Revelation of susceptibility differences due to Hg(II) accumulation in Streptococcus pyogenes against CX-AgNPs and Cefixime by atomic force microscopy

Ecotoxicol Environ Saf. 2018 Jan:147:9-16. doi: 10.1016/j.ecoenv.2017.08.030. Epub 2017 Aug 17.

Abstract

Solution based method for the formation of chemically modified silver nanoparticles (CX-AgNPs) using Cefixime as stabilizing and reducing agent was developed. The CX-AgNPs were characterized by AFM, UV-visible, FT-IR and MALDI-TOF MS. Bactericidal efficiency of CX-AgNPs and Cefixime against Streptococcus pyogenes was evaluated. Afterwards, susceptibility differences of Streptococcus pyogenes due to accumulation of Hg(II) against CX-AgNPs and Cefixime were estimated and validated through Atomic force microscopy. Selectivity and sensitivity of CX-AgNPs against Hg(II) was evaluated in a systematic manner. The CX-AgNPs was titrated against optically silent Hg(II) which induced enhancement in the SPR band of CX-AgNPs. The increase in intensity of SPR band of CX-AgNPs was determined to be proportionate to the concentration of Hg(II) in the range of 33.3-700µM obeying linear regression equation of y = 0.125x + 8.962 with the detection limit of 0.10µM and the coefficient of determination equals to 0.985 (n = 3). The association constant Ka of CX-AgNPs-Hg(II) was found to be 386.0095mol-1dm3 by using the Benesi Hildebrand plot.

Keywords: Antibiotic; Hg(II) accumulation; Silver nanoparticles; Streptococcus pyogenes.

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Cefixime / chemistry
  • Cefixime / pharmacology*
  • Limit of Detection
  • Mercury / metabolism*
  • Metal Nanoparticles / chemistry*
  • Microbial Sensitivity Tests
  • Microscopy, Atomic Force
  • Nanoconjugates / chemistry*
  • Silver / chemistry
  • Silver / pharmacology*
  • Spectroscopy, Fourier Transform Infrared
  • Streptococcus pyogenes / drug effects*
  • Streptococcus pyogenes / metabolism

Substances

  • Anti-Bacterial Agents
  • Nanoconjugates
  • Silver
  • Cefixime
  • Mercury