scholarly journals Molecular Mechanisms of Bacterial Resistance to Metal and Metal Oxide Nanoparticles

2019 ◽  
Vol 20 (11) ◽  
pp. 2808 ◽  
Author(s):  
Nereyda Niño-Martínez ◽  
Marco Felipe Salas Orozco ◽  
Gabriel-Alejandro Martínez-Castañón ◽  
Fernando Torres Méndez ◽  
Facundo Ruiz
Keyword(s):  
Metal Oxide ◽  
Molecular Mechanisms ◽  
Bacterial Resistance ◽  
Bacterial Species ◽  
Metal Oxide Nanoparticles ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Oxide Nanoparticles ◽  
Multidrug Resistant Bacteria

The increase in bacterial resistance to one or several antibiotics has become a global health problem. Recently, nanomaterials have become a tool against multidrug-resistant bacteria. The metal and metal oxide nanoparticles are one of the most studied nanomaterials against multidrug-resistant bacteria. Several in vitro studies report that metal nanoparticles have antimicrobial properties against a broad spectrum of bacterial species. However, until recently, the bacterial resistance mechanisms to the bactericidal action of the nanoparticles had not been investigated. Some of the recently reported resistance mechanisms include electrostatic repulsion, ion efflux pumps, expression of extracellular matrices, and the adaptation of biofilms and mutations. The objective of this review is to summarize the recent findings regarding the mechanisms used by bacteria to counteract the antimicrobial effects of nanoparticles.

scholarly journals High Colonization Rate and Heterogeneity of ESBL- and Carbapenemase-Producing Enterobacteriaceae Isolated from Gull Feces in Lisbon, Portugal

2020 ◽  
Vol 8 (10) ◽  
pp. 1487
Author(s):  
Marta Aires-de-Sousa ◽  
Claudine Fournier ◽  
Elizeth Lopes ◽  
Hermínia de Lencastre ◽  
Patrice Nordmann ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bacterial Species ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Vancomycin Resistant ◽  
Encoding Genes

In order to evaluate whether seagulls living on the Lisbon coastline, Portugal, might be colonized and consequently represent potential spreaders of multidrug-resistant bacteria, a total of 88 gull fecal samples were screened for detection of extended-spectrum β-lactamase (ESBL)- or carbapenemase-producing Enterobacteriaceae for methicillin-resistant Staphylococcus aureus (MRSA) and for vancomycin-resistant Enterococci (VRE). A large proportion of samples yielded carbapenemase- or ESBL-producing Enterobacteriaceae (16% and 55%, respectively), while only two MRSA and two VRE were detected. Mating-out assays followed by PCR and whole-plasmid sequencing allowed to identify carbapenemase and ESBL encoding genes. Among 24 carbapenemase-producing isolates, there were mainly Klebsiella pneumoniae (50%) and Escherichia coli (33%). OXA-181 was the most common carbapenemase identified (54%), followed by OXA-48 (25%) and KPC-2 (17%). Ten different ESBLs were found among 62 ESBL-producing isolates, mainly being CTX-M-type enzymes (87%). Co-occurrence in single samples of multiple ESBL- and carbapenemase producers belonging to different bacterial species was observed in some cases. Seagulls constitute an important source for spreading multidrug-resistant bacteria in the environment and their gut microbiota a formidable microenvironment for transfer of resistance genes within bacterial species.

A Review on Antimicrobial Properties of Metal Nanoparticles

2020 ◽  
Vol 20 (6) ◽  
pp. 3303-3339 ◽  
Author(s):  
Saee Gharpure ◽  
Aman Akash ◽  
Balaprasad Ankamwar
Keyword(s):  
Titanium Dioxide ◽  
Metal Oxide ◽  
Biomedical Applications ◽  
Antimicrobial Agents ◽  
Metal Oxide Nanoparticles ◽  
Antimicrobial Properties ◽  
Multidrug Resistant ◽  
Oxide Nanoparticles ◽  
Synthesis Methods ◽  
Micro Organisms

The field of nanotechnology elaborates the synthesis, characterization as well as application of nanomaterials. Applications of nanoparticles in various fields have interested scientists since decades due to its unique properties. Combination of pharmacology with nanotechnology has helped in development of newer antimicrobial agents in order to control the ever increasing multidrug resistant micro-organisms. Properties of metal and metal oxide nanoparticles like silver, gold, titanium dioxide as well as magnesium oxide as antimicrobial agents are very well known. This review elaborates synthesis methods and antimicrobial mechanisms of various metal as well as metal oxide nanoparticles for better understanding in order to utilize their potentials in various biomedical applications.

scholarly journals Occurrence of NDM-1 and VIM-2 Co-Producing Escherichia coli and OprD Alteration in Pseudomonas aeruginosa Isolated from Hospital Environment Samples in Northwestern Tunisia

Diagnostics ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1617
Author(s):  
Raouaa Maaroufi ◽  
Olfa Dziri ◽  
Linda Hadjadj ◽  
Seydina M. Diene ◽  
Jean-Marc Rolain ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Bacterial Resistance ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Hospital Environment ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Disk Diffusion Method

