scholarly journals In vitro biofabrication of silver nanoparticles: Optimization, characterization, and activity against beta-lactamases-resistant Enterococcus faecalis

2021 ◽  
Author(s):  
Bikhal Fattah ◽  
Huner Arif ◽  
Haider Hamzah
Keyword(s):  
Enterococcus Faecalis ◽  
Antibiotic Resistance Genes ◽  
Sem Images ◽  
Beta Lactamases ◽  
Stabilizing Agents ◽  
Afm Analysis ◽  
Synthesis Catalysts ◽  
Crystalline Nature ◽  
Alternative Sources

Abstract The rate at which nosocomial infections have spread throughout the globe has been alarming. Therefore, the data presented here sheds light on some aspects of AgNPs as promising anti-infective therapy. However, knowledge on the safe usage of AgNPs in the field of medicine is necessary to investigate. AgNPs synthesis, optimization, characterization, and mode of action against Enterococcus faecalis have been studied in this paper. We propose a combination of cell-free supernatant (C-FS) of the intimate organisms; Fusarium solani and Comamonas aquatica as synthesis catalysts. The optimization findings were at pH 9.0 for 72 h in 1 mM AgNO3 using 1:2 v/v (C-FS : AgNO3). UV-vis absorption peak appeared at 425 nm and the crystalline nature of synthesized particles was verified by XRD. FTIR analysis confirmed the presence of protein molecules that acted as reducing and stabilizing agents. Energy-dispersive X-ray analysis exhibited an intense peak at 3 KeV, confirming the formation of AgNPs. Further, FE-SEM images prove AgNPs synthesis. TEM and AFM analysis demonstrated that fabricated AgNPs were relatively monodispersed, approximately spherical, and of size 2-7.5 nm. The growth and biofilm of nosocomial E. faecalis were significantly decreased by the action of AgNPs. Furthermore, antibiotic resistance genes, blaTEM, and blaCTX, were detected in E. faecalis; both genes were degraded enormously via 9 % AgNPs. This is the first study proposing alternative sources to form AgNPs via synergistic metabolites of F. solani and C. aquatica. The results here offer a foundation for developing an effective therapy using AgNPs against nosocomial pathogens.

scholarly journals Fabrication And Optimization of Bio-silver Nanoparticles: Activity Evaluation Against Beta-lactamases-Resistant Enterococcus Faecalis

2021 ◽  
Author(s):  
Bikhal Fattah ◽  
Huner Arif ◽  
Haider Hamzah
Keyword(s):  
Silver Nanoparticles ◽  
Enterococcus Faecalis ◽  
Treatment Options ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Antibiotic Resistant ◽  
Beta Lactamases ◽  
Transmission Electron ◽  
Crystalline Nature ◽  
Alternative Sources

Abstract Due to the presence of antibiotic-resistant genes, treatment options of clinical isolates are exceedingly limited. This study was aimed to fabricate, optimize, characterize, and evaluate the action of silver nanoparticles (AgNPs) against a clinical isolate of Enterococcus faecalis. A combination of cell-free supernatant (C-FS) of the filamentous fungus Fusarium solani and Gram-negative Comamonas aquatica for AgNPs formation was proposed; the antigrowth and antibiofilm of AgNPs against E. faecalis harboring blaTEM and blaCTX-M genes were assessed. The ratio of 1:2 v/v (C-FS:AgNO3) at pH 9.0 for 72 h in 1 mM AgNO3 were the optimal conditions for AgNPs formation. UV-vis absorption peak appeared at 425 nm and the crystalline nature of synthesized particles was verified by X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) analysis confirmed the interaction of protein molecules with the AgNPs. Transmission electron microscopy (TEM) analysis demonstrated that fabricated AgNPs were relatively monodispersed, approximately spherical, and of size 2-7.5 nm. blaTEM and blaCTX-M were detected in E. faecalis; the growth and biofilm of E. faecalis were significantly decreased by the action of 12.5 µg/mL AgNPs. This is the first study proposing alternative sources to form AgNPs via synergistic metabolites of F. solani and C. aquatica. The results here offer a foundation for developing an effective therapy using AgNPs against clinical pathogens.

scholarly journals Fabrication and optimization of bio-silver nanoparticles: Activity evaluation against beta-lactamases-resistant Enterococcus faecalis

