Antibacterial potential of silver nanoparticles against multidrug resistant bacterial isolates from blood cultures

2020 ◽  
Vol 50 (11) ◽  
pp. 1150-1156
Author(s):  
Jogender Tanwar ◽  
Madhu Sharma ◽  
Aparna Parmar ◽  
Nimisha Tehri ◽  
Neelam Verma ◽  
...  
2022 ◽  
Author(s):  
Stephen Oloninefa ◽  
Abalaka Moses Enemaduku ◽  
Daniyan Safiya Yahaya ◽  
Mann Abdullahi

The menace of drug resistance, bioavailability and drug delivery to the target sites has motivated researchers to search for new antimicrobial agents from medicinal plants and subsequently use them for the biosynthesis of silver nanoparticles for effective killing of bacteria challenging to kill using crude extracts. The biosynthesis of silver nanoparticles was done using aqueous extract (AQE) of E<i>uphorbia heterophylla</i>, while characterization and the killing rate of conjugated silver nanoparticles (CA<sub>g</sub>NP<sub>s</sub>) were carried out using standard methods. The maximum wavelength obtained for CA<sub>g</sub>NP<sub>s</sub> was 410.33 nm, while the size distribution was 237.8 d.nm. The Fourier Transform Infra-Red result showed O-H (3308.94 cm<sup>-1</sup>), which is responsible for stabilising and reducing silver ions, while the Transmission Electron Microscopy revealed the presence of monodispersed spherical shapes CA<sub>g</sub>NP<sub>s</sub>. The Energy Dispersive Spectroscopy confirmed the presence of silver. There were reductions in the clinical bacterial isolates exposed to CA<sub>g</sub>NP<sub>s</sub> as the exposure time increased. <i>Escherichia coli</i> was killed between 6-7 h while<i> Salmonella typhimurium</i> was killed at the seven has the value of 0.00 log<sub>10</sub> CFU/ml was recorded respectively. However, there were increments in the populations of clinical bacterial isolates in control as the time of exposure increased. Therefore, the study suggests that the CA<sub>g</sub>NP<sub>s</sub> exhibit intense antimicrobial activity and the potential to be developed as an alternative agent to treat bacterial infections, curb multidrug-resistant bacterial infection, and promote speedy drug delivery to the target sites.


Author(s):  
Md. Abdullah Al Masud ◽  
Hamid Shaikh ◽  
Md. Shamsul Alam ◽  
M. Minnatul Karim ◽  
M. Abdul Momin ◽  
...  

Abstract Background The green synthesis strategy of metallic nanoparticles (NPs) has become popular due to being environmentally friendly. Stable silver nanoparticles (AgNPs) have been synthesized by natural products such as starch, soy protein, various extract of leaves, barks, and roots functioning both as reducing and stabilizing agents. Likewise, silk sericin (SS) is a globular protein discarded in the silk factory might be used for NP synthesis. In this research, we focus on the green synthesis and stabilization of AgNPs by SS as well as assessment of their antibacterial activities against some drug-resistant pathogen. Results SS was extracted from Bombyx mori silkworm cocoons in an aqueous medium. 17 w/w% of dry sericin powder with respect to the cocoon’s weight was obtained by freeze-drying. Furthermore, AgNPs conjugated to sericin, i.e., SS-capped silver nanoparticles (SS-AgNPs) were synthesized by easy, cost-effective, and environment-friendly methods. The synthesized SS-AgNPs were characterized by UV-visible spectroscopy, Fourier-transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction measurement. It has been found from the absorbance of UV-visible spectroscopy that a higher percent of SS-AgNPs was obtained at a higher concentration of silver nitrate solution. FTIR-ATR spectra showed that the carboxylate groups obtained from silk sericin act as a reducing agent for the synthesis of silver nanoparticles, while NH2+ and COO− act as a stabilizer of AgNPs. The X-ray diffractogram of SS-AgNPs was quite different from AgNO3 and sericin due to a change in the crystal structure. The diameter of AgNPs was around 20–70 nm observed using TEM. The synthesized SS-AgNPs exhibited strong antibacterial activity against multidrug-resistant pathogens, Escherichia coli and Pseudomonas aeruginosa. Minimal inhibitory/bactericidal concentrations against E. coli and P. aeruginosa were 20μg/mL. Conclusions This study encourages the use of Bombyx mori for the ecofriendly synthesis of SS-AgNPs to control multidrug-resistant microorganisms.


