scholarly journals Physiochemical properties and antibacterial activity of silver nanoparticles green synthesized by Camellia sinensis and Prunus africana extracts

2021 ◽  
Author(s):  
Kenneth Ssekatawa ◽  
Denis Byarugaba ◽  
Charles Kato ◽  
Eddie Wampande ◽  
Francis Ejobi ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Maximum Growth ◽  
Xrd Analysis ◽  
Resistant Bacteria ◽  
Prunus Africana ◽  
Carbapenem Resistant ◽  
Growth Inhibitory ◽  
Vis Spectroscopy ◽  
Biosynthesized Agnps ◽  
Average Size

Abstract Antibiotics have been the nucleus of chemotherapy since their discovery and introduction into the healthcare system in the 1940s. They are used routinely not only to treat bacterial infections but also to prevent infections in patients with compromised immune systems and enhancing growth in livestock. However, resistance to last-resort antibiotics used in the treatment of MDR infections has been reported worldwide. Therefore, the aim of this study was to evaluate green synthesized nanomaterials such as AgNPs as alternatives to antibiotics. UV Vis Spectroscopy surface plasmon resonance peaks for AgNPs were obtained between 417 to 475nm. XRD analysis generated 4 peaks for both PAE and CSE biosynthesized AgNPs positioned at 2θ angles of 38.2˚, 44.4˚, 64.5˚, and 77.4˚ corresponding to crystal planes (111), (200), (220) and (311) respectively. DLS registered mean zeta potential of + 6.3mV and + 0.9mV for PAE and CSE biosynthesized nanoparticles respectively. FTIR spectra exhibited bands corresponding to different organic functional groups confirming capping of AgNPs by PAE and CSE phytochemicals. FESEM imaging showed that AgNPs were spherical with average size distribution ranging from 10 to 19nm. Biosynthesized AgNPs exhibited maximum growth inhibitory zones of 21mm with MIC and MBC of 125µg/ml and 250µg/ml respectively against carbapenem resistant bacteria.

scholarly journals Green Strategy–Based Synthesis of Silver Nanoparticles for Antibacterial Applications

2021 ◽  
Vol 3 ◽  
Author(s):  
Kenneth Ssekatawa ◽  
Denis K. Byarugaba ◽  
Charles D. Kato ◽  
Eddie M. Wampande ◽  
Francis Ejobi ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Infections ◽  
Maximum Growth ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Microscopy Imaging ◽  
Prunus Africana ◽  
Vis Spectroscopy ◽  
Biosynthesized Agnps ◽  
Average Size

Antibiotics have been the nucleus of chemotherapy since their discovery and introduction into the healthcare system in the 1940s. They are routinely used to treat bacterial infections and to prevent infections in patients with compromised immune systems and enhancing growth in livestock. However, resistance to last-resort antibiotics used in the treatment of multidrug-resistant infections has been reported worldwide. Therefore, this study aimed to evaluate green synthesized nanomaterials such as silver nanoparticles (AgNPs) as alternatives to antibiotics. UV-vis spectroscopy surface plasmon resonance peaks for AgNPs were obtained between 417 and 475 nm. An X-ray diffraction analysis generated four peaks for both Prunus africana extract (PAE) and Camellia sinensis extract (CSE) biosynthesized AgNPs positioned at 2θ angles of 38.2°, 44.4°, 64.5°, and 77.4° corresponding to crystal planes (111), (200), (220), and (311), respectively. A dynamic light-scattering analysis registered the mean zeta potential of +6.3 mV and +0.9 mV for PAE and CSE biosynthesized nanoparticles, respectively. Fourier transform infrared spectroscopy spectra exhibited bands corresponding to different organic functional groups confirming the capping of AgNPs by PAE and CSE phytochemicals. Field emission scanning electron microscopy imaging showed that AgNPs were spherical with average size distribution ranging from 10 to 19 nm. Biosynthesized AgNPs exhibited maximum growth inhibitory zones of 21 mm with minimum inhibitory concentration and minimum bactericidal concentration of 125 and 250 μg/ml, respectively, against carbapenem-resistant bacteria.

