scholarly journals Effect of silver nanoparticles combined with antibiotics on different phylogenetic groups of Escherichia coli

2019 ◽  
Vol 70 (3) ◽  
Author(s):  
Ali Kazemnia
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Ag Nps ◽  
Phylogenetic Groups ◽  
Profound Impact ◽  
Polymeric Chains

Silver nanoparticles (Ag-NPs) can attach to flexible polymeric chains of antibiotics, hence it can be used in combination with antibiotics against resistant bacteria. In this study, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and MBC/MIC ratio of Ag-NPs and antibiotics (gentamicin, tetracycline, erythromycin, ciprofloxacin, nalidixic acid, cefixime, cephalexin, amoxicillin, ampicillin, and penicillin) were quantified against 50 Escherichia coli isolates (25 human urinary tract infection and 25 avian colibacillosis). All isolates had been assigned as four phylogenetic groups A, B1, B2, and D. The results showed that the majority of the human and broiler isolates belonged to phylogenetic groups A and B2. MBC/MIC ratio of Ag-NPs in combination with antibiotics was assessed. It was found that the MIC of the majority of broiler isolates to Ag-NPs was equal to or greater than 50 µg/ml. To conclude, as combination of penicillin with Ag-NPs and ciprofloxacin with Ag-NPs exhibited profound impact against isolates, the combinations might be used against multidrug resistant bacteria.

scholarly journals Combined efficacy of silver nanoparticles and commercial antibiotics on different phylogenetic groups of Escherichia coli

2019 ◽  
Vol 70 (3) ◽  
pp. 1647
Author(s):  
A. KAZEMNIA ◽  
M. AHMADI ◽  
K. MARDANI ◽  
M. MORADI ◽  
R. DARVISHZADEH
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Ag Nps ◽  
Phylogenetic Groups ◽  
Profound Impact ◽  
Polymeric Chains

Silver nanoparticles (Ag-NPs) can attach to flexible polymeric chains of antibiotics, hence it can be used in combination with antibiotics against resistant bacteria. In this study, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and MBC/MIC ratio of Ag-NPs and antibiotics (gentamicin, tetracycline, erythromycin, ciprofloxacin, nalidixic acid, cefixime, cephalexin, amoxicillin, ampicillin, and penicillin) were quantified against 50 Escherichia coli isolates (25 human urinary tract infection and 25 avian colibacillosis). All isolates had been assigned as four phylogenetic groups A, B1, B2, and D. The results showed that the majority of the human and broiler isolates belonged to phylogenetic groups A and B2. MBC/MIC ratio of Ag-NPs in combination with antibiotics was assessed. It was found that the MIC of the majority of broiler isolates to Ag-NPs was equal to or greater than 50 μg/ml. To conclude, a combination of penicillin and ciprofloxacin with Ag-NPs exhibited profound impact against isolates, the combinations might be applicable for treating multidrug-resistant bacteria.

scholarly journals Synthesis and biological characterization of silver nanoparticles derived from the cyanobacterium Oscillatoria limnetica

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ragaa A. Hamouda ◽  
Mervat H. Hussein ◽  
Rasha A. Abo-elmagd ◽  
Salwa S. Bawazir
Keyword(s):  
Silver Nanoparticles ◽  
Cell Line ◽  
Fourier Transforms ◽  
Human Colon ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Ag Nps ◽  
Human Colon Cancer ◽  
Visible Absorption ◽  
Ft Ir

Abstract Using aqueous cyanobacterial extracts in the synthesis of silver nanoparticle is looked as green, ecofriendly, low priced biotechnology that gives advancement over both chemical and physical methods. In the current study, an aqueous extract of Oscillatoria limnetica fresh biomass was used for the green synthesis of Ag-NPs, since O. limnetica extract plays a dual part in both reducing and stabilizing Oscillatoria-silver nanoparticles (O-AgNPs). The UV-Visible absorption spectrum, Fourier transforms infrared (FT-IR), transmission electron microscopy (TEM) and scanning electron microscope (SEM) were achieved for confirming and characterizing the biosynthesized O-AgNPs. TEM images detected the quasi-spherical Ag-NPs shape with diverse size ranged within 3.30–17.97 nm. FT-IR analysis demonstrated the presence of free amino groups in addition to sulfur containing amino acid derivatives acting as stabilizing agents as well as the presence of either sulfur or phosphorus functional groups which possibly attaches silver. In this study, synthesized Ag-NPs exhibited strong antibacterial activity against multidrug-resistant bacteria (Escherichia coli and Bacillus cereus) as well as cytotoxic effects against both human breast (MCF-7) cell line giving IC50 (6.147 µg/ml) and human colon cancer (HCT-116) cell line giving IC50 (5.369 µg/ml). Hemolytic activity of Ag-NPs was investigated and confirmed as being non- toxic to human RBCs in low concentrations.

