Antimicrobial Resistance

Aspartic acid unveils as antibiofilm agent and tobramycin adjuvant against mucoid and small colony variants of Pseudomonas aeruginosa isolates in vitro within cystic fibrosis airway mucus

Antibiotics are central to managing airway infections in cystic fibrosis (CF), yet current treatments often fail due to the presence of Pseudomonas aeruginosa biofilms, settling down the need for seeking therapies targeting biofilms. This study aimed to investigate the antibiofilm activity of aspartic acid and its potential as an adjuvant to tobramycin against P. aeruginosa biofilms formed by mucoid and small colony variant (SCV) tobramycin tolerant strain. We assessed the effect of aspartic acid on both surface-attached and suspended P. aeruginosa biofilms within CF artificial mucus and investigated the synergistic impact of combining it with non-lethal tobramycin concentrations. Our findings showed that aspartic acid inhibited planktonic P. aeruginosa without affecting its viability and prevented biofilm formation by hindering bacterial adhesion or interfering with EPS production, depending on the experimental conditions. In CF mucus, aspartic acid significantly reduced bacterial growth, with the highest inhibition observed when combined with tobramycin, showing notable effects against the mucoid and tolerant SCV strain. Despite these reductions, P. aeruginosa repopulated the mucus within 24 h of stress withdrawal. Additional strategies, including delayed tobramycin application and a second dose of co-application of aspartic acid and tobramycin were explored to address bacterial survival and recovery. Although none of the strategies eradicated P. aeruginosa, the second co-application resulted in slower bacterial recovery rates. In conclusion, this study highlighted aspartic acid as an effective antibiofilm agent and demonstrated for the first time its potential as an adjuvant to tobramycin. The combined use of aspartic acid and tobramycin offers a promising advancement in CF therapeutics, particularly against P. aeruginosa biofilms formed by mucoid and SCV strains, mitigating their antibiotic resistance.

Effect of subinhibitory concentrations on the spreading of the ampicillin resistance gene blaCMY-2 in an activated sludge microcosm

As the problem of multi-resistant bacteria grows a better understanding of the spread of antibiotic resistance genes is of utmost importance for society. Wastewater treatment plants contain subinhibitory concentrations of antibiotics and are thought to be hotspots for antibiotic resistance gene propagation. Here we evaluate the influence of sub-minimum inhibitory concentrations of antibiotics on the spread of resistance genes within the bacterial community in activated sludge laboratory-scale sequencing batch reactors. The mixed communities were fed two different ampicillin concentrations (500 and 5000 µg/L) and the reactors were run and monitored for 30 days. During the experiment the β-lactamase resistance gene blaCMY-2 was monitored via qPCR and DNA samples were taken to monitor the effect of ampicillin on the microbial community. The relative copy number of blaCMY-2 in the reactor fed with the sub-minimum inhibitory concentration of 500 µg/L ampicillin was spread out over a wider range of values than the control and 5000 µg/L ampicillin reactors indicating more variability of gene number in the 500 µg/L reactor. This result emphasises the problem of sub-minimum inhibitory concentrations of antibiotics in wastewater. High-throughput sequencing showed that continuous exposure to ampicillin caused a shift from a Bacteroidetes to Proteobacteria in the bacterial community. The combined use of qPCR and high-throughput sequencing showed that ampicillin stimulates the spread of resistance genes and leads to the propagation of microbial populations which are resistant to it.

Innovations in Snake Venom-Derived Therapeutics: A Systematic Review of Global Patents and Their Pharmacological Applications

Active compounds from natural sources, particularly snake venoms, are crucial for pharmaceutical development despite challenges in drug discovery. Snake venoms, historically used for medicinal purposes, contain bioactive peptides and enzymes that show therapeutic potential for conditions such as arthritis, asthma, cancer, chronic pain, infections and cardiovascular diseases. The objective of this study was to examine pharmacological and biomedical innovations by identifying the key research trends, the most studied snake species, and their therapeutic applications. A systematic review of patents related to snake venoms was conducted using the European Patent Office database, Espacenet, covering 2014 to mid-2024. The search employed the keyword "venom," applying IPC classification A61K38/00, resulting in 31 patents after screening. A PubMed survey on "snake venom derivatives innovations" was conducted to compare the scientific literature volume with the identified patents. This review highlights the therapeutic potential of snake venom-derived products for coagulation disorders, cancer, inflammation, and pain management. Despite challenges in pharmacokinetics and venom variability, advancements in biotechnology offer promise for personalized therapies. The future of snake venom-based treatments appears promising for addressing complex medical conditions.

Genetic insights into Staphylococcus aureus resistance: exploring AMR genes and molecular interactions

Antimicrobial resistance (AMR) among microorganisms remains a significant global concern in this century, posing an ongoing challenge for humanity. To solve this issue effectively, it is crucial to understand the genes responsible for AMR and how they create resistance. Staphylococcus aureus, which has AMR genes imparting resistance against numerous antibiotics, was the main subject of our investigation. We conducted a phylogenetic investigation to explore the evolutionary history of the gene network comprising rpl, rpoC, parE, and gyrB, providing insights into their genetic relationships and evolutionary connections. A gene interaction network with 46 functional partners was built and examined from the STRING Database and Cytoscape to increase our understanding. According to Cluego's enrichment analysis, 20 genes are significantly involved in biological processes, as are 14 genes in cellular components and 16 genes in molecular functions. RpoB, RpoC, FusA, RplI, and RpsL had the most interactions by Cytohubba when the degree and closeness of the network were studied, according to the gene interaction network analysis. Understanding the molecular basis of AMR requires analysis of the enriched pathways and Gene Ontologies (GO). The proposed study may also help researchers find new ways to battle the multidrug resistance of Staphylococcus aureus.

The Contribution of Human Antimicrobial Peptides to Fungi

Various species of fungi can be detected in the environment and within the human body, many of which may become pathogenic under specific conditions, leading to various forms of fungal infections. Antimicrobial peptides (AMPs) are evolutionarily ancient components of the immune response that are quickly induced in response to infections with many pathogens in almost all tissues. There is a wide range of AMP classes in humans, many of which exhibit broad-spectrum antimicrobial function. This review provides a comprehensive overview of the mechanisms of action of AMPs, their distribution in the human body, and their antifungal activity against a range of both common and rare clinical fungal pathogens. It also discusses the current research status of promising novel antifungal strategies, highlighting the challenges that must be overcome in the development of these therapies. The hope is that antimicrobial peptides, as a class of antimicrobial agents, will soon progress through large-scale clinical trials and be implemented in clinical practice, offering new treatment options for patients suffering from infections.

Linear and Polyvalent Peptides with Potent Antimicrobial Activity Against Sensitive and Multidrug-Resistant E. c oli Clinical Isolates

Peptides containing the sequences 20RRWQWR25 and 20RRWQWRMKKLG30 derived from Bovine lactoferricin (LfcinB) were synthesized and their antibacterial effect against reference strains and sensitive and resistant clinical isolates of E. coli was evaluated. Tetra-branched multiple antigen peptide (MAP) ((RRWQWR)2-K-Ahx-C)2 exhibited significant antibacterial activity against sensitive, resistant, and multidrug-resistant clinical isolates of E. coli. Peptide 3: RRWQWR-Nal-KKLG; MIC=16 μM, 26[F]: (RRWQWRFKKLG)2-K-Ahx; MIC=15 μM, 17: (RRWQWRFK)2-K-Ahx; MIC=9 μM, and LfcinB (20-25)2: (RRWQWR)2-K-Ahx; MIC=11 μM exhibited the highest antibacterial activity against E. coli strains, with bactericidal effect and haemolytic effect at MIC less than 5 % and a therapeutic index >1. A synergistic effect of peptides 26[F] and 17 with ciprofloxacin (CIP) or ceftriaxone (CEF) was observed. Prolonged treatment of E. coli ATCC 25922 with sublethal concentrations of CIP induced resistance in this strain, whereas some peptides did not induce resistance. These peptides can be considered to be promising candidates for treating infections caused by resistant strains of E. coli.

