scholarly journals No Correlation between Biofilm Formation, Virulence Factors, and Antibiotic Resistance in Pseudomonas aeruginosa: Results from a Laboratory-Based In Vitro Study

Antibiotics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1134
Author(s):  
Márió Gajdács ◽  
Zoltán Baráth ◽  
Krisztina Kárpáti ◽  
Dóra Szabó ◽  
Donatella Usai ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Pearson Correlation ◽  
Pigment Production ◽  
Virulence Determinants ◽  
Secretion Systems

Pseudomonas aeruginosa (P. aeruginosa) possesses a plethora of virulence determinants, including the production of biofilm, pigments, exotoxins, proteases, flagella, and secretion systems. The aim of our present study was to establish the relationship between biofilm-forming capacity, the expression of some important virulence factors, and the multidrug-resistant (MDR) phenotype in P. aeruginosa. A total of three hundred and two (n = 302) isolates were included in this study. Antimicrobial susceptibility testing and phenotypic detection of resistance determinants were carried out; based on these results, isolates were grouped into distinct resistotypes and multiple antibiotic resistance (MAR) indices were calculated. The capacity of isolates to produce biofilm was assessed using a crystal violet microtiter-plate based method. Motility (swimming, swarming, and twitching) and pigment-production (pyoverdine and pyocyanin) were also measured. Pearson correlation coefficients (r) were calculated to determine for antimicrobial resistance, biofilm-formation, and expression of other virulence factors. Resistance rates were the highest for ceftazidime (56.95%; n = 172), levofloxacin (54.97%; n = 166), and ciprofloxacin (54.64%; n = 159), while lowest for colistin (1.66%; n = 5); 44.04% (n = 133) of isolates were classified as MDR. 19.87% (n = 60), 20.86% (n = 63) and 59.27% (n = 179) were classified as weak, moderate, and strong biofilm producers, respectively. With the exception of pyocyanin production (0.371 ± 0.193 vs. non-MDR: 0.319 ± 0.191; p = 0.018), MDR and non-MDR isolates did not show significant differences in expression of virulence factors. Additionally, no relevant correlations were seen between the rate of biofilm formation, pigment production, or motility. Data on interplay between the presence and mechanisms of drug resistance with those of biofilm formation and virulence is crucial to address chronic bacterial infections and to provide strategies for their management.

scholarly journals Antimicrobial Resistance and Biofilm Formation of Pseudomonas aeruginosa

10.3823/846 ◽  
2020 ◽  
Vol 10 (2) ◽  
Author(s):  
Abdelraouf A Elmanama ◽  
Suhaila Al-Sheboul ◽  
Renad I Abu-Dan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Quorum Sensing ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Developmental Stages ◽  
Infection Site ◽  
Major Virulence Factor

Abstract Pseudomonas aeruginosa threatens patient’s care. It is considered as the most complicated health care associated pathogen to be eliminated from infection site. The biofilm forming ability of P. aeruginosa, being a major virulence factor for most pathogenic microorganism, protects it from host immunity and contribute to antibiotic resistance of this organism. It is estimated that about 80% of infectious diseases are due to biofilm mode of growth. Biofilm forming ability of bacteria imparts antimicrobial resistance that leads to many persistent and chronic bacterial infections. The world is becoming increasingly under the threat of entering the “post-antibiotic era”, an era in which the rate of death from bacterial infections is higher than from cancer. This review focus on P. aeruginosa biofilm forming ability; definition, developmental stages, and significance. In addition, the quorum sensing and the antibiotic resistance of this pathogen is discussed. Keywords: Biofilm; bacterial adhesion; Pseudomonas aeruginosa; antimicrobial resistance; quorum sensing.

scholarly journals An integrated model system to gain mechanistic insights into biofilm formation and antimicrobial resistance development in Pseudomonas aeruginosa MPAO1

2020 ◽  
Author(s):  
Adithi R. Varadarajan ◽  
Raymond N. Allan ◽  
Jules D. P. Valentin ◽  
Olga E. Castañeda Ocampo ◽  
Vincent Somerville ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Soft Lithography ◽  
Flow Chamber ◽  
Model System ◽  
Secretion Systems ◽  
Phenotypic Data ◽  
Biofilm Growth ◽  
Mutant Collection