scholarly journals Effects of biocide exposure on P. Aeruginosa, E. coli and A. Baumannii complex isolates from hospital and household environments

Infectio ◽  
2017 ◽  
Vol 21 (4) ◽  
Author(s):  
Daniel Felipe Vásquez-Giraldo ◽  
Gerardo Andrés Libreros-Zúñiga ◽  
María Del Pilar Crespo-Ortiz
Keyword(s):  
Escherichia Coli ◽  
Benzalkonium Chloride ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Multidrug Resistant ◽  
Environmental Isolates ◽  
E Coli ◽  
Acinetobacter Baumannii Complex ◽  
Cleaning And Disinfection ◽  
Reference Strains

Background: Bacterial responses to biocide exposure and its effects on survival and persistence remain to be studied in greater detail.Aim: To analyse the viability and survival of environmental isolates from household and hospital settings after biocide exposure.Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of chlorhexidine (CHxG), benzalkonium chloride (BAC) and triclosan (TC) were determined in isolates of Pseudomonas aeruginosa, Acinetobacter baumannii complex and Escherichia coli collected from hospital and households environments. Viability was monitored after exposure and removal of biocides using agar cultures and flow cytometry.Findings: P. aeruginosa isolates showed greater tolerance for all biocides tested whereas A. baumannii complex and E. coli were less tolerant.When compared with reference strains, biocide tolerance was up to 8 to 13-fold higher for TC and BAC respectively. Flow cytometry showed that biocide exposure may induce viable but non-growing states in P. aeruginosa and E. coli isolates before becoming fully replicative. Changes in the susceptibility profile in one isolate of A. baumannii complex were observed after biocide exposure.Discussion: Bacteria isolates from hospital and households were able to recover after biocide exposure at bactericidal concentrations favouring persistence and spread of biocide-tolerant strains. This study reinforces that cleaning compliance should be monitored by non-culture based tests. Novel formulations in cleaning and disinfection protocols should be revisited in hospitals harbouring P. aeruginosa and A. baumannii multidrug resistant isolates.

scholarly journals Antimicrobial Activities of Laurus nobilis Leaves Ethanol Extract on Staphylococcus aureus, Salmonellae typhi, and Escherichia coli.

2021 ◽  
Vol 9 (2) ◽  
pp. 119
Author(s):  
Khawla Abdullah Sakran ◽  
Dadik Raharjo ◽  
Ni Made Mertaniasih
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Minimum Bactericidal Concentration ◽  
Ethanol Extract ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Resistant Bacteria ◽  
Zone Of Inhibition ◽  
Laurus Nobilis

Laurus nobilis is one of the most well-known, most frequently used plants is from Lauraceae family which contains up 2.500 species that grow in the subtropics and tropics of the Mediterranean region and Indonesia. This study was supposed to investigate the antimicrobial eff ect of L.nobilis leaves ethanol extract on Staphylococcus aureus, Salmonellae typhi, and Escherichia coli. This preliminary study examined the antimicrobial eff ect of L.nobilis leaves ethanol extract. The method used Agar-well diff usion for determination of the zone of inhibition and the minimum bactericidal concentration to investigate the activity of L.nobilis leaves ethanol extract at 100% concentration . The results revealed that extract of L. nobilis leaves had the antibacterial activity against Staphylococcus aureus with a zone of inhibition (16.3 ±1.5 mm), Staphylococcus aureus with (14.5±0.5 mm), and weak antimicrobial activity against Escherichia coli (11.3±1.1mm). Also, through the minimum bactericidal concentration experiment, the L.nobilis leaves ethanol extract had activity on Staphylococcus aureus and Salmonellae typhi, it’s killed the bacteria in all concentration start it from 5×107 to 5×104. But the activity on Escherichia coli just weaken concentration 5×107 and 106. This research has concluded that the L.nobilis leaves ethanol extract exhibited a signifi cant antimicrobial eff ect against Staphylococcus aureus and Salmonellae typhi then Escherichia coli that is considered a kind of multidrug-resistant bacteria.

scholarly journals Biosynthesis and Characterization of Silver Nanoparticles produced by Phormidium ambiguum and Desertifilum tharense

2021 ◽  
Author(s):  
Amira Lotfy Hanna ◽  
Hayam Hamouda ◽  
Hanan Goda ◽  
Tarek Elsayed ◽  
Mahmoud Sadik
Keyword(s):  
Silver Nanoparticles ◽  
Micrococcus Luteus ◽  
16S Rrna Gene Sequencing ◽  
Inhibition Zone ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Rrna Gene ◽  
Face Centered Cubic ◽  
Ag Nps ◽  
Rrna Gene Sequencing

