, such as the use of nanotechnology (nanoparticles, solid-lipid nanoparticles, nanoemulsions, vesicular carriers, and liposomes) or the physical enhancement techniques like microneedles and ultrasound. In conclusion, the transdermal delivery systems could be a promising method for delivering antibiotics that have the potential to improve patient outcomes and enhance the efficacy of drugs. Further research and development are still needed to explore the potential of delivering more antibiotic drugs by using various transdermal drug delivery approaches.

A statistical approach to enhance the productivity of Streptomyces baarensis MH-133 for bioactive compounds

The goal of this study was to use statistical optimization to change the nutritional and environmental conditions so that Streptomyces baarensis MH-133 could make more active metabolites. Twelve trials were used to screen for critical variables influencing productivity using the Placket-Burman Design method. S. baarensis MH-133 is significantly influenced by elicitation, yeast extract, inoculum size, and incubation period in terms of antibacterial activity. A total of 27 experimental trials with various combinations of these factors were used to carry out the response surface technique using the Box-Behnken design. The analyses revealed that the model was highly significant (p < 0.001), with a lack-of-fit of 0.212 and a coefficient determination (R2) of 0.9224. Additionally, the model predicted that the response as inhibition zone diameter would reach a value of 27 mm. Under optimal conditions, S. baarensis MH-133 produced 18.0 g of crude extract to each 35L and was purified with column chromatography. The active fraction exhibiting antibacterial activity was characterized using spectroscopic analysis. The MIC and MBC values varied between 37.5 and 300 μg/ml and 75 and 300 μg/ml, respectively. In conclusion, the biostatistical optimization of the active fraction critical variables, including environmental and nutritional conditions, enhances the production of bioactive molecules by Streptomyces species.

Black seed oil reverses chronic antibiotic-mediated depression and social behaviour deficits via modulation of hypothalamic mitochondrial-dependent markers and insulin expression

Chronic antibiotic use has been reported to impair mitochondrial indices, hypothalamus-mediated metabolic function, and amygdala-regulated emotional processes. Natural substances such as black seed (Nigella sativa) oil could be beneficial in mitigating these impairments. This study aimed to assess the impact of black seed oil (NSO) on depression and sociability indices, redox imbalance, mitochondrial-dependent markers, and insulin expression in mice subjected to chronic ampicillin exposure. Forty adult male BALB/c mice (30 ± 2 g) were divided into five groups: the CTRL group received normal saline, the ABT group received ampicillin, the NSO group received black seed oil, the ABT/NSO group concurrently received ampicillin and black seed oil, and the ABT+NSO group experienced pre-exposure to ampicillin followed by subsequent treatment with black seed oil. The ampicillin-exposed group exhibited depressive-like behaviours, impaired social interactive behaviours, and disruptions in mitochondrial-dependent markers in plasma and hypothalamic tissues, accompanied by an imbalance in antioxidant levels. Moreover, chronic antibiotic exposure downregulated insulin expression in the hypothalamus. However, these impairments were significantly ameliorated in the ABT/NSO, and ABT+NSO groups compared to the untreated antibiotic-exposed group. Overall, findings from this study suggest the beneficial role of NSO as an adjuvant therapy in preventing and abrogating mood behavioural and neural-metabolic impairments of chronic antibiotic exposure.

Plant-based compositions for the treatment of local and topical bacterial infections: a patent review

Aim: To examine recent patents related to plants with antimicrobial effects. Methods: Our investigation was carried out using the Espacenet database, searching patents related to International Patent Classification (IPC) codes A61P31/04, and A61K36/00 between 2008 and 2023. Results: The study began with 360 patents, of which 15 were found to be duplicates; 144 were not related to the research topic and six were not available. Then, 48 patents were related to other administration routes. The final selection was 47 patents related to local administration compositions. The potential for these herbal compositions to be marketed as over-the-counter medicines was evident. Conclusion: Developing new plant-origin anti-infective agents could provide promising solutions for combating resistant infections and offer accessible treatment options.

Antimicrobial Action Mechanisms of Natural Compounds Isolated from Endophytic Microorganisms

Infectious diseases are a significant challenge to global healthcare, especially in the face of increasing antibiotic resistance. This urgent issue requires the continuous exploration and development of new antimicrobial drugs. In this regard, the secondary metabolites derived from endophytic microorganisms stand out as promising sources for finding antimicrobials. Endophytic microorganisms, residing within the internal tissues of plants, have demonstrated the capacity to produce diverse bioactive compounds with substantial pharmacological potential. Therefore, numerous new antimicrobial compounds have been isolated from endophytes, particularly from endophytic fungi and actinomycetes. However, only a limited number of these compounds have been subjected to comprehensive studies regarding their mechanisms of action against bacterial cells. Furthermore, the investigation of their effects on antibiotic-resistant bacteria and the identification of biosynthetic gene clusters responsible for synthesizing these secondary metabolites have been conducted for only a subset of these promising compounds. Through a comprehensive analysis of current research findings, this review describes the mechanisms of action of antimicrobial drugs and secondary metabolites isolated from endophytes, antibacterial activities of the natural compounds derived from endophytes against antibiotic-resistant bacteria, and biosynthetic gene clusters of endophytic fungi responsible for the synthesis of bioactive secondary metabolites.