2021 ◽  
Author(s):  
Bikhal Fattah ◽  
Huner Arif ◽  
Haider Mousa
Keyword(s):  
Silver Nanoparticles ◽  
Enterococcus Faecalis ◽  
Treatment Options ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Antibiotic Resistant ◽  
Beta Lactamases ◽  
Transmission Electron ◽  
Crystalline Nature ◽  
Alternative Sources

Abstract Objectives: Due to the presence of antibiotic-resistant genes, treatment options of clinical isolates are exceedingly limited. This study was aimed to fabricate, optimize, characterize, and evaluate the action of silver nanoparticles (AgNPs) against a clinical isolate of Enterococcus faecalis.Materials and Methods: A combination of cell-free supernatant (C-FS) of the filamentous fungus Fusarium solani and Gram-negative Comamonas aquatica for AgNPs formation was proposed; the antigrowth and antibiofilm of AgNPs against E. faecalis harboring blaTEM and blaCTX-M genes were assessed. Results: The ratio of 1:2 v/v (C-FS:AgNO3) at pH 9.0 for 72 h in 1 mM AgNO3 were the optimal conditions for AgNPs formation. UV-vis absorption peak appeared at 425 nm and the crystalline nature of synthesized particles was verified by X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) analysis confirmed the interaction of protein molecules with the AgNPs. Transmission electron microscopy (TEM) analysis demonstrated that fabricated AgNPs were relatively monodispersed, approximately spherical, and of size 2-7.5 nm. blaTEM and blaCTX-M were detected in E. faecalis; the growth and biofilm of E. faecalis were significantly decreased by the action of 12.5 µg/ml AgNPs. Conclusions: This is the first study proposing alternative sources to form AgNPs via synergistic metabolites of F. solani and C. aquatica. The results here offer a foundation for developing an effective therapy using AgNPs against clinical pathogens.

scholarly journals Conjugative delivery of CRISPR-Cas9 for the selective depletion of antibiotic-resistant enterococci

2019 ◽  
Author(s):  
Marinelle Rodrigues ◽  
Sara W. McBride ◽  
Karthik Hullahalli ◽  
Kelli L. Palmer ◽  
Breck A. Duerkop
Keyword(s):  
Antibiotic Resistance ◽  
Enterococcus Faecalis ◽  
Resistance Genes ◽  
Bacterial Infections ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Conjugative Plasmid ◽  
Antibiotic Resistant ◽  
Resistance Determinants

AbstractThe innovation of new therapies to combat multidrug-resistant (MDR) bacteria is being outpaced by the continued rise of MDR bacterial infections. Of particular concern are hospital-acquired infections (HAIs) recalcitrant to antibiotic therapies. The Gram-positive intestinal pathobiontEnterococcus faecalisis associated with HAIs and some strains are MDR. Therefore, novel strategies to controlE. faecalispopulations are needed. We previously characterized anE. faecalisType II CRISPR-Cas system and demonstrated its utility in the sequence-specific removal of antibiotic resistance determinants. Here we present work describing the adaption of this CRISPR-Cas system into a constitutively expressed module encoded on a pheromone-responsive conjugative plasmid that efficiently transfers toE. faecalisfor the selective removal of antibiotic resistance genes. Usingin vitrocompetition assays, we show that these CRISPR-Cas-encoding delivery plasmids, or CRISPR-Cas antimicrobials, can reduce the occurrence of antibiotic resistance in enterococcal populations in a sequence-specific manner. Furthermore, we demonstrate that deployment of CRISPR-Cas antimicrobials in the murine intestine reduces the occurrence of antibiotic-resistantE. faecalisby several orders of magnitude. Finally, we show thatE. faecalisdonor strains harboring CRISPR-Cas antimicrobials are immune to uptake of antibiotic resistance determinantsin vivo. Our results demonstrate that conjugative delivery of CRISPR-Cas antimicrobials may be adaptable for future deployment from probiotic bacteria for exact targeting of defined MDR bacteria or for precision engineering of polymicrobial communities in the mammalian intestine.ImportanceCRISPR-Cas nucleic acid targeting systems hold promise for the amelioration of multidrug-resistant enterococci, yet the utility of such tools in the context of the intestinal environment where enterococci reside is understudied. We describe the development of a CRISPR-Cas antimicrobial, deployed on a conjugative plasmid, for the targeted removal of antibiotic resistance genes from intestinalEnterococcus faecalis. We demonstrate that CRISPR-Cas targeting reduces antibiotic resistance ofE. faecalisby several orders of magnitude in the intestine. Although barriers exist that influence the penetrance of the conjugative CRISPR-Cas antimicrobial among target recipientE. faecaliscells, the removal of antibiotic resistance genes inE. faecalisupon uptake of the CRISPR-Cas antimicrobial is absolute. In addition, cells that obtain the CRISPR-Cas antimicrobial are immunized against the acquisition of new antibiotic resistance genes. This study suggests a potential path toward plasmid based CRISPR-Cas therapies in the intestine.

