scholarly journals Phloroglucinol-Gold and -Zinc Oxide Nanoparticles: Antibiofilm and Antivirulence Activities towards Pseudomonas aeruginosa PAO1

Marine Drugs ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. 601
Author(s):  
Fazlurrahman Khan ◽  
Min-Gyun Kang ◽  
Du-Min Jo ◽  
Pathum Chandika ◽  
Won-Kyo Jung ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Zinc Oxide ◽  
Virulence Factors ◽  
Antimicrobial Agents ◽  
Early Stage ◽  
Nanoparticle Synthesis ◽  
Synthesis Of Nanoparticles ◽  
Human Pathogenic Bacterium ◽  
Wide Range ◽  
Materials Used

With the advancement of nanotechnology, several nanoparticles have been synthesized as antimicrobial agents by utilizing biologically derived materials. In most cases, the materials used for the synthesis of nanoparticles from natural sources are extracts. Natural extracts contain a wide range of bioactive components, making it difficult to pinpoint the exact component responsible for nanoparticle synthesis. Furthermore, the bioactive component present in the extract changes according to numerous environmental factors. As a result, the current work intended to synthesize gold (AuNPs) and zinc oxide (ZnONPs) nanoparticles using pure phloroglucinol (PG). The synthesized PG-AuNPs and PG-ZnONPs were characterized using a UV–Vis absorption spectrophotometer, FTIR, DLS, FE-TEM, zeta potential, EDS, and energy-dispersive X-ray diffraction. The characterized PG-AuNPs and PG-ZnONPs have been employed to combat the pathogenesis of Pseudomonas aeruginosa. P. aeruginosa is recognized as one of the most prevalent pathogens responsible for the common cause of nosocomial infection in humans. Antimicrobial resistance in P. aeruginosa has been linked to the development of recalcitrant phenotypic characteristics, such as biofilm, which has been identified as one of the major obstacles to antimicrobial therapy. Furthermore, P. aeruginosa generates various virulence factors that are a major cause of chronic infection. These PG-AuNPs and PG-ZnONPs significantly inhibit early stage biofilm and eradicate mature biofilm. Furthermore, these NPs reduce P. aeruginosa virulence factors such as pyoverdine, pyocyanin, protease, rhamnolipid, and hemolytic capabilities. In addition, these NPs significantly reduce P. aeruginosa swarming, swimming, and twitching motility. PG-AuNPs and PG-ZnONPs can be used as control agents for infections caused by the biofilm-forming human pathogenic bacterium P. aeruginosa.

Characterization of Pseudomonas aeruginosa Quorum Sensing Inhibitors from the Endophyte Lasiodiplodia venezuelensis and Evaluation of Their Antivirulence Effects by Metabolomics

2021 ◽  
Vol 9 (9) ◽  
pp. 1807
Author(s):  
Léonie Pellissier ◽  
Sara Leoni ◽  
Laurence Marcourt ◽  
Emerson Ferreira Queiroz ◽  
Nicole Lecoultre ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Antimicrobial Agents ◽  
Fungal Endophytes ◽  
Opportunistic Pathogen ◽  
Single Step ◽  
Bioactive Natural Products ◽  
Quorum Sensing Inhibitors ◽  
Wide Range

The opportunistic pathogen Pseudomonas aeruginosa is one of the “critical priority pathogens” due to its multidrug resistance to a wide range of antibiotics. Its ability to invade and damage host tissues is due to the use of quorum sensing (QS) to collectively produce a plethora of virulence factors. Inhibition of QS is an attractive strategy for new antimicrobial agents because it disrupts the initial events of infection without killing the pathogen. Highly diverse microorganisms as endophytes represent an under-explored source of bioactive natural products, offering opportunities for the discovery of novel QS inhibitors (QSI). In the present work, the objective was to explore selective QSIs within a unique collection of fungal endophytes isolated from the tropical palm Astrocaryum sciophilum. The fungi were cultured, extracted, and screened for their antibacterial and specific anti-QS activities against P. aeruginosa. The endophytic strain Lasiodiplodia venezuelensis was prioritized for scaled-up fractionation for its selective activity, leading to the isolation of eight compounds in a single step. Among them, two pyran-derivatives were found to be responsible for the QSI activity, with an effect on some QS-regulated virulence factors. Additional non-targeted metabolomic studies on P. aeruginosa documented their effects on the production of various virulence-related metabolites.

