Aspects of silver tolerance in bacteria: infrared spectral changes and epigenetic clues

Gurbanov, Rafig; Özek, Nihal Şimşek; Tunçer, Sinem; Severcan, Feride; Gözen, Ayşe Gül

doi:10.1002/jbio.201700252

Cited by 22 publications

(5 citation statements)

References 47 publications

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“…Bacteria activate various efflux pumps in response to intracellular Ag + , primarily to expel the toxic Ag + . 58,59 Our RNA-seq data confirms this observation. Classic efflux pump genes such as acrAB-tolC 60,61 and marRAB were found to be highly upregulated, a feature that was sustained throughout the tested period of 30 min, possibly driven by the positive regulation via SoxS.…”

Section: Resultssupporting

confidence: 85%

Silver nanoparticles induce a triclosan-like antibacterial action mechanism in multi-drug resistant Klebsiella pneumoniae

Pareek

Devineau

Sivasankaran

et al. 2020

Preprint

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Infections associated with antimicrobial-resistant (AMR) bacteria now represent a significant threat to human health using conventional therapy. Since AMR bacterial infections are poised to overtake cancer as the main cause of death by 2050, scientists are exploring the efficacy of novel antimicrobial strategies, such as use of silver nanoparticles (Ag NPs) to combat infections. Whilst Ag NPs may hold therapeutic promise, their mode of action on the bacteria remains to be elucidated. In this study, lysozyme coated Ag NPs were synthesized and characterized by TEM-EDS, XRD, UV-vis, FTIR spectroscopy, zeta potential and oxidative potential assay. Ag NPs with an average diameter of 5.2 ± 1.2 nm were found to be bactericidal against multi-drug resistant Klebsiella pneumoniae MGH78578. Deep level transcriptional analysis using RNA sequencing revealed that Ag NPs induced a triclosan-like bactericidal mechanism. RNAseq data showed that Ag NPs were responsible for the inhibition of the type II fatty acid biosynthesis. Additionally, released Ag+ generated oxidative stress both extra- and intracellularly in K. pneumoniae. We show that triclosan-like activity and oxidative stress cumulatively underpinned the antibacterial activity of Ag NPs. This result was confirmed by the analysis of the bactericidal effect of Ag NPs against the isogenic K. pneumoniae MGH78578 ΔsoxS mutant, which exhibits a compromised oxidative stress response compared to the wild type. Here we provide evidence to extend our understanding of the anti-Klebsiella activity associated with silver nanoparticles. This allowed us to model how bacteria might develop resistance against silver nanoparticles, should the latter be used in therapy.

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Section: Resultssupporting

confidence: 85%

Silver nanoparticles induce a triclosan-like antibacterial action mechanism in multi-drug resistant Klebsiella pneumoniae

Pareek

Devineau

Sivasankaran

et al. 2020

Preprint

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“…Through the research, the 1088 cm −1 band can be associated with the vibrational modes stretching PO2 2 symmetric vibration found in B-form DNA 26 , 27 and the structural component phosphate I 21 , which is involved in processes of energy production inside the cell. The 1497 cm −1 band could be related to the vibrational mode of C=C and deformation C–.…”

Section: Resultsmentioning

confidence: 94%

“…The sharp increase in these proteins generates a hyperinflammatory response that leads to organ dysfunction and, in several cases, multiple organ failure. In the band at 1146 cm −1 , phosphates are also used as modular blocks of various substances, including those used by the cell for energy, cell membranes and DNA 26 , 27 , and can be indicated for the treatment of flu-like symptoms; oligosaccharides are found on the outer surface of the plasma membrane, in the blood, in the cellular matrix and in most of the secreted proteins 8 , 23 – 25 .…”

Section: Resultsmentioning

confidence: 99%

Rapid diagnosis of COVID-19 using FT-IR ATR spectroscopy and machine learning

Nogueira

Leal

Macarini

et al. 2021

Sci Rep

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Early diagnosis of COVID-19 in suspected patients is essential for contagion control and damage reduction strategies. We investigated the applicability of attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy associated with machine learning in oropharyngeal swab suspension fluid to predict COVID-19 positive samples. The study included samples of 243 patients from two Brazilian States. Samples were transported by using different viral transport mediums (liquid 1 or 2). Clinical COVID-19 diagnosis was performed by the RT-PCR. We built a classification model based on partial least squares (PLS) associated with cosine k-nearest neighbours (KNN). Our analysis led to 84% and 87% sensitivity, 66% and 64% specificity, and 76.9% and 78.4% accuracy for samples of liquids 1 and 2, respectively. Based on this proof-of-concept study, we believe this method could offer a simple, label-free, cost-effective solution for high-throughput screening of suspect patients for COVID-19 in health care centres and emergency departments.

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“…The obtained results showed that even after the entry of silver ions into the cell, the bacteria does not respond immediately as the bacterial cells are reported to tolerate the micromolar concentrations of heavy metals including silver. , This property of metal tolerance resides in their genetic makeup upon transcriptional regulation of certain genes, which helps them sustain under certain levels of metal stress. As discussed above, the bacterial defense system becomes activated at the later time points of silver species treatment and enabled the DNA and protein repair machinery as well as activation of the Suf system to maintain homeostasis.…”

Section: Results and Discussionmentioning

confidence: 99%

Does Silver in Different Forms Affect Bacterial Susceptibility and Resistance? A Mechanistic Perspective

Pareek

Gupta

Devineau

et al. 2022

ACS Appl. Bio Mater.

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The exceptional increase in antibiotic resistance in past decades motivated the scientific community to use silver as a potential antibacterial agent. However, due to its unknown antibacterial mechanism and the pattern of bacterial resistance to silver species, it has not been revolutionized in the health sector. This study deciphers mechanistic aspects of silver species, i.e., ions and lysozyme-coated silver nanoparticles (L-Ag NPs), against E. coli K12 through RNA sequencing analysis. The obtained results support the reservoir nature of nanoparticles for the controlled release of silver ions into bacteria. This study differentiates between the antibacterial mechanism of silver species by discussing the pathway of their entry in bacteria, sequence of events inside cells, and response of bacteria to overcome silver stress. Controlled release of ions from L-Ag NPs not only reduces bacterial growth but also reduces the likelihood of resistance development. Conversely, direct exposure of silver ions, leads to rapid activation of the bacterial defense system leading to development of resistance against silver ions, like the well-known antibiotic resistance problem. These findings provide valuable insight on the mechanism of silver resistance and antibacterial strategies deployed by E. coli K12, which could be a potential target for the generation of aim-based and effective nanoantibiotics.

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Aspects of silver tolerance in bacteria: infrared spectral changes and epigenetic clues

Cited by 22 publications

References 47 publications

Silver nanoparticles induce a triclosan-like antibacterial action mechanism in multi-drug resistant Klebsiella pneumoniae

Silver nanoparticles induce a triclosan-like antibacterial action mechanism in multi-drug resistant Klebsiella pneumoniae

Rapid diagnosis of COVID-19 using FT-IR ATR spectroscopy and machine learning

Does Silver in Different Forms Affect Bacterial Susceptibility and Resistance? A Mechanistic Perspective

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