Investigation on bla Ctx-M-1 , Virulence Factors and Multidruge Resistance in Pseudomonas Aeruginosa Bacteria

2017 ◽  
Vol 13 (3) ◽  
pp. 206-221
Author(s):  
Hadi Rahman Rasheed Al-Taai ◽  
◽  
Zainab Mohammed Hameed ◽  
Izdehar Mohammed Jasim
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors

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 Baicalin Represses Type Three Secretion System of Pseudomonas aeruginosa through PQS System

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1497
Author(s):  
Pansong Zhang ◽  
Qiao Guo ◽  
Zhihua Wei ◽  
Qin Yang ◽  
Zisheng Guo ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Mammalian Cells ◽  
Secretion System ◽  
Chinese Herbs ◽  
Infection Model ◽  
Lung Pathology ◽  
Promising Alternative ◽  
The Impact

Therapeutics that target the virulence of pathogens rather than their viability offer a promising alternative for treating infectious diseases and circumventing antibiotic resistance. In this study, we searched for anti-virulence compounds against Pseudomonas aeruginosa from Chinese herbs and investigated baicalin from Scutellariae radix as such an active anti-virulence compound. The effect of baicalin on a range of important virulence factors in P. aeruginosa was assessed using luxCDABE-based reporters and by phenotypical assays. The molecular mechanism of the virulence inhibition by baicalin was investigated using genetic approaches. The impact of baicalin on P. aeruginosa pathogenicity was evaluated by both in vitro assays and in vivo animal models. The results show that baicalin diminished a plenty of important virulence factors in P. aeruginosa, including the Type III secretion system (T3SS). Baicalin treatment reduced the cellular toxicity of P. aeruginosa on the mammalian cells and attenuated in vivo pathogenicity in a Drosophila melanogaster infection model. In a rat pulmonary infection model, baicalin significantly reduced the severity of lung pathology and accelerated lung bacterial clearance. The PqsR of the Pseudomonas quinolone signal (PQS) system was found to be required for baicalin’s impact on T3SS. These findings indicate that baicalin is a promising therapeutic candidate for treating P. aeruginosa infections.

Inhibition of biofilm formation, quorum sensing and other virulence factors in Pseudomonas aeruginosa by polyphenols of Gynura procumbens leaves

2021 ◽  
pp. 1-15
Author(s):  
Zulkar Nain ◽  
Fariha Jasin Mansur ◽  
Shifath Bin Syed ◽  
Md Ariful Islam ◽  
Hiroyuki Azakami ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation

scholarly journals Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors

Microbiology ◽  
2009 ◽  
Vol 155 (3) ◽  
pp. 712-723 ◽  
Author(s):  
Valérie Dekimpe ◽  
Eric Déziel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Transcriptional Regulator ◽  
Homoserine Lactone ◽  
The Other ◽  
Virulence Determinants ◽  
Late Stationary Phase ◽  
Regulatory Systems ◽  
Specific Factors

Pseudomonas aeruginosa uses the two major quorum-sensing (QS) regulatory systems las and rhl to modulate the expression of many of its virulence factors. The las system is considered to stand at the top of the QS hierarchy. However, some virulence factors such as pyocyanin have been reported to still be produced in lasR mutants under certain conditions. Interestingly, such mutants arise spontaneously under various conditions, including in the airways of cystic fibrosis patients. Using transcriptional lacZ reporters, LC/MS quantification and phenotypic assays, we have investigated the regulation of QS-controlled factors by the las system. Our results show that activity of the rhl system is only delayed in a lasR mutant, thus allowing the expression of multiple virulence determinants such as pyocyanin, rhamnolipids and C4-homoserine lactone (HSL) during the late stationary phase. Moreover, at this stage, RhlR is able to overcome the absence of the las system by activating specific LasR-controlled functions, including production of 3-oxo-C12-HSL and Pseudomonas quinolone signal (PQS). P. aeruginosa is thus able to circumvent the deficiency of one of its QS systems by allowing the other to take over. This work demonstrates that the QS hierarchy is more complex than the model simply presenting the las system above the rhl system.

scholarly journals P137 Effect of e-cigarette exposure on production of virulence factors by Pseudomonas aeruginosa

2019 ◽  
Vol 18 ◽  
pp. S96
Author(s):  
K. Gallagher ◽  
K.A. McGown ◽  
G. Carson ◽  
M. Tunney ◽  
D. Gilpin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors

scholarly journals A glycoconjugate-based gold nanoparticle approach for the targeted treatment of Pseudomonas aeruginosa biofilms

Nanoscale ◽  
2020 ◽  
Vol 12 (45) ◽  
pp. 23234-23240
Author(s):  
Chao Zhang ◽  
De-Tai Shi ◽  
Kai-Cheng Yan ◽  
Adam C. Sedgwick ◽  
Guo-Rong Chen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Gold Nanoparticle ◽  
Virulence Factors ◽  
Targeted Treatment ◽  
Therapeutic Delivery

Glycoconjugate-based AuNPs were developed for the targeted eradication of P. aeruginosa. This was achieved through carbohydrate-based recognition of key virulence factors followed by combined therapeutic delivery and light-based treatment (PDT/PTT).

