Bactericidal effect of silver nanoparticles against multidrug-resistant bacteria

  • Humberto H. LaraEmail author
  • Nilda V. Ayala-Núñez
  • Liliana del Carmen Ixtepan Turrent
  • Cristina Rodríguez Padilla
Original Paper


Infections caused by drug-resistant microorganisms result in significant increases in mortality, morbidity, and cost related to prolonged treatments. The antibacterial activity of silver nanoparticles against some drug-resistant bacteria has been established, but further investigation is needed to determine whether these particles could be an option for the treatment and prevention of drug-resistant microbial infections. Hence, we challenged different drug-resistant pathogens of clinical importance (multidrug-resistant Pseudomonas aeruginosa, ampicillin-resistant Escherichia coli O157:H7 and erythromycin-resistant Streptococcus pyogenes) with a suspension of silver nanoparticles. By means of a luciferase-based assay, it was determined that silver nanoparticles (1) inactivate a panel of drug-resistant and drug-susceptible bacteria (Gram positive and Gram negative), (2) exert their antibacterial activity through a bactericidal rather than bacteriostatic mechanism, and (3) inhibit the bacterial growth rate from the time of first contact between the bacteria and the nanoparticles. Additionally, strains with a resistant phenotype to silver nanoparticle were developed and used to explore the bactericidal mode of action of silver nanoparticles. Through a Kirby–Bauer test, it was shown that silver nanoparticles’ general mechanism of bactericidal action is based on inhibition of cell wall synthesis, protein synthesis mediated by the 30s ribosomal subunit, and nucleic acid synthesis. Our data suggest that silver nanoparticles are effective broad-spectrum biocides against a variety of drug-resistant bacteria, which makes them a potential candidate for use in pharmaceutical products and medical devices that may help to prevent the transmission of drug-resistant pathogens in different clinical environments.


Drug-resistant bacteria Silver nanoparticles Silver resistance Broad-spectrum agent Bactericidal agent Nanobiotechnology 



The following funding sources supported the data collection process: the Programa de Apoyo a la Investigacion en Ciencia y Tecnologia (PAICyT) from the Universidad Autonoma de Nuevo Leon, Mexico.


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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Humberto H. Lara
    • 1
    Email author
  • Nilda V. Ayala-Núñez
    • 1
  • Liliana del Carmen Ixtepan Turrent
    • 1
  • Cristina Rodríguez Padilla
    • 1
  1. 1.Laboratorio de Inmunologia y VirologiaUniversidad Autonoma de Nuevo LeonSan Nicolás de los GarzaMexico

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