Protecting the Last Line of Defense: Analytical Approaches for Sample Preparation and Determination of the Reserve Group of Antibiotics in the Environment

Drug resistance in microorganisms is a serious threat to life and health due to the limited number of antibiotics that show efficacy in treating infections and the difficulty in discovering new compounds with antibacterial activity. To address this issue, the World Health Organization created the AWaRe classification, a tool to support global and national antimicrobial stewardship programs. The AWaRe list categorizes antimicrobials into three groups - Access, Watch, and Reserve - according to their intended use. The Reserve group comprises "last resort" medicines used solely for treating infections caused by bacterial strains that are resistant to other treatments. It is therefore necessary to protect them, not only by using them as prudently as possible in humans and animals, but also by monitoring their subsequent fate. Unmetabolized antibiotics enter the environment through hospital and municipal wastewater or from manure, subsequently contaminating bodies of water and soils, thus contributing to the emergence and spread of antibiotic resistance. This article presents a review of determination methods for the Reserve group of antimicrobials in water, wastewater, and manure. Procedures for extracting and determining these substances in environmental samples are described, showing the limited research available, which is typically on a local level.

Gamma irradiation induced degradation of organic pollutants: Recent advances and future perspective

Different organic compounds in aquatic bodies have been recognized as an emerging issue in Environmental Chemistry. The gamma irradiation technique, as one of the advanced oxidation techniques, has been widely investigated in past decades as a technique for the degradation of organic molecules, such as dyes, pesticides, and pharmaceuticals, which show high persistence to degradation. This review gives an overview of what has been achieved so far using gamma irradiation for different organic compound degradations giving an explanation of the mechanisms of degradations as well as the corresponding limitations and drawbacks, and the answer to why this technique has not yet widely come to life. Also, a new approach, recently presented in the literature, regards coupling gamma irradiation with other techniques and materials, as the latest trend. A critical evaluation of the most recent advances achieved by coupling gamma irradiation with other methods and/or materials, as well as describing the reaction mechanisms of coupling, that is, additional destabilization of molecules achieved by coupling, emphasizing the advantages of the newly proposed approach. Finally, it was concluded what are the perspectives and future directions towards its commercialization since this technique can contribute to waste minimization i.e. not waste transfer to other media. Summarizing and generalization the model of radiolytic degradation with and without coupling with other techniques can further guide designing a new modular, mobile method that will satisfy all the needs for its wide commercial application.

Antimicrobial Resistance and Sports: The Scope of the Problem, Implications for Athletes' Health and Avenues for Collaborative Public Health Action

Antimicrobial resistance (AMR) poses a global threat, leading to increased mortality and necessitating urgent action-however, its impact on athletes and the world of sports has hitherto been neglected. Sports environments (including athletic and aquatic) exhibit high levels of microbial contamination, potentially contributing to the spread of resistant microorganisms during physical activities. Moreover, the literature suggests that travel for sports events may lead to changes in athletes' gut microbiomes and potentially impact their antibiotic resistance profiles, raising questions about the broader implications for individual and public/global health. The prevalence of Staphylococcus aureus (S. aureus) among athletes (particularly those engaged in contact or collision sports) ranges between 22.4% and 68.6%, with MRSA strains being isolated in up to 34.9% of tested individuals. Factors such as training frequency, equipment sharing, delayed post-training showers, and a history of certain medical conditions are linked to higher colonization rates. Moreover, MRSA outbreaks have been documented in sports teams previously, highlighting the importance of implementing preventive measures and hygiene protocols in athletic settings. In light of the growing threat of AMR, there is a critical need for evidence-based treatment guidelines tailored to athletes' unique physiological demands to ensure responsible antibiotic use and mitigate potential health risks. While various initiatives-such as incorporating AMR awareness into major sporting events-aim to leverage the broad audience of sports to communicate the importance of addressing AMR, proactive measures (including improved AMR surveillance during large sporting events) will be indispensable for enhancing preparedness and safeguarding both athletes' and the general public's health. This narrative review thoroughly assesses the existing literature on AMR and antibiotic usage in the context of sports, aiming to illuminate areas where information may be lacking and underscoring the significance of promoting global awareness about AMR through sports.

Efficacy of outer membrane permeabilization in promoting aromatic isothiocyanates-mediated eradication of multidrug resistant Gram-negative bacteria and bacterial persisters

Multidrug resistant (MDR) bacteria are recognized to be one of the most important problems in public health. The outer membrane permeability is a critical intrinsic mechanism of bacterial resistance. In addition, bacteria produce a small number of dormant persister cells causing multidrug tolerance that reduces antimicrobial efficacy. This study aimed to evaluate the inhibitory effects of the combination of aromatic isothiocyanates (ITCs) with membrane-active agents on bacterial persisters and MDR Gram-negative bacteria. Our study demonstrated that membrane-active agents, particularly ethylenediaminetetraacetic acid (EDTA) synergistically enhanced the inhibitory activity of aromatic benzyl ITC and phenethyl ITC against most Gram-negative bacteria strains with fractional inhibitory concentration index values ranging from 0.18 to 0.5 and 0.16 to 0.5, respectively, and contributed to an 8- to 64-fold minimal inhibitory concentration reduction compared with those of aromatic ITCs alone. The EDTA-aromatic ITCs combination effectively reduced the survival rates of tested bacteria and significantly eradicated bacterial persisters (p = 0.033 and 0.037, respectively). The growth kinetics analysis also supported the enhanced inhibitory effect of EDTA-aromatic ITCs combination against tested bacteria. Our results suggested an alternate treatment strategy against Gram-negative bacteria, promoting the entry of aromatic ITCs into bacterial cytoplasm to facilitate bacterial clearance and thus preventing the development of bacterial resistance.

