Antibacterial Effect Research Articles

Copper strontium phosphate glasses with high antimicrobial efficacy

The emergence of antibiotic-resistant strains caused by the extensive use of antibiotics in the world requires a preventive approach to stop the infection spread, especially in a hospital setting. So, there is a growing demand for materials that can inhibit bacteria growth or have bactericidal effects. In this paper, an inexpensive and durable Cu-containing strontium-modified phosphate glass with a considerable antimicrobial effect is proposed. The basic physical properties of the material are studied, and its antimicrobial effect is evaluated on Staphylococcus aureus bacteria, known to be the most common problem in hospital environments because of healthcare-associated infections. The glass powders demonstrate strong antibacterial efficacy with a concentration of only a few mg/mL, sufficient to eradicate the entire bacterial colonies within 24 h. Bulk surfaces of these glasses inhibit bacterial growth and release low, non-toxic levels of their constituent elements into simulated body fluid. On the basis of the obtained results, it is shown that the proposed glass can be used as a structural material for various medical equipment and/or components of antimicrobial coating/paint not only in medicine but also for high touch point articles in public places like schools, gyms, public offices and similar.

Use of commercial fertilizers in an IPDM protocol to mitigate Olive Quick Decline Syndrome caused by Xylella fastidiosa subsp. pauca in Southern Italy.

Management of Xylella fastidiosa subsp. pauca (Xfp) presents significant challenges due to the lack of genetic resistance in major crops, pathogen variability and resistance development against the main antimicrobial compounds, and the lack of effective chemical compounds for control. Traditional bactericides in the EU are restricted, and copper-based products are increasingly limited due to environmental impacts. In this study the antibacterial side effects of some commercial fertilizers against Xfp were evaluated. These products, containing metal ions (mainly copper and/or zinc) complexed with phosphites and bioavailable silicon, show antimicrobial and bactericidal activities in vitro which suggest their possible use to control the pathogen, as well as enhanced plant resistance to biotic and abiotic stresses. Greenhouse and open field trials showed that they can significantly reduce disease severity and pathogen population, thus improving fruit yield. The integrated pest and disease management (IPDM) strategy, which combines these treatments with agronomic and phytosanitary vector-control measures, leads to a reduction of disease symptoms in treated plants compared to untreated ones. These findings highlight the potential of systemic fertilizers to mitigate Xfp symptoms by providing antimicrobial collateral effects and probably enhance plant defenses, since similar compounds are known to be plant defense inducers in other pathosystems. Therefore, these products offer a sustainable solution for managing plant pathogenic bacteria and improving crop health and yield. This approach is crucial for the sustainability of olive production in Xf-affected areas. However, further research is needed to optimize these strategies for long-term effectiveness under field conditions. Overall, the results emphasize the value of the collateral effects of some mineral fertilizers in a comprehensive strategy aimed at mitigating the symptoms of Xfp and safeguarding the agricultural productivity as well as the invaluable heritage of centuries-old Apulian olive trees.

Investigating the Synergistic Bactericidal Effects of Cold Plasma and Ultraviolet Radiation on Pseudomonas fragi

Investigating the Synergistic Bactericidal Effects of Cold Plasma and Ultraviolet Radiation on Pseudomonas fragi

Artesunate, EDTA, and colistin work synergistically against MCR-negative and -positive colistin-resistant Salmonella.

Discovering new strategies to combat the multidrug-resistant bacteria constitutes a major medical challenge of our time. Previously, artesunate (AS) has been reported to exert antibacterial enhancement activity in combination with β-lactam antibiotics via inhibition of the efflux pump AcrB. However, combination of AS and colistin (COL) revealed a weak synergistic effect against a limited number of strains, and few studies have further explored its possible mechanism of synergistic action. In this article, we found that AS and EDTA could strikingly enhance the antibacterial effects of COL against mcr-1- and mcr-1+ Salmonella strains either in vitro or in vivo, when used in triple combination. The excellent bacteriostatic effect was primarily related to the increased cell membrane damage, accumulation of toxic compounds and inhibition of MCR-1. The potential binding sites of AS to MCR-1 (THR283, SER284, and TYR287) were critical for its inhibition of MCR-1 activity. Additionally, we also demonstrated that the CheA of chemosensory system and virulence-related protein SpvD were critical for the bacteriostatic synergistic effects of the triple combination. Selectively targeting CheA, SpvD, or MCR using the natural compound AS could be further investigated as an attractive strategy for the treatment of Salmonella infection. Collectively, our work opens new avenues toward the potentiation of COL and reveals an alternative drug combination strategy to overcome COL-resistant bacterial infections.