2021 ◽  
Vol 22 (13) ◽  
pp. 7202
Author(s):  
Tamara Bruna ◽  
Francisca Maldonado-Bravo ◽  
Paul Jara ◽  
Nelson Caro

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.


Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 97
Author(s):  
Suresh V. Chinni ◽  
Subash C. B. Gopinath ◽  
Periasamy Anbu ◽  
Neeraj Kumar Fuloria ◽  
Shivkanya Fuloria ◽  
...  

The present study was planned to characterize and analyze the antimicrobial activity of silver nanoparticles (AgNP) biosynthesized using a Coccinia indica leaf (CIL) ethanolic extract. The present study included the preparation of CIL ethanolic extract using the maceration process, which was further used for AgNP biosynthesis by silver nitrate reduction. Biosynthetic AgNPs were characterized using UV–Visible spectrometry, zeta potential analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) spectrometry. The biogenic AgNP and CIL extracts were further investigated against different bacterial strains for their antimicrobial activity. The surface plasmon resonance (SPR) signal at 425 nm confirmed AgNP formation. The SEM and TEM data revealed the spherical shape of biogenic AgNPs and size in the range of 8 to 48 nm. The EDX results verified the presence of Ag. The AgNPs displayed a zeta potential of −55.46 mV, suggesting mild AgNP stability. Compared to Gram-positive bacteria, the biogenic AgNPs demonstrated high antibacterial potential against Gram-negative bacteria. Based on the results, the current study concluded that AgNPs based on CIL extract have strong antibacterial potential, and it established that AgNP biosynthesis using CIL ethanol extract is an effective process.


Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 678
Author(s):  
Abdallah S. Abdelsattar ◽  
Rana Nofal ◽  
Salsabil Makky ◽  
Anan Safwat ◽  
Amera Taha ◽  
...  

The emergence and evolution of antibiotic-resistant bacteria is considered a public health concern. Salmonella is one of the most common pathogens that cause high mortality and morbidity rates in humans, animals, and poultry annually. In this work, we developed a combination of silver nanoparticles (AgNPs) with bacteriophage (phage) as an antimicrobial agent to control microbial growth. The synthesized AgNPs with propolis were characterized by testing their color change from transparent to deep brown by transmission electron microscopy (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). The phage ZCSE2 was found to be stable when combined with AgNPs. Both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated for AgNPs, phage, and their combination. The results indicated that MIC and MBC values were equal to 23 µg/mL against Salmonella bacteria at a concentration of 107 CFU/mL. The combination of 0.4× MIC from AgNPs and phage with Multiplicity of Infection (MOI) 0.1 showed an inhibitory effect. This combination of AgNPs and phage offers a prospect of nanoparticles with significantly enhanced antibacterial properties and therapeutic performance.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1530
Author(s):  
Amanuel Balemi ◽  
Balako Gumi ◽  
Kebede Amenu ◽  
Sisay Girma ◽  
Muuz Gebru ◽  
...  

A study was carried out from August 2017 to February 2018 on lactating dairy cows, one-humped dromedary camels, and goats to determine mastitis in the Bule Hora and Dugda Dawa districts of in Southern Ethiopia. Milk samples from 564 udder quarters and udder halves from 171 animals consisting of 60 dairy cows, 51 camels, and 60 goats were tested for mastitis. Sixty-four positive udder milk samples were cultured, and bacterial mastitis pathogens were isolated and identified. The antibiotic resistance of bacterial isolates from milk with mastitis was tested against nine antimicrobials commonly used in the study area. Cow- and quarter-level prevalence of mastitis in dairy cows, camels, and goats was 33.3%, 26.3%, and 25% and 17.6%, 14.5%, and 20%, respectively. In cattle, the prevalence was significantly higher in Dugda Dawa than in Bule Hora. Major bacterial isolates were coagulase-negative Staphylococcus species (39.1%), S. aureus (17.2%), S. hyicus (14.1%), and S. intermedius and Escherichia coli (9.4% each). In camels, udder abnormality and mastitis were significantly higher in late lactation than in early lactation. Mastitis tends to increase with parity in camels. E. coli isolates were highly resistant to spectinomycin, vancomycin, and doxycycline, whereas most S. aureus isolates were multidrug-resistant. Most of the rural and periurban communities in this area consume raw milk, which indicates a high risk of infection with multidrug-resistant bacteria. We recommend a community-focused training program to improve community awareness of the need to boil milk and the risk of raw milk consumption.


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