A comprehensive review on the fate and impact of antibiotic residues in the environment and public health: A special focus on the developing countries

The widespread application of antibiotics in human and veterinary medicine has led to the pervasive presence of antibiotic residues in the environment, posing a potential hazard to public health. This comprehensive review aims to scrutinize the fate and impact of antibiotic residues, with a particular focus on the context of developing nations. The investigation delves into the diverse pathways facilitating the entry of antibiotics into the environment and meticulously examines their effects on human health. The review delineates the current state of antibiotic residues, evaluates their exposure in developing nations, and elucidates existing removal methodologies. Additionally, it probes into the factors contributing to the endurance and ecotoxicity of antibiotic residues, correlating these aspects with usage rates and associated mortalities in these nations. The study also investigates removal techniques for antibiotic residues, assessing their efficiency in environmental compartments. The concurrent emergence of antibiotic-resistant bacteria, engendered by antibiotic residues, and their adverse ecological threats underscore the necessity for enhanced regulations, vigilant surveillance programs, and the adoption of sustainable alternatives. The review underlines the pivotal role of public education and awareness campaigns in promoting responsible antibiotic use. The synthesis concludes with strategic recommendations, strengthening the imperative for further research encompassing comprehensive monitoring, ecotoxicological effects, alternative strategies, socio-economic considerations, and international collaborations, all aimed at mitigating the detrimental effects of antibiotic residues on human health and the environment. PRACTITIONER POINTS: Antibiotic residues are widely distributed in different environmental compartments. Developing countries use more antibiotics than developed countries. Human and veterinary wastes are one of the most responsible sources of antibiotic pollution. Antibiotics interact with biological systems and trigger pharmacological reactions at low doses. Antibiotics can be removed using modern biological, chemical, and physical-chemical techniques.

Influence of Bacterial Contamination and Antibiotic Sensitivity on Cryopreserved Sperm Quality of Indian Red Jungle Fowl

Aims: Bacterial contamination may occur in feces during collection and processing of semen. Bacteria not only compete for nutrients with spermatozoa but also produce toxic metabolites and endotoxins and affect sperm quality. The aim of the present study was to investigate the effect of antibiotic supplementation on the sperm quality of Indian red jungle fowl, estimation and isolation of bacterial species and their antibiotic sensitivity. Materials and Methods: Semen was collected and initially evaluated, diluted, and divided into six experimental extenders containing gentamicin (2.5 μg/mL), kanamycin (31.2 μg/mL), neomycin (62.5 mg/mL), penicillin (200 U/mL), and streptomycin (250 μg/mL), and a control having no antibiotics were cryopreserved and semen quality was evaluated at post-dilution, post-cooling, post-equilibration, and post-thawing stages (Experiment 1). A total aerobic bacterial count was carried out after culturing bacteria (Experiment 2) and subcultured for antibiotic sensitivity (Experiment 3). Results: It was shown that penicillin-containing extender improved semen quality (sperm motility, plasma membrane integrity, viability, and acrosomal integrity) compared with the control and other extenders having antibiotics. The bacteria isolated from semen were Escherichia coli, Staphylococcus spp., and Bacillus spp. Antibiotic sensitivity results revealed that E. coli shows high sensitivity toward neomycin, kanamycin, and penicillin. Staphylococcus spp. shows high sensitivity toward streptomycin, neomycin, and penicillin. Bacillus spp. shows high sensitivity toward kanamycin and penicillin. Conclusions: It was concluded that antibiotics added to semen extender did not cause any toxicity and maintained semen quality as that of untreated control samples, and penicillin was identified as most effective antibiotic. It is recommended that penicillin can be added to the semen extender for control of bacterial contamination without affecting the semen quality of Indian red jungle fowl.

Green extraction of puromycin-based antibiotics from Streptomyces albofaciens (MS38) for sustainable biopharmaceutical applications

Background: Microbial secondary metabolites have shown promise as a source of novel antimicrobial agents. In this study, we aimed to isolate, characterize, and evaluate the antimicrobial activity of compound from a novel Streptomyces albofaciens strain MS38. The objective was to identify a potential bioactive compound with broad-spectrum antimicrobial properties. Methods: The isolated strain MS38 on starch casein agar was characterized using morphological, physiological, and molecular identification techniques. The compound was obtained from the fermented broth through extraction with n-butanol and further purification using silica gel column chromatography and high-performance liquid chromatography (HPLC). Structural elucidation was conducted using Ultraviolet (UV), Infrared (IR), nuclear magnetic resonance (NMR), and mass spectrometry (MS) techniques. The antimicrobial activity was evaluated using the agar well diffusion method and the microplate Alamar blue assay (MABA). Results: The isolated strain MS38 was identified as novel S. albofaciens based on morphological characteristics and confirmed by 16S sequences analysis and MALDI-TOF MS. The compound obtained from the fermented broth exhibited substantial antimicrobial activity against a variety of pathogenic bacteria and fungi. Structural analysis revealed a complex chemical structure with characteristic functional groups indicative of potential antimicrobial properties. The compound demonstrated strong activity against both Gram-positive (Staphylococcus Spp.) and Gram-negative (Klebsiella pneumoniae and Escherichia coli) bacteria, as well as fungi, including Candida albicans and Trichophyton rubrum. Conclusion: This study successfully isolated and characterized a bioactive compound from a novel S. albofaciens MS38. The compound exhibited significant antimicrobial activity against a range of pathogenic microorganisms. These findings underscore the importance of exploring microbial biodiversity for the discovery of novel antimicrobial agents. This study contributes to the growing knowledge of microbial secondary metabolites with potential therapeutic value.

