Characterization and complete genome analysis of Bacillus velezensis CB6 revealed ATP synthase subunit α against foodborne pathogens.

Given the serious threat of foodborne multidrug-resistant bacteria to animals and humans, finding an effective antibacterial compound has always been an important topic for scientists. Here, from the soil of Changbaishan, we have identified a bacterium that can inhibit the growth of Staphylococcus aureus. Nr genome database analysis and phylogenetic analysis showed that strain CB6 belongs to Bacillus velezensis. We found that the crude extract of strain CB6 has broad-spectrum antibacterial activity against foodborne pathogens. In addition, we showed that the crude extract loses antibacterial activity after treatment with papain. Next, strain CB6 was purified using ammonium sulfate precipitation, a Sephadex G-75 gel filtration column and high-performance liquid chromatography system (HPLC). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis indicated that the antibacterial compound was the protein ATP synthase subunit α (ATP-1), with a molecular weight of 55.397 KDa. Moreover, we reported the complete genome sequence of strain CB6, which is composed of a unique circular 3,963,507 bp chromosome with 3749 coding genes and a G + C content of 46.53%. The genome contained 12 gene clusters with antibacterial functions, which constituted over 20.947% of the complete genome. Of note, the amino acid sequence encoding the ATP-1 protein in the strain CB6 genome was identified. In addition to these findings, we speculate that the ATP-1 protein may provide energy for secondary metabolites, which in turn will improve the antibacterial activity of the secondary metabolites. All the above important features make the ATP-1 as a potential candidate for the development of new antibacterial drugs and food preservatives in the future.

Host-acting antibacterial compounds combat cytosolic bacteria.

The sharp increase in infections associated with multidrug-resistant (MDR) bacterial pathogens that have seriously compromised traditional chemotherapeutics is becoming a devastating public health threat worldwide. Thus, there is an urgent unmet demand to pursue alternative intervention strategies to circumvent this problem. Advances in host-acting antibacterial compounds (HACs) have provided promising, emerging approaches to reduce or eliminate internalized bacteria. In this review we focus mainly on the interactions between host cells and facultative intracellular bacteria to explore potential targets for the discovery and development of HACs. Additionally, we summarize the targets of recently described HACs and their modes of action and pharmacological activities against diverse pathogenic bacteria-associated infections. This overview of HACs sheds light on alternative strategies to treat clinical infections associated with cytosolic bacteria and the development of novel antibacterial agents.