Inhibition of biofilm formation and preformed biofilm in by resveratrol, chlorhexidine and benzalkonium: modulation of efflux pump activity.

Introduction: The persistence of in the contaminated environment is sustained by tolerance to biocides and ability to growth as biofilm. The aim of the study was to analyze the susceptibility of biofilms to chlorhexidine (CHX) and benzalkonium (BZK) biocides and the ability of natural monomeric stilbenoid resveratrol (RV) to modulate the phenomenon.

Methods: Biofilm formation and preformed biofilm were tested by Crystal violet and tetrazolium salt reduction assay, respectively.

Direct analysis by ultra-high-resolution mass spectrometry of lipid A and phospholipids from Acinetobacter baumannii cells.

Acinetobacter baumannii, classified as priority number one by the World Health Organization (WHO), is an opportunistic pathogen responsible for infection and is able to develop antibiotic resistance easily. Membranes are bacteria's first line of defense against external aggression, such as antibiotics. A chemical modification of a lipid family or a change in lipid composition can lead to resistance to antibiotics.

Lipidome of Acinetobacter baumannii antibiotic persister cells.

Persister cells constitute a bacterial subpopulation able to survive to high concentrations of antibiotics. This phenotype is temporary and reversible, and thus could be involved in the recurrence of infections and emergence of antibiotic resistance. To better understand how persister cells survive to such high antibiotic concentration, we examined changes in their lipid composition.

Antibiofilm and Antivirulence Properties of 6-Polyaminosteroid Derivatives against Antibiotic-Resistant Bacteria.

The emergence of multi-drug resistant pathogens is a major public health problem, leading us to rethink and innovate our bacterial control strategies. Here, we explore the antibiofilm and antivirulence activities of nineteen 6-polyaminosterol derivatives (squalamine-based), presenting a modulation of their polyamine side chain on four major pathogens, i.e.

Using Targeted Nano-Antibiotics to Improve Antibiotic Efficacy against Infections.

The poor bioavailability of antibiotics at infection sites is one of the leading causes of treatment failure and increased bacterial resistance. Therefore, developing novel, non-conventional antibiotic delivery strategies to deal with bacterial pathogens is essential. Here, we investigated the encapsulation of two fluoroquinolones, ciprofloxacin and levofloxacin, into polymer-based nano-carriers (nano-antibiotics), with the goal of increasing their local bioavailability at bacterial infection sites.

6-Polyaminosteroid Squalamine Analogues Display Antibacterial Activity against Resistant Pathogens.

A series of 6-polyaminosteroid analogues of squalamine were synthesized with moderate to good yields and evaluated for their antimicrobial properties against both susceptible and resistant Gram-positive (vancomycin-resistant and methicillin-resistant ) and Gram-negative (carbapenem-resistant and bacterial strains. Minimum inhibitory concentrations against Gram-positive bacteria ranged from 4 to 16 µg/mL for the most effective compounds, and , and showed an additive or synergistic effect with vancomycin or oxacillin. On the other hand, the derivative , which carries a spermine moiety like that of the natural trodusquemine molecule, was found to be the most active derivative against all the resistant Gram-negative bacteria tested, with an MIC value of 16 µg/mL.

Lysine Trimethylation in Planktonic and Pellicle Modes of Growth in .

Over the past 30 years, has been described as an important nosocomial pathogen due to frequent ventilator-associated infections. Many biological processes of remain elusive, such as the formation of an air-liquid biofilm (pellicle). Several studies demonstrated the importance of post-translational modifications (PTMs) in physiology.

MacAB-TolC Contributes to the Development of Biofilm at the Solid-Liquid Interface.

has emerged as one of the most problematic bacterial pathogens responsible for hospital-acquired and community infections worldwide. Besides its high capacity to acquire antibiotic resistance mechanisms, it also presents high adhesion abilities on inert and living surfaces leading to biofilm development. This lifestyle confers additional protection against various treatments and allows it to persist for long periods in various hospital niches.

Phosphorylation of Extracellular Proteins in in Sessile Mode of Growth.

is a problematic nosocomial pathogen owing to its increasing resistance to antibiotics and its great ability to survive in the hospital environment, which is linked to its capacity to form biofilms. Structural and functional investigations of post-translational modifications, such as phosphorylations, may lead to identification of candidates for therapeutic targets against this pathogen. Here, we present the first S/T/Y phosphosecretome of two strains, the reference strain ATCC 17978 and the virulent multi-drug resistant strain AB0057, cultured in two modes of growth (planktonic and biofilm) using TiO chromatography followed by high resolution mass spectrometry.

Membrane Proteocomplexome of Using 2-D Blue Native/SDS-PAGE Combined to Bioinformatics Analysis.

is the leading cause of the human bacterial foodborne infections in the developed countries. The perception cues from biotic or abiotic environments by the bacteria are often related to bacterial surface and membrane proteins that mediate the cellular response for the adaptation of to the environment. These proteins function rarely as a unique entity, they are often organized in functional complexes.

