Antimicrobial Research Articles

Ultrasound Treatment Combined with Rhamnolipids for Eliminating the Biofilm of Bacillus cereus

Biofilm formation by Bacillus cereus is a major cause of secondary food contamination, leading to significant economic losses. While rhamnolipids (RLs) have shown effectiveness against Bacillus cereus, their ability to remove biofilms is limited when used alone. Ultrasound (US) is a non-thermal sterilization technique that has been found to enhance the delivery of antimicrobial agents, but it is not highly effective on its own. In this study, we explored the synergistic effects of combining RLs with US for biofilm removal. The minimum biofilm inhibitory concentration (MBIC) of RLs was determined to be 32.0 mg/L. Using a concentration of 256.0 mg/L, RLs alone achieved a biofilm removal rate of 63.18%. However, when 32.0 mg/L RLs were combined with 20 min of US treatment, the removal rate increased to 62.54%. The highest biofilm removal rate of 78.67% was observed with 256.0 mg/L RLs and 60 min of US exposure. Scanning electron microscopy analysis showed that this combined treatment significantly disrupted the biofilm structure, causing bacterial deformation and the removal of extracellular polymeric substances. This synergistic approach not only inhibited bacterial metabolic activity, aggregation, and adhesion but also reduced early biofilm formation and decreased levels of extracellular polysaccharides and proteins. Furthermore, US treatment improved biofilm permeability, allowing better penetration of RLs and interaction with bacterial DNA, ultimately inhibiting DNA synthesis and secretion. The combination of RLs and US demonstrated superior biofilm removal efficacy, reduced the necessary concentration of RLs, and offers a promising strategy for controlling biofilm formation in the food industry.

Trends in Bacterial Distribution and Antimicrobial Resistance in Intensive Care Units of Hubei Province, China: A Four-year Surveillance Study (2020-2023).

To investigate the distribution characteristics of common bacteria and changes in antimicrobial resistance in intensive care unit (ICU) patients in 58 hospitals in Hubei Province from 2020-2023. The antimicrobial agents for antimicrobial susceptibility tests was selected based on the 2022 China Antimicrobial Resistance surveillance system (CARSS) technical scheme, and the specific experimental operation was based on the requirements of the CLSI M02 and M07 documents. The commercial instruments were used following the manufacturer's instructions. The interpretation of antimicrobial susceptibility test results was based on the 2023 CLSI M100 standard. There were 15 585, 19 258, 23 423 and 22 395 clinical isolates in the ICU from 2020 to 2023, respectively. Among them, gram-positive bacteria accounted for 20.5% (3190/15 585), 21.2% (4089/19 258), 21.6% (5067/23 423) and 21.6% (4 831/22 395), respectively. Gram-negative bacteria accounted for 79.5% (12 395/15 585), 78.8% (15 169/19 258), 78.4% (18 356/23 423) and 78.4% (17 564/22 395) of the bacteria, respectively. The top 5 isolates of gram-positive bacteria were Staphylococcus aureus, Enterococcus faecium, Streptococcus pneumoniae, Enterococcus faecalis, Staphylococcus epidermidis and gram-negative bacteria were Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa and Stenotrophomonas maltophil, respectively, but the proportions and rankings of the isolates in different years slightly differed. The detection rate of methicillin-resistant S. aureus (MRSA) decreased from 44.4% in 2020 to 36% in 2023, and that of methicillin-resistant coagulase-negative Staphylococcus (MRCNS) decreased from 79.8% in 2020 to 73.8% in 2022 and increased to 78.4% in 2023. The detection rates of both vancomycin-resistant E. faecium and E. faecalis were lower than 1%. The detection rate of carbapenem-resistant P. aeruginosa (CRPA) decreased from 25% in 2020 to 19.7% in 2022 and increased slightly to 20.6% in 2023. The detection rate of carbapenem-resistant A. baumannii (CRAB) decreased from 81.9% in 2020 to 79.7% in 2022 and increased to 82.9% in 2023. The detection rate of third-generation cephalosporin-resistant E. coli decreased from 59.8% in 2020 to 53.1% in 2022 and increased to 52.5% in 2023. The detection rate of fluoroquinolone-resistant E. coli decreased from 62.7% in 2020 to 50.2% in 2022 and increased slightly to 51.0% in 2023. The detection rate of carbapenem-resistant E. coli (CRECO) decreased from 3.3% in 2020 to 1.8% in 2022 and slightly increased to 2.1% in 2023. The detection rate of third-generation cephalosporin-resistant K. pneumoniae decreased from 34.3% in 2020 to 26.3% in 2022 and then increased to 32.4% in 2023. The detection rate of carbapenem-resistant K. pneumoniae (CRKPN) increased from 17.9% to 19.4% in 2020, decreased to 13.2% in 2022, and rose sharply to 20.4% in 2023. MRSA showed a continuous downwards trend from 2020 to 2023, while the detection rates of MRCNS and most multidrug-resistant gram-negative bacteria continuously decreased from 2020 to 2022 but tended to increase in 2023. Therefore, it is still necessary to strengthen the monitoring of bacterial resistance and rational application of antibiotics and actively and effectively control nosocomial infections.