Abstract The world faces a challenge with pervasion of multidrug resistant bacteria which encouraged the scientists to develop and discover alternative ecofriendly and easy to produce new antibacterial agents. Two Egyptian cyanobacteria were isolated and identified according to 16S rRNA gene sequencing as Phormidium ambiguum and Desertifilum tharense . The sequences were deposited in the GenBank with accession numbers of MW762709 and MW762710 for Desertifilum tharense and Phormidium ambiguum, respectively. These isolates have the ability to produce silver nanoparticles (Ag-NPs) extra- and intracellularly under light and dark conditions. The results of UV-Vis analysis showed promising extracellular Ag-NPs synthesis by Desertifilum tharense and Phormidium ambiguum under light conditions. Therefore, these Ag-NPs were characterized and evaluated for antibacterial and antioxidant activity. TEM, SEM and XRD analyses revealed the spherical crystals with face-centered cubic structures and size range of 6.24–11.4 nm and 6.46–12.2 nm for Ag-NPs of Desertifilum tharense and Phormidium ambiguum , respectively. XRD and EDX results clearly confirmed the successful synthesis of Ag-NPs in its oxide form or chloride form. The FTIR spectrum data confirmed the presence of hydroxyl and amide groups. Desertifilum tharense Ag-NPs displayed the largest inhibition zone ranged from 9 mm against Micrococcus luteus ATCC 10240 to 25 mm against methicillin resistant S. aureus (MRSA) ATCC 43300. For Phormidium ambiguum Ag-NPs, the inhibition zone diameter was in a range of 9–18 mm. The Ag-NPs of Phormidium ambiguum exhibited the highest scavenging activity of 48.7% comparing with that of Desertifilum tharense which displayed 43.753%.

scholarly journals Synthesis and Application of Silver Nanoparticles (Ag NPs) for the Prevention of Infection in Healthcare Workers

2019 ◽  
Vol 20 (15) ◽  
pp. 3620 ◽  
Author(s):  
Shingo Nakamura ◽  
Masahiro Sato ◽  
Yoko Sato ◽  
Naoko Ando ◽  
Tomohiro Takayama ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Healthcare Workers ◽  
High Efficiency ◽  
Particle Surface ◽  
Silver Ions ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Medical Field ◽  
Ag Nps ◽  
Environment Friendly

Silver is easily available and is known to have microbicidal effect; moreover, it does not impose any adverse effects on the human body. The microbicidal effect is mainly due to silver ions, which have a wide antibacterial spectrum. Furthermore, the development of multidrug-resistant bacteria, as in the case of antibiotics, is less likely. Silver ions bind to halide ions, such as chloride, and precipitate; therefore, when used directly, their microbicidal activity is shortened. To overcome this issue, silver nanoparticles (Ag NPs) have been recently synthesized and frequently used as microbicidal agents that release silver ions from particle surface. Depending on the specific surface area of the nanoparticles, silver ions are released with high efficiency. In addition to their bactericidal activity, small Ag NPs (<10 nm in diameter) affect viruses although the microbicidal effect of silver mass is weak. Because of their characteristics, Ag NPs are useful countermeasures against infectious diseases, which constitute a major issue in the medical field. Thus, medical tools coated with Ag NPs are being developed. This review outlines the synthesis and utilization of Ag NPs in the medical field, focusing on environment-friendly synthesis and the suppression of infections in healthcare workers (HCWs).

scholarly journals Green Synthesis of Silver Nanoparticles and Evaluation of Their Antibacterial Activity against Multidrug-Resistant Bacteria and Wound Healing Efficacy Using a Murine Model

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 902
Author(s):  
Vajravathi Lakkim ◽  
Madhava C. Reddy ◽  
Roja Rani Pallavali ◽  
Kakarla Raghava Reddy ◽  
Ch Venkata Reddy ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Wound Healing ◽  
Silver Nanoparticles ◽  
Multidrug Resistant ◽  
Biomedical Science ◽  
Resistant Bacteria ◽  
Zone Of Inhibition ◽  
Ag Nps ◽  
Bacteriolytic Activity ◽  
Vis Spectroscopy

Green nanotechnology has significant applications in various biomedical science fields. In this study, green-synthesized silver nanoparticles, prepared by using Catharanthus roseus and Azadirachta indica extracts, were characterized using UV–Vis spectroscopy, dynamic light scattering, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Silver nanoparticles (Ag NPs) synthesized from leaf extracts of C. roseus and A. indica effectively inhibited the growth of multidrug-resistant (MDR) bacteria isolated from patients with septic wound infections. The maximum bacteriolytic activity of the green-synthesized Ag NPs of C. roseus and A. indica against the MDR bacterium K. Pneumoniae was shown by a zone of inhibition of 19 and 16 mm, respectively. C. roseus Ag NPs exhibited more bacteriolytic activity than A. indica Ag NPs in terms of the zone of inhibition. Moreover, these particles were effective in healing wounds in BALB/c mice. Ag NPs of C. roseus and A. indica enhanced wound healing by 94% ± 1% and 87% ± 1%, respectively. Our data suggest that Ag NPs from C. roseus and A. indicia ameliorate excision wounds, and wound healing could be due to their effective antimicrobial activity against MDR bacteria. Hence, these Ag NPs could be potential therapeutic agents for the treatment of wounds.