Current innovations in mRNA vaccines for targeting multidrug-resistant ESKAPE pathogens

The prevalence of multidrug-resistant (MDR) ESKAPE pathogens, including Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, represents a critical global public health challenge. In response, mRNA vaccines offer an adaptable and scalable platform for immunotherapy against ESKAPE pathogens by encoding specific antigens that stimulate B-cell-driven antibody production and CD8+ T-cell-mediated cytotoxicity, effectively neutralizing these pathogens and combating resistance. This review examines recent advancements and ongoing challenges in the development of mRNA vaccines targeting MDR ESKAPE pathogens. We explore antigen selection, the nuances of mRNA vaccine technology, and the complex interactions between bacterial infections and antibiotic resistance. By assessing the potential efficacy of mRNA vaccines and addressing key barriers to their paraclinical implementation, this review highlights the promising function of mRNA-based immunization in combating MDR ESKAPE pathogens.

A mixed-method study on antimicrobial resistance infection drivers in neonatal intensive care units: pathways, risks, and solutions

BACKGROUND

Antimicrobial resistance (AMR) in neonatal intensive care units (NICUs) complicates treatment of healthcare-associated infections, causing high morbidity and mortality, especially among low-birth-weight and critically ill infants. This study evaluates AMR prevalence, risk factors, outcomes and infection control measures at Felege Hiwot Hospital, aiming to guide clinical practices, antimicrobial stewardship, and improved neonatal health outcomes.

METHODS

This mixed-methods study (Oct 2022-Jun 2023) assessed AMR in NICU neonates by analyzing 420 blood samples, environmental swabs, and staff insights. Bivariable and multivariable regressions identified significant variables, and content analysis was used for qualitative data.

RESULTS

Out of 420 samples, 35% tested positive for AMR pathogens, with Coagulase-Negative Staphylococci (16.7%), Klebsiella pneumoniae (12.9%), and Acinetobacter spp. (5.6%) being the most prevalent. Resistance rates for Gentamicin, Cotrimoxazole, and Ciprofloxacin were alarmingly high (98-100%), while Amikacin demonstrated low resistance (3.0-5.56%), indicating potential efficacy. Among the neonates admitted, 91.8% survived, and 8.2% succumbed. Risk factor analysis revealed that improper PPE usage (AOR 3.90, p < 0.001), non-functional handwashing sinks (AOR 3.20, p < 0.001), and inadequate disinfection practices (AOR 2.70, p < 0.001) were strongly associated with microbial contamination. Environmental factors, including cockroach presence (AOR 1.80, p = 0.040) and high traffic flow (AOR 2.10, p = 0.005), were also significant contributors. The qualitative data analysis confirmed that improper PPE use, inadequate disinfection practices, pest control challenges, and non-functional handwashing sinks significantly contributed to microbial contamination risks in the NICU, aligning with the quantitative findings.

CONCLUSIONS

This study underscores key factors driving AMR in NICUs, such as inadequate IPC practices and environmental contamination, alongside high resistance to Cotrimoxazole and Ciprofloxacin. Amikacin shows promise as an effective treatment for CONS. Urgent actions, including strengthened IPC measures, staff training, and environmental management, are crucial to combat AMR, ensuring improved neonatal care and outcomes.

Photosensitizer associated with efflux pump inhibitors as a strategy for photodynamic therapy against bacterial resistance

Antimicrobial resistance is currently one of the biggest challenges in controlling infectious diseases and was listed among the top 10 threats to global health by the World Health Organization (WHO) in 2023. The antibiotics misuse has led to the widespread emergence of antimicrobial resistance, marking the beginning of the alarming increase in antibiotic resistance. In this context, Antimicrobial Photodynamic Therapy (aPDT) has garnered significant attention from the scientific community due to its potential to effectively eliminate multidrug-resistant pathogenic bacteria and its low propensity to induce drug resistance, which bacteria can quickly develop against traditional antibiotic treatments. However, some efflux pumps can expel diverse substrates from inside the cell, including photosensitizers used in aPDT, contributing to multidrug-resistance mechanisms. Efflux Pump Inhibitors are potential solutions to combat resistance mediated by these pumps and can play a crucial role in enhancing aPDT's effectiveness against multidrug-resistant bacteria. Therefore, combining efflux pumps inhibitors with photosensitizers can possible to eliminate the pathogen more efficiently. This review summarizes the mechanisms in which bacteria resist conventional antibiotic treatment, with a particular emphasis on efflux pump-mediated resistance, and present aPDT as a promising strategy to combat antibiotic resistance. Additionally, we highlighted several molecules of photosensitizer associated with efflux pump inhibitors as potential strategies to optimize aPDT, aiming to offer a perspective on future research directions on aPDT for overcoming the limitations of antibiotic resistance.

Frontiers in superbug management: innovating approaches to combat antimicrobial resistance

Anti-microbial resistance (AMR) is a global health issue causing significant mortality and economic burden. Pharmaceutical companies' discontinuation of research hinders new agents, while MDR pathogens or "superbugs" worsen the problem. Superbugs pose a threat to common infections and medical procedures, exacerbated by limited antibiotic development and rapid antibiotic resistance. The rising tide of antimicrobial resistance threatens to undermine progress in controlling infectious diseases. This review examines the global proliferation of AMR, its underlying mechanisms, and contributing factors. The study explores various methodologies, emphasizing the significance of precise and timely identification of resistant strains. We discuss recent advancements in CRISPR/Cas9, nanoparticle technology, light-based techniques, and AI-powered antibiogram analysis for combating AMR. Traditional methods often fail to effectively combat multidrug-resistant bacteria, as CRISPR-Cas9 technology offers a more effective approach by cutting specific DNA sequences, precision targeting and genome editing. AI-based smartphone applications for antibiogram analysis in resource-limited settings face challenges like internet connectivity, device compatibility, data quality, energy consumption, and algorithmic limitations. Additionally, light-based antimicrobial techniques are increasingly being used to effectively kill antibiotic-resistant microbial species and treat localized infections. This review provides an in-depth overview of AMR covering epidemiology, evolution, mechanisms, infection prevention, control measures, antibiotic access, stewardship, surveillance, challenges and emerging non-antibiotic therapeutic approaches.

Phenotypic and Molecular Characterization of Extended-Spectrum β-Lactamase, Plasmid-Mediated- AmpC, and Carbapenemase-Producing Enterobacteriaceae Isolated from Companion and Production Animals in Brazil

The crisis of bacterial resistance is an emerging One Health challenge, driven by the overuse of antimicrobials in medical and agricultural settings. This study aimed to investigate extended-spectrum β-lactamase (ESBL), Ampicillinase (AmpC), and carbapenemase production, and the presence of genes encoding these enzymes in Escherichia coli, Klebsiella spp., and Proteus spp., major contributors to infections and resistance isolates from animals. From 2016 to 2021, 130 multidrug-resistant (MDR) or extensively drug-resistant (XDR) isolates were recovered from the secretions, excretions, and organs of companion and production animals with active infections. Antibacterial sensitivity tests, along with phenotypic and genotypic detection of resistance enzymes, were performed. To the best of our knowledge, this is the first study in Brazil to estimate the prevalence of XDR Enterobacteriales isolated from companion and production animals, which accounted for 13.8% of the strains. Statistically significant differences (P < 0.05) in resistant bacteria between different classes and within the same class of antibacterial bacteria were found. The statistical probability between genotypic detection of ESBL (OR = 3.1) and phenotypic tests for AmpC (OR = 2.3) was also established. Approximately 32.3%, 17.6%, and 16.8% of the strains had positive phenotypic tests for ESBL, AmpC, and carbapenemases, respectively. Genetic analysis revealed the presence of blaCTX-M (60.0%), blaAmpC (9.18%), blaKPC-2 (0.76%), and blaNDM (1.52%). AmpC genes were identified in 8.46% of the samples, with blaCMY being the most frequent (6.92%), followed by blaDHA (0.77%), and blaFOX (0.77%). The sequenced amplicons were deposited in NCBI. This study reveals critical data on Enterobacteriaceae with antibacterial resistance genes isolated from animals and may pose a significant threat to One health.

Characterization of Klebsiella pneumoniae Isolates Resistant to Cefiderocol from Hospitals and Outpatient Settings in Croatia

BACKGROUND/OBJECTIVES

We conducted this study to evaluate the genotypic and phenotypic profiles of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates, exhibiting resistance to cefiderocol (FDC), focusing on antibiotic susceptibility, β-lactamase production, the genetic environment of blaCARB and blaESBL genes and molecular epidemiology. FDC is now a last-line antibiotic for severe infections due to CRKP.

METHODS

Susceptibility to a wide range of antibiotics was determined by the disk diffusion and broth microdilution method. Carbapenemases were screened by a modified Hodge test while carbapenem hydrolysis was investigated using mCIM and eCIM tests. The screening for β-lactamase and fluoroquinolone cluster resistance genes was carried out by PCR. Plasmids were characterized by PCR-based replicon typing (PBRT). An inter-array genotyping CarbaResist test and whole genome sequencing (WGS) were applied on selected isolates.