scholarly journals Pseudomonas aeruginosa PA80 is a cystic fibrosis isolate deficient in RhlRI quorum sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Syed A. K. Shifat Ahmed ◽  
Michelle Rudden ◽  
Sabrina M. Elias ◽  
Thomas J. Smyth ◽  
Roger Marchant ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Genomic Islands ◽  
Clinical Strain ◽  
Whole Genome ◽  
Synonymous Mutations ◽  
Wide Range

AbstractPseudomonas aeruginosa uses quorum sensing (QS) to modulate the expression of several virulence factors that enable it to establish severe infections. The QS system in P. aeruginosa is complex, intricate and is dominated by two main N-acyl-homoserine lactone circuits, LasRI and RhlRI. These two QS systems work in a hierarchical fashion with LasRI at the top, directly regulating RhlRI. Together these QS circuits regulate several virulence associated genes, metabolites, and enzymes in P. aeruginosa. Paradoxically, LasR mutants are frequently isolated from chronic P. aeruginosa infections, typically among cystic fibrosis (CF) patients. This suggests P. aeruginosa can undergo significant evolutionary pathoadaptation to persist in long term chronic infections. In contrast, mutations in the RhlRI system are less common. Here, we have isolated a clinical strain of P. aeruginosa from a CF patient that has deleted the transcriptional regulator RhlR entirely. Whole genome sequencing shows the rhlR locus is deleted in PA80 alongside a few non-synonymous mutations in virulence factors including protease lasA and rhamnolipid rhlA, rhlB, rhlC. Importantly we did not observe any mutations in the LasRI QS system. PA80 does not appear to have an accumulation of mutations typically associated with several hallmark pathoadaptive genes (i.e., mexT, mucA, algR, rpoN, exsS, ampR). Whole genome comparisons show that P. aeruginosa strain PA80 is closely related to the hypervirulent Liverpool epidemic strain (LES) LESB58. PA80 also contains several genomic islands (GI’s) encoding virulence and/or resistance determinants homologous to LESB58. To further understand the effect of these mutations in PA80 QS regulatory and virulence associated genes, we compared transcriptional expression of genes and phenotypic effects with isogenic mutants in the genetic reference strain PAO1. In PAO1, we show that deletion of rhlR has a much more significant impact on the expression of a wide range of virulence associated factors rather than deletion of lasR. In PA80, no QS regulatory genes were expressed, which we attribute to the inactivation of the RhlRI QS system by deletion of rhlR and mutation of rhlI. This study demonstrates that inactivation of the LasRI system does not impact RhlRI regulated virulence factors. PA80 has bypassed the common pathoadaptive mutations observed in LasR by targeting the RhlRI system. This suggests that RhlRI is a significant target for the long-term persistence of P. aeruginosa in chronic CF patients. This raises important questions in targeting QS systems for therapeutic interventions.

scholarly journals Heterogeneous Antimicrobial Susceptibility Characteristics inPseudomonas aeruginosaIsolates from Cystic Fibrosis Patients

mSphere ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Xuan Qin ◽  
Chuan Zhou ◽  
Danielle M. Zerr ◽  
Amanda Adler ◽  
Amin Addetia ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Genomic Sequence ◽  
Sequence Data ◽  
Parental Origin ◽  
Adaptive Mutations ◽  
Wide Range ◽  
Susceptibility Patterns