Phenotype-Specific Semi-Mechanistic Modelling of Florfenicol Time-Kill Curves in G. Parasuis Compared to Other Respiratory Pathogens.

This study examines the pharmacodynamics (PD) of florfenicol (FFN) for treating porcine respiratory diseases by comparing its effects on Glaesserella parasuis, Actinobacillus pleuropneumoniae and Pasteurella multocida. Invitro time-kill assays and semi-mechanistic PD modeling were used to assess bacterial growth and killing rates at varying FFN concentrations. Species-specific PD models indicated that fAUC/MIC was the best PK/PD index across all species. A. pleuropneumoniae and P. multocida had target values of 1.05 and 1.66 × MIC, respectively for bacteriostasis and 1.12 and 1.87 × MIC for 99.9% kill. Two phenotypes of G. parasuis emerged "fast-kill" and "slow-kill" which displayed distinct bacterial eradication rates despite similar MICs. For "slow-kill" isolates, an average free drug concentration (fAUC/MIC) of 1.46 and 1.63 × MIC (median, range: 1.53-1.69) was required for bacteriostasis and 99.9% kill. "Fast-kill" isolates needed an average free drug concentration of 1.38 × MIC for bacteriostasis and 1.51 × MIC for a 99.9% reduction. Indicating that the rate of kill influences the respective average free concentration required to achieve an equivalent antibacterial effect. Simulations of clinical dosing of FFN predicted bacterial eradication for all species, highlighting the value of phenotype-specific PD modeling in guiding treatment strategies for porcine respiratory infections.

Antimicrobial capping agents on silver nanoparticles made via green method using natural products from banana plant waste.

Herein, we investigated the phytochemical composition and antibacterial activities of the organic layers from biosynthesized silver nanoparticles (AgNPs). AgNPs were synthesized using Musa paradisiaca and Musa sapientum extracts. UV-vis absorption in the 400-450 nm range indicated surface plasmonic resonance peak of AgNPs. Samples analyses using dynamic light scattering and transmission electron microscopy revealed the presence of particles within nanometric ranges, with sizes of 30-140 nm and 8-40 nm, respectively. Fourier transform infrared (FTIR) unveiled the presence of several organic functional groups on the surface of AgNPs, indicating the presence of phytochemicals from plant extracts. Thin layer chromatography (TLC) of the phytochemicals (capping agents) from AgNPs identified multiple groups of secondary metabolites. These phytochemical capping agents exhibited antibacterial activities against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, with minimum inhibitory concentrations ranging from 62.5 to 1000 µg/mL. Regardless of the bacterial species or plant parts (leaves or pseudo-stems), capping agents from M. sapientum nanoparticles displayed significantly enhanced antibacterial effectiveness compared to all other samples, including the raw plant extracts and biosynthesized capped and uncapped AgNPs. These results suggest the presence of antimicrobial phytochemicals on biosynthesized AgNPs, highlighting the promise of green nanoparticle synthesis as a valuable approach in bioprospecting antimicrobial agents.

Phytochemicals analysis of Arum palaestinum extracts and their antibacterial effect against Pseudomonas syringae pv. tomato (Pst)

Phytochemicals analysis of Arum palaestinum extracts and their antibacterial effect against Pseudomonas syringae pv. tomato (Pst)

Exploring the potential benefits of areca nut extract in animal production: a review

