American foulbrood is a devastating disease of honey bee, causing economic loss in the beekeeping industry. The disease mainly causes reduction in honey bee populations which negatively affect the honey bee’s major role as natural pollinators of significant crops and wildflowers. Thus, it is crucial to develop safe efficient strategies to control the disease and to improve bee colony health. Using lactic acid bacteria (LAB) as an alternative to chemical treatments is a promising novel technique for tackling honey bee diseases and improving their immunity. The endogenous LAB isolates were recovered from honey bee gut samples collected from different apiaries in two Egyptian governorates and screened for antagonistic activities against Paenibacillus larvae (pathogen of AFB disease). The results showed that 53.3% of tested LAB isolates (n = 120) exhibited antagonistic activities against P. larvae. The minimum inhibitory concentration and minimum bactericidal concentration of the most potent LAB isolate (with an inhibition zone of 44 mm) were 100 and 125 µL/mL, respectively. 16S rRNA sequencing identified the most potent isolate as Fructobacillus fructosus HI-1. The bioactive metabolites of F. fructosus were extracted with ethyl acetate and fractionated on thin-layer chromatography (TLC); also, bioactive fractions were detected. Heptyl 2-methylbutyrate, di-isobutyl phthalate, d-turanose, heptakis (trimethylsilyl), di-isooctyl phthalate, and hyodeoxycholic acid compounds were identified in the bioactive fractions. The result explores the promising administration of probiotic metabolites to control honey bee AFB disease, as a natural tool to substitute antibiotics and chemicals in disease-controlling strategies.

美国臭虫是蜜蜂的一种毁灭性疾病，给养蜂业造成经济损失。这种疾病主要导致蜜蜂种群减少，这对蜜蜂作为重要农作物和野花的天然传粉者的主要作用产生了负面影响。因此，制定安全有效的策略来控制疾病和改善蜂群健康至关重要。使用乳酸菌 (LAB) 作为化学治疗的替代品是一种很有前途的新技术，可用于治疗蜜蜂疾病并提高其免疫力。从埃及两个省的不同养蜂场采集的蜜蜂肠道样本中回收了内源性 LAB 分离物，并筛选了对类芽孢杆菌幼虫的拮抗活性（AFB 病的病原体）。结果表明，53.3% 的测试 LAB 分离株 ( n = 120) 表现出对P. 幼虫的拮抗活性。最有效的 LAB 分离物（抑制区为 44 mm）的最低抑菌浓度和最低杀菌浓度分别为 100 和 125 µL/mL。16S rRNA 测序鉴定出最有效的分离物为Fructobacillus fructosus HI-1 。F. fructosus的生物活性代谢物用乙酸乙酯萃取并在薄层色谱 (TLC) 上分离；此外，还检测到了生物活性组分。2-甲基丁酸庚酯、邻苯二甲酸二异丁酯、d在生物活性组分中鉴定出-松二糖、七溴二苯醚（三甲基甲硅烷基）、邻苯二甲酸二异辛酯和猪去氧胆酸化合物。该结果探索了使用益生菌代谢物来控制蜜蜂 AFB 疾病的前景，作为在疾病控制策略中替代抗生素和化学品的天然工具。