Bifunctional Carbosilane Dendrimers for the Design of Multipurpose Hydrogels with Antibacterial Action

The emergence of antibiotic resistance is a serious global health problem. There is an incessant demand for new antimicrobial drugs and materials that can address this global issue from different angles. Dendritic hydrogels have appeared as a promising strategy. A family of bifunctional amphiphilic carbosilane dendrimers was designed and employed as nanosized cross-linking points for the synthesis of high-swelling hydrogels using the highly efficient Thiol-Ene click reaction for their preparation. Both stoichiometric and off-stoichiometric conditions were studied, generating hydrogels with pendant hydroxyl or alkene moieties. These hydrogels were found to be tunable antibacterial materials. They can easily be postmodified with relevant antibiotic moieties through covalent attachment on the hydroxyl or alkene pendant groups, generating ammonium-decorated networks with temperature and pH-responsive properties. Additionally, they can efficiently encapsulate drugs with poor solubility in water, like ciprofloxacin, and perform a sustained release over time, as demonstrated in preliminary assays against Staphylococcus aureus.

Hydrotrope assisted green synthesis of dicoumarols and in silico and in vitro antibacterial, antioxidant and xanthine oxidase inhibition studies

Aqueous hydrotrope has been employed for the first time to synthesize heteroaryl dicoumarols by condensation of 4-hydroxycoumarin and different heterocyclic aldehydes. This method is highly efficient and green, and the same aqueous hydrotropic solution can be used up to five times without any considerable loss of yield in the product. The synthesized compounds showed good antibacterial potential against Gram-positive (Staphylococcus aureus/NTCC 0997 and B. oceanisediminis) and Gram-negative (Escherichia coli/D0157:H7 and E. coli rosetta) bacterial strains using the Resazurin microtiter plate visual method. The MIC value of 312 µg/ml for compounds 3b, 3k and 3l for S. aureus while 39 µg/ml for compounds 3a, 3b and 3k for E. coli and 625 µg/ml for 3a and 3b for B. oceanisediminis was observed. The compounds were screened via computational methods like molecular docking studies and molecular dynamic simulations with PDB Id's 2W9S and 2EX6. Antioxidant activity was assessed using DPPH and H2O2 assays. Five compounds with the best binding score in molecular docking with XO (PDB ID: 1FIQ) have been tested in an in-vitro study using an enzyme inhibition assay. Novel compound 3b gave the IC50 value of 0.28 µg/ml, comparable to the standard drug Allopurinol.Communicated by Ramaswamy H. Sarma.

The Rise of Non-typhoidal Salmonella Infections in India: Causes, Symptoms, and Prevention

Non-typhoidal Salmonella infections (NTS) are a growing concern in India, posing a significant health risk to the population. These infections are becoming more common at worrisome rates, primarily because of inadequate surveillance. Salmonella non-typhoidal causes severe gastroenteritis and can even cause invasive infections, such as bacteremia, and focal infections, such as meningitis and septic arthritis, and is acquired through contaminated food and water sources. From moderate to severe, the symptoms might vary. Certain serovars exhibit a stronger propensity for specific syndromes, with serious infections more commonly observed in vulnerable populations. Consuming contaminated food, using inadequate sanitation procedures while handling meat from animals slaughtered, and contaminated water supplies are some of the causes of these diseases. Proper food and water treatment, better sanitary facilities, public awareness campaigns, and adherence to food safety laws are all part of prevention measures. The issue of antimicrobial resistance further emphasizes the necessity for prudent antibiotic usage. The Indian government has put in place programs including public awareness campaigns, better sanitary facilities, and stricter food safety laws. In the future, efforts should, however, concentrate on improving laws, boosting hygienic practices, and funding the development of new medicines and vaccines. These actions will lessen the burden of NTS infections in India by assisting in their prevention and management. This review aims to understand the reasons for this growing tendency, which is essential for creating efficient control and prevention strategies.

Untargeted MS-Based Metabolomic Analysis of Termite Gut-Associated Streptomycetes with Antifungal Activity against Pyrrhoderma noxium

Pyrrhoderma noxium is a plant fungal pathogen that induces the disease of brown root rot in a large variety of tree species. It is currently infecting many of the amenity trees within Brisbane City of Queensland, Australia. Steering away from harmful chemical fungicides, biological control agents offer environmentally friendly alternatives. Streptomycetes are known for their production of novel bioactive secondary metabolites with biocontrol potential, particularly, streptomycete symbionts isolated from unique ecological niches. In this study, 37 termite gut-associated actinomycete isolates were identified using molecular methods and screened against P. noxium. A majority of the isolates belonged to the genus Streptomyces, and 15 isolates exhibited strong antifungal activity with up to 98.5% mycelial inhibition of the fungal pathogen. MS/MS molecular networking analysis of the isolates' fermentation extracts revealed several chemical classes with polyketides being among the most abundant. Most of the metabolites, however, did not have matches to the GNPS database, indicating potential novel antifungal compounds in the active extracts obtained from the isolates. Pathway enrichment and overrepresentation analyses revealed pathways relating to polyketide antibiotic production, among other antibiotic pathways, further confirming the biosynthetic potential of the termite gut-associated streptomycetes with biocontrol potential against P. noxium.

Identification of Robust Antibiotic Subgroups by Integrating Multi-Species Drug-Drug Interactions

Previous studies have shown that antibiotics can be divided into groups, and drug-drug interactions (DDI) depend on their groups. However, these studies focused on a specific bacteria strain (i.e., Escherichia coli BW25113). Existing datasets often contain noise. Noisy labeled data may have a bad effect on the clustering results. To address this problem, we developed a multi-source information fusion method for integrating DDI information from multiple bacterial strains. Specifically, we calculated drug similarities based on the DDI network of each bacterial strain and then fused these drug similarity matrices to obtain a new fused similarity matrix. The fused similarity matrix was combined with the T-distributed stochastic neighbor embedding algorithm, and hierarchical clustering algorithm can effectively identify antibiotic subgroups. These antibiotic subgroups are strongly correlated with known antibiotic classifications, and group-group interactions are almost monochromatic. In summary, our method provides a promising framework for understanding the mechanism of action of antibiotics and exploring multi-species group-group interactions.