Globally, the issue of antibiotic residues in agricultural products and their environments is increasingly critical, with the spread of microbial resistance becoming an urgent international challenge. Therefore, the development of ecological health feed additives is of paramount importance for advancing sustainable animal husbandry. Areca nut extract, derived from commonly available food sources, has garnered attention due to its exceptional bioactive properties. Its remarkable anti-inflammatory and antioxidant potential, along with its outstanding performance in antibacterial, antifungal, and antiviral activities, plays a crucial role in inhibiting various pathogens and protecting cells from oxidative damage. This review aims to comprehensively explore the biological activities of areca nut extract and delve into its practical application potential in enhancing animal production efficiency and promoting sustainable livestock development.The pervasive presence of antibiotic residues—including tetracyclines, sulfonamides, and quinolones—in agricultural products such as meat, milk, and eggs has raised significant concerns due to their extensive use in animal husbandry. This issue is not only a formidable challenge for food safety but also exacerbates the global crisis of antimicrobial resistance (AMR). To address these challenges, there is an urgent need for safe and sustainable alternatives to antibiotics in animal production. Among these alternatives, plant extracts have garnered considerable attention for their natural bioactive properties. Notably, areca nut extract has emerged as a promising candidate due to its diverse biological activities and potential applications in livestock production.Areca nut, derived from the dried ripe fruits, seeds, peels, and flowers of Areca catechu, is well-documented in traditional medicine sources such as the Pharmacopoeia of the People’s Republic of China (2010 Edition) for its medicinal properties, including antiparasitic effects, digestive support, and antimicrobial activity. This review focuses on the biological activities of areca nut extract, particularly its antioxidant, anti-inflammatory, antiparasitic, antibacterial, and microbiota-modulating effects, which collectively contribute to its potential role as a feed additive for enhancing animal health and performance.Key findings indicate that areca nut extract can promote livestock productivity by accelerating growth, enhancing immune responses, and reducing disease incidence. Additionally, its biological properties show potential for improving feed efficiency and mitigating the environmental footprint of livestock operations. By exploring these activities, we aim to provide theoretical insights and practical guidance for the application of areca nut extract in animal husbandry.This review highlights the promise of areca nut extract as a natural, effective, and sustainable alternative to antibiotics, offering solutions to the pressing issues of antibiotic residues and AMR. Its potential contributions to sustainable livestock production underscore the importance of further scientific exploration and interdisciplinary collaboration in this field.

The Effect of Environmental Factors on the Nitrate and Nitrite Metabolism of Oral Actinomyces and Schaalia Species.

Actinomyces naeslundii and Schaalia odontolytica belong to the most predominant nitrite-producing bacteria in the oral microbiome. Nitrite has antibacterial and vasodilatory effects that may contribute to maintaining oral and systemic health. We have previously elucidated the metabolic characteristics of the nitrite-producing activity of oral Veillonella species and the effects of oral environmental factors. However, this is still unknown for Actinomyces and Schaalia species. Furthermore, these bacteria are thought to degrade nitrite. Therefore, this study aimed to comprehensively elucidate the effects of environmental factors (pH, oxygen concentration, glucose, lactate, and the presence of nitrate/nitrite during growth) on nitrate and nitrite metabolism of these bacterial species using the type strains. Nitrite was quantified by Griess reagent, and final metabolites were analyzed by high-performance liquid chromatography (HPLC). The nitrite-producing activity of A. naeslundii and S. odontolytica was affected variously by environmental factors. Especially in A. naeslundii, under anaerobic conditions, the activity increased in a concentration-dependent manner with the addition of glucose or lactate and was higher at lower pH when lactate was added. The nitrite-degrading activity of both bacteria was lower than the nitrite-producing activity and was less affected by environmental factors. Metabolites from glucose by A. naeslundii were different with and without nitrate, suggesting that nitrate altered metabolic pathways. The growth was inhibited under anaerobic conditions but promoted under aerobic conditions. These results indicate that the nitrite-producing capacity of the oral microflora must take into account not only the composition and abundance of bacteria but also the variation in metabolic activity due to various environmental factors.

