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Enhanced antibacterial and anti-biofilm activities of silver nanoparticles against Gram-negative and Gram-positive bacteria.

Gurunathan S, Han JW, Kwon DN, Kim JH - Nanoscale Res Lett (2014)

Bottom Line: The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics.The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively.These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Animal Biotechnology, Konkuk University, 1 Hwayang-Dong, Gwangin-gu, Seoul 143-701, South Korea ; GS Institute of Bio and Nanotechnology, Coimbatore, Tamilnadu, India.

ABSTRACT
Silver nanoparticles (AgNPs) have been used as antibacterial, antifungal, antiviral, anti-inflammtory, and antiangiogenic due to its unique properties such as physical, chemical, and biological properties. The present study was aimed to investigate antibacterial and anti-biofilm activities of silver nanoparticles alone and in combination with conventional antibiotics against various human pathogenic bacteria. Here, we show that a simple, reliable, cost effective and green method for the synthesis of AgNPs by treating silver ions with leaf extract of Allophylus cobbe. The A. cobbe-mediated synthesis of AgNPs (AgNPs) was characterized by ultraviolet-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the antibacterial and anti-biofilm activity of antibiotics or AgNPs, or combinations of AgNPs with an antibiotic was evaluated using a series of assays: such as in vitro killing assay, disc diffusion assay, biofilm inhibition, and reactive oxygen species generation in Pseudomonas aeruginosa, Shigella flexneri, Staphylococcus aureus, and Streptococcus pneumonia. The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics. The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively. These data suggest that combining antibiotics and biogenic AgNPs can be used therapeutically for the treatment of infectious diseases caused by bacteria. This study presented evidence of antibacterial and anti-biofilm effects of A. cobbe-mediated synthesis of AgNPs and their enhanced capacity against various human pathogenic bacteria. These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases.

No MeSH data available.


Related in: MedlinePlus

Enhanced biofilm inhibitory activitity of antibiotics and AgNPs. The anti-biofilm activity of AgNPs was assessed by incubating all test strains with sublethal concentrations of ampicillin or AgNPs, or combinations of AgNPs with the ampicillin antibiotic for 4 h. The results are expressed as the means ± SD of three separate experiments, each of which contained three replicates. Treated groups showed statistically significant differences from the control group by the Student's t test (p < 0.05).
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Figure 11: Enhanced biofilm inhibitory activitity of antibiotics and AgNPs. The anti-biofilm activity of AgNPs was assessed by incubating all test strains with sublethal concentrations of ampicillin or AgNPs, or combinations of AgNPs with the ampicillin antibiotic for 4 h. The results are expressed as the means ± SD of three separate experiments, each of which contained three replicates. Treated groups showed statistically significant differences from the control group by the Student's t test (p < 0.05).

Mentions: Ampicillin has the potential to act at several different stages of biofilm activity with different mechanisms of action [55]. Morones-Ramirez et al. [21] demonstrated, using mouse models, that silver and antibiotic combinations, both in vitro and in vivo, have enhanced activity against bacteria that produce biofilms. To investigate whether sublethal concentrations of AgNPs in combination with antibiotics have synergistic effects, bacterial cells were grown to form biofilms and then treated with AgNPs alone or in combination with antibiotics. The results indicated that AgNPs alone inhibited biofilm activity by approximately 20%. Combinations of AgNPs and ampicillin inhibited biofilm activity in Gram-negative and Gram-positive bacteria by 70% and 55%, respectively. Combined treatments with AgNPs and vancomycin inhibited biofilm activity in Gram-negative and Gram-positive bacteria by 55% and 75%, respectively (Figure 11). Overall, these data show that combined treatments with AgNPs and antibiotics enhanced both the inhibition of biofilm activity and the levels of cell death. Therefore, combining AgNPs with different antibiotics at lower concentrations has the potential to become an effective anti-biofilm and antibacterial treatment.


