Inhibitory effect of gut bacteria from the Japanese honey bee, Apis cerana japonica, against Melissococcus plutonius, the causal agent of European foulbrood disease.

Meihua Wu,Mikio Yoshiyama,Kiyoshi Kimura,Demar Taylor,Yuya Sugimura,Noriko Takaya,Masaru Kobayashi,Kyoko Iwata,Daisuke Takamatsu,Thomas Miller

doi:10.1093/jis/14.1.129

Abstract

European foulbrood is a contagious bacterial disease of honey bee larvae. Studies have shown that the intestinal bacteria of insects, including honey bees, act as probiotic organisms. Microbial flora from the gut of the Japanese honey bee, Apis cerana japonica F. (Hymenoptera: Apidae) , were characterized and evaluated for their potential to inhibit the growth of Melissococcus plutonius corrig. (ex White) Bailey and Collins (Lactobacillales: Enterococcaceae) , the causative agent of European foulbrood. Analysis of 16S rRNA gene sequences from 17 bacterial strains isolated by using a culture-dependent method revealed that most isolates belonged to Bacillus, Staphylococcus, and Pantoea. The isolates were screened against the pathogenic bacterium M. plutonius by using an in vitro growth inhibition assay, and one isolate (Acja3) belonging to the genus Bacillus exhibited inhibitory activity against M. plutonius. In addition, in vivo feeding assays revealed that isolate Acja3 decreased the mortality of honey bee larvae infected with M plutonius, suggesting that this bacterial strain could potentially be used as a probiotic agent against European foulbrood.

Highlights

European honey bees (Apis mellifera L. (Hymenoptera: Apidae)) play a critical role in human well-being, through the provision of honey and by pollinating a great variety of crop plants
16S rRNA Gene Sequences and Phylogenetic Analysis of Isolates In total, 128 bacterial colonies were isolated from the gut of A. c. japonica by using a culture-dependent method
Sequence analysis of 16S rRNA genes revealed that most of the isolated bacteria belonged to the genus Bacillus, and in vivo feeding assays showed that one of these Bacillus isolates (Acja3) exhibited inhibitory activity against M. plutonius in A. mellifera

Summary

Introduction

European honey bees (Apis mellifera L. (Hymenoptera: Apidae)) play a critical role in human well-being, through the provision of honey and by pollinating a great variety of crop plants. (ex White) Bailey and Collins (Lactobacillales: Enterococcaceae) (Bailey and Collins 1982, Bailey 1983, Forsgren et al 2005) This infectious and contagious bacterial disease has caused extensive damage to the global apiculture industry (Belloy et al 2007, Forsgren 2010). The emergence of oxytetracyclineresistant strains of Paenibacillus larvae (White) (Bacillales: Paenibacillaceae), the etiological agent of American foulbrood, has become a serious problem (Miyagi et al 2000). In combination, these factors have contributed to a general decrease in the use of antibiotics in apiculture and even a ban in the European Union (de Graaf et al 2006). There is an urgent need to develop novel and alternative disease management techniques for controlling European foulbrood

Objectives

Methods

Results

Conclusion