Awafung Emmanuel Adie

The exploration of electrospun nanofibers has gained significant attention in wound healing due to their unique structural properties and potential to enhance therapeutic efficacy. This review examines the development and application of electrospun nanofibers, focusing on their antibacterial properties and biocompatibility, which are essential for effective wound management. Electrospinning techniques enable the production of nanofibers with high surface-area-to-volume ratios, tunable porosity, and controlled release profiles of therapeutic agents, making them ideal for wound dressings. We explore various biopolymers and synthetic polymers used in electrospun nanofiber fabrication, emphasizing their contributions to antibacterial effects and biocompatibility. The incorporation of antimicrobial agents, such as silver nanoparticles and essential oils, enhances infection prevention and promotes healing. Additionally, challenges related to the scalability of electrospinning processes and the need for standardized evaluation methods are discussed. The review also highlights the influence of nanofiber architecture such as fiber diameter, alignment, and surface modifications on cellular response and tissue integration. The findings underscore the potential of electrospun nanofibers to not only serve as passive wound dressings but also actively facilitate healing through antibacterial action and favorable biological interactions. Future research should focus on optimizing fabrication techniques, enhancing functional properties, and conducting in vivo studies to fully realize the clinical potential of these materials in wound care applications. Keywords: Electrospun, nanofibers, wound healing, antibacterial and biocompatibility

Enhanced dissolution and antibacterial potential of cinacalcet hydrochloride via ternary solid dispersions

Cinacalcet hydrochloride (HCl), a calcium-sensing receptor agonist used to treat hyperparathyroidism, suffers from poor solubility, reducing its bioavailability. Recently, cinacalcet HCl has been probed for repurposing as antibacterial agent. This work investigates cinacalcet HCl’s potential as an antibacterial agent and provides a formulation to improve the drug dissolution. Solid dispersion formulations using Poloxamer 407, with and without Soluplus®, were prepared via solvent evaporation and hot melt congealing methods. The resulting formulations were analyzed using differential scanning calorimetry, FTIR spectroscopy, X-ray powder diffraction, and dissolution studies. These formulations significantly enhanced cinacalcet HCl dissolution compared to the unprocessed form, achieving up to a 15-fold increase in Q5 (percent of cinacalcet HCl dissolved after 5 min). The dissolution efficiency rose from 28% for the pure drug to 94.8 and 87.8% for formulations F6 and F7, respectively. Microbiological evaluations confirmed the antibacterial effect of cinacalcet HCl, which was notably increased in the Poloxamer 407 and Soluplus® hybrid formulation (F7) with a MIC of 64–128 µg/ml. Antibiofilm activity was also observed, with qRT-PCR indicating downregulation of biofilm genes (icaA, icaD, and fnbA). This study introduces a cinacalcet HCl formulation prepared using a scalable, green approach, demonstrating significant potential for antimicrobial applications.

Effect of antibacterial agents on dentin bonding system: A systematic review and meta-analysis.

Research on antibacterial dental adhesives has increased over the last few years. However, whether antibacterial agents improve the efficacy of dentin bonding has not yet been determined. The purpose of this systematic review and meta-analysis was to evaluate whether antibacterial agents improve the efficacy of dentin bonding at the resin-dentin interface and to identify possible mechanisms. Studies published within the last 10years up to April 2024 were searched in 5 databases: PubMed (MedLine), EMBASE, Scopus, Web of Science, and Cochrane Library. A random-effects meta-analysis model was used, and pooled effect estimates were obtained by comparing the standardized mean difference (α=.05). A total of 61 studies with 9 different types of antibacterial agent were included in the qualitative and quantitative analyses. The meta-analysis indicated that treatment with metal-based inorganic antibacterial agents improved both the immediate and long-term bond strength values (P<.05). Moreover, incorporating carbon-based substances, quaternary ammonium compounds, chlorhexidine, methacrylate derivatives, and antibiotics enhanced the long-term bond strength of the resin composites to dentin (P<.05). Subgroup analysis indicated that including metal-based inorganic antibacterial agents, quaternary ammonium compounds, and methacrylate derivatives in etch-and-rinse (ER) adhesives improved dentin bond strength (P<.05), whereas carbon-based materials in self-etching (SE) adhesives showed better bonding performance. The introduction of some antibacterial agents into the bonding system improved in vitro bond strength and inhibited bacterial growth. However, clinical trials should be conducted to verify in vivo antibacterial effects and bond strength.

