Evaluation of antimicrobial activity of glycerol monolaurate nanocapsules against American foulbrood disease agent and toxicity on bees

Microb Pathog. 2016 Aug:97:183-8. doi: 10.1016/j.micpath.2016.05.014. Epub 2016 May 20.

Abstract

The American Foulbrood Disease (AFB) is a fatal larval bee infection. The etiologic agent is the bacterium Paenibacillus larvae. The treatment involves incineration of all contaminated materials, leading to high losses. The Glycerol Monolaurate (GML) is a known antimicrobial potential compound, however its use is reduced due to its low solubility in water and high melting point. The nanoencapsulation of some drugs offers several advantages like improved stability and solubility in water. The present study aimed to evaluate the antimicrobial activity against P. larvae and the toxicity in bees of GML nanoparticles. The nanocapsules were produced and presented mean diameter of 210 nm, polydispersity index of 0.044, and zeta potential of -23.4 mV demonstrating the acceptable values to predict a stable system. The microdilution assay showed that it is necessary 142 and 285 μg/mL of GML nanocapsules to obtain a bacteriostatic and bactericidal effect respectively. The time-kill curve showed the controlled release of compound, exterminating the microorganism after 24 h. The GML nanocapsules were able to kill the spore form of Paenibacillus larvae while the GML do not cause any effect. The assay in bees showed that the GML has a high toxicity while the GML nanoparticles showed a decrease on toxic effects. Concluding, the formulation shows positive results in the action to combat AFB besides not causing damage to bees.

Keywords: Antimicrobial activity; Beehives; Nanoparticle; Toxicity.

MeSH terms

  • Animals
  • Anti-Infective Agents / pharmacology*
  • Anti-Infective Agents / toxicity*
  • Bees / drug effects*
  • Laurates / pharmacology*
  • Laurates / toxicity*
  • Microbial Sensitivity Tests
  • Microbial Viability / drug effects
  • Monoglycerides / pharmacology*
  • Monoglycerides / toxicity*
  • Nanocapsules*
  • Paenibacillus larvae / drug effects*
  • Paenibacillus larvae / growth & development
  • Paenibacillus larvae / physiology
  • Spores, Bacterial / drug effects
  • Spores, Bacterial / growth & development
  • Spores, Bacterial / physiology
  • Survival Analysis

Substances

  • Anti-Infective Agents
  • Laurates
  • Monoglycerides
  • Nanocapsules
  • monolaurin