scholarly journals An overview of carbapenem, its resistance and therapeutic options for infections caused by carbapenem resistant bacteria

2020 ◽  
Vol 9 (9) ◽  
pp. 1454
Author(s):  
Hari P. Nepal ◽  
Rama Paudel
Keyword(s):  
Bacterial Infections ◽  
Carbapenem Resistance ◽  
Therapeutic Options ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Beta Lactam ◽  
Gram Negative ◽  
Penicillin Binding Proteins ◽  
Carbapenem Resistant ◽  
The World

Carbapenems are beta-lactam drugs that have broadest spectrum of activity. They are commonly used as the drugs of last resort to treat complicated bacterial infections. They bind to penicillin binding proteins (PBPs) and inhibit cell wall synthesis in bacteria. Important members that are in clinical use include doripenem, ertapenem, imipenem, and meropenem. Unlike other members, imipenem is hydrolyzed significantly by renal dehydropeptidase; therefore, it is administered together with an inhibitor of renal dehydropeptidase, cilastatin. Carbapenems are usually administered intravenously due to their low oral bioavailability. Most common side effects of these drugs include nausea, vomiting, diarrhea, skin rashes, and reactions at the infusion sites. Increasing resistance to these antibiotics is being reported throughout the world and is posing a threat to public health.  Primary mechanisms of carbapenem resistance include expulsion of drug and inactivation of the drug by production of carbapenemases which may not only hydrolyze carbapenem, but also cephalosporin, penicillin, and aztreonam. Resistance especially among Gram negative bacteria is of much concern since there are only limited therapeutic options available for infections caused by carbapenem resistant Gram-negative bacterial pathogens. Commonly used drugs to treat such infections include polymyxins, fosfomycin and tigecycline.

Ampicillin-augmented silver nanoparticles for synergistic antimicrobial response: A promising therapeutic approach

2021 ◽  
Vol 22 ◽  
Author(s):  
Kashan Khan ◽  
Mohd Aamir Qureshi ◽  
Ameer Azam ◽  
Moinuddin ◽  
Javed Musarrat ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Zeta Potential ◽  
Bacterial Infections ◽  
Colloidal Stability ◽  
Resistant Bacteria ◽  
Antimicrobial Drugs ◽  
Vis Spectroscopy ◽  
Microbial Infections ◽  
Ft Ir

Aims: Globally Scientists are working to find more efficient antimicrobial drugs to treat microbial infections and kill drug-resistant bacteria. Background: Despite the availability of numerous antimicrobial drugs bacterial infections still poses a serious threat to global health. Due to a constant decline in the effectiveness of antibiotics owing to their repeated exposure as well as shortlasting antimicrobial activity, led to the demand for developing novel therapeutic agents capable of controlling microbial infections. Objective: In this study, we report antimicrobial activity of chemically synthesized silver nanoparticles (cAgNPs) augmented with ampicillin (amp) in order to increase antimicrobial response against Escherichia coli (gram –ve), Staphylococcus aureus (gram +ve) and Streptococcus mutans (gram +ve). Methods: Nanostructure, colloidal stability, morphology and size of cAgNPs before and after functionalization were explored by UV-vis spectroscopy, FT-IR, zeta potential and TEM. The formation and functionalization of cAgNPs was confirmed from UV-vis spectroscopy and FT-IR patterns. From TEM the average sizes of cAgNPs and cAgNP-amp were found to be 13 and 7.8 nm respectively, and change in colloidal stability after augmentation was confirmed from zeta potential values. The antimicrobial efficacies of cAgNP-amp and cAgNPs against E. coli S. aureus and S. mutans were studied by determining minimum inhibitory concentrations (MICs), zone of inhibition, assessment of viable and non-viable bacterial cells and quantitative assessment of biofilm. Results & Discussion: Our results revealed cAgNP-amp to be highly bactericidal compared to cAgNPs or amp alone. The nano-toxicity studies indicated cAgNP-amp to be less toxic compared to cAgNPs alone. Results: This study manifested that cAgNPs show synergistic antimicrobial effect when they get functionalized with amp suggesting their application in curing long-term bacterial infections.