Mixotrophy in Marine Microalgae to Enhance Their Bioactivity

Photosynthetic microorganisms, such as microalgae, are remarkable for their ability to harness sunlight, fix carbon dioxide, and produce a variety of bioactive compounds. These organisms are pivotal in climate mitigation strategies as they can absorb carbon dioxide while generating valuable biomolecules. Among the diverse cultivation approaches, mixotrophic growth combines light energy with both inorganic and organic carbon sources, offering a unique strategy to enhance biomass production and metabolic diversity in microalgae. Here, microalgal species such as Nannochloropsis granulata, Phaeodactylum tricornutum, and Chlorella sp. were investigated for their potential applications under different cultivation methods, including phototrophy and mixotrophy. Mixotrophic conditions significantly improved biomass production across all tested species. Among these, Phaeodactylum tricornutum, a marine diatom, emerged as a promising candidate for bioactive compound production, exhibiting higher antiproliferative activity against human melanoma cells and antibacterial effects against Staphylococcus aureus. Importantly, Chlorella sp. was also found to possess antibacterial activity against Staphylococcus aureus, broadening its potential applications. Additionally, metabolomics analysis was performed on Chlorella sp. and Phaeodactylum tricornutum to identify the compounds responsible for the observed bioactivity. This study highlights the value of mixotrophic cultivation in enhancing the productivity and bioactivity of microalgae, positioning them as versatile organisms for sustainable biotechnological applications.

Bedaquiline and linezolid regimens for multidrug-resistant tuberculosis: a systematic review and meta-analysis

Objective: Multidrug-resistant tuberculosis (MDR-TB) remains a global public health challenge, complicating treatment strategies and requiring advanced therapeutic approaches. The persistence of MDR-TB has led to a demand for regimens that are more effective in improving treatment outcomes and controlling transmission. This systematic review and meta-analysis sought to examine the efficacy of linezolid (LZD) and bedaquiline (BDQ) in MDR-TB treatment regimens, evaluating their roles in enhancing therapeutic success and informing optimized management of MDR-TB. Methods: A comprehensive search was conducted across MEDLINE (PubMed), EMBASE, the Cochrane Central Register of Controlled Trials, Scopus, and Web of Science for randomized controlled trials assessing the efficacy of LZD and BDQ in MDR-TB patients up to September 14, 2024. We analyzed treatment outcomes, reporting favorable outcomes (cured and treatment completed) and unfavorable outcomes (death, treatment failure, and loss to follow-up) with a 95% confidence interval. Results: Our analysis included 11 trials, with a total of 1,999 participants. The findings indicate that BDQ+LZD-containing regimens yield significantly higher favorable treatment outcomes (84.5%; 95% CI, 79.8%-88.2%) and lower unfavorable outcomes (15.4%; 95% CI, 11.6%-20.2%). In contrast, regimens lacking either LZD or BDQ show lower efficacy, with favorable outcomes at 66.8% (95% CI, 59.5%-73.4%) and unfavorable outcomes at 33.0% (95% CI, 25.6%-41.4%). Conclusions: MDR-TB treatment regimens including BDQ and LZD lead to significantly better patient outcomes. The combined bactericidal and protein synthesis-inhibiting effects of BDQ and LZD create a powerful therapeutic synergy. Adding pretomanid further enhances this effectiveness, highlighting its value in complex cases. Future research should focus on optimizing these regimens for safety and efficacy and explore adjunctive therapies to improve MDR-TB outcomes even further.

In vitro assessment of the synergistic effects of cefotaxime, colistin, and fosfomycin combinations against foodborne resistant Escherichia coli and Salmonella isolates.

