Silver Nanoparticles (AgNPs) from <i>Lysinibacillus</i> sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical Antibiotics

Antibiotic-resistant bacteria pose problems for infection prevention and treatment, so developing new procedures or substances against infection is mandatory. Silver nanomaterials are among the more promising antibacterial agents. Herein, we describe the biogenic synthesis of silver nanoparticles (A...

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Main Authors: Carlos Pernas-Pleite, Amparo M. Conejo-Martínez, Irma Marín, José P. Abad
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Biomolecules
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Online Access:https://www.mdpi.com/2218-273X/15/5/731
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author Carlos Pernas-Pleite
Amparo M. Conejo-Martínez
Irma Marín
José P. Abad
author_facet Carlos Pernas-Pleite
Amparo M. Conejo-Martínez
Irma Marín
José P. Abad
author_sort Carlos Pernas-Pleite
collection DOAJ
description Antibiotic-resistant bacteria pose problems for infection prevention and treatment, so developing new procedures or substances against infection is mandatory. Silver nanomaterials are among the more promising antibacterial agents. Herein, we describe the biogenic synthesis of silver nanoparticles (AgNPs) using culture broths from an undescribed species of <i>Lysinibacillus</i>. Culture broths with or without NaCl and from the exponential and stationary growth phases produced four AgNP types. Nanoparticles’ shapes were quasi-spherical, with core sizes of 7.5–14.7 nm and hydrodynamic diameters of 48.5–80.2 nm. All the AgNPs contained Ag<sup>0</sup> crystals and some AgCl ones. Moreover, their coronas presented different proportions of carbohydrates, proteins, and aliphatic compounds. The AgNPs were good antibacterial agents against six bacterial species, three Gram-positive and three Gram-negative, with MICs of 0.3–9.0 µg/mL. Their activity was higher against the Gram-negative bacteria and particularly against <i>Pseudomonas aeruginosa</i>. These AgNPs acted synergistically with several of the fifteen tested antibiotics. Interestingly, AgNP combinations with some of these inhibited the growth of antibiotic-resistant bacteria, as in the case of <i>S. epidermidis</i> for streptomycin and <i>S. aureus</i> for colistin. The ROS production by <i>E. coli</i> and <i>S. aureus</i> when treated with most AgNPs suggested different mechanisms for bacterial killing depending on the AgNP.
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spelling doaj-art-14ecd5379d3d4ceabb7069c0b8b483d42025-08-20T03:14:32ZengMDPI AGBiomolecules2218-273X2025-05-0115573110.3390/biom15050731Silver Nanoparticles (AgNPs) from <i>Lysinibacillus</i> sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical AntibioticsCarlos Pernas-Pleite0Amparo M. Conejo-Martínez1Irma Marín2José P. Abad3Department of Molecular Biology, Biology Building, Faculty of Sciences, Autonomous University of Madrid, Cantoblanco, 28049 Madrid, SpainDepartment of Molecular Biology, Biology Building, Faculty of Sciences, Autonomous University of Madrid, Cantoblanco, 28049 Madrid, SpainDepartment of Molecular Biology, Biology Building, Faculty of Sciences, Autonomous University of Madrid, Cantoblanco, 28049 Madrid, SpainDepartment of Molecular Biology, Biology Building, Faculty of Sciences, Autonomous University of Madrid, Cantoblanco, 28049 Madrid, SpainAntibiotic-resistant bacteria pose problems for infection prevention and treatment, so developing new procedures or substances against infection is mandatory. Silver nanomaterials are among the more promising antibacterial agents. Herein, we describe the biogenic synthesis of silver nanoparticles (AgNPs) using culture broths from an undescribed species of <i>Lysinibacillus</i>. Culture broths with or without NaCl and from the exponential and stationary growth phases produced four AgNP types. Nanoparticles’ shapes were quasi-spherical, with core sizes of 7.5–14.7 nm and hydrodynamic diameters of 48.5–80.2 nm. All the AgNPs contained Ag<sup>0</sup> crystals and some AgCl ones. Moreover, their coronas presented different proportions of carbohydrates, proteins, and aliphatic compounds. The AgNPs were good antibacterial agents against six bacterial species, three Gram-positive and three Gram-negative, with MICs of 0.3–9.0 µg/mL. Their activity was higher against the Gram-negative bacteria and particularly against <i>Pseudomonas aeruginosa</i>. These AgNPs acted synergistically with several of the fifteen tested antibiotics. Interestingly, AgNP combinations with some of these inhibited the growth of antibiotic-resistant bacteria, as in the case of <i>S. epidermidis</i> for streptomycin and <i>S. aureus</i> for colistin. The ROS production by <i>E. coli</i> and <i>S. aureus</i> when treated with most AgNPs suggested different mechanisms for bacterial killing depending on the AgNP.https://www.mdpi.com/2218-273X/15/5/731AgNPsantibacterial activityantibiotic resistancegreen synthesisFICI<i>Lysinibacillus</i> sp.
spellingShingle Carlos Pernas-Pleite
Amparo M. Conejo-Martínez
Irma Marín
José P. Abad
Silver Nanoparticles (AgNPs) from <i>Lysinibacillus</i> sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical Antibiotics
Biomolecules
AgNPs
antibacterial activity
antibiotic resistance
green synthesis
FICI
<i>Lysinibacillus</i> sp.
title Silver Nanoparticles (AgNPs) from <i>Lysinibacillus</i> sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical Antibiotics
title_full Silver Nanoparticles (AgNPs) from <i>Lysinibacillus</i> sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical Antibiotics
title_fullStr Silver Nanoparticles (AgNPs) from <i>Lysinibacillus</i> sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical Antibiotics
title_full_unstemmed Silver Nanoparticles (AgNPs) from <i>Lysinibacillus</i> sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical Antibiotics
title_short Silver Nanoparticles (AgNPs) from <i>Lysinibacillus</i> sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical Antibiotics
title_sort silver nanoparticles agnps from i lysinibacillus i sp culture broths antibacterial activity mechanism insights and synergy with classical antibiotics
topic AgNPs
antibacterial activity
antibiotic resistance
green synthesis
FICI
<i>Lysinibacillus</i> sp.
url https://www.mdpi.com/2218-273X/15/5/731
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