Successful Treatment of a Case of Intracranial Infection Caused by Carbapenem-Resistant Klebsiella Pneumonia After Craniocerebral Operation in Patient with Severe Traumatic Brain Injury

2018 ◽  
Vol 10 (3) ◽  
pp. 447-450
Author(s):  
Xianchun Zhu ◽  
Jing Wang ◽  
Youmei Huang ◽  
Huaping Zhang
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Severe Traumatic Brain Injury ◽  
Bacterial Infections ◽  
Present Report ◽  
Resistant Bacteria ◽  
Klebsiella Pneumonia ◽  
Beta Lactam ◽  
Intracranial Infection ◽  
Carbapenem Resistant

Klebsiella pneumoniae (KP) is one of the most common clinical drug-resistant bacteria, which is mainly related to the production of broad-spectrum beta lactamase and cephalosporin hydrolase. Carbapenems, an atypical beta lactam antibiotic, has been the most effective antibiotic for the treatment of bacterial infections caused by KP in hospital. However, with the extensive application of carbapenem antibiotics in clinic, many reports on carbapenem-resistant Klebsiella Pneumonia (CRKP) have appeared in many parts of the world. The CRKP could cause a higher mortality and morbidity. Here, we report a 26-year-old male patient with severe traumatic brain injury who underwent intracranial infection caused by CRKP after craniocerebral operation. He was successfully cured with a combination of emergency craniotomy, multidisciplinary consultation, effective nursing and strict quarantine measures. In the present report, we emphasize the effective nursing and strict quarantine measures, which contribute to the treatment of bacterial infections caused by KP.

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 Treatment of Multi-Drug Resistant Gram-Negative Bacterial Pathogenic Infections

2020 ◽  
Vol 14 (3) ◽  
pp. 1639-1647
Author(s):  
Wardah Mohammad Akram ◽  
Godfred Antony Menezes ◽  
Nida Abbas ◽  
Wasim Ahmad ◽  
Ahmed Mohamed Ahmed
Keyword(s):  
Acinetobacter Baumannii ◽  
Bacterial Infections ◽  
Empirical Therapy ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Review Management ◽  
Emergence Of Resistance ◽  
Novel Therapeutic

The multidrug-resistant Gram-negative bacteria (MDR-GNB) infections in severely infected patients present numerous difficulties in terms of treatment failure where antibiotics cannot arrest such drug resistant bacteria. Based on the patient’s medical history and updated microbiological epidemiology data, an effective empirical treatment remains critical for optimal results to safeguard human health. The aim of this manuscript is to review management of MDR-Gram negative pathogenic bacterial infections. Quick diagnosis and narrow antimicrobial spectrum require rapid and timely diagnosis and effective laboratories in accordance with antimicrobial stewardship (AS) principles. Worldwide, there is an increased emergence of Carbapenem-resistant Enterobacteriaceae (CRE), Pseudomonas aeruginosa, and Acinetobacter baumannii. Recently, novel therapeutic options, such as meropenem/vaborbactam, ceftazidime/avibactam, ceftolozane/tazobactam, eravacycline and plazomicin became accessible to effectively counteract severe infections. Optimally using these delays the emergence of resistance to novel therapeutic agents. Further study is required, however, due to uncertainties in pharmacokinetic/pharmacodynamics optimization of dosages and therapeutic duration in severely ill patients. The novel agents should be verified for (i) action on carbapenem resistant Acinetobacter baumannii; (ii) action on CRE of β-lactam/β-lactamase inhibitors dependence on type of carbapenemase; (iii) emergence of resistance to novel antibacterials and dismiss selective pressure promoting development of resistance. Alternative treatments should be approached alike phage therapy or antibacterial peptides. The choice of empirical therapy is complicated by antibiotic resistance and can be combated by accurate antibiotic and their combinations usage, which is critical to patient survival. Noteworthy are local epidemiology, effective teamwork and antibiotic stewardship to guarantee that medications are utilized properly to counter the resistance.