The emergence of multidrug-resistant pathogens, particularly β-lactam, colistin, and fosfomycin-resistant Escherichia coli and Salmonella, is a significant public health concern. This study evaluated the in vitro synergistic effects of antimicrobial combinations against these resistant isolates. Ten isolates that originated from retail chicken meat, including five E. coli and five Salmonella isolates, were tested against cefotaxime (CTA), fosfomycin (FOS), and colistin (COL), both individually and in combinations. Antimicrobial susceptibility was assessed using the broth microdilution method, and synergistic interactions were evaluated using checkerboard and time-killing assays. All isolates were multidrug-resistant (MDR) and were resistant to CTA, COL, and FOS. The checkerboard assay showed varying levels of synergy: two out of five E. coli isolates exhibited synergy with FOS-COL, while one E. coli isolates out of four isolates showed synergy with CTA-COL. No E. coli isolates showed synergy with FOS-CTA. For Salmonella, two out of five isolates exhibited synergy with both FOS-CTA and FOS-COL, while three out of four isolates showed synergy with CTA-COL. The time-killing assay confirmed these results, with the FOS-COL combinations showing synergy against both E. coli and Salmonella strains. Notably, the FOS-COL combination demonstrated bactericidal effects against E. coli, and all three combinations were bactericidal against Salmonella. The study highlights the potential of antimicrobial combinations, particularly FOS-COL, in combating MDR E. coli and Salmonella. These findings support the use of combination therapy as a promising strategy to in effectively treating multi-drug-resistant foodborne infections, ensuring better medical outcomes and enhanced food safety, warranting further investigation into their mechanisms and clinical applications.

Real-time multimodal imaging of daptomycin action on the cell wall of adherent Staphylococcus aureus

ObjectivesThis study investigated the efficacy of daptomycin against adherent Staphylococcus aureus (S. aureus), a common colonizer of medical devices that leads to severe infections. For the first time, we evaluated the bactericidal effects of daptomycin on S. aureus immediately after adhesion, mimicking early-stage contamination of biomaterials. Time-kill curve assay and confocal laser scanning microscopy (CLSM) were used to analyze the process dynamics. In addition, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were employed to elucidate daptomycin-induced structural changes in the bacterial cell wall.Results descriptionDaptomycin, at clinically relevant concentrations, rapidly eradicated adherent bacteria in the exponential growth phase, demonstrating an efficiency comparable to its action against planktonic cells. Prolonged exposure to the antibiotic caused marked alterations in the bacterial cell wall, including surface roughening and perforation, as revealed by multimodal imaging. However, daptomycin effectiveness diminished as biofilm formation progressed, underscoring the need for further exploration of optimized clinical strategies.

Selective Adsorption to Pathogenic Bacteria Augments Antibacterial Activity via Adjusting the Physicochemical Property of Nanoparticles

AbstractOral antibiotics are the primary method used to treat bacterial infections in clinical practice. However, the non‐selectivity of antibiotics reduces the efficacy of treatment while also tending to damage normal flora and cause dysbiosis. Obviously, it is crucial to enhance the selectivity of antibiotics against bacteria. It is possible to modulate the physicochemical properties of orally administered nanosystems to achieve selective adsorption to bacteria, thereby achieving improving bactericidal effects. A series of nanoparticles are examined bacterial adhesion characteristics focusing on five aspects: particle size, shape, charge, surface hydrophilicity, and surface modification. Selective adsorption of nanoparticles is investigated pathogenic bacteria (S. aureus as an example), normal bacteria (E. coli as an example), and probiotic bacteria (E. faecium as an example). The results show that ≈50 nm chitosan‐modified spherical Poly(lactide‐co‐glycolide) (PLGA) nanoparticles exhibit a stronger adsorption capacity for pathogenic bacteria (Staphylococcus aureus). After loading with amoxicillin, the antibacterial nanoparticles are able to destroy pathogenic bacteria without disrupting the normal intestinal bacterial flora and reducing the typical side effects of ecological disruption caused by broad‐spectrum antibiotics. Thus, this work presents a convenient and versatile strategy for targeting bacteria to enhance the antibacterial efficacy of current antibiotics.

3D printed polycaprolactone/poly (L-lactide-co-ε-caprolactone) composite ureteral stent with biodegradable and antibacterial properties.