scholarly journals Enterococcus faecalisCRISPR-Cas is a robust barrier to conjugative antibiotic resistance dissemination in the murine intestine

2018 ◽  
Author(s):  
Valerie J. Price ◽  
Sara W. McBride ◽  
Karthik Hullahalli ◽  
Anushila Chatterjee ◽  
Breck A. Duerkop ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Enterococcus Faecalis ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Conjugative Plasmids ◽  
Resistance Plasmids ◽  
The Impact ◽  
Mammalian Intestine

AbstractCRISPR-Cas systems are barriers to horizontal gene transfer (HGT) in bacteria. Little is known about CRISPR-Cas interactions with conjugative plasmids, and studies investigating CRISPR-Cas/plasmid interactions inin vivomodels relevant to infectious disease are lacking. These are significant gaps in knowledge because conjugative plasmids disseminate antibiotic resistance genes among pathogensin vivo, and it is essential to identify strategies to reduce the spread of these elements. We use enterococci as models to understand the interactions of CRISPR-Cas with conjugative plasmids.Enterococcus faecalisis a native colonizer of the mammalian intestine and harbors pheromone-responsive plasmids (PRPs). PRPs mediate inter- and intraspecies transfer of antibiotic resistance genes. We assessedE. faecalisCRISPR-Cas anti-PRP activity in the mouse intestine and under varyingin vitroconditions. We observed striking differences in CRISPR-Cas efficiencyin vitroversusin vivo. With few exceptions, CRISPR-Cas blocked intestinal PRP dissemination, whilein vitro, the PRP frequently escaped CRISPR-Cas defense. Our results further the understanding of CRISPR-Cas biology by demonstrating that standardin vitroexperiments do not adequately model thein vivoanti-plasmid activity of CRISPR-Cas. Additionally, our work identifies several variables that impact the apparentin vitroanti-plasmid activity of CRISPR-Cas, including planktonic versus biofilm settings, different donor/recipient ratios, production of a plasmid-encoded bacteriocin, and the time point at which matings are sampled. Our results are clinically significant because they demonstrate that barriers to HGT encoded by normal human microbiota can have significant impacts onin vivoantibiotic resistance dissemination.ImportanceCRISPR-Cas is a type of immune system encoded by bacteria that is hypothesized to be a natural impediment to the spread of antibiotic resistance genes. In this study, we directly assessed the impact of CRISPR-Cas on antibiotic resistance dissemination in the mammalian intestine and under varyingin vitroconditions. We observed a robust effect of CRISPR-Cas onin vivobut notin vitrodissemination of antibiotic resistance plasmids in the native mammalian intestinal colonizerEnterococcus faecalis. We conclude that standard laboratory experiments currently do not appropriately model thein vivoconditions where antibiotic resistance dissemination occurs betweenE. faecalisstrains. Moreover, our results demonstrate that CRISPR-Cas encoded by native members of the mammalian intestinal microbiota can block the spread of antibiotic resistance plasmids.

scholarly journals Enterococcus faecalis CRISPR-Cas Is a Robust Barrier to Conjugative Antibiotic Resistance Dissemination in the Murine Intestine

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Valerie J. Price ◽  
Sara W. McBride ◽  
Karthik Hullahalli ◽  
Anushila Chatterjee ◽  
Breck A. Duerkop ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Enterococcus Faecalis ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Content Type ◽  
Conjugative Plasmids ◽  
Resistance Plasmids ◽  
Mammalian Intestine

