Investigation on the Synergy between Membrane Permeabilizing Amphiphilic α-Hydrazido Acids and Commonly Used Antibiotics against Drug-Resistant Bacteria.

The growth of (multi)drug resistance in bacteria is among the most urgent global health issues. Monocationic amphiphilic α-hydrazido acid derivatives are structurally simple mimics of antimicrobial peptides (AMPs) with fewer drawbacks. Their mechanism of membrane permeabilization at subtoxic concentrations was found to begin with an initial electrostatic attraction of isolated amphiphile molecules to the phospholipid heads, followed by a rapid insertion of the apolar portions.

Characterization of bacterial communities associated with seabed sediments in offshore and nearshore sites to improve Microbiologically Influenced Corrosion mitigation on marine infrastructures.

Microbiologically Influenced Corrosion (MIC) is one of the main threats for marine infrastructures, leading to severe safety and environmental risks associated with structural failures and/or leakages of dangerous fluids, together with potential huge economic losses and reputational damage for the involved parts. For a safe design and a proper installation of infrastructure systems in contact with the seabed, a deep knowledge of the site-specific microbial community of the sediments should be beneficial. Therefore, in addition to the simple detection or the sole quantification of Sulphate-Reducing Bacteria (SRB), the whole characterization of the microbial members involved in MIC phenomena is desirable.

Involvement of Acquired Tobramycin Resistance in the Shift to the Viable but Non-Culturable State in .

Persistent and viable but non-culturable (VBNC) cells are mainly responsible for the recurrence and non-responsiveness to antibiotics of cystic fibrosis (CF) lung infections. The sub-inhibitory antibiotic concentrations found in the CF lung in between successive therapeutic cycles can trigger the entry into the VBNC state, albeit with a strain-specific pattern. Here, we analyzed the VBNC cell induction in the biofilms of two CF isolates, exposed to starvation with/without antibiotics, and investigated the putative genetic determinants involved.

Zooplankton as a Transitional Host for in Freshwater.

This study shows that Escherichia coli can be temporarily enriched in zooplankton under natural conditions and that these bacteria can belong to different phylogroups and sequence types (STs), including environmental, clinical, and animal isolates. We isolated 10 E. coli strains and sequenced the genomes of two of them.

A proposal for the reference intervals of the Italian microbiota "scaffold" in healthy adults.

Numerous factors, ranging from genetics, age, lifestyle, and dietary habits to local environments, contribute to the heterogeneity of the microbiota in humans. Understanding the variability of a "healthy microbiota" is a major challenge in scientific research. The gut microbiota profiles of 148 healthy Italian volunteers were examined by 16S rRNA gene sequencing to determine the range and diversity of taxonomic compositions in the gut microbiota of healthy populations.

A combination of sugar esters and chitosan to promote in vivo wound care.

In recent years, researchers are exploring innovative green materials fabricated from renewable natural substances to meet formulation needs. Among them, biopolymers like chitosans and biosurfactants such as sugar fatty acid esters are of potential interest due to their biocompatibility, biodegradability, functionality, and cost-effectiveness. Both classes of biocompounds possess the ability to be efficiently employed in wound dressing to help physiological wound healing, which is a bioprocess involving uncontrolled oxidative damage and inflammation, with an associated high risk of infection.

The Natural Alkaloid Berberine Can Reduce the Number of Tolerant Cells.

The eradication of recurrent (PA) lung infection in cystic fibrosis (CF) patients may be hampered by the development of persistent bacterial forms, which can tolerate antibiotics through efflux pump overexpression. After demonstrating the efflux pump inhibitory effect of the alkaloid berberine on the PA MexXY-OprM efflux pump, in this study, we tested its ability (80/320 μg/mL) to enhance tobramycin (20xMIC/1000xMIC) activity against PA planktonic/biofilm cultures. Preliminary investigations of the involvement of MexY in PA tolerance to tobramycin treatment, performed on the isogenic pair PA K767 (wild type)/K1525 (Δ) growing in planktonic and biofilm cultures, demonstrated that the Δ mutant K1525 produced a lower (100 and 10 000 times, respectively) amount of tolerant cells than that of the wild type.

Contribution of Drugs Interfering with Protein and Cell Wall Synthesis to the Persistence of Biofilms: An In Vitro Model.

The occurrence of (PA) persisters, including viable but non-culturable (VBNC) forms, subpopulations of tolerant cells that can survive high antibiotic doses, is the main reason for PA lung infections failed eradication and recurrence in Cystic Fibrosis (CF) patients, subjected to life-long, cyclic antibiotic treatments. In this paper, we investigated the role of subinhibitory concentrations of different anti-pseudomonas antibiotics in the maintenance of persistent (including VBNC) PA cells in in vitro biofilms. Persisters were firstly selected by exposure to high doses of antibiotics and their abundance over time evaluated, using a combination of cultural, qPCR and flow cytometry assays.

A Fluorinated Analogue of Marine Bisindole Alkaloid 2,2-Bis(6-bromo-1-indol-3-yl)ethanamine as Potential Anti-Biofilm Agent and Antibiotic Adjuvant Against .

Methicillin resistant (MRSA) infections represent a major global healthcare problem. Therapeutic options are often limited by the ability of MRSA strains to grow as biofilms on medical devices, where antibiotic persistence and resistance is positively selected, leading to recurrent and chronic implant-associated infections. One strategy to circumvent these problems is the co-administration of adjuvants, which may prolong the efficacy of antibiotic treatments, by broadening their spectrum and lowering the required dosage.

Role of Tobramycin in the Induction and Maintenance of Viable but Non-Culturable in an In Vitro Biofilm Model.