Screening of Chemical Composition, Antimicrobial and Antioxidant Activities in Pomegranate, Quince, and Persimmon Leaf, Peel, and Seed: Valorization of Autumn Fruits By-Products for a One Health Perspective

Antimicrobial resistance is increasing globally and is now one of the major public health problems. Therefore, there is a need to search for new antimicrobial agents. The food industry generates large amounts of by-products that are rich in bioactive compounds, such as phenolic compounds, which are known to have several health benefits, including antioxidant and antimicrobial properties. Thus, we aimed to characterize the phenolic compounds present in pomegranate, quince, and persimmon by-products, as well as their antioxidant and antimicrobial activities. Phenolic compounds were extracted from pomegranate, quince, and persimmon leaves, seeds, and peels using a mixture of ethanol/water (80/20). The polyphenol profile of the extracts was determined by high-performance liquid chromatography. The antioxidant activity of the extracts was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) methods. Antimicrobial susceptibility was evaluated using the Kirby-Bauer disk diffusion method. In general, leaves showed higher concentrations of phenolics than the peel and seeds of fruits. In total, 23 phenolic compounds were identified and quantified, with sanguiin and apigenin-3-O-galactoside being present in the highest concentrations. Leaf extracts of pomegranate showed higher antioxidant activities than the other components in all methods used. In general, all extracts had a greater antimicrobial activity against Gram-positive bacteria. Persimmon leaf and seed extracts inhibited a greater number of bacteria, both Gram-positive and -negative. The lowest minimum inhibitory concentration (MIC) detected among Gram-positive and -negative bacteria was 10 mg/mL for pomegranate peel and leaf extracts against Staphylococcus aureus and S. pseudintermedius and for pomegranate leaf extract against Escherichia coli. Our results reinforce the need to value food industry by-products that could be used as food preservatives and antibiotic adjuvants against multiresistant bacteria.

Antifungal Activity and Potential Action Mechanism of Allicin against Trichosporon asahii

Trichosporon asahii is an emerging opportunistic pathogen that causes potentially fatal disseminated trichosporonosis. The global prevalence of coronavirus disease 2019 (COVID-19) poses an increasing fungal infection burden caused by T. asahii. Allicin is the main biologically active component with broad-spectrum antimicrobial activity in garlic. In this study, we performed an in-depth analysis of the antifungal characteristics of allicin against T. asahii based on physiological, cytological, and transcriptomic assessments. In vitro, allicin inhibited the growth of T. asahii planktonic cells and biofilm cells significantly. In vivo, allicin improved the mean survival time of mice with systemic trichosporonosis and reduced tissue fungal burden. Electron microscopy observations clearly demonstrated damage to T. asahii cell morphology and ultrastructure caused by allicin. Furthermore, allicin increased intracellular reactive oxygen species (ROS) accumulation, leading to oxidative stress damage in T. asahii cells. Transcriptome analysis showed that allicin treatment disturbed the biosynthesis of cell membrane and cell wall, glucose catabolism, and oxidative stress. The overexpression of multiple antioxidant enzymes and transporters may also place an additional burden on cells, causing them to collapse. Our findings shed new light on the potential of allicin as an alternative treatment strategy for trichosporonosis. IMPORTANCE Systemic infection caused by T. asahii has recently been recognized as an important cause of mortality in hospitalized COVID-19 patients. Invasive trichosporonosis remains a significant challenge for clinicians, due to the limited therapeutic options. The present work suggests that allicin holds great potential as a therapeutic candidate for T. asahii infection. Allicin demonstrated potent in vitro antifungal activity and potential in vivo protective effects. In addition, transcriptome sequencing provided valuable insights into the antifungal effects of allicin.

Fish Skin Mucus Extracts: An Underexplored Source of Antimicrobial Agents

The slow discovery of new antibiotics combined with the alarming emergence of antibiotic-resistant bacteria underscores the need for alternative treatments. In this regard, fish skin mucus has been demonstrated to contain a diverse array of bioactive molecules with antimicrobial properties, including peptides, proteins, and other metabolites. This review aims to provide an overview of the antimicrobial molecules found in fish skin mucus and its reported in vitro antimicrobial capacity against bacteria, fungi, and viruses. Additionally, the different methods of mucus extraction, which can be grouped as aqueous, organic, and acidic extractions, are presented. Finally, omic techniques (genomics, transcriptomics, proteomics, metabolomics, and multiomics) are described as key tools for the identification and isolation of new antimicrobial compounds. Overall, this study provides valuable insight into the potential of fish skin mucus as a promising source for the discovery of new antimicrobial agents.

Resistance, Tolerance, Virulence and Bacterial Pathogen Fitness-Current State and Envisioned Solutions for the Near Future

The current antibiotic crisis and the global phenomena of bacterial resistance, inherited and non-inherited, and tolerance-associated with biofilm formation-are prompting dire predictions of a post-antibiotic era in the near future. These predictions refer to increases in morbidity and mortality rates as a consequence of infections with multidrug-resistant or pandrug-resistant microbial strains. In this context, we aimed to highlight the current status of the antibiotic resistance phenomenon and the significance of bacterial virulence properties/fitness for human health and to review the main strategies alternative or complementary to antibiotic therapy, some of them being already clinically applied or in clinical trials, others only foreseen and in the research phase.