ABSTRACT CRISPR-Cas systems are barriers to horizontal gene transfer (HGT) in bacteria. Little is known about CRISPR-Cas interactions with conjugative plasmids, and studies investigating CRISPR-Cas/plasmid interactions in in vivo models relevant to infectious disease are lacking. These are significant gaps in knowledge because conjugative plasmids disseminate antibiotic resistance genes among pathogens in vivo, and it is essential to identify strategies to reduce the spread of these elements. We use enterococci as models to understand the interactions of CRISPR-Cas with conjugative plasmids. Enterococcus faecalis is a native colonizer of the mammalian intestine and harbors pheromone-responsive plasmids (PRPs). PRPs mediate inter- and intraspecies transfer of antibiotic resistance genes. We assessed E. faecalis CRISPR-Cas anti-PRP activity in the mouse intestine and under different in vitro conditions. We observed striking differences in CRISPR-Cas efficiency in vitro versus in vivo. With few exceptions, CRISPR-Cas blocked intestinal PRP dissemination, while in vitro, the PRP frequently escaped CRISPR-Cas defense. Our results further the understanding of CRISPR-Cas biology by demonstrating that standard in vitro experiments do not adequately model the in vivo antiplasmid activity of CRISPR-Cas. Additionally, our work identifies several variables that impact the apparent in vitro antiplasmid activity of CRISPR-Cas, including planktonic versus biofilm settings, different donor-to-recipient ratios, production of a plasmid-encoded bacteriocin, and the time point at which matings are sampled. Our results are clinically significant because they demonstrate that barriers to HGT encoded by normal (healthy) human microbiota can have significant impacts on in vivo antibiotic resistance dissemination. IMPORTANCE CRISPR-Cas is a type of immune system in bacteria that is hypothesized to be a natural impediment to the spread of antibiotic resistance genes. In this study, we directly assessed the impact of CRISPR-Cas on antibiotic resistance dissemination in the mammalian intestine and under different in vitro conditions. We observed a robust effect of CRISPR-Cas on in vivo but not in vitro dissemination of antibiotic resistance plasmids in the native mammalian intestinal colonizer Enterococcus faecalis. We conclude that standard in vitro experiments currently do not appropriately model the in vivo conditions where antibiotic resistance dissemination occurs between E. faecalis strains in the intestine. Moreover, our results demonstrate that CRISPR-Cas present in native members of the mammalian intestinal microbiota can block the spread of antibiotic resistance plasmids.

An In Vitro Analysis of Sodium Hypochlorite Decontamination for the Reuse of Implant Healing Abutments

2020 ◽  
Author(s):  
Ahmad Almehmadi
Keyword(s):  
Sodium Hypochlorite ◽  
Bacterial Culture ◽  
Brain Heart Infusion ◽  
In Vitro Study ◽  
Vitro Study ◽  
Sem Images ◽  
Streptococcus Sanguis ◽  
Implant Dentistry ◽  
Vitro Analysis

Abstract The re-use of healing abutments (HAs) has become common practice in implant dentistry for economic concerns and the aim of this in-vitro study was to assess the effect of sodium hypochlorite (NaOCl) in decontamination of HAs. 122 HAs (Used and sterilized n=107; New n=15) were procured from 3 centers, of which 3 samples were discarded due to perforation in sterilization pouch.  For sterility assessment, the used HAs (n=80) were cultured in Brain Heart Infusion Broth (BHI) and Potato Dextrose Agar (PDA), bacterial isolates were identified in 7 samples. Also, 24 used HAs were stained with Phloxine B, photographed and compared to new HAs (n=5). Scanning electron microscope (SEM) assessed the differences between the two sets of HAs, following which the 7 contaminated HAs along with 24 used HAs from staining experiment (Total=31) were subsequently treated with sodium hypochlorite (NaOCl) and SEM images were observed. About 8.75% of HAs tested positive in bacterial culture; Streptococcus sanguis, Dermabacter hominis, Staphylococcus haemolyticus, and Aspergillus species were isolated. Phloxine B staining was positive for used and sterilized HAs when compared to controls. The SEM images revealed deposits in the used HAs and although treatment with NaOCl eliminated the contamination of cultured HAs, the SEM showed visible debris in the HA thread region. This in-vitro study concluded that SEM images showed debris in used HAs at screw-hole and thread regions even though they tested negative in bacterial culture. The treatment with NaOCl of used HAs showed no bacterial contamination but the debris was observed in SEM images. Future studies on the chemical composition, biological implications, and clinical influence is warranted before considering the reuse of HAs.

