is an opportunistic pathogen causing acute and chronic infections, especially in immunocompromised patients. Its remarkable adaptability and resistance to various antimicrobial treatments make it difficult to eradicate. Its persistence is enabled by its ability to form a biofilm.
View Article and Find Full Text PDFUnlabelled: is an opportunistic pathogen causing chronic infections that are related to its ability to form biofilms. Mechanosensitive ion channels (Mcs) are cytoplasmic membrane proteins whose opening depends on a mechanical stress impacting the lipid bilayer. CmpX is a homologue of the small conductance MscS of .
View Article and Find Full Text PDFis an opportunistic pathogen, which causes chronic infections, especially in cystic fibrosis (CF) patients where it colonizes the lungs via the build-up of biofilms. Tobramycin, an aminoglycoside, is often used to treat infections in CF patients. Tobramycin at sub-minimal inhibitory concentrations enhances both biofilm biomass and thickness ; however, the mechanism(s) involved are still unknown.
View Article and Find Full Text PDFBiofilms are highly tolerant to antimicrobials and host immune defense, enabling pathogens to thrive in hostile environments. The diversity of microbial biofilm infections requires alternative and complex treatment strategies. In a previous work we demonstrated that the human Atrial Natriuretic Peptide (hANP) displays a strong anti-biofilm activity toward and that the binding of hANP by the AmiC protein supports this effect.
View Article and Find Full Text PDFBacteria sense their environment via the cell envelope, which in Gram-negative bacteria comprises the outer membrane, the periplasmic space, and the inner membrane. Pseudomonas aeruginosa is an opportunistic pathogen which is exposed to different cell wall stresses imposed by exposure to antibiotics, osmotic pressure, and long-time colonization of host tissues such as the lung in cystic fibrosis patients. In response to these stresses, P.
View Article and Find Full Text PDFPhthalates are used in a variety of applications-for example, as plasticizers in polyvinylchloride products to improve their flexibility-and can be easily released into the environment. In addition to being major persistent organic environmental pollutants, some phthalates are responsible for the carcinogenicity, teratogenicity, and endocrine disruption that are notably affecting steroidogenesis in mammals. Numerous studies have thus focused on deciphering their effects on mammals and eukaryotic cells.
View Article and Find Full Text PDFPf4 is a filamentous bacteriophage integrated as a prophage into the genome of Pseudomonas aeruginosa PAO1. Pf4 virions can be produced without killing P. aeruginosa.
View Article and Find Full Text PDFis an opportunistic pathogen highly resistant to a wide range of antimicrobial agents, making its infections very difficult to treat. Since microorganisms need to perpetually adapt to their surrounding environment, understanding the effect of carbon sources on physiology is therefore essential to avoid increasing drug-resistance and better fight this pathogen. By a global proteomic approach and phenotypic assays, we investigated the impact of various carbon source supplementations (glucose, glutamate, succinate, and citrate) on the physiology of the PA14 strain.
View Article and Find Full Text PDFPseudomonas aeruginosa is a Gram-negative bacterium which can cause serious infections among immune-depressed people including cystic fibrosis patients where it can colonize the lungs causing chronic infections. Iron is essential for P. aeruginosa and can be provided via three sources under aerobic conditions: its own siderophores pyochelin (PCH) and pyoverdine (PVD), xenosiderophores, or heme, respectively.
View Article and Find Full Text PDFPseudomonas aeruginosa biofilms cause chronic, antibiotic tolerant infections in wounds and lungs. Numerous recent studies demonstrate that bacteria can detect human communication compounds through specific sensor/receptor tools that modulate bacterial physiology. Consequently, interfering with these mechanisms offers an exciting opportunity to directly affect the infection process.
View Article and Find Full Text PDFis an important multidrug-resistant human pathogen by dint of its high intrinsic, acquired, and adaptive resistance mechanisms, causing great concern for immune-compromised individuals and public health. Additionally, resilience lies in the production of a myriad of virulence factors, which are known to be tightly regulated by the quorum sensing (QS) system. Anti-virulence therapy has been adopted as an innovative alternative approach to circumvent bacterial antibiotic resistance.
View Article and Find Full Text PDFis a highly adaptable Gram-negative opportunistic pathogen, notably due to its large number of transcription regulators. The extracytoplasmic sigma factor (ECFσ) AlgU, responsible for alginate biosynthesis, is also involved in responses to cell wall stress and heat shock via the RpoH alternative σ factor. The SigX ECFσ emerged as a major regulator involved in the envelope stress response via membrane remodeling, virulence and biofilm formation.
View Article and Find Full Text PDFPAO1 has an integrated Pf4 prophage in its genome, encoding a relatively well-characterized filamentous phage, which contributes to the bacterial biofilm organization and maturation. Pf4 variants are considered as superinfectives when they can re-infect and kill the prophage-carrying host. Herein, the response of H103 to Pf4 variant infection was investigated.