RESULTS

All of the 31 isolates studied exhibited high-level resistance to amoxicillin-clavulanate, piperacillin-tazobactam, cefuroxime, expanded-spectrum cephalosporins (ESC), cefepime, ceftolozan-tazobactam and ciprofloxacin and the majority to gentamicin, and amikacin. Colistin and ceftazidime-avibactam preserved activity against 71% and 87% of the isolates, respectively. The combined disk method with clavulanic acid was positive in all but one isolate, indicating the production of an ESBL. Twenty-eight isolates carried one single carbapenemase-encoding gene, whereas three harbored double blaCARB genes. Among the studied isolates, 61% carried blaOXA-48, 29% blaKPC and 12.9% blaNDM genes. The inter-array genotyping CarbaResist test and WGS identified additional aminoglycoside-, sulphonamide- and trimethoprim-resistance genes.

CONCLUSION

To our knowledge, this is the first study on FDC resistance in Croatia. The diffusion of FDC-resistant isolates was detected in both hospital and outpatient settings, emphasizing the need for a "One Health" approach.

Optimizing antibiotic stewardship and reducing antimicrobial resistance in Central Asia: A study protocol for evidence-based practice and policy

Antimicrobial resistance (AMR) poses a significant global health challenge, prompting the World Health Organization (WHO) to stress the importance of monitoring antibiotic consumption and sales to address AMR effectively. This study protocol aims to optimize antibiotic stewardship and combat AMR in Central Asia through evidence-based practices and policies. The protocol includes objectives such as conducting systematic reviews of interventions to promote judicious antibiotic use, assessing antibiotic consumption trends, and investigating antibiotic overuse practices among healthcare providers. The study aims to raise awareness among stakeholders to enhance appropriate antibiotic prescribing practices. By establishing regulatory frameworks, monitoring policies' effectiveness, and providing training programs for healthcare professionals, this study seeks to contribute to the global efforts in combating AMR and promoting prudent antibiotic use.

Comparative antibacterial activity of clove extract against Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen belonging to the γ-proteobacteria family, known to cause pneumonia linked with ventilator use and nosocomial infections. With the increasing prevalence of antibiotic-resistant bacteria, there is a pressing need to identify alternatives to conventional antibiotics. Plant-derived substances (PDSs) offer potential not only as antibacterial agents but also as modulators of antibiotic resistance. In this study, diffusion assay using disc agar, and the minimum inhibitory concentration (MIC) assay of each imipenem, amoxicillin-clavulanic acid, and clove extract was determined. The clove extract was analyzed via the UHPLC/MS, and the checkerboard assay was employed to evaluate the potential synergistic effects of combining clove extract with both antibiotics. The combination of clove extract to each antibiotic led to a significant reduction in their respective MICs. Moreover, each antibiotic exhibited synergistic effects on the fractional inhibitory concentration value (FIC) of clove extract. The analysis identified seventeen components in the clove extract, predominantly flavonoids and phenolic compounds. The antibacterial efficacy of the Syzygium aromaticum Myrtaceae extract against P. aeruginosa indicated its potential as a promising antibacterial agent capable of enhancing the effectiveness of existing medications.

Synthesis of new coumarin derivatives and assessment of their antimicrobial efficacy

AIM

Developing new antimicrobial agents in response to the urgent challenge of antimicrobial resistance.

METHODS

Synthesis of the targeted coumarins, elucidation of their structures using spectroscopic tools, and investigation of their antimicrobial activity.

RESULTS

Coumarin-pyrazole 11 with CF3 in the 3-position of the pyrazole ring displayed the lowest minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) with values of 1.95 and 15.6 µg/ml, respectively, against Bacillus pumilis. In addition, it exhibited the best inhibitory activity against Saccharomyces cerevisiae (MIC = 3.91 µg/ml) compared to the rest of the derivatives (7.81-62.5 µg/ml). Surprisingly, coumarin 14 with the S-CH3 group had higher ability to inhibit the Staphylococcus faecalis strain with an MIC value of 1.95 µg/ml, which is twice that of penicillin G (MIC = 3.91 µg/ml). At the same time, compounds 6, 8, 11, 16, and penicillin G showed similar activity with an MIC value of 3.91 µg/ml against Staphylococcus faecalis. Also, the lowest MIC value (3.91 µg/ml) was obtained for S-CH3 derivative 14 against Enterobacter cloacae. Coumarins 14 and 1,3,4-thiadiazine derivative 6 recorded the lowest MBC (15.6 µg/ml) against Escherichia coli.

CONCLUSION

Finally, it can be concluded that some designed coumarins have a high potential to act as potent antimicrobial agents. Some of them displayed higher efficacy than or equal to the reference drug.

Enhancing antibiotic prescribing practices at the main military training hospital of Tunis: A study of pharmaceutical interventions

BACKGROUND

Bacterial infections have historically posed significant challenges until the discovery of antibiotics, which revolutionized infectious disease treatment. However, bacterial adaptation mechanisms over time have led to increased antimicrobial resistance, necessitating judicious antibiotic use.

OBJECTIVES

This study aims to comprehensively analyze pharmaceutical interventions related to antibiotic prescriptions governed by antibiotic order forms to identify and rectify medication errors, optimizing antibiotic prescribing practices.

MATERIAL AND METHODS

Approval for this research was obtained from the institutional review board of the Main Military Training Hospital of Tunis, Tunisia. A retrospective study was conducted at the main military training hospital of Tunis over 4 months. Pharmaceutical validation of antibiotic prescriptions through antibiotic order forms was conducted by a pharmacy resident. Pharmaceutical interventions were initiated upon detection of errors, and patient records were accessed through institutional software.

RESULTS

Out of 1100 prescription forms analyzed, 41 pharmaceutical interventions were conducted for 7 antibiotics. Twenty-four percent of all interventions were related to antibiotic order forms, with the intensive care unit accounting for the highest number of errors. Under-dosage and prescription errors were common.

CONCLUSION

Our pharmaceutical interventions related to antibiotic order forms are crucial for optimizing antibiotic therapy. Feedback mechanisms to healthcare teams are essential for enhancing prescription quality and patient care outcomes. Ongoing surveillance and improvement efforts are necessary to address medication errors and enhance antimicrobial stewardship.

Bats as an Important Source of Antimicrobial-Resistant Bacteria: A Systematic Review

Background/Objectives: Bats are the second-largest known order of mammals, accounting for about twenty percent of the species described to date. This group has special importance in health and epidemiology because they are considered hosts of a wide range of antimicrobial-resistant human pathogens. Over the past few decades, the emergence of pathogenic bacteria resistant to antimicrobials has been a growing threat to public health, especially given its repercussions such as deaths associated with antimicrobial resistance and economic losses in the healthcare sector. Results: The diversity of antimicrobial-resistant bacteria, the different methodologies in numeric analysis, and the variety of antibiotics reported in this review make it difficult to establish the scope of the effect of bats on the antimicrobial resistance crisis. Methods: In this systematic review, we focus on the existence of antibiotic-resistant bacteria associated with bats and summarize the main findings of studies conducted on the topic to date. Conclusions: Surveillance is essential to control the emergence of resistant bacteria related to bats, which could eventually affect humans, as this is a problem of a 'One Health' nature, with effects on human, animal, and environmental health.

Discovery and biological evaluation of nitrofuranyl-pyrazolopyrimidine hybrid conjugates as potent antimicrobial agents targeting Staphylococcus aureus and methicillin-resistant S. aureus

Nitrofuran and pyrazolopyrimidine-based compounds possess a broad antimicrobial spectrum including Gram-positive and Gram-negative bacteria. In the present work, a series of conjugates of these scaffolds was synthesized and evaluated for antimicrobial activity against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Many compounds showed MIC values of ≤2 μg ml-1, with compound 35 demonstrating excellent activity (MICs: 0.7 and 0.15 μg ml-1 against S. aureus and MRSA, respectively) and safety up to 50 μg ml-1 in HepG2 cells. Compound 35 also exhibited no hemolytic activity, biofilm eradication, and effectiveness against efflux-pump-overexpressing strains (NorA, TetK, MsrA) without resistance development. It showed synergistic effects with vancomycin (S. aureus) and rifampicin (MRSA). Mechanistic studies revealed that compound 35 exhibits good membrane-targeting abilities, as evidenced by DAPI/PI staining and scanning electron microscopy (SEM). In an intracellular model, it reduced bacterial load efficiently in both S. aureus and MRSA strains. With a strong in vitro profile, compound 35 demonstrated favorable oral pharmacokinetics at 30 mg kg-1 and potent in vivo anti-MRSA activity, highlighting its potential against antibiotic-resistant infections.