The clinical application of biodegradable ureteral stents holds significant potential. There is an urgent need to develop new materials for ureteral stents to address the limitations related to performance degradation and antibacterial properties observed in current designs. Here, we developed a Polycaprolactone (PCL)/Poly (L-lactide-co-ε-caprolactone) (PLCL) composite ureteral stent by 3D printing, which exhibits biodegradable and antibacterial properties. Silver nanoparticles (AgNPs) were bonded to the surface of the stent through the polymerization of dopamine (PDA) and coating with type I collagen (Col I). The ureteral stent (PP-PDA-Ag-Col) had a densely spiraled structure and higher hydrophilicity. The release behavior of silver ions from the stent was found to be slow and continuous when coated with AgNPs, which can enable long-term antibacterial effects after being implanted in vivo. Additionally, in vitro degradation experiments demonstrated that the different ratios of ureteral stents degraded slowly in artificial urine over 6 weeks without compromising functionality. The stent exhibits excellent hemocompatibility and cell compatibility. The subcutaneous implantation experiment in SD rats showed that the PP-PDA-Ag-Col stent degraded slowly in vivo and had good biocompatibility. The stent PCL5/PLCL5 was the most promising ureteral stent regarding antibacterial, mechanical properties, and degradation. The novel 3D-printed PP-PDA-Ag-Col stent exhibits biocompatibility for safe in vivo transplantation and antibacterial properties that reduce reliance on antibiotics. Additionally, its biodegradability eliminates the need for secondary surgical removal, making it a promising option for the clinical application of ureteral stents.

Identification of Pseudomonas protegens and Bacillus subtilis Antimicrobials for Mitigation of Fuel Biocontamination

Hydrocarbon fuel biofouling and biocorrosion require expensive cleanup of aviation infrastructures unless appropriate sustainment measures are applied. The identification of novel biological control agents offers promising alternatives to the current chemical biocides used in fuel sustainment. In this study, 496 microbial fuel isolates from our in-house repository were screened to identify new endogenously produced antimicrobial compounds. Using agar plug screening, liquid culture growth testing, and Jet A fuel culture assays, the two fuel-isolate strains Pseudomonas protegens #133, and Bacillus subtilis #232 demonstrated promising biocontrol activity against bacteria, yeast, and filamentous fungi. Liquid chromatography-quadrupole time of flight tandem mass spectrometry (LC-QTOF-MS/MS) of #232 culture filtrate identified several common lipopeptide antimicrobials including gageostatin C, gageopeptin B, and miscellaneous macrolactins. In contrast, LC-QTOF-MS/MS identified the siderophore pyochelin as one of the predominant compounds in #133 culture filtrate with previously demonstrated antimicrobial effect. Jet fuel microbial consortium culture testing of #133 culture filtrate including flow-cytometry live/dead cell mechanism determination demonstrated antimicrobial action against Gram-positive bacteria. The study concludes that antimicrobial compounds secreted by #133 have bactericidal effects against Gordonia sp. and cause cell death through bacterial lysis and membrane damage with potential applications in the biocidal treatment of hydrocarbon-based aviation fuels.

Antimicrobial Blue Light Reduces Human-Wound Pathogens’ Resistance to Tetracycline-Class Antibiotics in Biofilms

Biofilms contribute to chronic infections and the development of antimicrobial resistance (AMR). We are developing an antimicrobial blue light (aBL) device to reduce bacterial bioburden in wounds and decrease reliance on systemic antibiotics. aBL induces the generation of reactive oxygen species (ROS) through photoexcitation of endogenous chromophores, causing bacterial damage and death. This study explores the combination of tetracyclines (TCs) with aBL for the treatment of biofilm infections in vitro. Tetracyclines (TCs), including second-generation minocycline (MC), doxycycline (DOCT), and third-generation agents omadacycline (OM) and tigecycline (TG), were evaluated for their ability to enhance bactericidal effects and ROS production during aBL treatment of abiotic biofilm. TCs were tested under dark conditions and with varying aBL light parameters against biofilms of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (PA), and Escherichia coli (E. coli). Results showed that TCs alone were ineffective against these biofilm cultures. However, when combined with aBL either before or after TC treatment, significant enhancement of microbicidal activity was observed. When the aBL is added before the TCs, there was equivalent bactericidal effect, indicating that TCs primary action against biofilms were not as photosensitizers. These findings suggest that aBL can significantly enhance the antimicrobial activity of TCs, potentially offering a new effective approach to treating biofilm-associated infections and combating AMR when aBL is applicable.