View Article and Find Full Text PDFis capable to deploy a collection of virulence factors that are not only essential for host infection and persistence, but also to escape from the host immune system and to become more resistant to drug therapies. Thus, developing anti-virulence agents that may directly counteract with specific virulence factors or disturb higher regulatory pathways controlling the production of virulence armories are urgently needed. In this regard, this study reports that L.
View Article and Find Full Text PDFBiofilms produced by present a serious threat to cystic fibrosis patients. Here, we report the draft genome sequences of four cystic fibrosis isolates displaying various mucoid and biofilm phenotypes. The estimated average genome size was about 6,255,986 ± 50,202 bp with a mean G+C content of 66.
View Article and Find Full Text PDFBiofilms are commonly recalcitrant to antibiotics, through incompletely elucidated mechanisms such as tolerance and persistence. We aimed at investigating how a biofilm escapes ciprofloxacin treatment. PA14 mature biofilms were challenged with supra-MIC ciprofloxacin concentrations.
View Article and Find Full Text PDFBiofilms are structured microbial communities that are the leading cause of numerous chronic infections which are difficult to eradicate. Within the lungs of individuals with cystic fibrosis (CF), causes persistent biofilm infection that is commonly treated with aminoglycoside antibiotics such as tobramycin. However, sublethal concentrations of this aminoglycoside were previously shown to increase biofilm formation by , but the underlying adaptive mechanisms still remain elusive.
View Article and Find Full Text PDFMZF16 has been isolated from artisanal Tunisian meat so called "Dried Ossban," an original ecological niche, and identified by MALDI-TOF mass spectrometry and 16S rDNA sequencing. This bacterium showed a high tolerance to gastric stress conditions, and toward bile salts. MZF16 also demonstrated a hydrophobic surface profile (high adhesion to xylene), autoaggregation, and adhesive abilities to the human intestinal Caco-2/TC7 cell line.
View Article and Find Full Text PDFIn Pseudomonas aeruginosa, SigX is an extra-cytoplasmic function σ factor that belongs to the cell wall stress response network. In previous studies, we made the puzzling observation that sigX mutant growth was severely affected in rich lysogeny broth (LB) but not in minimal medium. Here, through comparative transcriptomic and proteomic analysis, we show that the absence of SigX results in dysregulation of genes, whose products are mainly involved in transport, carbon and energy metabolisms.
View Article and Find Full Text PDFBacterial biofilms constitute a critical problem in hospitals, especially in resuscitation units or for immunocompromised patients, since bacteria embedded in their own matrix are not only protected against antibiotics but also develop resistant variant strains. In the last decade, an original approach to prevent biofilm formation has consisted of studying the antibacterial potential of host communication molecules. Thus, some of these compounds have been identified for their ability to modify the biofilm formation of both Gram-negative and Gram-positive bacteria.
View Article and Find Full Text PDFBiochim Biophys Acta Gene Regul Mech
July 2019
The opportunistic pathogen Pseudomonas aeruginosa, like all members of the genus Pseudomonas, has the capacity to thrive in very different environments, ranging from water, plant roots, to animals, including humans to whom it can cause severe infections. This remarkable adaptability is reflected in the number of transcriptional regulators, including sigma factors in this bacterium. Among those, the 19 to 21 extracytoplasmic sigma factors (ECFσ) are endowed with different regulons and functions, including the iron starvation σ (PvdS, FpvI, HasI, FecI, FecI2 and others), the cell wall stress ECFσ AlgU, SigX and SbrI, and the unorthodox σ involved in the expression of virulence.
View Article and Find Full Text PDFWe have previously shown that the C-type Natriuretic Peptide (CNP), a peptide produced by lungs, is able to impact physiology. In the present work, the effect of CNP at different concentrations on biofilm formation was studied and the mechanisms of action of this human hormone on were deciphered. CNP was shown to inhibit dynamic biofilm formation in a dose-dependent manner without affecting the bacterial growth at any tested concentrations.
View Article and Find Full Text PDFPseudomonas aeruginosa is a Gram-negative bacterium belonging to the γ-proteobacteria. Like other members of the Pseudomonas genus, it is known for its metabolic versatility and its ability to colonize a wide range of ecological niches, such as rhizosphere, water environments and animal hosts, including humans where it can cause severe infections. Another particularity of P.
View Article and Find Full Text PDFis a pathogenic micro-organism responsible for many hospital-acquired infections. It is able to adhere to solid surfaces and develop an immobilized community or so-called biofilm. Many studies have been focusing on the use of specific materials to prevent the formation of these biofilms, but the reactivity of the bacteria in contact to surfaces remains unknown.
View Article and Find Full Text PDFWe have previously shown that the eukaryotic C-type natriuretic peptide hormone (CNP) regulates Pseudomonas aeruginosa virulence and biofilm formation after binding on the AmiC sensor, triggering the amiE transcription. Herein, the involvement of the aliphatic amidase AmiE in P. aeruginosa virulence regulation has been investigated.
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