Antimicrobial Peptides from Porcine Blood Cruor Hydrolysates as a Promising Source of Antifungal Activity

Porcine blood, a significant byproduct of the pork industry, represents a potential source of antimicrobial peptides (AMPs). AMPs offer a promising alternative to chemical antimicrobials, which can be used as natural preservatives in the food industry. AMPs can exhibit both antibacterial and/or antifungal properties, thus improving food safety and addressing the growing concern of antibiotic and antifungal resistance. The objective of this study was to evaluate the antimicrobial activity of potential AMPs previously identified from porcine cruor hydrolysates. To this end, a total of sixteen peptides were chemically synthesized and their antimicrobial activities (antibacterial, anti-mold, and anti-yeast) were evaluated using microtitration and agar well diffusion methods against a wide range of microorganisms. Five new peptide sequences demonstrated antifungal activity, with Pep5 (FQKVVAGVANALAHKYH), an alpha-helix peptide, exhibiting the most promising results. Pep5 demonstrated efficacy against nine of the eleven fungal isolates, exhibiting low minimum inhibitory concentrations (MICs) and a fungicidal effect against key spoilage fungi (Rhodotorula mucilaginosa, Debaryomyces hansenii, Candida guilliermondii, Paecilomyces spp., Eurotium rubrum, Mucor racemosus, Aspergillus versicolor, Penicillium commune, and P. chrysogenum). These findings illustrate the potential of porcine blood hydrolysates as a source of AMPs, particularly antifungal peptides, which are less known and less studied than the antibacterial ones. Among the tested sequences, Pep5 exhibited the most promising characteristics, including broad-spectrum activity, low MICs, and a fungicidal effect. It is, therefore, a promising candidate for further research and for potential applications in the porcine industry and beyond.

Antioxidant and Antimicrobial Activities of 4H-Chromene Based Indole-Pyrimidine Hybrids: Synthesis and Molecular Docking Studies

A series of 4H-Chromene Based Indole-Pyrimidine Hybrids synthesized using simple and efficient multicomponent reaction. The title molecules were evaluated for their invitro antioxidant and antimicrobial activities. Compounds 8 g containing bromo substituted naphthalene displayed potent antioxidant activity with IC50 value of 1.09±0.34 μM and 1.10±0.36 μM. Compound 10 a, a 4-methylphenyl derivative presented potent activity with antioxidant activity with IC50 value of 1.29±0.35 μM and 1.43±0.38 μM. Subsequently, compounds 8 a, 8 b, 8 d and 10 g had shown prominent percentage of inhibition and derived effective IC50 values in comparison to reference drug Ascorbic Acid. The invitro antimicrobial activity carried out against two gram positive and two gram-negative bacteria, and two fungal strains using Ampicillin and Itraconazole as refence drugs. Compound 10 f exhibited exceptional efficacy against all types of bacterial and fungal strains compared to Ampicillin and Itraconazole, compounds 8 e and 8 g showed activity against bacterial strains whereas compound 10 g exhibited the most effective zone of inhibition against fungal strains. The molecular docking study against crystal structure of NADPH oxidase obtained supporting docking scores and showed notable binding interactions such as H-bond and hydrophobic.

Recombinant Live-Attenuated Salmonella Vaccine for Veterinary Use

Vaccination is essential for maintaining animal health, with priority placed on safety and cost effectiveness in veterinary use. The development of recombinant live-attenuated Salmonella vaccines (RASVs) has enabled the construction of balanced lethal systems, ensuring the stability of plasmid vectors encoding protective antigens post-immunization. These vaccines are particularly suitable for production animals, providing long-term immunity against a range of bacterial, viral, and parasitic pathogens. This review summarizes the progress made in this field, with a focus on clinical trials demonstrating the efficacy and commercial potential of RASVs in veterinary medicine.

Fecal Carriage and Risk Factors Associated with Extended-Spectrum β-Lactamase-/AmpC-/Carbapenemase-Producing Escherichia coli in Dogs from Italy

MDR bacteria are an emerging global threat to public health, and the role of dogs in the rise of antimicrobial resistance is under investigation. This study investigated the fecal shedding of extended-spectrum β-lactamase (ESBL)-, AmpC- and carbapenemase (CP)-producing Escherichia coli and associated risk factors in dogs admitted to the Veterinary Teaching Hospital of Lodi, University of Milan, or other veterinary clinics and kennels in Northen Italy. Feces collected in 2020-2022 were microbiologically and molecularly analyzed. ESBL-/AmpC-/CP-producing E. coli was detected in 14/100 (14%) dogs. Eleven (11%), five (5%) and one (1%) dogs carried ESBL-, AmpC- and CP-producing E. coli phenotypes, respectively, supported by the PCR detection of blaCTX-M and/or blaTEM in ESBL-producing E. coli; blaCMY-2 and the presence of putative low-level AmpC production in AmpC-producing E. coli; and blaOXA-48 in CP-producing E. coli. Different combinations of resistance genes and genetic features were observed. Multidrug resistance was observed in 13/14 (92.9%) E. coli isolates. Binary logistic regression analysis showed that ESBL-/AmpC-/CP-producing E. coli fecal shedding tended to be associated with antibiotic treatment (p = 0.058; OR = 3.87). The detection of ESBL-/AmpC-producing E. coli, along with the presence of a carbapenemase-resistant E. coli isolate from domestic dogs, although still limited, emphasizes the need for antimicrobial stewardship and specific surveillance programs, particularly for CP-producing bacteria in companion animals.

The longitudinal trend and influential factors exploring of global antimicrobial resistance in Klebsiella pneumoniae

Klebsiella pneumoniae (Kp) is a human symbiotic opportunistic pathogen capable of causing severe hospital-based infections and community-acquired infections. The problem of antimicrobial resistance (AMR) has become increasing serious over time, posing a major threat to socio-economic and human development. In this study, we explored the global trend of AMR in 1786 strains of Kp isolated between 1982 and 2023. The number of antibiotic resistance genes (ARGs) in Kp increased significantly from 24.29 ± 5.44 to 32.42 ± 8.52 over time. Mobile genetic elements (MGEs) were responsible for the ARGs horizontal transfer of Kp strains. The results of structural equation modeling (SEM) indicated a strong association between the human development index and the increase of antibiotic consumption, which indirectly affected the occurrence and development of antibiotic resistance in Kp. The results of Generalized Linear Models (GLM) indicated that the influence of environmental factors such as temperature on the development of Kp resistance could not be ignored. Overall, this study monitored the longitudinal trend of antimicrobial resistance in Kp, explored the factors influencing antibiotic resistance, and provided insights for mitigating the threat of antimicrobial resistance.

Screening for antimicrobial and antioxidant activities of quinazolinone based isoxazole and isoxazoline derivatives, synthesis and In silico studies

Two novel series of quinazolinone based isoxazole and isoxazoline hybrid compounds were synthesized from 6-aminoquinazolinone as a key precursor. The title compounds were achieved in synthetic routes via propargylation and allylation reactions of the precursor followed by cyclization with various chloroximes. The new compounds 4a-g and 6a-g were screened for their antimicrobial activity against two Gram-positive bacteria, two Gram-negative bacteria and two fungi by employing Ampicillin and Itraconazole as standard reference. Among all, the 4-bromosubstituted analogues in isoxazole series 4d and in isoxazoline series 6d demonstrated potent activity against all bacterial and fungal strains compared to Ampicillin as well as Itraconazole. The MIC of these compounds were determined as 0.012 μM. The antioxidant investigation revealed that compounds 4f and 6f with dimethyl substitution, exhibited significant activity. Their respective IC50 values were 1.28 ± 0.33, 1.39 ± 0.38 µM and 1.07 ± 0.24, 1.10 ± 0.26 µM, when compared to Ascorbic acid. The compounds 4 g and 6 g with dichloro substitution, exhibited promising results with IC50 values were 2.72 ± 0.34 µM and 2.78 ± 0.41 µM for 4 g, and 2.24 ± 0.93 µM and 2.45 ± 0.53 µM for 6 g, respectively. Their antimicrobial and antioxidant activities were authenticated by the molecular docking study against crystal structure of DNA gyrase and NADPH oxidase. The predicted ADME properties of these molecules progressed favourable drug-likeness properties.

