Explore the vast range of titles available.

Gram-negative bacteria release Outer Membrane Vesicles (OMVs) into the extracellular environment. Recent studies recognized these vesicles as vectors to horizontal gene transfer; however, the parameters that mediate OMVs transfer within bacterial communities remain unclear. The present study highlights for the first time the transfer of plasmids containing resistance genes via OMVs derived from Klebsiella pneumoniae (K. pneumoniae). This mechanism confers DNA protection, it is plasmid copy number dependent with a ratio of 3.6 times among high copy number plasmid (pGR) versus low copy number plasmid (PRM), and the transformation efficiency was 3.6 times greater. Therefore, the DNA amount in the vesicular lumen and the efficacy of horizontal gene transfer was strictly dependent on the identity of the plasmid. Moreover, the role of K. pneumoniae-OMVs in interspecies transfer was described. The transfer ability was not related to the phylogenetic characteristics between the donor and the recipient species. K. pneumoniae-OMVs transferred plasmid to Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa and Burkholderia cepacia. These findings address the pivotal role of K. pneumoniae-OMVs as vectors for antimicrobial resistance genes spread, contributing to the development of antibiotic resistance in the microbial communities.

Triterpene acids are a class of pentacyclic natural carboxylic compounds endowed with a variety of biological activities including antitumor, antimicrobial, and hepatoprotective effects. In this work, several oleanolic acid derivatives were synthesized by structurally modifying them on the C-3 position. All synthesized derivatives were evaluated for possible antibacterial and antiviral activity, and among all the epimers, 6 and 7 demonstrated the best biological activities. Zone-of-inhibition analyses were conducted against two strains, E. coli as a Gram-negative and S. aureus as a Gram-positive model. Subsequently, experiments were performed using the microdilution method to determine the minimum inhibitory concentration (MIC). The results showed that only the derivative with reduced hydrogen bonding ability on ring A possesses remarkable activity toward E. coli. The conversion from acid to methyl ester implies a loss of activity, probably due to a reduced affinity with the bacterial membrane. Before the antiviral activity, the cytotoxicity of triterpenes was evaluated through a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Samples 6 and 7 showed less than 50% cytotoxicity at 0.625 and 1 mg/mL, respectively. The antiviral activity against SARS-CoV-2 and PV-1 did not indicate that triterpene acids had any inhibitory capacity in the sub-toxic concentration range.

The increasing spread of multidrug-resistant pathogenic bacteria is one of the major threats to public health worldwide. Bacteria can acquire antibiotic resistance and virulence genes through horizontal gene transfer (HGT). A novel horizontal gene transfer mechanism mediated by outer membrane vesicles (OMVs) has been recently identified. OMVs are rounded nanostructures released during their growth by Gram-negative bacteria. Biologically active toxins and virulence factors are often entrapped within these vesicles that behave as molecular carriers. Recently, OMVs have been reported to contain DNA molecules, but little is known about the vesicle packaging, release, and transfer mechanisms. The present review highlights the role of OMVs in HGT processes in Gram-negative bacteria.

Metal and metal oxide nanostructured materials have been chemically and physically characterized and tested concerning methylene blue (MB) photoremoval and UV antibacterial activity against Escherichia coli and Staphylococcus aureus. In detail, silver nanoparticles and commercial BaTiO3 nanoparticles were modified to obtain nanocomposites through sonicated sol–gel TiO2 synthesis and the photodeposition of Ag nanoparticles, respectively. The characterization results of pristine nanomaterials and synthetized photocatalysts revealed significant differences in specific surface area (SSA), the presence of impurities in commercial Ag nanoparticles, an anatase phase with brookite traces for TiO2-based nanomaterials, and a mixed cubic–tetragonal phase for BaTiO3. Silver nanoparticles exhibited superior antibacterial activity at different dosages; however, they were inactive in the photoremoval of the dye. The silver–TiOx nanocomposite demonstrated an activity in the UV photodegradation of MB and UV inhibition of bacterial growth. Specifically, TiO2/AgNP (30–50 nm) reduced growth by 487.5 and 1.1 × 103 times for Escherichia coli and Staphylococcus aureus, respectively, at a dose of 500 μg/mL under UV irradiation.