scholarly journals Tackling Virulence of Pseudomonas aeruginosa by the Natural Furanone Sotolon

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 871
Author(s):  
Mohammed F. Aldawsari ◽  
El-Sayed Khafagy ◽  
Ahmed Al Saqr ◽  
Ahmed Alalaiwe ◽  
Hisham A. Abbas ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Bacterial Infections ◽  
Therapeutic Agent ◽  
Bacterial Resistance ◽  
Inhibitory Concentration ◽  
Bacterial Biofilm ◽  
Resistant Bacteria ◽  
Resistance Development

The bacterial resistance development due to the incessant administration of antibiotics has led to difficulty in their treatment. Natural adjuvant compounds can be co-administered to hinder the pathogenesis of resistant bacteria. Sotolon is the prevailing aromatic compound that gives fenugreek its typical smell. In the current work, the anti-virulence activities of sotolon on Pseudomonas aeruginosa have been evaluated. P. aeruginosa has been treated with sotolon at sub-minimum inhibitory concentration (MIC), and production of biofilm and other virulence factors were assessed. Moreover, the anti-quorum sensing (QS) activity of sotolon was in-silico evaluated by evaluating the affinity of sotolon to bind to QS receptors, and the expression of QS genes was measured in the presence of sotolon sub-MIC. Furthermore, the sotolon in-vivo capability to protect mice against P. aeruginosa was assessed. Significantly, sotolon decreased the production of bacterial biofilm and virulence factors, the expression of QS genes, and protected mice from P. aeruginosa. Conclusively, the plant natural substance sotolon attenuated the pathogenicity of P. aeruginosa, locating it as a plausible potential therapeutic agent for the treatment of its infections. Sotolon can be used in the treatment of bacterial infections as an alternative or adjuvant to antibiotics to combat their high resistance to antibiotics.

scholarly journals Isolation and characterizations of a novel recombinant scFv antibody against exotoxin A of Pseudomonas aeruginosa

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zahra Shadman ◽  
Safar Farajnia ◽  
Mohammad Pazhang ◽  
Mohammadreza Tohidkia ◽  
Leila Rahbarnia ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
High Reactivity ◽  
Scfv Antibody ◽  
Phage Library ◽  
Human Antibody ◽  
Exotoxin A ◽  
Phage Elisa ◽  
Human Scfv ◽  
Domain I

Abstract Background Pseudomonas aeruginosa is the leading cause of nosocomial infections, especially in people with a compromised immune system. Targeting virulence factors by neutralizing antibodies is a novel paradigm for the treatment of antibiotic-resistant pseudomonas infections. In this respect, exotoxin A is one of the most potent virulence factors in P. aeruginosa. The present study was carried out to identify a novel human scFv antibody against the P. aeruginosa exotoxin A domain I (ExoA-DI) from a human scFv phage library. Methods The recombinant ExoA-DI of P. aeruginosa was expressed in E. coli, purified by Ni-NTA column, and used for screening of human antibody phage library. A novel screening procedure was conducted to prevent the elimination of rare specific clones. The phage clone with high reactivity was evaluated by ELISA and western blot. Results Based on the results of polyclonal phage ELISA, the fifth round of biopanning leads to the isolation of several ExoA-DI reactive clones. One positive clone with high affinity was selected by monoclonal phage ELISA and used for antibody expression. The purified scFv showed high reactivity with the recombinant domain I and full-length native exotoxin A. Conclusions The purified anti-exotoxin A scFv displayed high specificity against exotoxin A. The human scFv identified in this study could be the groundwork for developing a novel therapeutic agent to control P. aeruginosa infections.

New Strategies Targeting Virulence Factors of Staphylococcus aureus and Pseudomonas aeruginosa

2017 ◽  
Vol 38 (03) ◽  
pp. 346-358 ◽  
Author(s):  
Bruno François ◽  
Charles-Edouard Luyt ◽  
C. Stover ◽  
Jeffery Brubaker ◽  
Jean Chastre ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Effective Utilization ◽  
Mechanically Ventilated ◽  
Stage Of Development ◽  
Antivirulence Agents ◽  
Interventional Therapies ◽  
Improve Patient ◽  
New Strategies

AbstractMorbidity, mortality, and economic burden of nosocomial pneumonia caused by Staphylococcus aureus and Pseudomonas aeruginosa remain high in mechanically ventilated and hospitalized patients despite the use of empirical antibiotic therapy or antibiotics against specific classes of pathogens and procedures to reduce nosocomial infections in hospital settings. Newer agents that neutralize or inhibit specific S. aureus or P. aeruginosa virulence factors may eliminate or reduce the risk for developing pneumonia before or during mechanical ventilation and may improve patient outcomes through mechanisms that differ from those of antibiotics. In this article, we review the types, mechanisms of action, potential advantages, and stage of development of antivirulence agents (AVAs) that hold promise as alternative preventive or interventional therapies against S. aureus– and P. aeruginosa–associated nosocomial pneumonias. We also present and discuss challenges to the effective utilization of AVAs separately from or in addition to antibiotics and the design of clinical trials and meaningful study end points.

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