ABSTRACTClinical isolates ofPseudomonas aeruginosafrom patients with cystic fibrosis (CF) are known to differ from those associated with non-CF hosts by colony morphology, drug susceptibility patterns, and genomic hypermutability.Pseudomonas aeruginosaisolates from CF patients have long been recognized for their overall reduced rate of antimicrobial susceptibility, but their intraclonal MIC heterogeneity has long been overlooked. Using two distinct cohorts of clinical strains (n= 224 from 56 CF patients,n= 130 from 68 non-CF patients) isolated in 2013, we demonstrated profound Etest MIC heterogeneity in CFP. aeruginosaisolates in comparison to non-CFP. aeruginosaisolates. On the basis of whole-genome sequencing of 19 CFP. aeruginosaisolates from 9 patients with heterogeneous MICs, the core genome phylogenetic tree confirmed the within-patient CFP. aeruginosaclonal lineage along with considerable coding sequence variability. No extrachromosomal DNA elements or previously characterized antibiotic resistance mutations could account for the wide divergence in antimicrobial MICs betweenP. aeruginosacoisolates, though many heterogeneous mutations in efflux and porin genes and their regulators were present. A unique OprD sequence was conserved among the majority of isolates of CFP. aeruginosaanalyzed, suggesting a pseudomonal response to selective pressure that is common to the isolates. Genomic sequence data also suggested that CF pseudomonal hypermutability was not entirely due to mutations inmutL,mutS, anduvr. We conclude that the net effect of hundreds of adaptive mutations, both shared between clonally related isolate pairs and unshared, accounts for their highly heterogeneous MIC variances. We hypothesize that this heterogeneity is indicative of the pseudomonal syntrophic-like lifestyle under conditions of being “locked” inside a host focal airway environment for prolonged periods.IMPORTANCEPatients with cystic fibrosis endure “chronic focal infections” with a variety of microorganisms. One microorganism,Pseudomonas aeruginosa, adapts to the host and develops resistance to a wide range of antimicrobials. Interestingly, as the infection progresses, multiple isogenic strains ofP. aeruginosaemerge and coexist within the airways of these patients. Despite a common parental origin, the multiple strains ofP. aeruginosadevelop vastly different susceptibility patterns to actively used antimicrobial agents—a phenomenon we define as “heterogeneous MICs.” By sequencing pairs ofP. aeruginosaisolates displaying heterogeneous MICs, we observed widespread isogenic gene lesions in drug transporters, DNA mismatch repair machinery, and many other structural or cellular functions. Coupled with the heterogeneous MICs, these genetic lesions demonstrated a symbiotic response to host selection and suggested evolution of a multicellular syntrophic bacterial lifestyle. Current laboratory standard interpretive criteria do not address the emergence of heterogeneous growth and susceptibilitiesin vitrowith treatment implications.

scholarly journals Pseudomonas aeruginosatype IV minor pilins and PilY1 regulate virulence by modulating FimS-AlgR activity

2017 ◽  
Author(s):  
Victoria A. Marko ◽  
Sara L.N. Kilmury ◽  
Lesley T. MacNeil ◽  
Lori L. Burrows
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Feedback Inhibition ◽  
Regulatory System ◽  
Type Iv Pili ◽  
Infection Model ◽  
Type Iv ◽  
Wide Range ◽  
Lung Infections ◽  
Pilus Assembly

AbstractType IV pili are expressed by a wide range of prokaryotes, including the opportunistic pathogenPseudomonas aeruginosa. These flexible fibres mediate twitching motility, biofilm maturation, surface adhesion, and virulence. The pilus is composed mainly of major pilin subunits while the low abundance minor pilins FimU-PilVWXE and the putative adhesin PilY1 prime pilus assembly and are proposed to form the pilus tip. The minor pilins and PilY1 are encoded in an operon that is positively regulated by the FimS-AlgR two-component system. Independent of pilus assembly, PilY1 is proposed to be a mechanosensory component that - in conjunction with minor pilins - triggers up-regulation of acute virulence phenotypes upon surface attachment. Here, we investigated the link between the minor pilins and virulence.pilW, pilX, andpilY1mutants had reduced virulence towardsCaenorhabditis elegansrelative to wild type or a major pilin mutant, implying a role in pathogenicity that is independent of pilus assembly. We hypothesized that loss of specific minor pilins relieves feedback inhibition on FimS-AlgR, increasing transcription of the minor pilin operon and other members of the AlgR regulon. Reporter assays confirmed that FimS-AlgR were required for the increased expression from the minor pilin operon promoter upon loss of select minor pilins. Overexpression of AlgR or its hyperactivation via point mutation reduced virulence, and the virulence defects ofpilW,pilX, andpilY1mutants were dependent on FimS-AlgR expression and activation. We propose that PilY1 and the minor pilins inhibit their own expression, and that loss of these proteins leads to FimS-mediated activation of AlgR and reduced expression of acute-phase virulence factors. This mechanism could contribute to adaptation ofP. aeruginosain chronic lung infections, as mutations in the minor pilin operon result in the loss of piliation and increased expression of AlgR-dependent virulence factors – such as alginate – that are characteristic of such infections.Author summaryPseudomonas aeruginosacauses dangerous infections, including chronic lung infections in cystic fibrosis patients. It uses many strategies to infect its hosts, including deployment of grappling hook-like fibres called type IV pili. Among the components involved in assembly and function of the pilus are five proteins called minor pilins that - along with a larger protein called PilY1 - may help the pilus attach to surfaces. In a roundworm infection model, loss of PilY1 and specific minor pilins delayed killing, while loss of other pilus proteins did not. We traced this effect to increased activation of the FimS-AlgR regulatory system that inhibits expression of virulence factors used to initiate infections, while positively regulating chronic infection traits such as alginate production, a phenotype called mucoidy. A disruption in the appropriate timing of FimS-AlgR-dependent virulence factor expression when select minor pilins or PilY1 are missing may explain why those pilus-deficient mutants have reduced virulence compared with others whose products are not under FimS-AlgR control. Increased FimS-AlgR activity upon loss of PilY1 and specific minor pilins could help to explain the frequent co-occurrence of the non-piliated and mucoid phenotypes that are hallmarks of chronicP. aeruginosalung infections.

