RESUMEN
Taking into account that fructophilic lactic acid bacteria (FLAB) can play an important role in the health of honey bees and can be used as probiotics, phenotypic properties of probiotic interest of Lactobacillus kunkeei (12 strains) and Fructobacillus fructossus bacteria (2 strains), isolated from Apis mellifera gastrointestinal tract, have been studied. We have evaluated survival of tested FLAB in honey bee gut, their susceptibility to antibiotics (ampicillin, erythromycin, tylosin), cell surface hydrophobicity, auto-aggregation ability, co-aggregation with model pathogenic bacteria, biofilm formation capacity, and effect of studied FLAB, added to sucrose syrup bee diet, on longevity of honey bees. The tested FLAB exhibited good gastrointestinal tract tolerance and high antibiotic susceptibility, which are important criteria in the screening of probiotic candidates. It was also found that all FLAB studied have high cell surface hydrophobicity and fulfil next selection criterion for their use as probiotics. Symbionts of A. mellifera showed also auto- and co-aggregation capacities regarded as valuable features for biofilm formation and inhibition of pathogens adhesion to the bee gut cells. Biofilm-development ability is a desired characteristic of probiotic lactic acid bacteria. As indicated by quantitative crystal violet-stained microplate assay and confocal laser scanning microscopy imaging, all studied A. mellifera gut isolates exhibit a biofilm positive phenotype. Moreover, it was also documented, on honey bees kept in cages, that supplementation of A. mellifera sucrose diet with FLAB decreases mortality and improves significantly longevity of honey bees. Presented research showed that A. mellifera FLAB symbionts are good candidates for application as probiotics.
RESUMEN
This paper describes taxonomic position, phylogeny, and phenotypic properties of 14 lactic acid bacteria (LAB) originating from an Apis mellifera guts. Based on the 16S rDNA and recA gene sequence analyses, 12 lactic acid bacteria were assigned to Lactobacillus kunkeei and two others were classified as Fructobacillus fructosus. Biochemically, all isolated lactic acid bacteria showed typical fructophilic features and under anaerobic conditions grew well on fructose, but poorly on glucose. Fast growth of bacteria on glucose was noted in the presence of oxygen or fructose as external electron acceptors. The residents of honeybee guts were classified as heterofermentative lactic acid bacteria. From glucose, they produced almost equimolar amounts of lactic acid, acetic acid, and trace amounts of ethanol. Furthermore, they inhibited the growth of the major honeybee pathogen, Paenibacillus larvae, meaning that the LAB studied may have the health-conferring properties of probiotics.