Implementing a community-based antimicrobial stewardship intervention in Malaysia

Background

In Malaysia, the unregulated use of antibiotics and lack of awareness about antimicrobial resistance (AMR) among pharmacists pose significant challenges. Implementing community-based Antimicrobial Stewardship (AMS) initiatives is crucial to address the rising AMR.

Methods

We developed a bespoke AMS intervention, aligned with the World Health Organization's AMS modules, as a 2-day online educational seminar for community pharmacists. The effectiveness of the workshop was evaluated using pre- and post-seminar questionnaires, focusing on AMS knowledge and attitudes towards antimicrobial usage.

Results

Among 528 participants, 489 completed both questionnaires. Pre-seminar, only 59% correctly understood the concept of antibiotic resistance reversibility, which improved to 85.9% post-seminar (p = .002). The average AMS knowledge score increased from 5/10 to 8/10 post-intervention (p < .05). A significant improvement was also noted in pharmacists' ability to select appropriate antibiotic therapies, particularly for urinary tract infections, with an increase from 78% to 90% correct responses.

Conclusion

The AMS seminar was well-received and significantly improved the AMS knowledge of community pharmacists. The results underline the need for more AMS-focused interventions in this demographic in Malaysia, contributing to the development of formalized AMS programs. Such initiatives are expected to enhance antibiotic use awareness, encourage optimal antibiotic practices, and positively shift professional conduct in community settings.

Detection of Extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Escherichia coli in wastewaters of Madurai, India

The present study aimed to determine the presence of Klebsiella pneumoniae and Escherichia coli with extended-spectrum β-lactamase (ESBL)s property from treated wastewater effluents. Treated effluent samples were collected from two major water treatment plants which located at Avaniyapuram and Sakkimangalam, Madurai, Tamil Nadu, India. Among the 51 isolates, 56.86 % represented E. coli (18 from Avaniyapuram and 11 from Sakkimangalam) and 43.14 % were K. pneumoniae (7 from Avaniyapuram and 15 from Sakkimangalam). Based on the ESBL propensity, E. coli was overrepresented in the present study. All the isolates turned positive for ESBL, while 5.88 % of K. pneumoniae and 7.84 % of E. coli were positive for carbapenemases. Further, K. pneumoniae isolates from both sites showed 100 % resistance to beta-lactams, with resistance to other antibiotics such as tetracycline and meropenem. E. coli isolates were 100 % resistant to ceftazidime and cefuroxime, and 88.9 % were resistant to amoxicillin/clavulanate and ceftriaxone. The MAR indices observed in the present study for E. coli and K. pneumoniae were above the threshold value of 0.2 suggested a high risk of environmental contamination. These findings highlighted the need for routine surveillance at appropriate intervals for the presence of ESBL producing pathogens and other MDR pathogens in the environment to provide proper clinical management, develop various counter measures and policies to address and halt the spread of such potential threats.

A Review of Medicinal Plants Used in the Management of Microbial Infections in Angola

The use of medicinal plants in the management of microbial infections is significant to the health of the indigenous people in many Angolan communities. The present study provides a comprehensive overview of medicinal plants used for the management of microbial infections in Angola. Relevant information was extracted from research articles published and associated with the use of medicinal plants in the management of microbial infections in Angola (from January 1976 to November 2023). Data or information were gathered from the literature sourced from Wiley Online, SciFinder, Google Scholar, Web of Science, Scopus, ScienceDirect, BMC, Elsevier, SpringerLink, PubMed, books, journals and published M.Sc. and Ph.D. thesis. A total of 27 plant species, representing 19 families, were recorded in this study. Hypericaceae (11%), Lamiaceae (11%), Malvaceae (11%), Phyllanthaceae (11%), Fabaceae (16%) and Rubiaceae (16%) were the most predominant families. The leaves are the most used parts (96%), followed by bark (74%) and root (70%). The data revealed that medicinal plants continue to play significant roles in the management of microbial infections in Angola. In order to explore the benefits of the therapeutic potential of indigenous medicinal plants for diseases related to infections; further scientific research studies are important to produce data on their effectiveness using appropriate test models. This approach might assist with the continuing drive regarding the integration of Angolan traditional medicine within mainstream healthcare systems.

Nanocomposites: silver nanoparticles and bacteriocins obtained from lactic acid bacteria against multidrug-resistant Escherichia coli and Staphylococcus aureus

Drug-resistant bacteria such as Escherichia coli and Staphylococcus aureus represent a global health problem that requires priority attention. Due to the current situation, there is an urgent need to develop new, more effective and safe antimicrobial agents. Biotechnological approaches can provide a possible alternative control through the production of new generation antimicrobial agents, such as silver nanoparticles (AgNPs) and bacteriocins. AgNPs stand out for their antimicrobial potential by employing several mechanisms of action that can act simultaneously on the target cell such as the production of reactive oxygen species and cell wall rupture. On the other hand, bacteriocins are natural peptides synthesized ribosomally that have antimicrobial activity and are produced, among others, by lactic acid bacteria (LAB), whose main mechanism of action is to produce pores at the level of the cell membrane of bacterial cells. However, these agents have disadvantages. Nanoparticles also have limitations such as the tendency to form aggregates, which decreases their antibacterial activity and possible cytotoxic effects, and bacteriocins have a narrow spectrum of action, require high doses to be effective, and can be degraded by proteases. Given these limitations, nanoconjugates of these two agents have been developed that can act synergistically in the control of pathogenic bacteria resistant to antibiotics. This review focuses on knowing relevant aspects of the antibiotic resistance of E. coli and S. aureus, the characteristics of these new generation antibacterial agents, and their effect alone or forming nanoconjugates that are more effective against the multiresistant mentioned bacteria.

Occurrence, genetic diversity, and antimicrobial resistance of methicillin-resistant Staphylococcus spp. in hospitalized and non-hospitalized cats in Brazil

Methicillin-resistant Staphylococci (MRS) cause infections at various sites and exhibit multidrug resistance. Despite their importance in veterinary medicine, only little is known about Staphylococcus spp. colonizing and infecting cats. Therefore, in this study, we aimed to isolate and identify Staphylococcus spp. colonizing hospitalized and non-hospitalized domestic cats and analyze their antimicrobial resistance profiles, genetic diversity, and risk factors associated with MRS colonization. A total of 218 oral and axillary swabs were obtained from 109 cats, including 77 non-hospitalized and 32 hospitalized cats. After plating on selective media, the isolates were identified via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and rpoB and 16S rRNA gene sequencing. Subsequently, antimicrobial sensitivity of the strains was assessed, and they were screened for mecA gene. Methicillin-resistant S. haemolyticus (MRSH) isolates were subjected to multilocus sequence typing, whereas methicillin-resistant S. pseudintermedius (MRSP) and S. felis isolates were subjected to whole genome sequencing. S. felis was most commonly isolated from non-hospitalized cats (28.1%), whereas S. pseudintermedius and MRS were commonly isolated from hospitalized cats (25%). MRSH isolates from hospitalized animals were classified as ST3. The identified MRSP strains belonged to two well-known sequence types, ST551 and ST71. Moreover, antimicrobial use (p = 0.0001), hospitalization (p = 0.0141), and comorbidities (p = 0.002) were associated with increased MRS prevalence in cats.

An Overview of the Recent Advances in Antimicrobial Resistance

Antimicrobial resistance (AMR), frequently considered a major global public health threat, requires a comprehensive understanding of its emergence, mechanisms, advances, and implications. AMR's epidemiological landscape is characterized by its widespread prevalence and constantly evolving patterns, with multidrug-resistant organisms (MDROs) creating new challenges every day. The most common mechanisms underlying AMR (i.e., genetic mutations, horizontal gene transfer, and selective pressure) contribute to the emergence and dissemination of new resistant strains. Therefore, mitigation strategies (e.g., antibiotic stewardship programs-ASPs-and infection prevention and control strategies-IPCs) emphasize the importance of responsible antimicrobial use and surveillance. A One Health approach (i.e., the interconnectedness of human, animal, and environmental health) highlights the necessity for interdisciplinary collaboration and holistic strategies in combating AMR. Advancements in novel therapeutics (e.g., alternative antimicrobial agents and vaccines) offer promising avenues in addressing AMR challenges. Policy interventions at the international and national levels also promote ASPs aiming to regulate antimicrobial use. Despite all of the observed progress, AMR remains a pressing concern, demanding sustained efforts to address emerging threats and promote antimicrobial sustainability. Future research must prioritize innovative approaches and address the complex socioecological dynamics underlying AMR. This manuscript is a comprehensive resource for researchers, policymakers, and healthcare professionals seeking to navigate the complex AMR landscape and develop effective strategies for its mitigation.

