Retention of antibiotic activity against resistant bacteria harbouring aminoglycoside-N-acetyltransferase enzyme by adjuvants: a combination of in-silico and in-vitro study

Sci Rep. 2020 Nov 9;10(1):19381. doi: 10.1038/s41598-020-76355-0.

Abstract

Interference with antibiotic activity and its inactivation by bacterial modifying enzymes is a prevailing mode of bacterial resistance to antibiotics. Aminoglycoside antibiotics become inactivated by aminoglycoside-6'-N-acetyltransferase-Ib [AAC(6')-Ib] of gram-negative bacteria which transfers an acetyl group from acetyl-CoA to the antibiotic. The aim of the study was to disrupt the enzymatic activity of AAC(6')-Ib by adjuvants and restore aminoglycoside activity as a result. The binding affinities of several vitamins and chemical compounds with AAC(6')-Ib of Escherichia coli, Klebsiella pneumoniae, and Shigella sonnei were determined by molecular docking method to screen potential adjuvants. Adjuvants having higher binding affinity with target enzymes were further analyzed in-vitro to assess their impact on bacterial growth and bacterial modifying enzyme AAC(6')-Ib activity. Four compounds-zinc pyrithione (ZnPT), vitamin D, vitamin E and vitamin K-exhibited higher binding affinity to AAC(6')-Ib than the enzyme's natural substrate acetyl-CoA. Combination of each of these adjuvants with three aminoglycoside antibiotics-amikacin, gentamicin and kanamycin-were found to significantly increase the antibacterial activity against the selected bacterial species as well as hampering the activity of AAC(6')-Ib. The selection process of adjuvants and the use of those in combination with aminoglycoside antibiotics promises to be a novel area in overcoming bacterial resistance.

MeSH terms

  • Acetyltransferases* / antagonists & inhibitors
  • Acetyltransferases* / chemistry
  • Bacterial Proteins* / antagonists & inhibitors
  • Bacterial Proteins* / chemistry
  • Drug Resistance, Bacterial*
  • Escherichia coli / enzymology*
  • Klebsiella pneumoniae / enzymology*
  • Molecular Docking Simulation*
  • Shigella sonnei / enzymology*

Substances

  • Bacterial Proteins
  • Acetyltransferases
  • aminoglycoside N(6')-acetyltransferase