Enhanced antibacterial and anti-biofilm activities of silver nanoparticles against Gram-negative and Gram-positive bacteria.

Gurunathan S, Han JW, Kwon DN, Kim JH - Nanoscale Res Lett (2014)

Enhanced biofilm inhibitory activitity of antibiotics and AgNPs. The anti-biofilm activity of AgNPs was assessed by incubating all test strains with sublethal concentrations of ampicillin or AgNPs, or combinations of AgNPs with the ampicillin antibiotic for 4 h. The results are expressed as the means ± SD of three separate experiments, each of which contained three replicates. Treated groups showed statistically significant differences from the control group by the Student's t test (p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4127560&req=5

Figure 11: Enhanced biofilm inhibitory activitity of antibiotics and AgNPs. The anti-biofilm activity of AgNPs was assessed by incubating all test strains with sublethal concentrations of ampicillin or AgNPs, or combinations of AgNPs with the ampicillin antibiotic for 4 h. The results are expressed as the means ± SD of three separate experiments, each of which contained three replicates. Treated groups showed statistically significant differences from the control group by the Student's t test (p < 0.05).
Mentions: Ampicillin has the potential to act at several different stages of biofilm activity with different mechanisms of action [55]. Morones-Ramirez et al. [21] demonstrated, using mouse models, that silver and antibiotic combinations, both in vitro and in vivo, have enhanced activity against bacteria that produce biofilms. To investigate whether sublethal concentrations of AgNPs in combination with antibiotics have synergistic effects, bacterial cells were grown to form biofilms and then treated with AgNPs alone or in combination with antibiotics. The results indicated that AgNPs alone inhibited biofilm activity by approximately 20%. Combinations of AgNPs and ampicillin inhibited biofilm activity in Gram-negative and Gram-positive bacteria by 70% and 55%, respectively. Combined treatments with AgNPs and vancomycin inhibited biofilm activity in Gram-negative and Gram-positive bacteria by 55% and 75%, respectively (Figure 11). Overall, these data show that combined treatments with AgNPs and antibiotics enhanced both the inhibition of biofilm activity and the levels of cell death. Therefore, combining AgNPs with different antibiotics at lower concentrations has the potential to become an effective anti-biofilm and antibacterial treatment.

Bottom Line: The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics.The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively.These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Animal Biotechnology, Konkuk University, 1 Hwayang-Dong, Gwangin-gu, Seoul 143-701, South Korea ; GS Institute of Bio and Nanotechnology, Coimbatore, Tamilnadu, India.

ABSTRACT
Silver nanoparticles (AgNPs) have been used as antibacterial, antifungal, antiviral, anti-inflammtory, and antiangiogenic due to its unique properties such as physical, chemical, and biological properties. The present study was aimed to investigate antibacterial and anti-biofilm activities of silver nanoparticles alone and in combination with conventional antibiotics against various human pathogenic bacteria. Here, we show that a simple, reliable, cost effective and green method for the synthesis of AgNPs by treating silver ions with leaf extract of Allophylus cobbe. The A. cobbe-mediated synthesis of AgNPs (AgNPs) was characterized by ultraviolet-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the antibacterial and anti-biofilm activity of antibiotics or AgNPs, or combinations of AgNPs with an antibiotic was evaluated using a series of assays: such as in vitro killing assay, disc diffusion assay, biofilm inhibition, and reactive oxygen species generation in Pseudomonas aeruginosa, Shigella flexneri, Staphylococcus aureus, and Streptococcus pneumonia. The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics. The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively. These data suggest that combining antibiotics and biogenic AgNPs can be used therapeutically for the treatment of infectious diseases caused by bacteria. This study presented evidence of antibacterial and anti-biofilm effects of A. cobbe-mediated synthesis of AgNPs and their enhanced capacity against various human pathogenic bacteria. These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases.

No MeSH data available.


Related in: MedlinePlus