Characterization of a Putative Lysin from Enterococcus faecalis Phage IME-EFm1 and Determination of its Protective Efficacy in Mice.

The rising tide of bacterial drug resistance has sparked renewed interest in bacteriophages, the natural predators of bacteria. Our study highlights IME-EFm1, a Caudoviricetes bacteriophage specifically targeting Enterococcus faecium. Through our investigations, we identified that the gene IME-EFm1-ORF24 encodes an amidase, referred to as gp24, with promising lytic capabilities. Remarkably, gp24 exhibited a wider lytic spectrum than its parent phage, successfully lysing 26 out of 32 E. faecium strains, compared to the phage's ability to lyse only 21. This protein demonstrated robust antibacterial activity, remaining effective at temperatures between 25°C and 60°C and across a pH range of 6 to 12. Additionally, gp24 displayed significant anti-biofilm properties, effectively dismantling established biofilms in vitro. In a mouse model of abdominal infection, gp24 achieved a 75% protection rate against a dose of 2 × 109 colony-forming units of E. faecium En383, significantly outperforming the control group (p < 0.05). These compelling results suggest that gp24 holds great potential as a novel antimicrobial agent for treating E. faecium infections.

Antimicrobial Susceptibility Patterns and Antimicrobial Therapy of Infections Caused by Elizabethkingia Species

Background and Objectives: Elizabethkingia species have become significant sources of infections acquired in hospital settings and are commonly linked to high mortality rates. Antimicrobial resistance can be influenced by Elizabethkingia species, geographical location, antimicrobial susceptibility testing methods, and the time of bacterial isolation. There are distinct antimicrobial susceptibility patterns among species, and the investigation into potential antibiotic susceptibility variations among species is beneficial. There is no guidance on the treatment of Elizabethkingia species infections in the literature. Consequently, the purpose of this review was to elaborate on the antimicrobial susceptibility patterns of Elizabethkingia species through a scoping review of existing studies on the antibiograms of the Elizabethkingia species and on the illness caused by Elizabethkingia species. Materials and Methods: A comprehensive literature search in PubMed and Web of Science between 1 January 2000 and 30 April 2024 identified all studies, including those that examined antimicrobial susceptibility patterns and antimicrobial therapy of infections caused by Elizabethkingia species. I considered studies on antimicrobial susceptibility testing for Elizabethkingia species in which only broth microdilution methods and agar dilution methods were used. Results: The sensitivity levels of Elizabethkingia meningoseptica to piperacillin–tazobactam (5–100%), ciprofloxacin (0–43.4%), levofloxacin (30–81.8%), trimethoprim–sulfamethoxazole (0–100%), tigecycline (15–100%), minocycline (60–100%), and rifampicin (94–100%) varied. The sensitivity levels of Elizabethkingia anophelis to piperacillin–tazobactam (3.3–93.3%), ciprofloxacin (1–75%), levofloxacin (12–100%), trimethoprim–sulfamethoxazole (1.02–96.7%), tigecycline (0–52.2%), minocycline (97.5–100%), and rifampicin (20.5–96%) varied. The sensitivity levels of Elizabethkingia miricola to piperacillin–tazobactam (41.6–94.0%), ciprofloxacin (14–75%), levofloxacin (77.0–100%), trimethoprim–sulfamethoxazole (18.0–100%), tigecycline (50%), minocycline (100%), and rifampicin (66–85.7%) varied. Conclusions: The majority of the isolates of Elizabethkingia species were susceptible to minocycline and rifampin. This issue requires professional knowledge integration and treatment recommendations.