Hospital environments constitute the main reservoir of multidrug-resistant bacteria. In this study we aimed to investigate the presence of Gram-negative bacteria in one Northwestern Tunisian hospital environment, and characterize the genes involved in bacterial resistance. A total of 152 environmental isolates were collected from various surfaces and isolated using MacConkey medium supplemented with cefotaxime or imipenem, with 81 fermenter bacteria (27 Escherichia coli, and 54 Enterobacter spp., including 46 Enterobacter cloacae), and 71 non-fermenting bacteria (69 Pseudomonas spp., including 54 Pseudomonas aeruginosa, and 2 Stenotrophomonas maltophilia) being identified by the MALDI-TOF-MS method. Antibiotic susceptibility testing was performed by disk diffusion method and E-Test was used to determine MICs for imipenem. Several genes implicated in beta-lactams resistance were characterized by PCR and sequencing. Carbapenem resistance was detected among 12 isolates; nine E. coli (blaNDM-1 (n = 8); blaNDM-1 + blaVIM-2 (n = 1)) and three P. aeruginosa were carbapenem-resistant by loss of OprD porin. The whole-genome sequencing of P. aeruginosa 97H was determined using Illumina MiSeq sequencer, typed ST285, and harbored blaOXA-494. Other genes were also detected, notably blaTEM (n = 23), blaCTX-M-1 (n = 10) and blaCTX-M-9 (n = 6). These new epidemiological data imposed new surveillance strategies and strict hygiene rules to decrease the spread of multidrug-resistant bacteria in this area.

scholarly journals Post-antibiotic era in hemodialysis? Two case reports of simultaneous colonization and bacteremia by multidrug-resistant bacteria

2020 ◽  
Author(s):  
Johanna M. Vanegas ◽  
Lorena Salazar-Ospina ◽  
Gustavo A. Roncancio ◽  
Julián Builes ◽  
Judy Natalia Jiménez
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Case Reports ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Control Measures ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
E Coli ◽  
Carbapenem Resistant

ABSTRACT The emergence of resistance mechanisms not only limits the therapeutic options for common bacterial infections but also worsens the prognosis in patients who have conditions that increase the risk of bacterial infections. Thus, the effectiveness of important medical advances that seek to improve the quality of life of patients with chronic diseases is threatened. We report the simultaneous colonization and bacteremia by multidrug-resistant bacteria in two hemodialysis patients. The first patient was colonized by carbapenem- and colistin-resistant Klebsiella pneumoniae, carbapenem-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA). The patient had a bacteremia by MRSA, and molecular typing methods confirmed the colonizing isolate was the same strain that caused infection. The second case is of a patient colonized by extended-spectrum beta-lactamases (ESBL)-producing Escherichia coli and carbapenem-resistant Pseudomonas aeruginosa. During the follow-up period, the patient presented three episodes of bacteremia, one of these caused by ESBL-producing E. coli. Molecular methods confirmed colonization by the same clone of ESBL-producing E. coli at two time points, but with a different genetic pattern to the strain isolated from the blood culture. Colonization by multidrug-resistant bacteria allows not only the spread of these microorganisms, but also increases the subsequent risk of infections with limited treatments options. In addition to infection control measures, it is important to establish policies for the prudent use of antibiotics in dialysis units.

scholarly journals Bacteriophages: Protagonists of a Post-Antibiotic Era

Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 66 ◽  
Author(s):  
Pilar Domingo-Calap ◽  
Jennifer Delgado-Martínez
Keyword(s):  
Bacterial Resistance ◽  
Multidrug Resistant ◽  
Therapeutic Agents ◽  
Point Of View ◽  
Resistant Bacteria ◽  
Natural Killers ◽  
Food Control ◽  
Multidrug Resistant Bacteria ◽  
Clinical Point ◽  
Excellent Tool

Despite their long success for more than half a century, antibiotics are currently under the spotlight due to the emergence of multidrug-resistant bacteria. The development of new alternative treatments is of particular interest in the fight against bacterial resistance. Bacteriophages (phages) are natural killers of bacteria and are an excellent tool due to their specificity and ecological safety. Here, we highlight some of their advantages and drawbacks as potential therapeutic agents. Interestingly, phages are not only attractive from a clinical point of view, but other areas, such as agriculture, food control, or industry, are also areas for their potential application. Therefore, we propose phages as a real alternative to current antibiotics.

scholarly journals Two Mechanisms of Killing of Pseudomonas aeruginosa by Tobramycin Assessed at Multiple Inocula via Mechanism-Based Modeling

2015 ◽  
Vol 59 (4) ◽  
pp. 2315-2327 ◽  
Author(s):  
Jürgen B. Bulitta ◽  
Neang S. Ly ◽  
Cornelia B. Landersdorfer ◽  
Nicholin A. Wanigaratne ◽  
Tony Velkov ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Protein Synthesis ◽  
Outer Membrane ◽  
Bacterial Resistance ◽  
Multidrug Resistant ◽  
Quantitative Model ◽  
Great Promise ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Bacterial Killing