Membrane phospholipid composition of Pseudomonas aeruginosa grown in a cystic fibrosis mucus-mimicking medium.

Background: Pseudomonas aeruginosa is a bacterium able to induce serious pulmonary infections in cystic fibrosis (CF) patients. This bacterium is very often antibiotic resistant, partly because of its membrane impermeability, which is linked to the membrane lipid composition. This work aims to study the membrane phospholipids of P.

Determination of the collision cross sections of cardiolipins and phospholipids from Pseudomonas aeruginosa by traveling wave ion mobility spectrometry-mass spectrometry using a novel correction strategy.

Collision cross section (CCS) values are descriptors of the 3D structure of ions which can be determined by ion mobility spectrometry (IMS). Currently, most lipidomic studies involving CCS value determination concern eukaryote samples (e.g.

Chronic wound healing: A specific antibiofilm protein-asymmetric release system.

Chronic infection is a major cause of delayed wound-healing. It is recognized to be associated with infectious bacterial communities called biofilms. Currently used conventional antibiotics alone often reveal themselves ineffective, since they do not specifically target the wound biofilm.

BioFlux™ 200 Microfluidic System to Study A. baumannii Biofilm Formation in a Dynamic Mode of Growth.

The ability of A. baumannii to develop biofilms on a wide range of surfaces can be associated to its persistence in hospital settings and the emergence of recalcitrant and chronic infections. Few compounds are available to eradicate A.

Anti-persister activity of squalamine against Acinetobacter baumannii.

Squalamine is a natural polycationic aminosterol extracted from the shark Squalus acanthias. Squalamine displays remarkable efficacy against antimicrobial-resistant Gram-negative and Gram-positive bacteria. Its membranolytic activity and low cytotoxicity make squalamine one of the most promising agents to fight nosocomial pathogens such as Acinetobacter baumannii.

Identification by mass spectrometry of glucosaminylphosphatidylglycerol, a phosphatidylglycerol derivative, produced by Pseudomonas aeruginosa.

Rationale: Pseudomonas aeruginosa is an opportunistic pathogen bacterium widely considered to be an excellent research model in several areas of molecular studies, namely genomics and proteomics. However, its lipid metabolism is still not totally decrypted. While it is known that this bacterium has the particularity to produce phosphatidylcholine, a lipid mainly found in eukaryotes, other singularities are still to be discovered.

Lysine Succinylation and Acetylation in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a multi-drug-resistant human opportunistic pathogen largely involved in nosocomial infections. Unfortunately, effective antibacterial agents are lacking. Exploring its physiology at the post-translational modifications (PTMs) level may contribute to the renewal of combat tactics.

Unsaturated Fatty Acids Affect Quorum Sensing Communication System and Inhibit Motility and Biofilm Formation of Acinetobacter baumannii.

The increasing threat of as a nosocomial pathogen is mainly due to the occurrence of multidrug-resistant strains that are associated with the real problem of its eradication from hospital wards. The particular ability of this pathogen to form biofilms contributes to its persistence, increases antibiotic resistance, and promotes persistent/device-related infections. We previously demonstrated that virstatin, which is a small organic compound known to decrease virulence of via an inhibition of T4-pili expression, displayed very promising activity to prevent biofilm development.

Chemical modification of xanthan in the ordered and disordered states: An open route for tuning the physico-chemical properties.

The impact of the chain stiffness on physicochemical properties has been studied by chemical modification of xanthan under both ordered and disordered conformations. Corresponding rheological properties were studied and results showed that amphiphilic xanthan exhibited completely different behaviors depending on its conformation during modification. Xanthan, when modified under ordered conformation, exhibits similar behavior to non-modified one, only the chain relaxation being strongly slowed down.

Carboxymethylpullulan Grafted with Aminoguaiacol: Synthesis, Characterization, and Assessment of Antibacterial and Antioxidant Properties.

Aminoguaiacol, the aminated derivative of guaiacol, a natural phenolic compound, was chemically grafted onto a polysaccharide (carboxymethylpullulan, CMP) in the presence of the activator agent 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDCI). The grafted polysaccharides were characterized by FTIR and H NMR spectroscopy to confirm and quantify the grafting. All polysaccharide derivatives (grafting rates of aminoguaiacol between 16% and 58%) were soluble in water.

Global Dynamic Proteome Study of a Pellicle-forming Acinetobacter baumannii Strain.

For several decades, many bacteria, among which A. baumannii, have shown their ability to colonize the upper surface of static liquids, forming a biofilm at the air-liquid interface named pellicle. Despite the ubiquity of these pellicles in both natural and artificial environments, few studies have investigated this biofilm type.

Proteomic characterization of Nα- and Nε-acetylation in Acinetobacter baumannii.

Unlabelled: Nα- and Nε-acetylation represent a pivotal post-translational modification used by both eukaryotes and prokaryotes to modulate diverse biological processes. Acinetobacter baumannii has been described as an important nosocomial pathogen for the past 30 years, frequently involved in ventilator-associated pneumonia, bloodstream and urinary tract infections. Many aspects of the biology of A.