AbstractPseudomonas aeruginosa MPAO1 is the parental strain of the widely utilized transposon mutant collection for this important clinical pathogen. Here, we validate a model system to identify genes involved in biofilm growth and antibiotic resistance.Our model employs a genomics-driven workflow to assemble the complete MPAO1 genome, identify unique and conserved genes by comparative genomics with the PAO1 reference strain and missed genes by proteogenomics. Among over 200 unique MPAO1 genes, we identified six general essential genes that were overlooked when mapping public Tn-seq datasets against PAO1, including an antitoxin. Genomic data were integrated with phenotypic data from an experimental workflow using a user-friendly, soft lithography-based microfluidic flow chamber for biofilm growth. Experiments conducted across three laboratories delivered reproducible data on P. aeruginosa biofilms and validated both known and novel genes involved in biofilm growth and antibiotic resistance identified in screens of the mutant collection. Differential protein expression data from planktonic cells versus biofilm confirmed upregulation of candidates known to affect biofilm formation, of structural and secreted proteins of type six secretion systems, and provided proteogenomic evidence for some missed MPAO1 genes. This integrated, broadly applicable model promises to improve the mechanistic understanding of biofilm formation, antimicrobial tolerance and resistance evolution.

scholarly journals An integrated model system to gain mechanistic insights into biofilm-associated antimicrobial resistance in Pseudomonas aeruginosa MPAO1

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Adithi R. Varadarajan ◽  
Raymond N. Allan ◽  
Jules D. P. Valentin ◽  
Olga E. Castañeda Ocampo ◽  
Vincent Somerville ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Soft Lithography ◽  
Flow Chamber ◽  
Model System ◽  
Secretion Systems ◽  
Phenotypic Data ◽  
Biofilm Growth ◽  
Resistance Evolution

Abstract Pseudomonas aeruginosa MPAO1 is the parental strain of the widely utilized transposon mutant collection for this important clinical pathogen. Here, we validate a model system to identify genes involved in biofilm growth and biofilm-associated antibiotic resistance. Our model employs a genomics-driven workflow to assemble the complete MPAO1 genome, identify unique and conserved genes by comparative genomics with the PAO1 reference strain and genes missed within existing assemblies by proteogenomics. Among over 200 unique MPAO1 genes, we identified six general essential genes that were overlooked when mapping public Tn-seq data sets against PAO1, including an antitoxin. Genomic data were integrated with phenotypic data from an experimental workflow using a user-friendly, soft lithography-based microfluidic flow chamber for biofilm growth and a screen with the Tn-mutant library in microtiter plates. The screen identified hitherto unknown genes involved in biofilm growth and antibiotic resistance. Experiments conducted with the flow chamber across three laboratories delivered reproducible data on P. aeruginosa biofilms and validated the function of both known genes and genes identified in the Tn-mutant screens. Differential protein abundance data from planktonic cells versus biofilm confirmed the upregulation of candidates known to affect biofilm formation, of structural and secreted proteins of type VI secretion systems, and provided proteogenomic evidence for some missed MPAO1 genes. This integrated, broadly applicable model promises to improve the mechanistic understanding of biofilm formation, antimicrobial tolerance, and resistance evolution in biofilms.

scholarly journals Mechanistic analysis of a synthetic inhibitor of the Pseudomonas aeruginosa LasI quorum-sensing signal synthase

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
O. Lidor ◽  
A. Al-Quntar ◽  
E. C. Pesci ◽  
D. Steinberg
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
In Silico ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Site Directed Mutagenesis ◽  
Great Promise ◽  
Acyl Homoserine Lactone ◽  
Virulence Determinants

Abstract Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen responsible for many human infections. LasI is an acyl-homoserine lactone synthase that produces a quorum-sensing (QS) signal that positively regulates numerous P. aeruginosa virulence determinants. The inhibition of the LasI protein is therefore an attractive drug target. In this study, a novel in silico to in vitro complementation was applied to screen thiazolidinedione-type compounds for their ability to inhibit biofilm formation at concentrations not affecting bacterial growth. The compound (z)-5-octylidenethiazolidine-2, 4-dione (TZD-C8) was a strong inhibitor of biofilm formation and chosen for further study. Structural exploration of in silico docking predicted that the compound had high affinity for the LasI activity pocket. The TZD-C8 compound was also predicted to create hydrogen bonds with residues Arg30 and Ile107. Site-directed mutagenesis (SDM) of these two sites demonstrated that TZD-C8 inhibition was abolished in the lasI double mutant PAO-R30D, I107S. In addition, in vitro swarming motility and quorum sensing signal production were affected by TZD-C 8, confirming this compound alters the cell to cell signalling circuitry. Overall, this novel inhibitor of P. aeruginosa quorum sensing shows great promise and validates our mechanistic approach to discovering inhibitors of LuxI-type acyl-homoserine lactone synthases.