scholarly journals Characterization of diarrheagenic Escherichia coli strains associated with diarrhea in children, Khouzestan, Iran

2018 ◽  
Vol 12 (08) ◽  
pp. 649-656 ◽  
Author(s):  
Sanaz Mahdavi Broujerdi ◽  
Mohammad Roayaei Ardakani ◽  
Seyedeh Elham Rezatofighi
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistant ◽  
Progressive Increase ◽  
Etiologic Agent ◽  
Phylogenetic Group ◽  
Resistant Bacteria ◽  
Phylogenetic Groups ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Extended Spectrum Beta Lactamases

Introduction: Diarrheagenic Escherichia coli (DEC) is a major etiologic agent among the pathogens that cause diarrhea in children. Methodology: To investigate the presence and pathotypes of DEC in children under five years of age, living in the province of Khouzestan, Iran. 208 diarrhea stool samples were screened by multiplex-PCR. The isolated DEC isolates were investigated for resistance to various antimicrobials including the production of extended-spectrum beta-lactamases (ESBLs) and phylogenetic groups were determined. Results: DEC isolates were identified in 54 (26%) diarrhea samples, and 4 (7%) cases contained two DEC pathotypes. DEC isolated included 35 (16.8%) enteroaggregative E. coli (EAEC), ten (4.8%) enteropathogenic E. coli (EPEC), six (2.9%) enteroinvasive E. coli (EIEC), six (2.9%) enterotoxigenic E. coli (ETEC) and one (0.48%) LEE-positive EAEC. Shiga-toxin producing E. coli (STEC) was not identified in any diarrheal samples. The most prevalent resistance was observed with ceftazidime (88%), followed by ceftizoxime (83%) and ceftriaxone (71%). The majority of isolates (> 75%) were sensitive to Imipenem, ciprofloxacin, and amikacin. More than 65% of the pathogenic isolates showed a multidrug-resistant phenotype. ESBL-producing strains was observed in 79.3% of all DEC isolates. Phylogenetic group B2 was the most predominant group with a frequency of 44.8%. A significant association was observed between the B2 phylogenetic group and the DEC isolates (P < 0.05). Conclusions: Overall, our findings highlight the importance of the role of DEC isolates in the etiology of diarrhea in children in Iran. The progressive increase in antimicrobial resistance among DEC isolates makes it imperative to implement policies to control the spread of resistant bacteria.

Green and Simple Synthesis of Silver Nanoparticles by Aqueous Extract of Perovskia abrotanoides: Characterization, Optimization and Antimicrobial Activity

2020 ◽  
Vol 21 (11) ◽  
pp. 1129-1137 ◽  
Author(s):  
Somayeh Mirsadeghi ◽  
Masoumeh F. Koudehi ◽  
Hamid R. Rajabi ◽  
Seied M. Pourmortazavi
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Minimum Inhibitory Concentration ◽  
Plant Extract ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Extraction Temperature ◽  
Silver Particles ◽  
Silver Nps ◽  
Perovskia Abrotanoides

Background: Herein, we report the biosynthesis procedure to prepare silver nanoparticles as reduction and capping agents with the aqueous plant extract of Perovskia abrotanoides. Methods: The therapeutic application of silver nanoparticles entirely depends on the size and shape of the nanoparticles therefore, their control during the synthesis procedure is so important. The effects of synthesis factors, for example, silver ion concentration, the mass of plant extract, reaction time and extraction temperature, on the size of silver particles were considered and optimized. Several analytical methods were used for the characterization of silver NPs including FT-IR and UV–Vis spectrophotometer, XRD and SEM. Results: The results showed that the mean size of the silver particles was about 51 nm. Moreover, the antibacterial properties of biosynthesized silver NPs were investigated by the minimum inhibitory concentration, minimum bactericidal concentration, and Well-diffusion tests. The minimum inhibitory concentration/ minimum bactericidal concentration values of silver NPs and aqueous plant extract versus Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (E. coli) were 3.03/0.00, 1.20/0.01, 3.06/0.00, 0.98/1.04, 1.00/0.05 and 1.30/0.03 (mg/mL), respectively. Conclusion: The antimicrobial activity study displayed that the synthesized silver nanoparticles by plant extract have better antimicrobial properties compared to aqueous plant extract of Perovskia abrotanoides.

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