Bacillus licheniformis and Bacillus subtilis, Probiotics That Induce the Formation of Macrophage Extracellular Traps

Abstract

Probiotics are considered living microorganisms that help preserve the health of the host who uses them. Bacillus are a genus of Gram-positive bacteria used as probiotics for animal and human consumption. They are currently distributed in various commercial forms. Two of the species used as probiotics are B. licheniformis and B. subtilis. Macrophages are central cells in the immune response, being fundamental in the elimination of microbial pathogens, for which they use various mechanisms, including the formation of extracellular traps (METs). There have been very few studies carried out on the participation of macrophages in response to the interaction of probiotics of the genus Bacillus with the host. In this work, we used macrophages from the J774A mouse cell line.1, and we found that they are susceptible to infection by the two Bacillus species. However, both species were eliminated as the infection progressed. Using confocal microscopy, we identified the formation of METs from the first hours of infection, which were characterized by the presence of myeloperoxidase (MPO) and citrullinated histone (Hit3Cit). Quantitative data on extracellular DNA release were also obtained; release was observed starting in the first hour of infection. The induction of METs by B. licheniformis caused a significant decrease in the colony-forming units (CFU) of Staphylococcus aureus. The induction of METS by bacteria of the Bacillus genus is a mechanism that participates in controlling the probiotic and potentially pathogenic bacteria such as S. aureus. The induction of METs to control pathogens may be a novel mechanism that could explain the beneficial effects of probiotics of the genus Bacillus.

Extracellular trap can be trained as a memory response

“…Macrophages generated extracellular traps are involved in the elimination of pathogens similar to neutrophils [ 2 , 15 ]. Since ET has been associated with extracellular pathogen killing, we investigated whether the enhanced extracellular bacterial killing was mediated by the release of ETs.…”

“…As described previously [ 15 ], for quantitative detection of extracellular DNA, primed and non-primed cells were stimulated with Clostridium perfringens (MOI = 5) at different time points (2 h, 3 h, and 4 h) and centrifuged at 3000 rpm for 5 min to collect the supernatant. An equal amount of RPMI 1640 medium was added to the uninfected control group.…”

The role of extracellular traps in ischemia reperfusion injury

“…Researchers have previously shown that statins induce the release of ETs from monocytes/macrophages by inhibiting the sterol pathway ( 4 ). Like neutrophils, macrophages can release ETs to defend the body against attack from various microorganisms, such as Escherichia coli , Bacillus licheniformis , Haemophilus influenzae , Mycobacterium tuberculosis , and Candida albicans ( 26 – 28 ). However, it has also been reported that the macrophage ETs (METs) induced by Mycobacterium massiliense do not have bactericidal activity and instead provide a favorable environment for bacterial aggregation and promote bacterial growth ( 29 ).…”

The effectivity of probiotic containing Bacillus spp. applicated in the rearing of mud crab Scylla tranquebarica larvae to produce crablet

“…One of the several techniques for the prevention of developing pathogenic bacteria is using the probiotic application [6][7][8][9][10]. Specifically for two species, B. licheniformis and B. subtilis, the Grampositive Bacillus bacteria are utilized as probiotics [11]. Bacteriocins, lysozyme, proteases, siderophores, hydrogen peroxide, and organic acids are just a few examples of the anti-bacterial substances that probiotic bacteria can produce [12] as well as an immune response, antimutagenic, anticarcinogenic, growth-inducing compounds [13], which can be added to cultured larvae to complement feed sources or aid in food digestion and decrease the number of harmful microorganisms in the culture tank.…”