scholarly journals Bacterial synthesis of nanoparticles: A green approach

2020 ◽  
Vol 28 (1) ◽  
pp. 9-17 ◽  
Author(s):  
S. I. Tsekhmistrenko ◽  
V. S. Bityutskyy ◽  
O. S. Tsekhmistrenko ◽  
L. P. Horalskyi ◽  
N. O. Tymoshok ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Large Scale ◽  
Heterogeneous Catalysts ◽  
Nanoparticle Synthesis ◽  
Catalytic Efficiency ◽  
High Energy ◽  
Synthesis Of Nanoparticles ◽  
Green Approach ◽  
Wide Range ◽  
Catalytic Applications

In recent decades, the attention of scientists has been drawn towards nanoparticles (NPs) of metals and metalloids. Traditional methods for the manufacturing of NPs are now being extensively studied. However, disadvantages such as the use of toxic agents and high energy consumption associated with chemical and physical processes impede their continued use in various fields. In this article, we analyse the relevance of the use of living systems and their components for the development of "green" synthesis of nano-objects with exceptional properties and a wide range of applications. The use of nano-biotechnological methods for the synthesis of nanoparticles has the potential of large-scale application and high commercial potential. Bacteria are an extremely convenient target for green nanoparticle synthesis due to their variety and ability to adapt to different environmental conditions. Synthesis of nanoparticles by microorganisms can occur both intracellularly and extracellularly. It is known that individual bacteria are able to bind and concentrate dissolved metal ions and metalloids, thereby detoxifying their environment. There are various bacteria cellular components such as enzymes, proteins, peptides, pigments, which are involved in the formation of nanoparticles. Bio-intensive manufacturing of NPs is environmentally friendly and inexpensive and requires low energy consumption. Some biosynthetic NPs are used as heterogeneous catalysts for environmental restoration, exhibiting higher catalytic efficiency due to their stability and increased biocompatibility. Bacteria used as nanofactories can provide a new approach to the removal of metal or metalloid ions and the production of materials with unique properties. Although a wide range of NPs have been biosynthetic and their synthetic mechanisms have been proposed, some of these mechanisms are not known in detail. This review focuses on the synthesis and catalytic applications of NPs obtained using bacteria. Known mechanisms of bioreduction and prospects for the development of NPs for catalytic applications are discussed.

scholarly journals Effect of Biosynthesized ZnO Nanoparticles on Multi-Drug Resistant Pseudomonas Aeruginosa

Antibiotics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 260 ◽  
Author(s):  
Syed Ghazanfar Ali ◽  
Mohammad Azam Ansari ◽  
Mohammad A. Alzohairy ◽  
Mohammad N. Alomary ◽  
Mohammad Jalal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Environmentally Friendly ◽  
Cost Effective ◽  
Multidrug Resistant ◽  
Zno Nps ◽  
Synthesis Of Nanoparticles ◽  
Transmission Electron ◽  
Average Size

