1-alkyl-(N,N-dimethylamino)pyridinium bromides: inhibitory effect on virulence factors of Candida albicans and on the growth of bacterial pathogens

J Med Microbiol. 2013 Feb;62(Pt 2):241-248. doi: 10.1099/jmm.0.050070-0. Epub 2012 Nov 1.

Abstract

A homologous series of 1-alkyl-(N,N-dimethylamino)pyridinium bromides, termed compounds 1-11, was synthesized and studied for antibacterial and antifungal activity. Of these, compound 8, containing a ten-carbon alkyl chain, showed maximum inhibition against all the tested bacterial strains. The highest antibacterial activity using a disc diffusion method was recorded against Mycobacterium smegmatis [zone of inhibition (ZOI): 45.75±0.25 mm], followed by Escherichia coli, Proteus mirabilis, Vibrio cholerae, Staphylococcus aureus and Salmonella typhi. In addition to antibacterial activity, compounds 3-11 displayed good inhibitory action against the human opportunistic yeast pathogens Cryptococcus neoformans and various Candida spp. The maximum ZOI was observed against Cryptococcus neoformans (51.5±0.5 mm) using compound 8, with ZOIs of 23.5±0.5, 32.0±0.0, 27.75±0.25 and 41.5±0.5 mm against Candida albicans, Candida glabrata, Candida tropicalis and Candida krusei, respectively. Furthermore, compound 8 caused inhibition of the candidal yeast-hyphae transition at a concentration of 0.29 µM and also inhibited the secretion of extracellular hydrolytic enzyme such as secreted aspartyl proteinase at subinhibitory concentrations. Compound 8 showed very little haemolytic activity at a concentration of 0.58 µM (1.315±0.75 %), with its highest haemolytic activity (47.806±2.32 %) observed at a concentration of 2.9 µM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Antifungal Agents / pharmacology*
  • Bacteria / drug effects*
  • Bacteria / growth & development
  • Candida albicans / drug effects*
  • Candida albicans / growth & development
  • Candida albicans / pathogenicity
  • Cryptococcus neoformans / drug effects
  • Drug Resistance, Multiple, Bacterial
  • Drug Resistance, Multiple, Fungal
  • Escherichia coli / drug effects
  • Microbial Sensitivity Tests
  • Mycobacterium smegmatis / drug effects
  • Proteus mirabilis / drug effects
  • Pyridinium Compounds / pharmacology*
  • Salmonella typhi / drug effects
  • Staphylococcus aureus / drug effects
  • Vibrio cholerae / drug effects

Substances

  • Anti-Bacterial Agents
  • Antifungal Agents
  • Pyridinium Compounds