Antibacterial Activities of Culture-dependent Bacteria Isolated from Apis nigrocincta Gut

Apis nigrocincta is a honeybee endemic to Mindanao island (the Philippines), Sangihe island (North Sulawesi, Indonesia) and Sulawesi mainland (Indonesia). The genus Apis is well known to have symbiont in their guts, which helps balance the microbiome in the gut and host health.

The objective of this study was to determine whether the bacteria isolated from the gut of honeybee Apis nigrocincta produce metabolites with potential growth inhibition against Staphylococcus aureus and Escerichia coli, the bacteria which are important pathogens in humans and animals.

Bacteria isolated from honeybee gut were cultured in MRSA and several isolates were purified for testing. The antibacterial activity test method used in this study was well diffusion agar. Pure isolates were grown on NB. The treatments given were heating and also neutralizing the supernatant from each isolate.

Five bacterial isolates were successfully isolated from honeybee gut and purified. The five isolates showed antibacterial activity against pathogenic bacterial strain indicators. The results of molecular identification showed that four of these isolates were Bacillus cereus and the other one was Staphylococcus arlettae. Neutralized supernatant showed strong activity on both indicator strains. The five isolates showed higher inhibition activity against S. aureus compared to E. coli.

The finding of this research concluded that two bacterial strains, B. cereus and S. arlettae isolated from A. nigrocincta gut can be investigated further as agents which produce bioactive compounds that have potential as an antibacterial.