Antibacterial Activity of Ethanol Extract of the Marine Sponge (Agelas sp) Symbiont Bacillus cereus MH997647 IA5 against Klebsiella pneumoniae ESBL

Abstract

Klebsiella pneumoniae ESBL is the major causative organism of pneumonia, a lower respiratory tract infection that could be lethal. In 2019, pneumonia was ranked the fourth-leading cause of death worldwide. This study aims to investigate the antibacterial activity of the ethanol extract of Bacillus cereus MH997647 IA5, a symbiont of the marine sponge Agelas sp. against Klebsiella pneumoniae ESBL as well as to identify the secondary metabolites present in the extract. The antibacterial activity of the sponge symbiont was assessed using the disc diffusion assay. The ethanol extract of the sponge symbiont was subjected to liquid chromatography-mass spectrometry (LC-MS-MS) to identify the compounds present in the extract. The results of the antibacterial activity screening showed that the sponge symbiont had growth inhibitory activity against Klebsiella pneumoniae ESBL with an average inhibition zone diameter of 7.72 mm. The LC-MS/MS analysis identified seven compounds in the ethanol extract of the sponge symbiont Bacillus cereus MH997647 IA5, namely DL-phenylalanine, L-(+)-leucine, DL-tyrosine, L-(+)-valine, choline, noradrenaline, and tributyl citrate acetate. These compounds could be responsible for the antibacterial activity of the ethanol extract of Bacillus cereus MH997647 IA5 against Klebsiella pneumoniae ESBL. Therefore, Bacillus cereus MH997647 IA5 could be a potential source of active compounds for the treatment of bacterial infection particularly pneumonia.