Synthesis of nanoparticles using the plants has several advantages over other methods due to the environmentally friendly nature of plants. Besides being environmentally friendly, the synthesis of nanoparticles using plants or parts of the plants is also cost effective. The present study focuses on the biosynthesis of zinc oxide nanoparticles (ZnO NPs) using the seed extract of Butea monsoperma and their effect on to the quorum-mediated virulence factors of multidrug-resistant clinical isolates of Pseudomonas aeruginosa at sub minimum inhibitory concentration (MIC). The synthesized ZnO NPs were characterized by different techniques, such as Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and transmission electron microscopy (TEM). The average size of the nanoparticles was 25 nm as analyzed by TEM. ZnO NPs at sub MIC decreased the production of virulence factors such as pyocyanin, protease and hemolysin for P. aeruginosa (p ≤ 0.05). The interaction of NPs with the P. aeruginosa cells on increasing concentration of NPs at sub MIC levels showed greater accumulation of nanoparticles inside the cells as analyzed by TEM.

scholarly journals Roles of Two-Component Systems in Pseudomonas aeruginosa Virulence

2021 ◽  
Vol 22 (22) ◽  
pp. 12152
Author(s):  
Maria Sultan ◽  
Rekha Arya ◽  
Kyeong Kyu Kim
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Opportunistic Pathogen ◽  
Secretion Systems ◽  
Chronic Infections ◽  
Potential Threat ◽  
Wide Range ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

Pseudomonas aeruginosa is an opportunistic pathogen that synthesizes and secretes a wide range of virulence factors. P. aeruginosa poses a potential threat to human health worldwide due to its omnipresent nature, robust host accumulation, high virulence, and significant resistance to multiple antibiotics. The pathogenicity of P. aeruginosa, which is associated with acute and chronic infections, is linked with multiple virulence factors and associated secretion systems, such as the ability to form and utilize a biofilm, pili, flagella, alginate, pyocyanin, proteases, and toxins. Two-component systems (TCSs) of P. aeruginosa perform an essential role in controlling virulence factors in response to internal and external stimuli. Therefore, understanding the mechanism of TCSs to perceive and respond to signals from the environment and control the production of virulence factors during infection is essential to understanding the diseases caused by P. aeruginosa infection and further develop new antibiotics to treat this pathogen. This review discusses the important virulence factors of P. aeruginosa and the understanding of their regulation through TCSs by focusing on biofilm, motility, pyocyanin, and cytotoxins.

Multidrug-resistant Pseudomonas aeruginosa isolated from ear and wound swabs in some selected hospital laboratories in Sokoto Metropolis, Nigeria

2020 ◽  
Vol 3 ◽  
pp. 31-35
Author(s):  
A. I. Umar ◽  
I. Garba ◽  
M. L. Jidda ◽  
A. M. Ganau ◽  
A. S. Fana ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Opportunistic Infections ◽  
Antibiotic Sensitivity ◽  
Diffusion Method ◽  
Resistance Pattern ◽  
Multiple Drug ◽  
Drug Resistant ◽  
Sensitivity Testing ◽  
Wide Range

Objective: Pseudomonas aeruginosa is a metabolically versatile bacterium that can cause a wide range of severe opportunistic infections in patients with serious underlying conditions and can be found in most communities in Nigeria. The study was to determine the prevalence, resistance pattern and distribution of multiple drug resistant P. aeruginosa (MDR-PA) isolated from ear and wound specimens in patients attending Specialist Hospital Sokoto and Maryam Abacha Women and Children Hospital Sokoto. Materials and Methods: A total of 150 samples were analysed by standard bacteriological methods. Screening for MDR-PA was carried out by antibiotic sensitivity testing using disc diffusion method with ceftazidime (30 µg), ofloxacin (5 µg), cefuroxime (30 µg), cloxacillin (30 µg), amoxicillin (30 µg), ceftriaxone (30 µg), imipenem (10 µg), gentamycin (10 µg) and colistin (10 µg) discs on Mueller Hinton agar. Results: Of a total of 55 (36.7%) isolates of P. aeruginosa strains were obtained, 30 (54.5%) isolates were resistant to imipenem, 31 (56.3%) were resistant to ofloxacin, 44 (80.0%) to gentamycin, 53 (96.3%) to ceftazidime and cefuroxime, 50 (90.9%) to ceftrizone, 54 (98.1%) to cloxacillin and amoxycillin and lastly 15 (27.2%) to colistin. All the isolates were multi drug resistant, this probably due to improper use or over the counter purchase of antibiotics without professional oversight. Conclusion: Almost all the isolates were resistant to all the antibiotics used including colistin. There is need to improve on the public health awareness on the indiscriminate use of antimicrobial agents as it is one of the major ways microbes develop resistance to them.

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