ATIVIDADE ANTIMICROBIANA IN VITRO DO EXTRATO AQUOSO, HIDROALCOÓLICO E ALCOÓLICO DE FOLHAS DE ESPÉCIES DA FAMÍLIA LAMIACEAE

2018 ◽  
Vol 4 ◽  
Author(s):  
Karlynne Freire Mendonça ◽  
José Klauber Roger Carneiro ◽  
Maria Auxiliadora Silva Oliveira
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Enterococcus Faecalis ◽  
Streptococcus Pyogenes ◽  
Mentha Arvensis ◽  
Ocimum Gratissimum ◽  
Mueller Hinton ◽  
Plectranthus Amboinicus

Objetivos: avaliar a atividade antimicrobiana em extrato aquoso, hidroalcoólico e alcoólico das folhas de espécies da família Lamiaceae frente a bactérias de interesse. Método: Foram escolhidas quatro espécies: Ocimum gratissimum, Plectranthus amboinicus, Mentha arvensis e Plectranthus barbatus. A partir das folhas foram confeccionados os extratos aquoso, hidroalcoólico e alcoólico nas concentrações 100mg/mL, 50mg/mL e 25mg/mL. Foram selecionadas as bactérias Streptococcus pyogenes, Enterococcus faecalis, Staphylococcus aureus e Pseudomonas aeruginosa para os ensaios de antibiose em Ágar Mueller-Hinton. Resultados: P. barbatus, em seu extrato hidroalcoólico mostrou ativo nas três concentrações para bactéria S. aureus, e ainda foi ativo para P. aeruginosa, demonstrando no extrato alcoólico atividade frente as bactérias. Para M. arvensis e P. amboinicus, seus extratos hidroalcoólico e alcoólico apresentaram atividade para S. aureus. Conclusão: Sugere-se que as espécies em questão apresentem boa atividade antimicrobiana, sendo necessária a realização de mais estudos para melhor entender esse mecanismo.

An in-vitro study on the effectiveness of different irrigation solutions against Enterococcus faecalis with/without Erbium laser activation

2020 ◽  
Vol 2 (4) ◽  
pp. 1-1
Author(s):  
Gülşah Balan ◽  
Sadık Kalaycı ◽  
Ayşen Yarat ◽  
Serap Akyüz ◽  
Firettin Şahin
Keyword(s):  
Enterococcus Faecalis ◽  
In Vitro Study ◽  
Vitro Study ◽  
Erbium Laser

Potential for Treatment of Neurodegenerative Diseases with Natural Products or Synthetic Compounds that Stabilize Microtubules

2020 ◽  
Vol 26 (35) ◽  
pp. 4362-4372
Author(s):  
John H. Miller ◽  
Viswanath Das
Keyword(s):  
Natural Products ◽  
Neurodegenerative Diseases ◽  
In Vivo Models ◽  
Synthetic Compounds ◽  
Stabilizing Agents ◽  
Animal Models Of Disease ◽  
Model Studies ◽  
Models Of Disease

No effective therapeutics to treat neurodegenerative diseases exist, despite significant attempts to find drugs that can reduce or rescue the debilitating symptoms of tauopathies such as Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, amyotrophic lateral sclerosis, or Pick’s disease. A number of in vitro and in vivo models exist for studying neurodegenerative diseases, including cell models employing induced-pluripotent stem cells, cerebral organoids, and animal models of disease. Recent research has focused on microtubulestabilizing agents, either natural products or synthetic compounds that can prevent the axonal destruction caused by tau protein pathologies. Although promising results have come from animal model studies using brainpenetrant natural product microtubule-stabilizing agents, such as paclitaxel analogs that can access the brain, epothilones B and D, and other synthetic compounds such as davunetide or the triazolopyrimidines, early clinical trials in humans have been disappointing. This review aims to summarize the research that has been carried out in this area and discuss the potential for the future development of an effective microtubule stabilizing drug to treat neurodegenerative disease.

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