scholarly journals Pseudomonas aeruginosa Keratitis: Protease IV and PASP as Corneal Virulence Mediators

2019 ◽  
Vol 7 (9) ◽  
pp. 281 ◽  
Author(s):  
Richard O’Callaghan ◽  
Armando Caballero ◽  
Aihua Tang ◽  
Michael Bierdeman
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Contact Lenses ◽  
Corneal Tissue ◽  
Deficient Mutant ◽  
Interleukin 22 ◽  
Mammalian Lung ◽  
Corneal Damage ◽  
Extensive Degradation ◽  
Protease Iv

Pseudomonas aeruginosa is a leading cause of bacterial keratitis, especially in users of contact lenses. These infections are characterized by extensive degradation of the corneal tissue mediated by Pseudomonas protease activities, including both Pseudomonas protease IV (PIV) and the P. aeruginosa small protease (PASP). The virulence role of PIV was determined by the reduced virulence of a PIV-deficient mutant relative to its parent strain and the mutant after genetic complementation (rescue). Additionally, the non-ocular pathogen Pseudomonas putida acquired corneal virulence when it produced active PIV from a plasmid-borne piv gene. The virulence of PIV is not limited to the mammalian cornea, as evidenced by its destruction of respiratory surfactant proteins and the cytokine interleukin-22 (IL-22), the key inducer of anti-bacterial peptides. Furthermore, PIV contributes to the P. aeruginosa infection of both insects and plants. A possible limitation of PIV is its inefficient digestion of collagens; however, PASP, in addition to cleaving multiple soluble proteins, is able to efficiently cleave collagens. A PASP-deficient mutant lacks the corneal virulence of its parent or rescue strain evidencing its contribution to corneal damage, especially epithelial erosion. Pseudomonas-secreted proteases contribute importantly to infections of the cornea, mammalian lung, insects, and plants.

scholarly journals Isolation of an IHF-deficient mutant of a Pseudomonas aeruginosa mucoid isolate and evaluation of the role of IHF in algD gene expression

Microbiology ◽  
1996 ◽  
Vol 142 (10) ◽  
pp. 2785-2793 ◽  
Author(s):  
I. Delic-Attree ◽  
B. Toussaint ◽  
A. Froger ◽  
J. C. Willison ◽  
P. M. Vignais
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Deficient Mutant

scholarly journals Models of experimental pseudomonas keratitis: microbiological and clinical aspects

2020 ◽  
Vol 24 (1) ◽  
pp. 129-133
Author(s):  
N.V. Malachkova ◽  
N.V. Kryvetska ◽  
I.M. Vovk ◽  
I.M. Kovalenko ◽  
A.V. Kryzhanovskaya
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Contact Lenses ◽  
Clinical Aspects ◽  
Tissue Destruction ◽  
Negative Results ◽  
Bacterial Films ◽  
Eye Tissues ◽  
Microbiological Examination ◽  
Corneal Damage ◽  
Current Guidelines

Annotation. Over the last ten years, there has been an increase in the incidence of bacterial keratitis caused by Pseudomonas aeruginosa, associated with contact lenses use. Certain features of the course of such keratitis, the mechanisms of corneal damage, the factors that affect the severity and depth of tissue destruction remain unclear. Therefore, the aim of our work was to model experimental pseudomonal keratitis in rabbits using different methods of infection and to investigate the microbiological and clinical aspects of keratitis depending on the method of infection. As a result of the study, we were able to reproduce superficial and deep keratitis with different methods of infection. Our proposed method cornea infection with bacterial films on a contact lens allowed to reproduce severe keratitis with a longer release of the pathogen from the surface of the affected cornea. It was also found that the results of microbiological examination of the material from the affected eye do not correlate with the course of severe keratitis: negative results of microbiological examination did not demonstrate the elimination of the pathogen from eye tissues, which deepens into corneal tissues, that was proved with microbiological examination of the cornea autopsy samples. These models of experimental keratitis can be used to study the pathomorphology, and pathophysiology of the keratitis caused by Pseudomonas aeruginosa, as well as to conduct experimental research of new antimicrobials and improve current guidelines for treatment of this pathology.