scholarly journals Infections with Carbapenem-Resistant Gram-Negative Bacteria are a Serious Problem Among Critically Ill Children: A Single-Centre Retrospective Study

Pathogens ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 69 ◽  
Author(s):  
Fatih Aygun ◽  
Fatma Deniz Aygun ◽  
Fatih Varol ◽  
Cansu Durak ◽  
Haluk Çokuğraş ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Critically Ill ◽  
Bacterial Infections ◽  
Invasive Mechanical Ventilation ◽  
Critically Ill Children ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Culture Positive

Children in paediatric intensive care units (PICUs) are vulnerable to infections because invasive devices are frequently used during their admission. We aimed to determine the prevalence, associated factors, and prognosis of infections in our PICU. This retrospective study evaluated culture results from 477 paediatric patients who were treated in the PICU between January 2014 and March 2019. Ninety patients (18.9%) had bacterial infections, with gram-negative bacteria being the predominant infectious agents. Culture-positive patients were younger than culture-negative patients, and age was related to mortality and various clinical factors. Culture-positive bacterial infections in the PICU were associated with increased use of invasive mechanical ventilation (odds ratio(OR); 2.254), red blood cell (RBC) transfusions (OR:2.624), and inotropic drugs (OR:2.262). Carbapenem resistance was found in approximately one-third of gram-negative bacteria, and was most common in tracheal aspirate specimens and cases involving Klebsiella spp. Total parenteral nutrition was a significant risk factor (OR:5.870). Positive blood culture results were associated with poorer patient survival than other culture results. These findings indicate that infections, especially those involving carbapenem-resistant bacteria, are an important issue when treating critically ill children.

scholarly journals Biosynthesis of Silver Nanoparticles Using Ligustrum Ovalifolium Fruits and Their Cytotoxic Effects

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 627 ◽  
Author(s):  
Bianca Moldovan ◽  
Vladislav Sincari ◽  
Maria Perde-Schrepler ◽  
Luminita David
Keyword(s):  
Silver Nanoparticles ◽  
Synthesis Method ◽  
Cost Effective ◽  
Bioactive Molecules ◽  
Energetic Cost ◽  
Fruit Extract ◽  
Vis Spectroscopy ◽  
Biosynthesized Agnps ◽  
Average Size

The present study reports for the first time the efficacy of bioactive compounds from Ligustrum ovalifolium L. fruit extract as reducing and capping agents of silver nanoparticles (AgNPs), developing a green, zero energetic, cost effective and simple synthesis method of AgNPs. The obtained nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR), confirming that nanoparticles were crystalline in nature, spherical in shape, with an average size of 7 nm. The FTIR spectroscopy analysis demonstrated that the AgNPs were capped and stabilized by bioactive molecules from the fruit extract. The cytotoxicity of the biosynthesized AgNPs was in vitro evaluated against ovarian carcinoma cells and there were found to be effective at low concentration levels.

Anticancer and Antibacterial Activities of Silver Nanoparticles (AgNPs) Synthesized from Cucumis melo L.