The recurrence of (PA) biofilm infections is a major issue in cystic fibrosis (CF) patients. A pivotal role is played by the presence of antibiotic-unresponsive persisters and/or viable but non-culturable (VBNC) forms, whose development might be favored by subinhibitory antibiotic concentrations. The involvement of tobramycin and ciprofloxacin, widely used to treat CF PA lung infections, in the abundance of VBNC cells was investigated in PA biofilms models.

Diffusion and Characterization of Pseudomonas aeruginosa Aminoglycoside Resistance in an Italian Regional Cystic Fibrosis Centre.

Aims: Extensively-drug-resistant Pseudomonas aeruginosa constitutes a serious threat to patients suffering from Cystic Fibrosis (CF). In these patients, P. aeruginosa lung infection is commonly treated with aminoglycosides, but treatments are largely unsuccessful due a variety of resistance mechanisms.

Plasmid Replicon Typing of Antibiotic-Resistant From Clams and Marine Sediments.

Unlike human isolates, environmental isolates have not been thoroughly investigated for the diversity and transferability of antibiotic-resistant plasmids. In this study, antibiotic-resistant strains from marine sediment ( = 50) and clams ( = 53) were analyzed (i) for their plasmid content using a PCR-based plasmid replicon typing (PBRT) kit and (ii) for the transferability of plasmid-associated antibiotic resistance (AR) traits by mating experiments. Fifteen of the thirty replicons targeted by the PBRT kit were detected in the isolates; 8/15 were identified in both sediment and clam isolates, although at different frequencies.

Simple amphiphilic α-hydrazido acids: Rational design, synthesis, and in vitro bioactivity profile of a novel class of potential antimicrobial compounds.

Pursuing the search for a new class of structurally simple mimics of antimicrobial peptides, we optimized a short, cheap and high-yielding synthesis of mono-charged amphiphilic α-hydrazido acid derivatives. The most active derivatives furnished MICs that are among the best values reported in literature for synthetic amphiphilic membranolytic compounds. They exhibited a broad-spectrum in vitro activity against a variety of Gram-positive and Gram-negative bacteria, including two multidrug-resistant strains.

Erythromycin-resistant lactic acid bacteria in the healthy gut of vegans, ovo-lacto vegetarians and omnivores.

Diet can affect the diversity and composition of gut microbiota. Usage of antibiotics in food production and in human or veterinary medicine has resulted in the emergence of commensal antibiotic resistant bacteria in the human gut. The incidence of erythromycin-resistant lactic acid bacteria (LAB) in the feces of healthy vegans, ovo-lacto vegetarians and omnivores was analyzed.

Natural Alkaloid Berberine Activity against MexXY-Mediated Aminoglycoside Resistance: and Studies.

The multidrug efflux system MexXY-OprM, inside the resistance-nodulation-division family, is a major determinant of aminoglycoside resistance in . In the fight aimed to identify potential efflux pump inhibitors among natural compounds, the alkaloid berberine emerged as a putative inhibitor of MexXY-OprM. In this work, we elucidated its interaction with the extrusor protein MexY and assessed its synergistic activity with aminoglycosides.

Characterization of a new transferable MDR plasmid carrying the pbp5 gene from a clade B commensal Enterococcus faecium.

Objectives: To evaluate the transferability of antibiotic resistance from an MDR clade B Enterococcus faecium and to characterize the genetic elements involved.

Methods: The erm(B)-positive strain E. faecium 37BA (donor) and strains E.

Detection of viable but non-culturable Pseudomonas aeruginosa in cystic fibrosis by qPCR: a validation study.

Background: Routine culture-based diagnosis of Pseudomonas aeruginosa lung infection in Cystic Fibrosis (CF) patients can be hampered by the phenotypic variability of the microorganism, including its transition to a Viable But Non-Culturable (VBNC) state. The aim of this study was to validate an ecfX-targeting qPCR protocol developed to detect all viable P. aeruginosa bacteria and to identify VBNC forms in CF sputum samples.

Antibiotic and heavy metal resistance in enterococci from coastal marine sediment.

Sediment samples from three coastal sites - two beach resorts (Beach 1 and Beach 2 sites) and an area lying between an oil refinery and a river estuary (Estuarine site) - were analyzed for antibiotic- and heavy metal (HM)-resistant enterococci. A total of 123 enterococci, 36 E. faecium, 34 E.

Defence strategies and antibiotic resistance gene abundance in enterococci under stress by exposure to low doses of peracetic acid.

Peracetic acid (PAA) is an organic compound used efficiently as disinfectant in wastewater treatments. Yet, at low doses it may cause selection; thus, the effect of low doses of PAA on Enterococcus faecium as a proxy of human-related microbial waste was evaluated. Bacteria were treated with increasing doses of PAA (from 0 to 25 mg L min) and incubated in regrowth experiments under non-growing, limiting conditions and under growing, favorable conditions.

Adherence and intracellular survival within human macrophages of Enterococcus faecalis isolates from coastal marine sediment.

Enterococcus faecalis is part of the human intestinal microbiota and an important nosocomial pathogen. It can be found in the marine environment, where it is also employed as a fecal indicator. To assess the pathogenic potential of marine E.

Multiparameter analysis of apoptosis in puromycin-treated Saccharomyces cerevisiae.

In Saccharomyces cerevisiae, a typical apoptotic phenotype is induced by some stress factors such as sugars, acetic acid, hydrogen peroxide, aspirin and age. Nevertheless, no data have been reported for apoptosis induced by puromycin, a damaging agent known to induce apoptosis in mammalian cells. We treated S.