Efficacy of Plant Extract-Based Solutions Compared to Chlorhexidine and Miconazole Shampoo for the Treatment of Superficial Pyoderma in Dogs.

Canine superficial pyoderma (CSP) is common. Antibiotic and potential antiseptic resistance is a rising concern; natural topicals may provide valuable alternative options. Compare natural topicals containing essential oils, plant-extracted essential fatty acids and N-acetylcysteine to a medicated shampoo with chlorhexidine, miconazole and micronized silver in treating CSP. Thirty dogs diagnosed with CSP, divided into three groups as outlined below. Group 1 bathed using a shampoo (PYOclean Shampoo) twice weekly and application of a rinse-free mousse (PYOclean Mousse) once daily, Group 2 bathed using the same shampoo as above twice weekly and application of a spray (PYOclean Spray) once daily, and Group 3 bathed using a medicated shampoo (Biohex Shampoo) twice weekly. Cytology, lesion and pruritus visual analogue (PVAS) scores were evaluated on Days (D) 0, 7 and 15. All three groups showed decreased polymorphonuclear cells (PMN) on D15. The reduction was significant, and more significant in Groups 1 and 2 (90.48% and 98.93%) compared to Group 3 (85.96%); extracellular cocci (cocci EC) significantly decreased by 92.8% and 93.38% in Groups 1 and 2, whereas decreased by 81% in Group 3 on D15. The number of yeasts on D15 decreased by 90% in Group 3 and 82% and 92%, respectively, in Groups 1 and 2. Lesion scores decreased on D15 by 90.61% and 87.95% in Groups 1 and 2 and by 62.94% in Group 3. PVAS decreased on D15 by 95.78% and 96.75%, respectively, in Groups 1 and 2 and by 69.88% in Group 3. Efficacy of three natural topicals in treating dogs with superficial pyoderma without adding any systemic antimicrobial drugs was demonstrated. Such solutions can be complementary to medications such as chlorhexidine and miconazole in addressing CSP.

Integron-Mediated Antimicrobial Resistance and Virulence Factors in Salmonella Typhimurium Isolated from Poultry

This study investigates antimicrobial-resistant (AMR) Salmonella Typhimurium in poultry, focusing on how class I integrons contribute to AMR and virulence. Using whole genome sequencing, researchers analyzed 26 S. Typhimurium isolates from U.S. poultry, finding that three isolates contained integrons (1000 base pairs each). These integron-positive isolates exhibited significantly higher resistance to beta-lactams, phenicols, and tetracyclines compared to integron-free isolates (p = 0.004, 0.009, and 0.02, respectively) and harbored genes like ges, imp, and oxa, which are linked to extended-spectrum beta-lactamase resistance. Most AMR gene classes (64%) were chromosome-based, with integron-positive isolates showing a broader array of resistance genes, including catB and tetA. Integron-bearing isolates had higher occurrences of bacteriocin genes and specific AMR genes like aminoglycoside and beta-lactam resistance genes, while integron-free isolates had more fimbrial and pilus genes. The presence of integrons may trend with increased AMR genes and virulence factors, highlighting the role of integron screening in enhancing AMR surveillance and reducing the need for high-priority antimicrobial treatments in poultry. These findings could support better AMR stewardship practices in poultry production, potentially lowering infection risks in humans and livestock.