Tityus stigmurus-Venom-Loaded Cross-Linked Chitosan Nanoparticles Improve Antimicrobial Activity

The rapid resistance developed by pathogenic microorganisms against the current antimicrobial pool represents a serious global public health problem, leading to the search for new antibiotic agents. The scorpion Tityus stigmurus, an abundant species in Northeastern Brazil, presents a rich arsenal of bioactive molecules in its venom, with high potential for biotechnological applications. However, venom cytotoxicity constitutes a barrier to the therapeutic application of its different components. The objective of this study was to produce T. stigmurus-venom-loaded cross-linked chitosan nanoparticles (Tsv/CN) at concentrations of 0.5% and 1.0% to improve their biological antimicrobial activity. Polymeric nanoparticles were formed with a homogeneous particle size and spherical shape. Experimental formulation parameters were verified in relation to mean size (<180 nm), zeta potential, polydispersity index and encapsulation efficiency (>78%). Tsv/CN 1.0% demonstrated an ability to increase the antimicrobial venom effect against Staphylococcus aureus bacteria, exhibiting an MIC value of 44.6 μg/mL. It also inhibited different yeast species of the Candida genus, and Tsv/CN 0.5% and 1.0% led to a greater inhibitory effect of C. tropicalis and C. parapsilosis strains, presenting MIC values between 22.2 and 5.5 µg/mL, respectively. These data demonstrate the biotechnological potential of these nanosystems to obtain a new therapeutic agent with potential antimicrobial activity.

Unveiling the Bioactive Potential of Bacterial Isolates from Extreme Environments of Pakistan by In Vitro and In Silico Approaches

The soil hosts a wide array of bacterial species capable of producing diverse bioactive compounds. This research aimed to screen bacterial isolates for their bioactive potential from extreme environments in Pakistan. Out of the 69 isolates examined, only 7 exhibited antagonistic activity against Bacillus sp. and Escherichia coli test strains. Notably, the B. cereus DS-2 strain demonstrated the highest antibacterial potential (31 mm and 15 mm) against the Bacillus and E. coli test strains, respectively. Mode-of-action studies suggested that the crude extract might have induced morphological abnormalities in the Bacillus sp. (test strain), causing cell contraction, chain breakage, and deformation. Furthermore, the B. cereus DS-2 strain displayed significant antioxidant potential (64.8%) as revealed by the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Thin-layer chromatography (TLC) of the DS-2 crude extract led to the separation of six components, with only spots 3 and 4 exhibiting the antibacterial potential (3 mm and 5 mm, respectively). Subsequently, gas chromatography-mass spectrometry (GC-MS) analysis of the bioactive fraction extracted from TLC revealed the presence of diisooctyl phthalate, dibutyl phthalate, hexadecanoic acid methyl ester, and octadecanoic acid methyl ester. Molecular docking analysis of diisooctyl phthalate and dibutyl phthalate revealed their binding affinity against E. coli and Bacillus sp. targets. ADMET analysis confirmed the solubility, toxicity, and drug-like properties of the ligands based on Lipinski's rule of five. Current findings suggest that these compounds hold promise as antibacterial agents in drug development. This study underscores the diverse microbial community present in extreme environments and highlights the versatile applications of natural products derived from these strains.

Mechanisms underlying the effects, and clinical applications, of oral microbiota in lung cancer: current challenges and prospects

The oral cavity contains a site-specific microbiota that interacts with host cells to regulate many physiological processes in the human body. Emerging evidence has suggested that changes in the oral microbiota can increase the risk of lung cancer (LC), and the oral microbiota is also altered in patients with LC. Human and animal studies have shown that oral microecological disorders and/or specific oral bacteria may play an active role in the occurrence and development of LC through direct and/or indirect mechanisms. These studies support the potential of oral microbiota in the clinical treatment of LC. Oral microbiota may therefore be used in the prevention and treatment of LC and to improve the side effects of anticancer therapy by regulating the balance of the oral microbiome. Specific oral microbiota in LC may also be used as screening or predictive biomarkers. This review summarizes the main findings in research on oral microbiome-related LC and discusses current challenges and future research directions.

The Biological Characteristics of Mycobacterium Phage Henu3 and the Fitness Cost Associated with Its Resistant Strains

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is an infectious disease that seriously affects human life and health. Despite centuries of efforts to control it, in recent years, the emergence of multidrug-resistant bacterial pathogens of M. tuberculosis due to various factors has exacerbated the disease, posing a serious threat to global health. Therefore, a new method to control M. tuberculosis is urgently needed. Phages, viruses that specifically infect bacteria, have emerged as potential biocontrol agents for bacterial pathogens due to their host specificity. In this study, a mycobacterium phage, Henu3, was isolated from soil around a hospital. The particle morphology, biological characteristics, genomics and phylogeny of Henu3 were characterized. Additionally, to explore the balance between phage resistance and stress response, phage Henu3-resistant strains 0G10 and 2E1 were screened by sequence passage and bidirectional validation methods, which significantly improved the sensitivity of phage to antibiotics (cefotaxime and kanamycin). By whole-genome re-sequencing of strains 0G10 and 2E1, 12 genes involved in cell-wall synthesis, transporter-encoded genes, two-component regulatory proteins and transcriptional regulatory factor-encoded genes were found to have mutations. These results suggest that phage Henu3 has the potential to control M. tuberculosis pathogens, and phage Henu3 has the potential to be a new potential solution for the treatment of M. tuberculosis infection.

Recent advances in nanostructured delivery systems for vancomycin

Despite the development of new generations of antibiotics, vancomycin remained as a high-efficacy antibiotic for treating the infections caused by MRSA. Researchers have explored various nanoformulations, aiming to enhance the therapeutic efficacy of vancomycin. Such novel formulations improve the effectiveness of drug cargoes in treating bacterial infections and minimizing the risk of adverse effects. The vast of researches have focuses on enhancing the permeation ability of vancomycin through different biological barriers especially those of gastrointestinal tract. Increasing the drug loading and tuning the drug release from nanocarrier are other important goal for many conducted studies. This study reviews the newest nano-based formulations for vancomycin as a key antibiotic in treating hospitalized bacterial infections.

Synthesis and evaluation of di-heterocyclic benzazole compounds as potential antibacterial and anti-biofilm agents against Staphylococcus aureus

Cumulative escalation in antibiotic-resistant pathogens necessitates the quest for novel antimicrobial agents, as current options continue to diminish bacterial resistance. Herein, we report the synthesis of di-heterocyclic benzazole structures (12-19) and their in vitro evaluation for some biological activities. Compounds 16 and 17 demonstrated potent antibacterial activity (MIC = 7.81 μg/mL) against Staphylococcus aureus, along with significant anti-biofilm activity. Noteworthy is the capability of Compound 17 to inhibit biofilm formation by at least 50% at sub-MIC (3.90 μg/mL) concentration. Furthermore, both compounds exhibited the potential to inhibit preformed biofilm by at least 50% at the MIC concentration (7.81 μg/mL). Additionally, Compounds 16 and 17 were examined for cytotoxic effects in HFF-1 cells, using the MTT method, and screened for binding interactions within the active site of S. aureus DNA gyrase using in silico molecular docking technique, employing AutoDock 4.2.6 and Schrödinger Glidse programs. Overall, our findings highlight Compounds 16 and 17 as promising scaffolds warranting further optimization for the development of effective antibacterial and anti-biofilm agents.

Mini review advantages and limitations of lytic phages compared with chemical antibiotics to combat bacterial infections

The overuse of antibiotics has caused the emergence of antibiotic-resistant strains, such as multidrug-resistant, extensively drug-resistant, and pandrug-resistant bacteria. The treatment of infections caused by such strains has become a formidable challenge. In the post-antibiotic era, phage therapy is an attractive solution for this problem and some successful phase 1 and 2 studies have demonstrated the efficacy and safety of phage therapy over the last decade. It is a form of evolutionary medicine, phages exhibit immunomodulatory and anti-inflammatory properties. However, phage therapy is limited by factors, such as the narrow spectrum of host strains, the special pharmacokinetics and pharmacodynamics in vivo, immune responses, and the development of phage resistance. The aim of this minireview was to compare the potencies of lytic phages and chemical antibiotics to treat bacterial infections. The advantages of phage therapy has fewer side effects, self-replication, evolution, bacterial biofilms eradication, immunomodulatory and anti-inflammatory properties compared with chemical antibiotics. Meanwhile, the disadvantages of phage therapy include the narrow spectrum of available host strains, the special pharmacokinetics and pharmacodynamics in vivo, immune responses, and phage resistance hurdles. Recently, some researchers continue to make efforts to overcome these limitations of phage therapy. Phage therapy will be a welcome addition to the gamut of options available for treating antibiotic-resistant bacterial infections. We focus on the advantages and limitations of phage therapy with the intention of exploiting the advantages and overcoming the limitations.