2020 ◽  
Vol 20 (7) ◽  
pp. 4143-4151 ◽  
Author(s):  
Yun Wang ◽  
Xudong Zhang ◽  
Yuzhuo Bai ◽  
Wei Li ◽  
Xu Li ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Cell Viability ◽  
Cucumis Melo ◽  
Xrd Analysis ◽  
Antibacterial Activities ◽  
Biological Evaluation ◽  
Face Centered Cubic ◽  
X Ray ◽  
Biosynthesized Agnps ◽  
Average Size

The current investigation reports the structural and biological evaluation of silver nanoparticles (AgNPs) biosynthesized from the pericarp extract of Cucumis melo L. (muskmelon). The AgNPs were characterized by ultraviolet-visible (UV-Vis) spectrophotometry, XRD (X-ray diffraction), SEM (scanning electron microscopy) and EDAX (energy-dispersive X-ray spectroscopy). The XRD analysis showed that biosynthesized AgNPs were having FCC (face centered cubic) crystalline structures. Further, the SEM and EDAX showed spherically shaped AgNPs having an average size of 25 nm. The AgNPs effectively inhibited the growth of Bacillus subtilis and Escherichia coli. Moreover, the cytotoxic assay of AgNPs revealed effective cytotoxicity against different cancer cells, such as HeLa, HCT-116, PC-3 and Jurkat in a dose reliant way. The cell viability was noticed to range from 50% to 60% with IC50 values ranging from 150 μg/mL to 224 μg/mL. The lower cell viability indicates the toxic effects of biosynthesized AgNPs against these malignant cells. Thus, the current study shows that these biosynthesized AgNPs could be utilized in various medical applications in near future.

scholarly journals European intensive care physicians’ experience of infections due to antibiotic-resistant bacteria

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Alain Lepape ◽  
Astrid Jean ◽  
Jan De Waele ◽  
Arnaud Friggeri ◽  
Anne Savey ◽  
...  
Keyword(s):  
Intensive Care ◽  
Bacterial Infections ◽  
Western Europe ◽  
Antimicrobial Treatment ◽  
Resistant Bacteria ◽  
European Economic Area ◽  
The European Union ◽  
Online Questionnaire ◽  
Carbapenem Resistant ◽  
Almost All

Abstract Background Antimicrobial resistance (AMR) compromises the treatment of patients with serious infections in intensive care units (ICUs), and intensive care physicians are increasingly facing patients with bacterial infections with limited or no adequate therapeutic options. A survey was conducted to assess the intensive care physicians’ perception of the AMR situation in the European Union/European Economic Area (EU/EEA). Methods Between May and July 2017, physicians working in European ICUs were invited to complete an online questionnaire hosted by the European Society of Intensive Care Medicine. The survey included 20 questions on hospital and ICU characteristics, frequency of infections with multidrug-resistant (MDR) bacteria and relevance of AMR in the respondent’s ICU, management of antimicrobial treatment as well as the use of last-line antibiotics in the six months preceding the survey. For the analysis of regional differences, EU/EEA countries were grouped into the four sub-regions of Eastern, Northern, Southern and Western Europe. Results Overall, 1062 responses from four European sub-regions were analysed. Infections with MDR bacteria in their ICU were rated as a major problem by 257 (24.2%), moderate problem by 360 (33.9%) and minor problem by 391 (36.8%) respondents. Third-generation cephalosporin-resistant Enterobacteriaceae were the most frequently encountered MDR bacteria followed by, in order of decreasing frequency, meticillin-resistant Staphylococcus aureus, carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Pseudomonas aeruginosa and vancomycin-resistant enterococci. Perception of the relevance of the AMR problem and the frequency of specific MDR bacteria varied by European sub-region. Bacteria resistant to all or almost all available antibiotics were encountered by 132 (12.4%) respondents. Many physicians reported not having access to specific last-line antibiotics. Conclusions The percentage of European ICU physicians perceiving AMR as a substantial problem in their ICU is high with variation by sub-region in line with epidemiological studies. The reports of bacteria resistant to almost all available antibiotics and the limited availability of last-line antibiotics in ICUs in the EU/EEA are of concern.

Sign in / Sign up

Export Citation Format

Share Document