Use of Lactobacillus plantarum in Preventing Clinical Cases of American and European Foulbrood in Central Italy

American and European Foulbrood (AFB and EFB) are considered the most contagious infectious diseases affecting honeybees worldwide. New sustainable strategies need to be implemented for their prevention and control, and probiotics may represent one solution to investigate. In our study, we evaluated the efficacy of one strain of Lactobacillus plantarum (L. plantarum) isolated from northern Italy, orally administered to the bees for AFB and EFB prevention. From March to September 2014, a total of 979 honeybee colonies (9.6% of Viterbo province—Central Italy) were taken under observation from 22 apiaries. Overall prevalence of AFB was 5.3% in treated colonies and 5.1% in the untreated ones. On the contrary, EFB prevalence was lower in the treated colonies (2.5%) compared to the untreated ones (4.5%). L. plantarum showed a significant effect in reducing insurgence of cases of EFB up to 35 days after the end of the treatment (p-value: 0.034). Thanks to this study we could investigate the preventive efficacy of L. plantarum in controlling AFB and EFB, and obtain official data on their clinical prevalence in Central Italy.