Preparation and properties of calcium oxide and calcium peroxide from eggshell waste for enhanced antimicrobial activity

Calcium peroxide (CaO2), which releases hydrogen peroxide (H2O2) upon contact with water, has garnered attention as a potential alternative to liquid H2O2. Researchers have explored various methods to enhance the production of CaO2 with reduced environmental impact. This study focuses on the preparation of two potent antimicrobial agents, calcined calcium oxide (C-CaO) and synthesized calcium peroxide (S-CaO2) from eggshell waste. These agents were then incorporated into ethylene vinyl alcohol (EVOH) composite films for antimicrobial packaging. The synthesized CaO and CaO2 were analyzed using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA) and Scanning electron microscopy (SEM). The results confirmed the successful synthesis of high-purity CaO and CaO2 from eggshell waste. Compared to CaO (a well-known antimicrobial agent), CaO2 exhibited approximately 1.6 to 2 times higher antimicrobial activity, which is attributed to its release of H2O2. EVOH films containing 3% of CaO2 demonstrated significant microbial growth deactivation, reaching 99.99% and 97.24% for gram-negative and gram-positive bacteria, while EVOH films containing 3% of CaO exhibited relatively low deactivation ability of 79.01% and 48.82, respectively. This study underscores the potential of eggshell waste as a valuable resource for producing high-value materials. Moreover, CaO2 emerges as an effective antimicrobial agent, particularly in antimicrobial packaging applications, showcasing its versatility across various sectors.

Preliminary characterization in antimicrobial stability, phytochemical and toxicity profiling of Sauropus androgynus L. (Sweet leaf vegetable) extract: Evaluate the potential of new antimicrobial agent

Preliminary characterization in antimicrobial stability, phytochemical and toxicity profiling of Sauropus androgynus L. (Sweet leaf vegetable) extract: Evaluate the potential of new antimicrobial agent

An explainable few-shot learning model for the directed evolution of antimicrobial peptides

Due to the persistent threat of antibiotic resistance posed by Gram-negative pathogens, the discovery of new antimicrobial agents is of critical importance. In this study, we employed deep learning-guided directed evolution to explore the chemical space of antimicrobial peptides (AMPs), which present promising alternatives to traditional small-molecule antibiotics. Utilizing a fine-tuned protein language model tailored for small dataset learning, we achieved structural modifications of the lipopolysaccharide-binding domain (LBD) derived from Marsupenaeus japonicus, a prawn species of considerable value in aquaculture and commercial fisheries. The engineered LBDs demonstrated exceptional activity against a range of Gram-negative pathogens. Drawing inspiration from evolutionary principles, we elucidated the bactericidal mechanism through molecular dynamics simulations and mapped the directed evolution pathways using a ladderpath framework. This work highlights the efficacy of explainable few-shot learning in the rational design of AMPs through directed evolution.

Underutilized edible Himalayan herb, Viola canescens Wall.; chemical composition, antioxidant and antimicrobial activity against respiratory tract pathogens