Role of rhizobia in suppressing the root rot and root knot disease of chili used alone or with Pseudomonas aeruginosa

2019 ◽  
Vol 52 (3) ◽  
Author(s):  
Gulnaz Parveen ◽  
Faizah Urooj ◽  
Hafiza Asma Shafique ◽  
Afshan Rahman ◽  
Syed Ehteshamul Haque
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Root Rot

scholarly journals Sub-Inhibitory Concentrations of Ciprofloxacin Alone and Combinations with Plant-Derived Compounds against P. aeruginosa Biofilms and Their Effects on the Metabolomic Profile of P. aeruginosa Biofilms

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 414
Author(s):  
Didem Kart ◽  
Tuba Reçber ◽  
Emirhan Nemutlu ◽  
Meral Sagiroglu
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Inhibitory Concentration ◽  
Molecular Level ◽  
Metabolomic Profile ◽  
Gene Expressions ◽  
New Agents ◽  
Qrt Pcr ◽  
Metabolomic Approach

Introduction: Alternative anti-biofilm agents are needed to combat Pseudomonas aeruginosa infections. The mechanisms behind these new agents also need to be revealed at a molecular level. Materials and methods: The anti-biofilm effects of 10 plant-derived compounds on P. aeruginosa biofilms were investigated using minimum biofilm eradication concentration (MBEC) and virulence assays. The effects of ciprofloxacin and compound combinations on P. aeruginosa in mono and triple biofilms were compared. A metabolomic approach and qRT-PCR were applied to the biofilms treated with ciprofloxacin in combination with baicalein, esculin hydrate, curcumin, and cinnamaldehyde at sub-minimal biofilm inhibitory concentration (MBIC) concentrations to highlight the specific metabolic shifts between the biofilms and to determine the quorum sensing gene expressions, respectively. Results: The combinations of ciprofloxacin with curcumin, baicalein, esculetin, and cinnamaldehyde showed more reduced MBICs than ciprofloxacin alone. The quorum sensing genes were downregulated in the presence of curcumin and cinnamaldehyde, while upregulated in the presence of baicalein and esculin hydrate rather than for ciprofloxacin alone. The combinations exhibited different killing effects on P. aeruginosa in mono and triple biofilms without affecting its virulence. The findings of the decreased metabolite levels related to pyrimidine and lipopolysaccharide synthesis and to down-regulated alginate and lasI expressions strongly indicate the role of multifactorial mechanisms for curcumin-mediated P. aeruginosa growth inhibition. Conclusions: The use of curcumin, baicalein, esculetin, and cinnamaldehyde with ciprofloxacin will help fight against P. aeruginosa biofilms. To the best of our knowledge, this is the first study of its kind to define the effect of plant-based compounds as possible anti-biofilm agents with low MBICs for the treatment of P. aeruginosa biofilms through metabolomic pathways.

scholarly journals The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa

2021 ◽  
Vol 22 (8) ◽  
pp. 3982
Author(s):  
Karolina Kotecka ◽  
Adam Kawalek ◽  
Kamil Kobylecki ◽  
Aneta Agnieszka Bartosik
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Transcriptional Profiling ◽  
Mrna Level ◽  
Transcriptional Regulators ◽  
Resistance Mechanisms ◽  
Chronic Infections ◽  
Environmental Signals ◽  
Regulatory Systems

Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459–PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459–PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.

scholarly journals Role of rgsA in Oxidative Stress Resistance in Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Shuyi Hou ◽  
Jiaqin Zhang ◽  
Xiaobo Ma ◽  
Qiang Hong ◽  
Lili Fang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Stress Resistance ◽  
Oxidative Stress Resistance
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