Extracellular vesicles (EVs) are nanometer-sized lipid structures actively secreted by Gram-negative and Gram-positive bacteria, representing a sophisticated microbial adaptation and communication strategy. These structures are involved in biomolecular transport, the regulation of biological processes, the modulation of host–pathogen interactions, and adaptation to hostile environmental conditions. EVs also play a crucial role in virulence, antibiotic resistance, and biofilm formation. This review will explore the biogenesis, composition, and biological mechanisms of outer membrane vesicles (OMVs) secreted by Gram-negative bacteria and membrane vesicles (MVs) generated by Gram-positive bacteria. In detail, the modulation of EVs in response to antibiotic exposure will be addressed. The role of EV morpho-functional adaptations will be studied in antimicrobial resistance, the gene determinant spread, and survival in adverse environments. This study aims to provide a comprehensive overview of the EV role in bacterial physiology, highlighting their ecological, evolutionary, and biotechnological implications. An overview of the enzymes and proteins mainly involved in OMV-mediated resistance mechanisms will also be provided. These insights could open new perspectives for developing therapeutic strategies that counteract EV secretion and biotechnological applications, such as vaccines and drug delivery systems.

This study investigated the performance of 24 commercial disinfectants present on the market during last year according to the manufacturer’s instructions. Recently, national and international organizations of public health performed studies on disinfection products due to the increasing awareness of the potential and growing risks on human health, such as skin damage and reactions in the mucosal lining, especially for the healthcare workers in their frequent daily use. However, there are many limitations in the common cleaning/disinfection products on market as in the selection of effective disinfectants to decontaminate inanimate surfaces. We analyzed the disinfection power of hydrogen peroxide, quaternary ammonium compounds, alcohols, phenols and aldehydes used as active principles according to international guidelines. The antimicrobial properties were assessed by broth microdilution, and antibiofilm properties against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ); their virucidal efficacy was tested against Herpes simplex virus type 1 (HSV-1) and Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The quaternary ammonium compounds demonstrated better efficacy than others and in some cases ready to use products had also virucidal and antimicrobial activities after dilution at 0.125%. The scientific evidence indicates that many commercial products are used at high concentrations and high doses and this could have deleterious effects both on human health and the environment. A lower concentration of active ingredients would avoid the excessive release of chemicals into the environment and improve skin tolerance, ensuring the health and safety protection of workers, including the healthcare operators at their workplace.

Root canal treatment represents a significant challenge as current cleaning and disinfection methodologies fail to remove persistent bacterial biofilms within the intricate anatomical structures. Recently, the field of nanotechnology has emerged as a promising frontier with numerous biomedical applications. Among the most notable contributions of nanotechnology are nanoparticles, which possess antimicrobial, antifungal, and antiviral properties. Nanoparticles cause the destructuring of bacterial walls, increasing the permeability of the cell membrane, stimulating the generation of reactive oxygen species, and interrupting the replication of deoxyribonucleic acid through the controlled release of ions. Thus, they could revolutionize endodontics, obtaining superior results and guaranteeing a promising short- and long-term prognosis. Therefore, chitosan, silver, graphene, poly(lactic) co-glycolic acid, bioactive glass, mesoporous calcium silicate, hydroxyapatite, zirconia, glucose oxidase magnetic, copper, and zinc oxide nanoparticles in endodontic therapy have been investigated in the present review. The diversified antimicrobial mechanisms of action, the numerous applications, and the high degree of clinical safety could encourage the scientific community to adopt nanoparticles as potential drugs for the treatment of endodontic diseases, overcoming the limitations related to antibiotic resistance and eradication of the biofilm.