Fabrication of mulberry leaf extract (MLE)- and tasar pupal oil (TPO)-loaded silk fibroin (SF) hydrogels and their antimicrobial properties

Biocomposites have gained tremendous advantages over synthetic composites due to their biocompatibility, sustainable degradation, and ability to easily combine with other substances. In the present study, we have prepared silk fibroin (SF) hydrogel, mulberry leaf extract (MLE), tasar pupal oil (TPO), and their composites, such as TPO-loaded SF hydrogel and MLE-loaded SF hydrogel, and characterized them by using a phase contrast microscope (PCM), scanning electron microscope (SEM) SEM- EDX, and Fourier transform infrared spectroscopy (FTIR). In addition, 1H-NMR was used for profiling of mulberry leaf extract and GC-MS was used to find tasar pupal oil composition. Further, the disc diffusion method evaluated their antimicrobial activities against S. aureus, E. coli, A. flavus, and A. brassicae. PCM, SEM, and FTIR results validated the conjugation of MLE and SF hydrogel composite; 1H-NMR confirmed the 41 metabolites in MLE, and GC-MS established the composition of tasar pupal oil. Since both composites, such as TPO-loaded SF hydrogel and MLE-loaded SF hydrogel, reduced the S. aureus and E. coli activities at all tested concentrations, the antibacterial results were unambiguous in their conclusion. S. aureus could only be inhibited by SF hydrogel at a high concentration (300 g/ml), despite suppressing E. coli growth at all tested concentrations. At 300 g/ml, MLE demonstrated antibacterial action against S. aureus. Furthermore, at a dosage of 300 g/ml, TPO inhibited both S. aureus and E. coli. Both mulberry leaf extract (at 200 and 300 g/ml) and the MLE-loaded SF hydrogel composite displayed antifungal activity against A. flavus at all tested concentrations (100, 200, and 300 g/ml).

Antimicrobial Resistance and Recent Alternatives to Antibiotics for the Control of Bacterial Pathogens with an Emphasis on Foodborne Pathogens

Antimicrobial resistance (AMR) is one of the most important global public health problems. The imprudent use of antibiotics in humans and animals has resulted in the emergence of antibiotic-resistant bacteria. The dissemination of these strains and their resistant determinants could endanger antibiotic efficacy. Therefore, there is an urgent need to identify and develop novel strategies to combat antibiotic resistance. This review provides insights into the evolution and the mechanisms of AMR. Additionally, it discusses alternative approaches that might be used to control AMR, including probiotics, prebiotics, antimicrobial peptides, small molecules, organic acids, essential oils, bacteriophage, fecal transplants, and nanoparticles.

Exploration of the chemical constituents and its antioxidant, antibacterial activities of endophytic fungi isolated from the medicinal plant Dillenia indica

Assam, India being the pool for ethnomedicinal plants harbors diverse endophytic fungi constituting major bioactive metabolites. The present study was designed to screen the antioxidant, antibacterial activities along with the chemical constituents of the endophytic fungi isolated from the fruits of Dillenia indica (commonly known as Otenga in Assam). Screening of such metabolic compounds and their antioxidant, antibacterial activities can have tremendous potential in suppressing certain diseases. Agar well diffusion method has been used to carry out the antibacterial assay against three pathogenic bacteria two gram positive [Bacillus subtilis (MTCC No. 441); Staphylococcus aureus (MTCC No. 740)] and one gram negative [Escherichia coli (MTCC No. 739)]. Aspergillus fumigatus of ethyl acetate extract showed a prominent activity against Staphylococcus aureus followed by Aspergillus flavus and Aspergillus niger. Antioxidants have the potential to neutralize and inhibit the action of free radicals. The highest scavenging activity was exhibited by ethyl acetate extract of Aspergillus fumigatus in DPPH assay. Furthermore, the phytochemical screening revealed the presence of flavonoids, alkaloids, terpenoids and saponins. Result showed that ethyl acetate extract of Aspergillus fumigatus showed the highest phenolic content (236.81 ± 0.2 mg.g^-1) and least was shown by Aspergillus flavus (92.12 ± 1.4 mg.g^-1). Total flavonoids content for Aspergillus fumigatus (39.08 ± 0.2 mg.g^-1) was found to be highest compared to other isolates. Molecular identification of the endophytic fungus showing highest activity was done based on 18S rRNA. The sequenced was submitted in Genbank with accession number MH540721 showing high similarities with Aspergillus fumigatus strain 3,162,954. A. fumigatus strain is subjected to GC/MS analysis that revealed the chemical constituents 2-isopropyl-5-methyl-1-heptanol, dodecane, 1-fluoro-pentanoic acid, 2-ethylhexyl ester, 1-octanol, 2-butyl-1-dodecanol. Thus, the present work reveals that endophytic fungi colonizing in ethnomedicinal plant Dillenia indica could be a promising source for antioxidant and antibacterial activity. Further work is needed to add value in various therapeutic and pharmaceutical fields.

Protective Effect of [Cu(NN1)2](ClO4) Complex in Rainbow Trout Challenged against Flavobacterium psychrophilum

Previously, we reported an in vitro evaluation regarding antibacterial effects against F. psychrophilum by a new Cu (I) complex, [Cu(NN1)2](ClO4). This study presents the results of an in vivo evaluation of [Cu(NN1)2](ClO4) added as a dietary supplement against F. psychrophilum in rainbow trout. The results showed that the administration of [Cu(NN1)2](ClO4) at 29 and 58 µg/g of fish for 15 days does not affect the growth of rainbow trout. On the other hand, the amount of copper present in the liver, intestine, and muscle of rainbow trout was determined. The results showed that the amount of copper in the liver, when compared between treated fish and control fish, does not change. While, in the intestine, an increase in the fish fed at 58 µg/g of fish was observed. In muscle, a slight decrease at 29 µg/g was obtained. Additionally, copper concentrations in the pond water after 15 days of feeding with the [Cu(NN1)2](ClO4) complex showed the highest levels of copper. Finally, the effect of the administration of [Cu(NN1)2](ClO4) for 15 days at 58 µg/g of fish was evaluated against F. psychrophilum, where a 75% survival was obtained during 20 days of challenge.