Understanding the intricacies of herbs and foods against bacterial infections is paramount for informed therapeutic choices. Delving into this domain, current study was focused to assess antimicrobial properties of Viola canescens organ specific extracts against prevalent respiratory tract pathogens (Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pneumonia). Our methodology entailed proximate composition, TPC, TFC, Total condensed tannins and comprehensive chemical profiling by GC-MS, UPLC-PDA, and UPLC-MS/MS. Further, in-vitro, antioxidant potential through ABTS ֹ+ and DPPH ֹ radical scavenging assays was assessed. The root showed higher amount of proximate composition than its counterparts. Further, ethanol extract showed highest TPC (32.15±0.92mg GAE/g), TFC (125.61±2.28mg RE/g), and comparable TCT with methanol extract (34±0.19mg CE/g). UPLC analysis showed that p-coumaric acid was most predominant followed by rutin and luteolin among the V. canescens parts. In GC/MS analysis, methyl linoleate emerged as a major component as 10.70%, 17.62%, and 35.90% in flowers, leaves, and roots, respectively. Further, UHPLC- MS/MS data-based METLIN search revealed the presence of flavonoids, coumarins, terpenoids, and fatty acid derivatives etc. Chemo-metric analysis also showed variations of metabolites in different parts. All samples showed significant antioxidant activity with highest in methanol and ethanol flower extracts (0.037±0.001, 0.071±0.001 DPPHֹ and ABTS ֹ + IC50 mg/mL). The study suggested aerial parts can be a promising source of antioxidant and antimicrobial agents that may protect against respiratory tract pathogens similar to azithromycin. This substantiates the potential of V. canescens as a foundational ingredient for novel therapeutics.

Evaluation of smart bi-functional dressing based on polysaccharide hydrogels and Brassica oleracea extract for wound healing and continuous monitoring

Skin wounds can drive global impacts, socially and economically, in parallel with their elevated incidence rate. Therefore, utilizing the dual-activity of Brassica Oleracea (Red Cabbage) extract, of being pH-sensitive and biologically active in designing novel, therapeutic, and pH-sensitive wound dressings with an easily stripped-off feature, is critical. Wound dressings were designed using two separate hydrogels based on chitosan (CS) and hydroxyethylcellulose (HEC), each loaded with RCE. The pH sensitivity of prepared bandages exhibited a noticeable visual change in color during wound treatment. Wound closure has reached 99.69 % for CS/RCE dressings. Results showed that RCE had raised the hydroxyproline and collagen content in the healed skin. Histopathological investigation proves that skin returned to its regular thickness within 10 days of treatment. RCE showed marked improvement in the healing quality by acting as an antioxidant, anti-inflammatory, and antimicrobial agent. Therefore, dual-function dressings are potential candidates to sense and cure skin wounds.

Smart chitosan-based nanofibers for real-time monitoring and promotion of wound healing

Timely healing of acute wounds and stopping wound chronicity are current and future priorities in wound therapy. It is urgent and relevant to develop a wound dressing that has antimicrobial and monitors the wound microenvironment in real time. In this study, quaternary ammonium chitosan (HTCC) was selected as the antimicrobial agent and CS/PEO/HTCC nanofiber membranes (CPHs) were prepared by electrostatic spinning technique. The nanofiber membrane (CPH91) with the best antimicrobial performance was screened by the disk diffusion method and drug susceptibility testing by dilution method, and its antimicrobial effect on S. aureus was better than that of E. coli. Subsequently, functional carbon dots (CDs) were synthesized by solvothermal method and doped into CPH91 nanofibers by electrospinning. A good linear relationship between pH value (5.0–8.0) and the fluorescence intensity of CDs was observed. In addition, the nanofibers (CPH91@CDs) had good morphology, hydrophilicity, and biocompatibility. Changes in fluorescence intensity of CPH91@CDs at different pH (5.0–8.0) were monitored and converted into RGB values that were linearly fitted to pH value. Finally, the potential of CPH91@CDs of improving wound healing and instantaneously controlling wound healing process was confirmed by an infected wound model (S. aureus) on the back of SD rats.

Combating multidrug-resistant (MDR) Staphylococcus aureus infection using terpene and its derivative.

