Abstract
The aim of study was to isolate and identify the gut bacteria of Apis mellifera and to evaluate antagonistic effect of the bacteriota against Paenibacillus larvae, which causes American foulbrood (AFB) in honeybees. The dilution plating method was used for the quantification of selected microbial groups from digestive tract of bees, with an emphasis on the bacteriota of the bees’ intestines. Bacteria were identified using mass spectrometry (MALDI-TOF-MS Biotyper). Overall, five classes, 27 genera and 66 species of bacteria were identified. Genera Lactobacillus (10 species) and Bacillus (8 species) were the most abundant. Gram-negative bacteria were represented with 16 genera, whereas Gram-positive with 10 genera. Delftia acidovorans and Escherichia coli were the most abundant in the digestive tract of honey bee. Resistance to a selection of antimicrobials was assessed for the bacterial isolates from bee gut and confirmed against all antimicrobials included in the study, with the exception of cefepime. Lactobacillus spp., especially L. kunkeei, L. crispatus and L. acidophilus. showed the strongest antimicrobial activity against P. larvae, the causal pathogen of AFB. Antimicrobial activity of essential oils against isolated bacteria and two isolates of P. larvae were assessed. Application of a broad selection of plant essential oils indicated that Thymus vulgaris had the highest antimicrobial activity against P. larvae.
Highlights
The digestive tract of the worker bee is inhabited with a variety of microorganisms diverse in their morphology, physiology and metabolism
The highest counts of aerobic microorganisms were found in the intestine of winter bees (5.39 ± 0.14 log cfu/g) and the lowest in the rectum of summer bees (4.48 ± 0.13 log cfu/g)
The total counts of anaerobic microorganisms ranged from 8.12 ± 0.06 in the intestine of summer bees to 9.25 ± 0.15 log cfu/g in the rectum of winter bees
Summary
The digestive tract of the worker bee is inhabited with a variety of microorganisms diverse in their morphology, physiology and metabolism. The microbiota of digestive tract consists of yeasts (1%), Gram-positive bacteria (29%) and Gram-negative and gram-variable bacteria (70%) [1]. Subsequent reports on microflora studies of bees and microorganisms in their diet were published in the 1960s [2,3]. American foulbrood (AFB) is a disease caused by aerobic to microaerophilic, Gram-positive, spore-forming rod, Paenibacillus larvae. Bacterial spores germinate in the gut of larvae, bacteria multiply and kill the larvae at pre-pupal or pupal stage. The disease is highly contagious as more than 2.5 billion oval spores could be produced in 10 days. AFB does not affect the adult bees, but they facilitate the spread of infection within a colony [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