Review on Plant-Based Management in Combating Antimicrobial Resistance - Mechanistic Perspective

Antimicrobial resistance (AMR) occurs when microbes no longer respond to any pharmacological agents, rendering the conventional antimicrobial agents ineffective. AMR has been classified as one of the top 10 life-threatening global health problems needed multilevel attention and global cooperation to attain the Sustainable Development Goals (SDGs) according to the World Health Organization (WHO), making the discovery of a new and effective antimicrobial agent a priority. The recommended treatments for drug-resistant microbes are available but limited. Furthermore, the transformation of microbes over time increases the risk of developing drug resistance. Hence, plant metabolites such as terpenes, phenolic compounds and alkaloids are widely studied due to their antibacterial, antiviral, antifungal and antiparasitic effects. Plant-derived antimicrobials are preferred due to their desirable efficacy and safety profile. Plant metabolites work by targeting microbial cell membranes, interfering with the synthesis of microbial DNA/RNA/enzymes and disrupting quorum sensing and efflux pump expression. They also work synergistically with conventional antibiotics to enhance antimicrobial effects. Accordingly, this review aims to identify currently available pharmacological therapies against microbes and AMR, as well as to discuss the importance of plant and secondary metabolites as a possible solution for AMR together with their mechanisms of action. All the information was obtained from government databases, WHO websites, PubMed, Springer, Google Scholar and Science Direct. Based on the information obtained, AMR is regarded as a significant warning to global healthcare. Plant derivatives such as secondary metabolites may be considered as potential therapeutic targets to mitigate the non-ending AMR.

Antibiotic Therapy and Athletes: Is the Mitochondrial Dysfunction the Real Achilles’ Heel?

It is widely recognized that athletes consume oral antibiotics almost twice as often as observed in the non-sports population in order to reduce as much as possible the period of inactivity due to bacterial diseases. However, increasing evidences have demonstrated the ability of some classes of antibiotics to induce muscle weakness, pain, and a feeling of fatigue upon resuming physical activity conditions that considerably limit the athletic performance of athletes, ascribable to alterations in the biochemical mechanisms underlying normal musculoskeletal activity, such as mitochondrial respiration. For this reason, tailoring a treatment plan for effective antibiotics that limit an athlete’s risk is paramount to their safety and ability to maintain adequate athletic performance. The present review illustrates and critically analyzes the evidence on the use of antibiotics in sports, deepening the molecular mechanisms underlying the onset and development of muscle–tendon alterations in athletes as well as delineating the pharmacological strategies aimed at counteracting such adverse events.

Plasma trough concentration distribution and safety of high-dose teicoplanin for patients with augmented renal clearance

WHAT IS KNOWN AND OBJECTIVE

There are few reports on the distribution of the plasma trough concentration (C_min ) of teicoplanin in patients with augmented renal clearance (ARC) and on the safety of a high-dose regimen (HD; 800 mg loading dose for q12h three times followed by an 800 mg qd maintenance dose). The objective of this study was to determine the C_min values of teicoplanin in ARC patients using HD teicoplanin to provide a reference for individualized medication.

METHODS

Data on patients treated with teicoplanin from January 2019 to January 2021 were collected retrospectively and divided into ARC (creatinine clearance rate [CCr] >130 ml/min, n = 22) and non-ARC (60 ml/min ≤ CCr ≤130 ml/min, n = 24) groups. The C_min values in the two patient groups were analysed during the HD and the low-dose regimen (LD; all other regimens) on the third day of medication and during the dose maintenance period. Liver and kidney function indexes were also analysed before and after medication.

RESULTS AND DISCUSSIONS

On the third day of the HD, C_min did not differ significantly between the ARC and non-ARC groups (17.3 ± 9.2 mg/L [mean ± SD] vs. 15.5 ± 7.9 mg/L, p = 0.663), while C_min in the ARC group was significantly lower for the LD (6.8 ± 3.9 mg/L, p = 0.039). During the dose maintenance period, C_min in the ARC group when receiving the HD (18.3 ± 5.1 mg/L) was significantly lower than that in the non-ARC group (25.5 ± 11.9 mg/L, p = 0.016) and significantly higher than that for the LD (12.2 ± 6.3 mg/L, p = 0.022). Nephrotoxicity and hepatotoxicity incidence rates did not differ significantly between these groups.

WHAT IS NEW AND CONCLUSION

These results suggest that it is necessary to apply a loading dose of 800 mg (but not higher) q12h three times for patients with ARC, with 800 mg needed as a maintenance dose during severe infection, and 600 mg or 400 mg for mild infection.

Combating antimicrobial resistance: an evidence-based overview of bacteriophage therapy

Antimicrobial resistance (AMR) problems cause an enormous challenge to our world in medicine and in agriculture and many other fields. The current situation makes bacteriophage therapy an attractive therapeutic candidate. Nevertheless, very limited clinical trials on bacteriophage therapy were performed and completed as of presence. Bacteriophage therapy alludes to infecting bacteria with a virus, this often results in a bactericidal effect. The compiled studies support the feasibility of treating AMR with bacteriophage. However, the efficacy of specific bacteriophage strains and the accurate dosage have to be further studied and tested rigorously.

