Antibacterial effects of Lactobacillus casei and Lactobacillus acidophilus on the Paenibacillus larvae causative agent of honeybee American foulbrood disease In vitro

In this survey antibacterial effects of Lactobacillus casei and Lactobacillus acidophilus against Painibacillus larvae, causative agent of honeybee American foulbrood disease, has investigated by Agar spot test, Well diffusion and Microdilution methods. In Agar spot test 107cfu/ml of Lactobacillus casei and Lactobacillus acidophilus made inhibition zone 45 and 40 mm around spots on the agar medium respectively. In the well diffusion method, 100 microliters of cell free supernatant (cfcs) of Lactobacillus casei and Lactobacillus acidophilus mede inhibition zone 40 and 30 mm around wells respectively, 50 microlitrs of L. casei and L. acidophilus supernatant mede inhibition zone 30 and 25 mm around wells respectively and 30 microlitrs of L. casei and L. acidophilus supernatant made inhibition zone 20 and 12 mm around wells respectively. In the microdulation method 103 -108cfu/ml concentrations of two lactobacillus inhibited P. lrvae growth completely, but 102 and 10 cfu/ml of two lactobacillus have not any effect on the P. larvae growth. The results of this study show that L. casei and L. acidophilus have antibacterial effects on the P. larvae, causative agant of the honeybee American foulbrood disease and can use as a safe remedy for treatment of this disease.