Multidrug-resistant (MDR) Staphylococcus aureus represents a major global health issue resulting in a wide range of debilitating infections and fatalities. The slow progression of new antibiotics, limited choices for treatment, and scarcity of new drug approvals create immense obstacles in new drug line development. S. aureus poses a significant public health risk, due to the emergence of methicillin-resistant (MRSA) and vancomycin-resistant strains (VRSA), necessitating novel antibiotics for effective control management. Current studies are delving into the terpenes' potential as an antimicrobial agent, indicating positive prospects as promising substitutes or complementary to conventional antibiotics. Concurrent reactions of terpenes with conventional antibiotics create synergistic effects that significantly enhance antibiotic efficacy. Accumulated evidence has shown that while efflux pump (e.g., NorA, TetK, and MepA) is revealed as an essential defense of S. aureus against antibiotics, terpene and its derivative act as its potent inhibitor, suggesting the promising potential of terpenes in combating those infectious pathogens. Furthermore, pronounced cell membrane disruptive activity and antibiofilm properties by terpenes have been exerted, signifying their significance as promising prevention against microbial pathogenesis and antimicrobial resistance. This review provides an overview of the potential of terpenes and their derivatives in combating S. aureus infections, highlighting their potential mechanisms of action (MOA), synergistic effects with conventional antibiotics, and challenges in clinical translation. The unique properties of terpenes offer an opportunity for their use in developing an exceptional defense strategy against antibiotic-resistant S. aureus.

Implementation of Silver Nanoparticles Green Synthesized with Leaf Extract of Coccinia grandis as Antimicrobial Agents Against Head and Neck Infection MDR Pathogens.

Head and neck infections (HNI) associated with multidrug resistance (MDR) offer several health issues on a global scale due to inaccurate diagnosis. This study aimed to identify the bacteria and Candidal isolates and implement the silver nanoparticles green synthesized with leaf extract of Coccinia grandis (Cg-AgNPs) as a therapeutic approach against HNI pathogens. The Cg-AgNPs were characterized by the UV-visible spectrophotometer, FT-IR analysis, Zeta particle size, Zeta potential, and field emission scanning electron microscope (FESEM) analysis to validate the synthesis of nanoparticles. Additionally, the antimicrobial activity of Cg-AgNPs was presented by the zone of inhibition (ZOI), minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC), and antibiofilm assay. Moreover, the cell wall rupture assay was visualized on SEM for the morphological study of antimicrobial activities, and the in-vivo toxicity was performed in a swiss mice model to evaluate the impact of Cg-AgNPs on various biological parameters. Different bacterial strains (Staphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa) and Candida sp. (Candida albicans, Candida tropicalis, Candida orthopsilosis, and Candida glabrata) were identified. The MIC, MBC, and antibiofilm potential of Cg-AgNPs were found to be highest against A. baumannii: 1.25 μg/ml, 5 μg/ml, and 85.01±5.19% respectively. However, C. albicans and C. orthopsilosis revealed 23 mm and 21 mm of ZOI. Subsequently, the micromorphology of the cell wall rupture assay confirmed the efficacy of Cg-AgNPs, and no significant alterations were seen in biochemical and hematological parameters on the swiss mice model in both acute and subacute toxicity studies. The green synthesized Cg-AgNPs have multifunctional activities like antibacterial, anticandidal, and antibiofilm activity with no toxicity and can be introduced against the HNI pathogens.

Combined action of two synthetic ultrashort antimicrobial peptides exhibiting synergistic effects against clinically significant resistant bacteria

Background and Aim: The emergence and proliferation of multidrug-resistant bacteria pose a global health crisis. This issue arises from the overuse and misuse of antibiotics, coupled with the pharmaceutical industry’s limited development of new drugs, which is constrained by financial disincentives and regulatory hurdles. This study aimed to investigate the combined antibacterial efficacy and safety profile of the combined ultrashort antimicrobial peptides (AMPs) WW-185 and WOW against antibiotic-resistant bacterial strains. Materials and Methods: The WW-185 and WOW peptides were synthesized through solid-phase methods and purified using reverse-phase high-performance liquid chromatography, and their purity was confirmed by mass spectrometry. Antibacterial activity was evaluated using broth dilution and checkerboard assays to assess both individual and combined effects of the peptides against Staphylococcus aureus (including methicillin-resistant Staphylococcus aureus [MRSA]) and Escherichia coli (including extended-spectrum beta-lactamases [ESBL]-producing strains). The synergy between the peptides was quantified using fractional inhibitory concentration indices. Hemolytic activity was also assessed to determine cytotoxicity toward red blood cells. Results: The combination of WW-185 and WOW exerted synergistic effects against both MRSA and ESBL-producing E. coli, with reduced minimal inhibitory concentrations compared with the individual treatments. The peptides exhibited minimal hemolytic activity, indicating low toxicity. Conclusion: The combination of the ultrashort AMPs WW-185 and WOW shows promising synergistic antibacterial effects against resistant bacteria, with potential for further therapeutic development due to their enhanced efficacy and low toxicity. Keywords: antimicrobial agents, bacterial infections, multidrug resistance, synergistic effects, ultra-short peptides.