Synergistic Effect of Polyphenol-Rich Complex of Plant and Green Propolis Extracts with Antibiotics against Respiratory Infections Causing Bacteria

Bacterial infections are a prevalent complication after primary viral respiratory infections and are associated with high morbidity and mortality. Antibiotics are widely used against bacterial respiratory pathogens; however, the rise in antibiotic-resistant strains urges us to search for new antimicrobial compounds, including ones that act synergistically with antibiotics. In this study, the minimal inhibitory (MIC) and minimal bactericidal (MBC) concentrations of a polyphenol-rich complex of green propolis, Tabebuia avellanedae bark, and Olea europaea leaf extracts against Staphylococcus aureus, Haemophilus influenzae, and Klebsiella pneumoniae were determined, followed by an analysis of the synergistic effect with clarithromycin, azithromycin, and amoxiclav (875/125 mg amoxicillin/clavulanic acid). A combination of extracts showed activity against all three bacterial strains, with MIC values ranging from 0.78 to 12.5 mg/mL and MBC values from 1.56 to 12.5 mg/mL. The extracts showed synergistic activity with azithromycin and clarithromycin against S. aureus, with clarithromycin against K. pneumoniae, and with all three tested antibiotics against H. influenzae. Synergy with clarithromycin was additionally evaluated in a time-kill assay where the synergistic effects against S. aureus and K. pneumoniae were seen within the first 6 h of incubation. The results show the potential of polyphenol-rich extracts in enhancing the efficacy of antibiotic therapy and indicate their potential to be used in the management of respiratory infections.

Prophylactic Catechin-Rich Green Tea Extract Treatment Ameliorates Pathogenic Enterotoxic Escherichia coli-Induced Colitis

In this study, we explored the potential beneficial effects of green tea extract (GTE) in a pathogenic Escherichia coli (F18:LT:STa:Stx2e)-induced colitis model. The GTE was standardized with catechin and epigallocatechin-3-gallate content using chromatography analysis. Ten consecutive days of GTE (500 and 1000 mg/kg) oral administration was followed by 3 days of a pathogenic E. coli challenge (1 × 10⁹ CFU/mL). In vitro antibacterial analysis showed that GTE successfully inhibited the growth of pathogenic E. coli, demonstrating over a 3-fold reduction under time- and concentration-dependent conditions. The in vivo antibacterial effect of GTE was confirmed, with an inhibition rate of approximately 90% when compared to that of the E. coli alone group. GTE treatment improved pathogenic E. coli-induced intestinal injury with well-preserved epithelial linings and villi. In addition, the increased expression of annexin A1 in GTE-treated jejunum tissue was detected, which was accompanied by suppressed inflammation-related signal expression, including TNFA, COX-2, and iNOS. Moreover, proliferation-related signals such as PCNA, CD44, and Ki-67 were enhanced in the GTE group compared to those in the E. coli alone group. Taken together, these results indicate that GTE has an antibacterial activity against pathogenic E. coli and ameliorates pathogenic E. coli-induced intestinal damage by modulating inflammation and epithelial cell proliferation.

Heteroaryl-Ethylenes as New Lead Compounds in the Fight against High Priority Bacterial Strains

The widespread use of antibiotics has led to a gradual increase in drug-resistant bacterial infections, which severely weakens the clinical efficacy of antibacterial therapies. In recent decades, stilbenes aroused great interest because of their high bioavailability, as well as their manifold biological activity. Our research efforts are focused on synthetic heteroaromatic stilbene derivatives as they represent a potentially new type of antibiotic with a wide antibacterial spectrum. Herein, a preliminary molecular modeling study and a versatile synthetic scheme allowed us to define eight heteroaromatic stilbene derivatives with potential antimicrobial activity. In order to evaluate our compound’s activity spectrum and antibacterial ability, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests have been performed on Gram-positive and Gram-negative ATCC strains. Compounds PB4, PB5, PB7, and PB8 showed the best values in terms of MIC and were also evaluated for MBC, which was found to be greater than MIC, confirming a bacteriostatic activity. For all compounds, we evaluated toxicity on colon-rectal adenocarcinoma cells tumor cells (CaCo2), once it was established that the whole selected set was more active than 5-Fluorouracil in reducing CaCo-2 cells viability. To the best of our knowledge, the biological assays have shown for these derivatives an excellent bacteriostatic activity, compared to similar molecular structures previously reported, thus paving the way for a new class of antibiotic compounds.

Two Antibiotics, Ampicillin and Tetracycline, Exert Different Effects in HT-29 Colorectal Adenocarcinoma Cells in Terms of Cell Viability and Migration Capacity

Antibiotics are considered the cornerstone of modern medicine; however, currently, antibiotic resistance has become a global health issue. Antibiotics also find new uses in the treatment of other pathologies as well as cancer. The present study aimed to verify the impact of tetracycline and ampicillin in a colorectal adenocarcinoma cell line, HT-29. The effects of the two antibiotics on cell viability and nucleus were evaluated by the means of MTT assay and the Hoechst staining method, respectively. The irritant potential at vascular level of the chorioallantoic membrane was tested by the HET-CAM assay. Treatment of HT-29 cells with the two antibiotics determined different effects: (i) tetracycline induced a dose- and time-dependent cytotoxic effect characterized by decreased cell viability, changes in cells morphology, apoptotic features (nuclear fragmentation), and inhibition of cellular migration, whereas (ii) ampicillin exerted a biphasic response-cytotoxic at low doses and proliferative at high concentrations. In terms of effect on blood vessels, both antibiotics exerted a mild irritant effect. These results are promising and could be considered as starting point for further in vitro studies to define the molecular mechanisms involved in the cytotoxic/proliferative effects.