Silver-coated carbon nanotubes downregulate the expression of Pseudomonas aeruginosa virulence genes: a potential mechanism for their antimicrobial effect

Background: Pseudomonas aeruginosa is the primary cause of infection with impaired defense mechanisms. P. aeruginosa commonly causes nosocomial infections and is the most common pathogen isolated from patients hospitalized for longer than 1 week. We examined the antimicrobial effect of multilayered carbon nanotubes on multi-drug-resistant. Materials and Methods: In this research, 20 clinical isolates collected at Motahari Hospital (Tehran, Iran) were compared with the standard (ATCC 27853) and identified as P. aeruginosa based on biochemical testing. Conventional disk diffusion assay demonstrated the methicillin resistance of the isolates. Minimal inhibitory concentrations for antibiotics and the multilayer CNTs were determined using the microdilution method. Single-walled CNTs were prepared and their efficacy and potential synergism with antibiotics was assessed. Results: Synergism against P. aeruginosa was evident for methicillin + single-walled CNTs. Conclusion: The inhibitory effect of single-walled CNTs and methicillin was synergistic against the growth of P. aeruginosa.

Download Full-text

Carbapenem-Resistant Pseudomonas aeruginosa Strains-Distribution of the Essential Enzymatic Virulence Factors Genes

Antibiotics ◽

10.3390/antibiotics10010008 ◽

2020 ◽

Vol 10 (1) ◽

pp. 8

Author(s):

Tomasz Bogiel ◽

Małgorzata Prażyńska ◽

Joanna Kwiecińska-Piróg ◽

Agnieszka Mikucka ◽

Eugenia Gospodarek-Komkowska

Keyword(s):

Pseudomonas Aeruginosa ◽

Alkaline Protease ◽

Virulence Genes ◽

Virulence Gene ◽

Hospital Environment ◽

Gene Encoding ◽

Virulence Gene Expression ◽

Carbapenem Resistant ◽

Antimicrobial Resistance Genes ◽

The Difference

Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with increasing isolation frequency in nosocomial infections. Herein, we investigated whether antimicrobial-resistant P. aeruginosa strains, e.g., metallo-beta-lactamase (MBL)-producing isolates, may possess a reduced number of virulence genes, resulting from appropriate genome management to adapt to a changing hospital environment. Hospital conditions, such as selective pressure, may lead to the replacement of virulence genes by antimicrobial resistance genes that are crucial to survive under current conditions. The study aimed to compare, using PCR, the frequency of the chosen enzymatic virulence factor genes (alkaline protease-aprA, elastase B-lasB, neuraminidases-nan1 and nan2, and both variants of phospholipase C-plcH and plcN) to MBL distribution among 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. The gene encoding alkaline protease was noted with the highest frequency (100%), while the neuraminidase-1 gene was observed in 37.4% of the examined strains. The difference in lasB and nan1 prevalence amongst the MBL-positive and MBL-negative strains, was statistically significant. Although P. aeruginosa virulence is generally more likely determined by the complex regulation of the virulence gene expression, herein, we found differences in the prevalence of various virulence genes in MBL-producers.

Download Full-text

Tailoring the dispersibility of non-covalent functionalized multi-walled carbon nanotube (MWCNT) nanosuspension using shellac (SL) bio-resin: Structure-property relationship and cytotoxicity of shellac coated carbon nanotubes (SLCNTs)

Colloids and Interface Science Communications ◽

10.1016/j.colcom.2021.100395 ◽

2021 ◽

Vol 42 ◽

pp. 100395

Author(s):

A.K.M. Moshiul Alam ◽

M.D.H. Beg ◽

R.M. Yunus ◽

M.R. Islam ◽

Quazi T.H. Shubhra

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

Structure Property ◽

Property Relationship ◽

Multi Walled Carbon Nanotube ◽

Structure Property Relationship ◽

Coated Carbon

Download Full-text

Control of a programmed cell death pathway in Pseudomonas aeruginosa by an antiterminator

Nature Communications ◽

10.1038/s41467-021-21941-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Jennifer M. Peña ◽

Samantha M. Prezioso ◽

Kirsty A. McFarland ◽

Tracy K. Kambara ◽

Kathryn M. Ramsey ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Dna Damage ◽

Cell Death ◽

Programmed Cell Death ◽

Rna Polymerase ◽

Virulence Genes ◽

Opportunistic Pathogen ◽

Transcription Activator ◽

Present Evidence ◽

Cell Death Pathway

AbstractIn Pseudomonas aeruginosa the alp system encodes a programmed cell death pathway that is switched on in a subset of cells in response to DNA damage and is linked to the virulence of the organism. Here we show that the central regulator of this pathway, AlpA, exerts its effects by acting as an antiterminator rather than a transcription activator. In particular, we present evidence that AlpA positively regulates the alpBCDE cell lysis genes, as well as genes in a second newly identified target locus, by recognizing specific DNA sites within the promoter, then binding RNA polymerase directly and allowing it to bypass intrinsic terminators positioned downstream. AlpA thus functions in a mechanistically unusual manner to control the expression of virulence genes in this opportunistic pathogen.

Download Full-text