Green-Synthesis of CuO and Ce-Doped CuO Nanoparticles Using Aqueous Extract of Yam Peel and their Antimicrobial Properties

The rise of drug-resistant microbes presents a critical global health challenge in the 21st century, necessitating the development of potent antimicrobial agents with broad-spectrum activity. Therefore, in this study, we explored the antimicrobial activity of copper oxide (CuO) and cerium-doped CuO (Ce-doped CuO) obtained through a facile green synthesis approach. The nanoparticles were synthesized using aqueous extract of Dioscorea spp (yam peel) and characterized for their physicochemical properties using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), electron microscopy, and UV-Vis spectroscopy. Their antimicrobial efficacy was tested against three bacterial strains—Enterococcus faecalis, Escherichia coli, and Listeria monocytogenes—and three fungal strains—Aspergillus niger, Mucor mucedo, and Penicillium chrysogenum. The results demonstrated that cerium doping significantly altered the physicochemical properties of CuO, leading to enhanced antimicrobial activity. The antibacterial zone of inhibition ranged from 7.50 to 16.55 mm for CuO and 11.80 to 19.50 mm for Ce-doped CuO. For antifungal activity, the minimum inhibitory concentration (MIC) ranged from 0.25 to 0.30 mg/mL for CuO and 0.025 to 0.03 mg/mL for Ce-doped CuO. Notably, the Ce-doped CuO nanoparticles exhibited antimicrobial effects comparable to standard antibiotics. These findings highlight the potential of green-synthesized Ce-doped CuO nanoparticles as effective antimicrobial agents. By leveraging green synthesis and elemental doping, this study offers a promising solution to combat a wide spectrum of infectious pathogens.

Caught Between Stewardship and Resistance: How to Treat Acute Complicated Diverticulitis in Areas of Low Antimicrobial Susceptibility?

Antimicrobial resistance is one of the main threats to public health, with multidrug-resistant (MDR) pathogens on the rise across continents. Although treatment guidelines generally recommend antimicrobial therapy for acute complicated diverticulitis, they do not specify treatment pathways according to local or national resistance profiles. There is sparse data regarding specific pathogens involved in Hinchey II–IV patients who undergo surgery. This study seeks to address these issues and determine how often and what types of MDR bacteria occur in patients undergoing emergency surgery. We prospectively enrolled patients admitted between 2020–2023 and who underwent emergency surgery for complicated acute diverticulitis. We analysed the inflammatory response parameters at admission, the type of surgery employed for source control, identified pathogens in the peritoneal samples, their antimicrobial susceptibility, the efficacy of antimicrobial empiric therapy, and mortality. Gram-negative bacteria were identified most often, with Escherichia coli being mostly MDR (43.9%) or extended-spectrum beta-lactamase producing (ESBL +ve) (24.4%), while most strains of Klebsiella pneumoniae were extended-spectrum beta-lactamase positive (ESBL +ve) (80%) and MDR (80%). Of the Enterococcus spp., 57.14% were vancomycin-resistant (VRE) strains. Patients with Hinchey III/IV were significantly more associated with MDR. Patients with multiple pathogens were significantly associated with ESBL+/VRE strains. Age, leucocytosis, and procalcitonin levels at admission were good indicators for mortality prediction, which occurred in four cases. In an age when antibiotic stewardship is advisable especially in emergency settings, the treatment should be tailored according to local profiles of MDR to ensure adequate outcomes for patients.