Microbial biofilms pose a serious threat to patients requiring medical devices (MDs). Prolonged periods of implantation carry a high risk of device-related infections (DRIs). Patients with DRIs often have negative outcomes following the failure of antibiotic treatment. Resistant DRIs are mainly due to the MDs contamination by bacteria producing biofilm. The present study aimed to detect biofilm formation among MD bacterial isolates and to explore their antibiotic resistance profile. The study was conducted on 76 MDs, collected at University Hospital of Campania “Luigi Vanvitelli,” between October 2019 and September 2020. Identification of isolates and antibiotic susceptibility testing were performed using Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) and Phoenix Becton Dickinson, respectively. Biofilm-forming abilities were assessed using the tissue culture plate (TCP) method. Among the 94 MDs isolated strains, 42.7% were Gram-positive, 40.3% Gram-negative, and 17% Candida species. Among 78 bacterial strains, 43.6% were non-biofilm producers while 56.4% produced biofilms. All biofilm producing isolates were sensitive to a limited spectrum of antibiotic classes. All moderate and strong biofilm producers and 81% of weak biofilm producers were Multidrug Resistance (MDR) strains. In contrast, among non-biofilm producers, only 11.8% were classified as MDR strains. Our results highlighted that Sulfamides and Glycopeptides for the major Gram-positive strains and Fluoroquinolones, Carbapenems, and Aminoglycosides for the most represented Gram-negative isolates could be the most suitable therapeutic choice for most biofilm-DRIs.

Cervical cancer ranks as the fourth most prevalent cancer among women globally, with approximately 600,000 new cases being diagnosed each year. The principal driver of cervical cancer is the human papillomavirus (HPV), where viral oncoproteins E6 and E7 undertake the role of driving its carcinogenic potential. Despite extensive investigative efforts, numerous facets concerning HPV infection, replication, and pathogenesis remain shrouded in uncertainty. The virus operates through a variety of epigenetic mechanisms, and the epigenetic signature of HPV-related tumors is a major bottleneck in our understanding of the disease. Recent investigations have unveiled the capacity of viral oncoproteins to influence epigenetic changes within HPV-related tumors, and conversely, these tumors exert an influence on the surrounding epigenetic landscape. Given the escalating occurrence of HPV-triggered tumors and the deficiency of efficacious treatments, substantial challenges emerge. A promising avenue to address this challenge lies in epigenetic modulators. This review aggregates and dissects potential epigenetic modulators capable of combatting HPV-associated infections and diseases. By delving into these modulators, novel avenues for therapeutic interventions against HPV-linked cancers have come to the fore.

Efficient predictive biomarkers are needed for immune checkpoint inhibitor (ICI)-based immunotherapy in non-small cell lung cancer (NSCLC). Testing the predictive value of single nucleotide polymorphisms (SNPs) in programmed cell death 1 ( PD-1 ) or its ligand 1 ( PD-L1 ) has shown contrasting results. Here, we aim to validate the predictive value of PD-L1 SNPs in advanced NSCLC patients treated with ICIs as well as to define the molecular mechanisms underlying the role of the identified SNP candidate. rs822336 efficiently predicted response to anti-PD-1/PD-L1 immunotherapy in advanced non-oncogene addicted NSCLC patients as compared to rs2282055 and rs4143815. rs822336 mapped to the promoter/enhancer region of PD-L1 , differentially affecting the induction of PD-L1 expression in human NSCLC cell lines as well as their susceptibility to HLA class I antigen matched PBMCs incubated with anti-PD-1 monoclonal antibody nivolumab. The induction of PD-L1 expression by rs822336 was mediated by a competitive allele-specificity binding of two identified transcription factors: C/EBPβ and NFIC. As a result, silencing of C/EBPβ and NFIC differentially regulated the induction of PD-L1 expression in human NSCLC cell lines carrying different rs822336 genotypes. Analysis by binding microarray further validated the competitive allele-specificity binding of C/EBPβ and NFIC to PD-L1 promoter/enhancer region based on rs822336 genotype in human NSCLC cell lines. These findings have high clinical relevance since identify rs822336 and induction of PD-L1 expression as novel biomarkers for predicting anti-PD-1/PD-L1-based immunotherapy in advanced NSCLC patients.