ABSTRACTBacterial resistance is among the most serious threats to human health globally, and many bacterial isolates have emerged that are resistant to all antibiotics in monotherapy. Aminoglycosides are often used in combination therapies against severe infections by multidrug-resistant bacteria. However, models quantifying different antibacterial effects of aminoglycosides are lacking. While the mode of aminoglycoside action on protein synthesis has often been studied, their disruptive action on the outer membrane of Gram-negative bacteria remains poorly characterized. Here, we developed a novel quantitative model for these two mechanisms of aminoglycoside action, phenotypic tolerance at high bacterial densities, and adaptive bacterial resistance in response to an aminoglycoside (tobramycin) against threePseudomonas aeruginosastrains. At low-intermediate tobramycin concentrations (<4 mg/liter), bacterial killing due to the effect on protein synthesis was most important, whereas disruption of the outer membrane was the predominant killing mechanism at higher tobramycin concentrations (≥8 mg/liter). The extent of killing was comparable across all inocula; however, the rate of bacterial killing and growth was substantially lower at the 108.9CFU/ml inoculum than that at the lower inocula. At 1 to 4 mg/liter tobramycin for strain PAO1-RH, there was a 0.5- to 6-h lag time of killing that was modeled via the time to synthesize hypothetical lethal protein(s). Disruption of the outer bacterial membrane by tobramycin may be critical to enhance the target site penetration of antibiotics used in synergistic combinations with aminoglycosides and thereby combat multidrug-resistant bacteria. The two mechanisms of aminoglycoside action and the new quantitative model hold great promise to rationally design novel, synergistic aminoglycoside combination dosage regimens.

Toxic Effects of Metal Oxide Nanoparticles Based on the Enzymatic Activity and Biosynthesis of β-Galactosidase Using a Mutant Strain of E. coli

2020 ◽  
Vol 20 (3) ◽  
pp. 1440-1446
Author(s):  
In Chul Kong ◽  
Xin Yang ◽  
Wonil Wi ◽  
Minji Kim ◽  
Kyung-Seok Ko
Keyword(s):  
Enzyme Activity ◽  
Metal Oxide ◽  
Mutant Strain ◽  
Molecular Mechanisms ◽  
Metal Oxide Nanoparticles ◽  
Metabolic Process ◽  
Toxic Effects ◽  
Systematic Research ◽  
Oxide Nanoparticles ◽  
E Coli

The effects of six metal oxide nanoparticles (MO-NPs) on the activity and biosynthesis of an enzyme (β-galactosidase) were examined using a mutant strain of E. coli. Different sensitivities were observed according to the type of NP and metabolic process. The toxic effects on enzyme activity were significantly greater than on biosynthesis (p < 0.011), except in the presence of NiO. In both cases, ZnO NP caused the greatest inhibition among the tested NPs, followed by CuO. The EC50s for ZnO were 0.19 and 3.68 mg/L for enzyme activity and biosynthesis, respectively. Similar orders of toxicity were observed as follows: ZnO > CuO > NiO > Co3O4 > TiO2, Al2O3 for enzyme activity; and ZnO > CuO > NiO ≫ Al2O3, TiO2, Co3O4 for the biosynthetic process. More systematic research, including in-depth studies like investigation of the molecular mechanisms, is necessary to elucidate the detailed mechanisms of inhibition involved in both metabolic processes.

scholarly journals Metal Oxide Nanoparticles in Therapeutic Regulation of Macrophage Functions

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1631 ◽  
Author(s):  
Marina S. Dukhinova ◽  
Artur. Y. Prilepskii ◽  
Alexander A. Shtil ◽  
Vladimir V. Vinogradov
Keyword(s):  
Metal Oxide ◽  
Molecular Mechanisms ◽  
Viral Infections ◽  
Metal Oxide Nanoparticles ◽  
Cell Polarization ◽  
Innate Immune ◽  
Diagnostic Tools ◽  
Oxide Nanoparticles ◽  
Inflammatory Microenvironment ◽  
Anti Inflammatory

Macrophages are components of the innate immune system that control a plethora of biological processes. Macrophages can be activated towards pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes depending on the cue; however, polarization may be altered in bacterial and viral infections, cancer, or autoimmune diseases. Metal (zinc, iron, titanium, copper, etc.) oxide nanoparticles are widely used in therapeutic applications as drugs, nanocarriers, and diagnostic tools. Macrophages can recognize and engulf nanoparticles, while the influence of macrophage-nanoparticle interaction on cell polarization remains unclear. In this review, we summarize the molecular mechanisms that drive macrophage activation phenotypes and functions upon interaction with nanoparticles in an inflammatory microenvironment. The manifold effects of metal oxide nanoparticles on macrophages depend on the type of metal and the route of synthesis. While largely considered as drug transporters, metal oxide nanoparticles nevertheless have an immunotherapeutic potential, as they can evoke pro- or anti-inflammatory effects on macrophages and become essential for macrophage profiling in cancer, wound healing, infections, and autoimmunity.

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