Complex Hospital-Based Electronic Prescribing-Based Intervention to Support Antimicrobial Stewardship: Qualitative Study

BACKGROUND

Antimicrobial resistance (AMR) represents a growing concern for public health.

OBJECTIVE

We sought to explore the challenges associated with development and implementation of a complex intervention designed to improve AMS in hospitals.

METHODS

We conducted a qualitative evaluation of a complex AMS intervention with educational, behavioral, and technological components in 5 wards of an English hospital. At 2 weeks and 7 weeks after initiating the intervention, we interviewed 25 users of the intervention, including senior and junior prescribers, a senior nurse, a pharmacist, and a microbiologist. Topics discussed included perceived impacts of different elements of the intervention and facilitators and barriers to effective use. Interviews were supplemented by 2 observations of ward rounds to gain insights into AMS practices. Data were audio-recorded, transcribed, and inductively and deductively analyzed thematically using NVivo12.

RESULTS

Tracing the adoption and impact of the various components of the intervention was difficult, as it had been introduced into a setting with competing pressures. These particularly affected behavioral and educational components (eg, training, awareness-building activities), which were often delivered ad hoc. We found that the participatory intervention design had addressed typical use cases but had not catered for edge cases that only became visible when the intervention was delivered in real-world settings (eg, variations in prescribing workflows across different specialties and conditions).

CONCLUSIONS

Effective user-focused design of complex interventions to promote AMS can support acceptance and use. However, not all requirements and potential barriers to use can be fully anticipated or tested in advance of full implementation in real-world settings.

Antibacterial Size Effect of ZnO Nanoparticles and Their Role as Additives in Emulsion Waterborne Paint

Nosocomial infections, a prevalent issue in intensive care units due to antibiotic overuse, could potentially be addressed by metal oxide nanoparticles (NPs). However, there is still no comprehensive understanding of the impact of NPs' size on their antibacterial efficacy. Therefore, this study provides a novel investigation into the impact of ZnO NPs' size on bacterial growth kinetics. NPs were synthesized using a sol-gel process with monoethanolamine (MEA) and water. X-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy confirmed their crystallization and size variations. ZnO NPs of 22, 35, and 66 nm were tested against the most common nosocomial bacteria: Escherichia coli, Pseudomonas aeruginosa (Gram-negative), and Staphylococcus aureus (Gram-positive). Evaluation of minimum inhibitory and bactericidal concentrations (MIC and MBC) revealed superior antibacterial activity in small NPs. Bacterial growth kinetics were monitored using optical absorbance, showing a reduced specific growth rate, a prolonged latency period, and an increased inhibition percentage with small NPs, indicating a slowdown in bacterial growth. Pseudomonas aeruginosa showed the lowest sensitivity to ZnO NPs, attributed to its resistance to environmental stress. Moreover, the antibacterial efficacy of paint containing 1 wt% of 22 nm ZnO NPs was evaluated, and showed activity against E. coli and S. aureus.

Metal Nanoparticle-Based Biosensors for the Early Diagnosis of Infectious Diseases Caused by ESKAPE Pathogens in the Fight against the Antimicrobial-Resistance Crisis

The species included in the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and the genus Enterobacter) have a high capacity to develop antimicrobial resistance (AMR), a health problem that is already among the leading causes of death and could kill 10 million people a year by 2050. The generation of new potentially therapeutic molecules has been insufficient to combat the AMR "crisis", and the World Health Organization (WHO) has stated that it will seek to promote the development of rapid diagnostic strategies. The physicochemical properties of metallic nanoparticles (MNPs) have made it possible to design biosensors capable of identifying low concentrations of ESKAPE bacteria in the short term; other systems identify antimicrobial susceptibility, and some have been designed with dual activity in situ (bacterial detection and antimicrobial activity), which suggests that, in the near future, multifunctional biosensors could exist based on MNPs capable of quickly identifying bacterial pathogens in clinical niches might become commercially available. This review focuses on the use of MNP-based systems for the rapid and accurate identification of clinically important bacterial pathogens, exhibiting the necessity for exhaustive research to achieve these objectives. This review focuses on the use of metal nanoparticle-based systems for the rapid and accurate identification of clinically important bacterial pathogens.

Synthesis, Characterization, and Study of the Antimicrobial Potential of Dimeric Peptides Derived from the C-Terminal Region of Lys49 Phospholipase A2 Homologs

Currently, the search for new alternatives to conventional antibiotics to combat bacterial resistance is an urgent task, as many microorganisms threaten human health due to increasing bacterial resistance to traditional medicines. Thus, new molecules such as antimicrobial peptides have emerged as promising alternatives because of their low induction of resistance and broad spectrum of action. In this context, in the past few years, our research group has synthesized and characterized a peptide derived from the C-terminal region of the Lys49 PLA2-like BthTX-I, named p-BthTX-I. After several studies, the peptide (p-BthTX-I)2K was proposed as the molecule with the most considerable biotechnological potential. As such, the present work aimed to evaluate whether the modifications made on the peptide (p-BthTX-I)2K can be applied to other molecules originating from the C-terminal region of PLA2-like Lys49 from snake venoms. The peptides were obtained through the solid-phase peptide synthesis technique, and biochemical and functional characterization was carried out using dichroism techniques, mass spectrometry, antimicrobial activity against ESKAPE strains, hemolytic activity, and permeabilization of lipid vesicles. The antimicrobial activity of the peptides was promising, especially for the peptides (p-AppK)2K and (p-ACL)2K, which demonstrated activity against all strains that were tested, surpassing the model molecule (p-BthTX-I)2K in most cases and maintaining low hemolytic activity. The modifications initially proposed for the (p-BthTX-I)2K peptide were shown to apply to other peptides derived from Lys49 PLA2-like from snake venoms, showing promising results for antimicrobial activity. Future assays comparing the activity of the dimers obtained through this strategy with the monomers of these peptides should be carried out.

Evolutionary Dynamics of Accelerated Antiviral Resistance Development in Hypermutator Herpesvirus

Antiviral therapy is constantly challenged by the emergence of resistant pathogens. At the same time, experimental approaches to understand and predict resistance are limited by long periods required for evolutionary processes. Here, we present a herpes simplex virus 1 mutant with impaired proofreading capacity and consequently elevated mutation rates. Comparing this hypermutator to parental wild type virus, we study the evolution of antiviral drug resistance in vitro. We model resistance development and elucidate underlying genetic changes against three antiviral substances. Our analyzes reveal no principle difference in the evolutionary behavior of both viruses, adaptive processes are overall similar, however significantly accelerated for the hypermutator. We conclude that hypermutator viruses are useful for modeling adaptation to antiviral therapy. They offer the benefit of expedited adaptation without introducing apparent bias and can therefore serve as an accelerator to predict natural evolution.

Metabolomics unveil key pathways underlying the synergistic activities of aztreonam and avibactam against multidrug-resistant Escherichia coli

PURPOSE

Aztreonam/avibactam is effective against serious infections caused by Gram-negative bacteria including Enterobacterales harboring metallo-β-lactamases. While the utility of this combination has been established in vitro and in clinical trials, the purpose of this study is to enhance our understanding of the underlying mechanism responsible for their activities through metabolomic profiling of a multidrug-resistant Escherichia coli clinical isolate.

METHODS

Metabolomic analyses of time-dependent changes in endogenous bacterial metabolites in a clinical isolate of a multidrug-resistant E. coli treated with aztreonam and avibactam were performed. E. coli metabolomes were compared at 15 min, 1 h and 24 h following treatments with either avibactam (4 mg/L), aztreonam (4 mg/L), or aztreonam (4 mg/L) + avibactam (4 mg/L).