scholarly journals Salicylidene Acylhydrazides and Hydroxyquinolines Act as Inhibitors of Type Three Secretion Systems in Pseudomonas aeruginosa by Distinct Mechanisms

2017 ◽  
Vol 61 (6) ◽  
Author(s):  
Ahalieyah Anantharajah ◽  
Julien M. Buyck ◽  
Charlotta Sundin ◽  
Paul M. Tulkens ◽  
Marie-Paule Mingeot-Leclercq ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Transcriptional Activation ◽  
Yersinia Pseudotuberculosis ◽  
Effector Proteins ◽  
Inflammasome Activation ◽  
Protective Effects ◽  
Secretion Systems ◽  
Content Type

ABSTRACT Type 3 secretion systems (T3SSs) are major virulence factors in Gram-negative bacteria. Pseudomonas aeruginosa expresses two T3SSs, namely, an injectisome (iT3SS) translocating effector proteins in the host cell cytosol and a flagellum (fT3SS) ensuring bacterial motility. Inhibiting these systems is an appealing therapeutic strategy for acute infections. This study examines the protective effects of the salicylidene acylhydrazide INP0341 and of the hydroxyquinoline INP1750 (previously described as T3SS inhibitors in other species) toward cytotoxic effects of P. aeruginosa in vitro. Both compounds reduced cell necrosis and inflammasome activation induced by reference strains or clinical isolates expressing T3SS toxins or only the translocation apparatus. INP0341 inhibited iT3SS transcriptional activation, including in strains with constitutive iT3SS expression, and reduced the total expression of toxins, suggesting it targets iT3SS gene transcription. INP1750 inhibited toxin secretion and flagellar motility and impaired the activity of the YscN ATPase from Yersinia pseudotuberculosis (homologous to the ATPase present in the basal body of P. aeruginosa iT3SS and fT3SS), suggesting that it rather targets a T3SS core constituent with high homology among iT3SS and fT3SS. This mode of action is similar to that previously described for INP1855, another hydroxyquinoline, against P. aeruginosa. Thus, although acting by different mechanisms, INP0341 and INP1750 appear as useful inhibitors of the virulence of P. aeruginosa. Hydroxyquinolines may have a broader spectrum of activity by the fact they act upon two virulence factors (iT3SS and fT3SS).

scholarly journals In vitro activities of cellulase and ceftazidime, alone and in combination against Pseudomonas aeruginosa biofilms

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Esmat Kamali ◽  
Ailar Jamali ◽  
Ahdieh Izanloo ◽  
Abdollah Ardebili
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Glycoside Hydrolase ◽  
Dependent Manner ◽  
Wound Infections ◽  
Persistent Infections ◽  
Novel Strategy ◽  
Dose Dependent

Abstract Background Biofilms are a main pathogenicity feature of Pseudomonas aeruginosa and has a significant role in antibiotic resistance and persistent infections in humans. We investigated the in vitro activities of antibiotic ceftazidime and enzyme cellulase, either alone or in combination against biofilms of P. aeruginosa. Results Both ceftazidime and cellulase significantly decreased biofilm formation in all strains in a dose-dependent manner. Combination of enzyme at concentrations of 1.25, 2.5, 5, and 10 U/mL tested with 1/16× MIC of antibiotic led to a significant reduction in biofilm biomass. Cellulase showed a significant detachment effect on biofilms at three concentrations of 10 U/mL, 5 U/mL, and 2.5 U/mL. The MIC, MBC, and MBEC values of ceftazidime were 2 to 4 µg/mL, 4 to 8 µg/mL, and 2048 to 8192 µg/mL. When combined with cellulase, the MBECs of antibiotic showed a significant decrease from 32- to 128-fold. Conclusions Combination of the ceftazidime and the cellulase had significant anti-biofilm effects, including inhibition of biofilm formation and biofilm eradication in P. aeruginosa. These data suggest that glycoside hydrolase therapy as a novel strategy has the potential to enhance the efficacy of antibiotics and helps to resolve biofilm-associated wound infections caused by this pathogen.

scholarly journals Inhibition of Pseudomonas aeruginosa Biofilm Formation with Surface Modified Polymeric Nanoparticles

Pathogens ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 55 ◽  
Author(s):  
Tyler Flockton ◽  
Logan Schnorbus ◽  
Agustin Araujo ◽  
Jill Adams ◽  
Maryjane Hammel ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Polymeric Nanoparticles ◽  
Bacterial Pathogen ◽  
Gram Negative ◽  
Treatment Technologies ◽  
New Treatment ◽  
Surface Modified

The gram-negative bacterial pathogen Pseudomonas aeruginosa represents a prominent clinical concern. Due to the observed high levels of antibiotic resistance, copious biofilm formation, and wide array of virulence factors produced by these bacteria, new treatment technologies are required. Here, we present the development of a series of P. aeruginosa LecA-targeted polymeric nanoparticles and demonstrate the anti-adhesion and biofilm inhibitory properties of these constructs.