Investigations on Photodegradation and Antibacterial Activity of Mixed Oxide Nanocrystalline Materials

In this study, we synthesized cobalt-doped molybdenum supported on silica (Co/MS) nanocomposites with varying concentrations of cobalt (1, 5, 10, 15, and 20 wt%) using the sol-gel method. We investigated their physico-chemical properties, photocatalytic activity, and antimicrobial efficacy. The synthesized nanocomposites were characterized using a range of techniques, including X-ray powder diffraction (XRD) to determine crystal structure, UV-vis spectroscopy for optical properties, Fourier transform infrared spectroscopy (FT-IR) for functional group analysis, and scanning electron microscopy coupled with energy-dispersive X-ray microanalysis (SEM-EDX) for morphological and elemental composition analysis. The photocatalytic performance of these catalysts was assessed by their ability to degrade organic dyes, specifically methyl orange and methylene blue, under visible light irradiation. Our results demonstrated that the photocatalytic efficiency increased with higher cobalt content, with the 20 wt% Co/MS nanocomposite showing the highest degradation rates. Additionally, we evaluated the antibacterial activity of the nanocomposites against a range of microorganisms, including Gram-positive and Gram-negative bacteria, as well as fungal species. The 20 wt% Co/MS nanocomposite exhibited superior antimicrobial activity compared to the other samples, indicating its potential for applications in environmental remediation and antimicrobial treatments.

Single-step purification and characterization of Pseudomonas aeruginosa azurin.

Azurin is a small periplasmic blue copper protein found in bacterial strains such as Pseudomonas and Alcaligenes where it facilitates denitrification. Azurin is extensively studied for its ability to mediate electron-transfer processes, but it has also sparked interest of the pharmaceutical community as a potential antimicrobial or anticancer agent. Here we offer a novel approach for expression and single-step purification of azurin in Escherichia coli with high yields and optimal metalation. A fusion tag strategy using an N-terminal GST tag was employed to obtain pure protein without requiring any additional purification steps. After the on-column cleavage by HRV 3C Protease, azurin is collected and additionally incubated with copper sulphate to ensure sufficient metalation. UV-VIS absorption, mass spectroscopy, and circular dichroism analysis all validated the effective production of azurin, appropriate protein folding and the development of an active site with an associated cofactor. MD simulations verified that incorporation of the N-terminal GPLGS segment does not affect azurin structure. In addition, the biological activity of azurin was tested in HeLa cells.

Repurposing of monocyclic β-lactams as anti-inflammatory agents – The case of new ferrocene-azetidin-2-one hybrids

There is growing interest in developing monotherapy drugs that treat inflammation caused by microbial infections, focusing on dual antimicrobial and anti-inflammatory agents with minimal side effects and high safety margins. This study synthesized and characterized a library of novel cis-4-ferrocenylazetidin-2-ones, evaluating their antimicrobial and anti-inflammatory activities. These organometallic monocyclic β-lactams showed moderate in vitro antimicrobial activity against various standard microbial strains, including yeasts and Gram-negative and Gram-positive bacteria. Some compounds overcame the resistance of clinical Staphylococcus aureus isolates. Traditionally, monocyclic β-lactams target Gram-negative bacilli, but adding a ferrocene moiety and substituting the COOH group near the N-1 position with a non-ionizable ester group (COOR) extended their activity spectrum. The anti-inflammatory properties were assessed in macrophage-based models, revealing non-cytotoxicity below 10 μM. Two compounds were shown to be strong and selective arginase inhibitors, while five others effectively suppressed excessive NO formation without affecting basal NO production. The presence of a phenoxy group at C-3 of the β-lactam ring appeared to be crucial for selective NO inhibition. These hybrids did not scavenge NO but inhibited NO synthesis by suppressing iNOS expression. Overall, two novel hybrids were identified as promising hit candidates for treating infection-induced inflammatory reactions.