RESULTS

Drug treatment affected 326 metabolites with magnitude changes of at least 2-fold, most of which are involved primarily in peptidoglycan biosynthesis, nucleotide metabolism, and lipid metabolism. The feedstocks for peptidoglycan synthesis were depleted by aztreonam/avibactam combination; a significant downstream increase in nucleotide metabolites and a release of lipids were observed at the three timepoints.

CONCLUSION

The findings indicate that the aztreonam/avibactam combination accelerates structural damage to the bacterial membrane structure and their actions were immediate and sustained compared to aztreonam or avibactam alone. By inhibiting the production of crucial cell wall precursors, the combination may have inflicted damages on bacterial DNA.

Advances in single-cell sequencing technology in microbiome research

With the rapid development of histological techniques and the widespread application of single-cell sequencing in eukaryotes, researchers desire to explore individual microbial genotypes and functional expression, which deepens our understanding of microorganisms. In this review, the history of the development of microbial detection technologies was revealed and the difficulties in the application of single-cell sequencing in microorganisms were dissected as well. Moreover, the characteristics of the currently emerging microbial single-cell sequencing (Microbe-seq) technology were summarized, and the prospects of the application of Microbe-seq in microorganisms were distilled based on the current development status. Despite its mature development, the Microbe-seq technology was still in the optimization stage. A retrospective study was conducted, aiming to promote the widespread application of single-cell sequencing in microorganisms and facilitate further improvement in the technology.

Unveiling the Druggable Landscape of Bacterial Peptidyl tRNA Hydrolase: Insights into Structure, Function, and Therapeutic Potential

Bacterial peptidyl tRNA hydrolase (Pth) or Pth1 emerges as a pivotal enzyme involved in the maintenance of cellular homeostasis by catalyzing the release of peptidyl moieties from peptidyl-tRNA molecules and the maintenance of a free pool of specific tRNAs. This enzyme is vital for bacterial cells and an emerging drug target for various bacterial infections. Understanding the enzymatic mechanisms and structural intricacies of bacterial Pth is pivotal in designing novel therapeutics to combat antibiotic resistance. This review provides a comprehensive analysis of the multifaceted roles of Pth in bacterial physiology, shedding light on its significance as a potential drug target. This article delves into the diverse functions of Pth, encompassing its involvement in ribosome rescue, the maintenance of a free tRNA pool in bacterial systems, the regulation of translation fidelity, and stress response pathways within bacterial systems. Moreover, it also explores the druggability of bacterial Pth, emphasizing its promise as a target for antibacterial agents and highlighting the challenges associated with developing specific inhibitors against this enzyme. Structural elucidation represents a cornerstone in unraveling the catalytic mechanisms and substrate recognition of Pth. This review encapsulates the current structural insights of Pth garnered through various biophysical techniques, such as X-ray crystallography and NMR spectroscopy, providing a detailed understanding of the enzyme's architecture and conformational dynamics. Additionally, biophysical aspects, including its interaction with ligands, inhibitors, and substrates, are discussed, elucidating the molecular basis of bacterial Pth's function and its potential use in drug design strategies. Through this review article, we aim to put together all the available information on bacterial Pth and emphasize its potential in advancing innovative therapeutic interventions and combating bacterial infections.

Influence of β-lactam pharmacodynamics on the systems microbiology of gram-positive and gram-negative polymicrobial communities

Objectives

We sought to evaluate the pharmacodynamics of β-lactam antibacterials against polymicrobial communities of clinically relevant gram-positive and gram-negative pathogens.

Methods

Two Enterococcus faecalis isolates, two Staphylococcus aureus isolates, and three Escherichia coli isolates with varying β-lactamase production were evaluated in static time-killing experiments. Each gram-positive isolate was exposed to a concentration array of ampicillin (E. faecalis) or cefazolin (S. aureus) alone and during co-culture with an E. coli isolate that was β-lactamase-deficient, produced TEM-1, or produced KPC-3/TEM-1B. The results of the time-killing experiments were summarized using an integrated pharmacokinetic/pharmacodynamics analysis as well as mathematical modelling to fully characterize the antibacterial pharmacodynamics.

Results

In the integrated analysis, the maximum killing of ampicillin (Emax) against both E. faecalis isolates was ≥ 4.11 during monoculture experiments or co-culture with β-lactamase-deficient E. coli, whereas the Emax was reduced to ≤ 1.54 during co-culture with β-lactamase-producing E. coli. In comparison to monoculture experiments, culturing S. aureus with KPC-producing E. coli resulted in reductions of the cefazolin Emax from 3.25 and 3.71 down to 2.02 and 2.98, respectively. Two mathematical models were created to describe the interactions between E. coli and either E. faecalis or S. aureus. When in co-culture with E. coli, S. aureus experienced a reduction in its cefazolin Kmax by 24.8% (23.1%RSE). Similarly, β-lactamase-producing E. coli preferentially protected the ampicillin-resistant E. faecalis subpopulation, reducing Kmax,r by 90.1% (14%RSE).

Discussion

β-lactamase-producing E. coli were capable of protecting S. aureus and E. faecalis from exposure to β-lactam antibacterials.

PET/CT Imaging of Infectious Diseases: Overview of Novel Radiopharmaceuticals

Infectious diseases represent one of the most common causes of hospital admission worldwide. The diagnostic work-up requires a complex clinical approach, including laboratory data, CT and MRI, other imaging tools, and microbiologic cultures. PET/CT with 18F-FDG can support the clinical diagnosis, allowing visualization of increased glucose metabolism in activated macrophages and monocytes; this tracer presents limits in differentiating between aseptic inflammation and infection. Novel PET radiopharmaceuticals have been developed to overcome these limits; 11C/18F-labeled bacterial agents, several 68Ga-labeled molecules, and white blood cells labeled with 18F-FDG are emerging PET tracers under study, showing interesting preliminary results. The best choice among these tracers can be unclear. This overview aims to discuss the most common diagnostic applications of 18F-FDG PET/CT in infectious diseases and, as a counterpoint, to describe and debate the advantages and peculiarities of the latest PET radiopharmaceuticals in the field of infectious diseases, which will probably improve the diagnosis and prognostic stratification of patients with active infectious diseases.

LL-37: Structures, Antimicrobial Activity, and Influence on Amyloid-Related Diseases

Antimicrobial peptides (AMPs), as well as host defense peptides (HDPs), constitute the first line of defense as part of the innate immune system. Humans are known to express antimicrobial precursor proteins, which are further processed to generate AMPs, including several types of α/β defensins, histatins, and cathelicidin-derived AMPs like LL37. The broad-spectrum activity of AMPs is crucial to defend against infections caused by pathogenic bacteria, viruses, fungi, and parasites. The emergence of multi-drug resistant pathogenic bacteria is of global concern for public health. The prospects of targeting antibiotic-resistant strains of bacteria with AMPs are of high significance for developing new generations of antimicrobial agents. The 37-residue long LL37, the only cathelicidin family of AMP in humans, has been the major focus for the past few decades of research. The host defense activity of LL37 is likely underscored by its expression throughout the body, spanning from the epithelial cells of various organs-testis, skin, respiratory tract, and gastrointestinal tract-to immune cells. Remarkably, apart from canonical direct killing of pathogenic organisms, LL37 exerts several other host defense activities, including inflammatory response modulation, chemo-attraction, and wound healing and closure at the infected sites. In addition, LL37 and its derived peptides are bestowed with anti-cancer and anti-amyloidogenic properties. In this review article, we aim to develop integrative, mechanistic insight into LL37 and its derived peptides, based on the known biophysical, structural, and functional studies in recent years. We believe that this review will pave the way for future research on the structures, biochemical and biophysical properties, and design of novel LL37-based molecules.

Combating antimicrobial resistance: the silent war

Once hailed as miraculous solutions, antibiotics no longer hold that status. The excessive use of antibiotics across human healthcare, agriculture, and animal husbandry has given rise to a broad array of multidrug-resistant (MDR) pathogens, posing formidable treatment challenges. Antimicrobial resistance (AMR) has evolved into a pressing global health crisis, linked to elevated mortality rates in the modern medical era. Additionally, the absence of effective antibiotics introduces substantial risks to medical and surgical procedures. The dwindling interest of pharmaceutical industries in developing new antibiotics against MDR pathogens has aggravated the scarcity issue, resulting in an exceedingly limited pipeline of new antibiotics. Given these circumstances, the imperative to devise novel strategies to combat perilous MDR pathogens has become paramount. Contemporary research has unveiled several promising avenues for addressing this challenge. The article provides a comprehensive overview of these innovative therapeutic approaches, highlighting their mechanisms of action, benefits, and drawbacks.