Antimicrobial activity of phytomolecules against Paenibacillus larvae

SZAWARSKI NICOLAS; GIMÉNEZ MARTÍNEZ PABLO DARIAN; FUSELLI SANDRA; LAMATTINA LORENZO; MAGGI MATIAS

Congreso; Eurbee 8; 2018

Pollination is vital to the maintenance of both wild plant communities and agricultural productivity. However, pollinatorslike Apis mellifera are threatened by different biotic and abiotic stressors that affect the bee survival. Pathogens andparasites are among the most important factors that cause mortality of bees. Paenibacillus larvae, the causative agentof American foulbrood, is one of the most important bacterial pathogens that affect bee health. The use of antibiotics,particularly tetracycline hydrochloride, is the most common method for prevention and treatment of infected colonies.The extended use of synthetic drugs is known to generate several problems, including the presence of chemical residuesin the beehive products and occurrence of resistant strains. An ecological alternative is the use of vegetal moleculesthat can be found in floral rewards, such as polyphenols and phytohormones. In recent years the study of this type ofmolecules has been put in focus, showing that they can be extremely important and very beneficial in the immunityof bees. The aim of the present study was to evaluate the antimicrobial activity of abscisic acid (ABA), indole acetic acid(IAA), gibberellic acid (GA) and p-coumaric acid against P. larvae by the broth microdilution method. The p-coumaricacid showed antimicrobial activity against P. larvae genotype ERIC I, resulting the MIC equal to 650 μgmL-1 and MNICto 500 μgmL-1. On the other hand, ABA, IAA and GA did not show antimicrobial activity in the range from 1000 to 15.6ugmL-1. Of all the phytomomolecules analyzed in the present study, only p-coumaric acid showed antimicrobial activity.This molecule could be a possible potential as a natural alternative for the control of P. larvae, avoiding the problemsgenerated by the use of synthetic antibiotics, such as the presence of residues in the beehives products and the appearanceof resistant strains.