Inhibitors of bacterial H2S biogenesis targeting antibiotic resistance and tolerance

Science ◽  
2021 ◽  
Vol 372 (6547) ◽  
pp. 1169-1175
Author(s):  
Konstantin Shatalin ◽  
Ashok Nuthanakanti ◽  
Abhishek Kaushik ◽  
Dmitry Shishov ◽  
Alla Peselis ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Hydrogen Sulfide ◽  
Small Molecules ◽  
Biofilm Formation ◽  
Drug Target ◽  
Human Pathogens ◽  
Defense System

Emergent resistance to all clinical antibiotics calls for the next generation of therapeutics. Here we report an effective antimicrobial strategy targeting the bacterial hydrogen sulfide (H2S)–mediated defense system. We identified cystathionine γ-lyase (CSE) as the primary generator of H2S in two major human pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, and discovered small molecules that inhibit bacterial CSE. These inhibitors potentiate bactericidal antibiotics against both pathogens in vitro and in mouse models of infection. CSE inhibitors also suppress bacterial tolerance, disrupting biofilm formation and substantially reducing the number of persister bacteria that survive antibiotic treatment. Our results establish bacterial H2S as a multifunctional defense factor and CSE as a drug target for versatile antibiotic enhancers.

scholarly journals Condensins are essential for Pseudomonas aeruginosa corneal virulence through their control of phenotypic programs

2020 ◽  
Author(s):  
Hang Zhao ◽  
April L. Clevenger ◽  
Phillip S. Coburn ◽  
Michelle C. Callegan ◽  
Valentin Rybenkov
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Intracellular Signaling ◽  
Primary Metabolism ◽  
Essential Factor ◽  
Secretion Systems ◽  
Biofilm Growth ◽  
Structural Chromosome

AbstractPseudomonas aeruginosa is a significant opportunistic pathogen responsible for a variety of human infections. Its high pathogenicity resides in a diverse array of virulence factors and an ability to adapt to hostile environments. We report that these factors are tied to the activity of condensins, SMC and MksBEF, which primarily function in structural chromosome maintenance. This study revealed that both proteins are required for P. aeruginosa virulence during corneal infection. The reduction in virulence was traced to broad changes in gene expression. Transcriptional signatures of smc and mksB mutants were largely dissimilar and non-additive, with the double mutant displaying a distinct gene expression profile. Affected regulons included those responsible for lifestyle control, primary metabolism, surface adhesion and biofilm growth, iron and sulfur assimilation, and denitrification. Additionally, numerous virulence factors were affected, including type 3 and type 6 secretion systems, hemagglutinin, pyocin and macroglobulin production, and a host of virulence regulators. in vitro properties of condensin mutants mirrored their transcriptional profiles. MksB-deficient cells were impaired in pyocyanin, c-di-GMP production, and sessile growth whereas smc mutants mildly upregulated c-di-GMP, secreted fewer proteases and were growth deficient under nutrient-limiting conditions. Moreover, condensin mutants displayed an abnormal regulation upon transition to stationary phase. These data reveal that condensins are integrated into the control of multiple genetic programs related to epigenetic and virulent behavior, establishing condensins as an essential factor in P. aeruginosa ocular infections.Author SummaryBacterial pathogenicity is a complex phenomenon dependent on the ability of a bacterium to thrive in a hostile environment while combating the host using an array of virulence factors. This study reports that pathogenicity is also tied to structural chromosome maintenance through condensins, proteins that are responsible for the global organization of the chromosome. We show that the two Pseudomonas aeruginosa condensins, SMC and MksB, act as global regulators of gene expression. The inactivation of SMC and MksB induces opposite regulatory programs in the cell that resemble those observed during the acute and chronic phases of infection. A substantial portion of this regulation is mediated by the intracellular signaling network of P. aeruginosa. Accordingly, virulence regulation is altered in condensin mutants. The results were validated by genetic, phenotypic and virulence studies of condensin mutants. Overall, these data establish condensins as an essential factor during ocular P. aeruginosa infections revealing their involvement in the regulatory virulence network and the control of the bacterial lifestyle.

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