## 4 Discussion
homitis_ in honey [3,22,79]. Moreover, all _Staphylococcus_ spp. identified in this study, except _S. arlettae_, have been described as part of the honeybee gastrointestinal microbiome [3,61,62,66,80,81]. _S. arlettae_ is commonly found in the skin and nares of poultry and goats [82]. Surprisingly, none of the bacterial isolates grown on MRS agar that exerted antimicrobial activity in this study was identified as lactic acid bacteria. However, all four isolates were identified as _Staphylococcus_ spp., one of them (_S. homitis_) previously isolated using MRS agar [83]. Only 10% of the characterized bacterial isolates were identified as Gram-negative bacteria, namely _Pseudomonas_ sp., _P. coleopterorum_, _P. fulva_, _P. stutzeri_, and _A. lwoffii_. _Pseudomonas_ spp. and _Actinetobacter_ spp. are often present in soil [7]. However, [PERSON] et al. [84] isolated for the first time the bacterium _A. lwoffii_ from a Transylvanian honey sample, suggesting that it was derived from the honeybee microbiota. _Pseudomonas_ spp. have been identified both in honey and the digestive tract of honeybees [9,10,17,22,62]. The _Pseudomonas_ genus is very diverse and comprises 272 species, organized in several major taxonomic groups that are widely distributed in diverse niches [85]. Some of these strainsexert biotechnology interesting metabolic potential (denitrification, degradation of aromatic compounds, nitrogen fixation) [86; 87; 88; 89]. _P. fulva_ is a widespread environmental species exhibiting high biodegradation potential. It is reported to degrade neonicotinoid insecticides that contribute to honeybee colony collapse disorder [86], as well as a pyrethroid insecticide, reported to be accumulated in honeybee wax samples [87]. On the other hand, _P. cooleopterorum_ was detected in the gut microbiota of some plant-related insects [90]. See products have been suggested as a rich source of beneficial bacteria that might be potential biocontrol agents against bee pathogens [4; 28; 42]. Several _Bacillus_ strains produce compounds against pathogenic and food-spoilage bacteria [2; 51]. Moreover, _B. subtilis_, _B. amyloliquefaciens_, _B. pumilus_, and _B. licheniformis_ are considered as probiotics and antibiotic producers. Indeed, _B. subtilis_ has already been used as a probiotic supplement for human and animal diets [23; 42]. LABs commonly isolated from honey produce secondary metabolites, like bacteriocins and lipopeptides [6; 91; 42; 92]. However, we did not identify any LABs exhibiting antibacterial activity in the present study, presumably due to the relatively small number of isolates grown on MRS agar. Nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs) are often implicated in the biosynthesis of medically useful secondary metabolites, such as antibiotics, antitumor agents, immunosuppressants, siderophores, and toxins [30; 31; 33]. In this study we report the detection of genes encoding NRPSs and PKSs in 14 and 6 out of 50 identified isolates, respectively. NRPS genes were detected more often in _Bacillus_ spp. It is known that _Bacillus_ and _Paenibacillus_ genera produce non-ribosomally synthesized lipopeptides with significant antimicrobial activity, such as iturin, fengycin, surfactin, and bacillomycin. These compounds are abundantly synthesized, particularly by _B. amyloliquefaciens_, _B. subtilis_, _B. licheniformis_, and _B. pumilus_[92; 93]. Furthermore, NRPs have been identified in _Pseudomonas_ spp. by several studies [94; 95; 96; 97]. Analysis of _P. fluorescens_ In5 revealed the presence of two antifungal NRPs, runamycin and runapeptide [94]. Another study showed that a monomodular NRPS from _Pseudomonas fluorescens_ HKI0770 is implicated in biosynthesis of the antimicrobial pyreudiones [96]. [PERSON] et al. [51] have targeted seven antibacterial peptide biosynthetic genes present in two _B. velezensis_ honey isolates using specific primers.