Nutrient availability and biofilm polysaccharide shape the bacillaene-dependent antagonism of Bacillus subtilis against Salmonella Typhimurium

Podnar, Eli (author), Erega, Andi (author), Danevčič, Tjaša (author), Kovačec, Eva (author), Lories, Bram (author), Steenackers, Hans (author), Mandić-Mulec, Ines (author)

Salmonella enterica is one of the most common foodborne pathogens and, due to the spread of antibiotic resistance, new antimicrobial strategies are urgently needed to control it. In this study, we explored the probiotic potential of Bacillus subtilis PS-216 and elucidated the mechanisms that underlie the interactions between this soil isolate and the model pathogenic strain S. Typhimurium SL1344. The results reveal that B. subtilis PS-216 inhibits the growth and biofilm formation of S. Typhimurium through the production of the pks cluster-dependent polyketide bacillaene. The presence of S. Typhimurium enhanced the activity of the P$_{pksC}$ promoter that controls bacillaene production, suggesting that B. subtilis senses and responds to Salmonella. The level of Salmonella inhibition, overall P$_{pksC}$ activity, and P$_{pksC}$ induction by Salmonella were all higher in nutrient-rich conditions than in nutrient-depleted conditions. Although eliminating the extracellular polysaccharide production of B. subtilis via deletion of the epsA-O operon had no significant effect on inhibitory activity against Salmonella in nutrient-rich conditions, this deletion mutant showed an enhanced antagonism against Salmonella in nutrient-depleted conditions, revealing an intricate relationship between exopolysaccharide production, nutrient availability, and bacillaene synthesis. Overall, this work provides evidence on the regulatory role of nutrient availability, sensing of the competitor, and EpsA-O polysaccharide in the social outcome of bacillaene-dependent competition between B. subtilis and S. Typhimurium.

• Language: English
• Keywords: Bacillus subtilis, Salmonella enterica, probiotics, enteric pathogen, biofilm, polysaccharides, microbial competition, nutrients
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 14 str.
• Numbering: Vol. 10, iss. 6
• PID: 20.500.12556/RUL-153973
• UDC: 579.22/.26
• ISSN on article: 2165-0497
• DOI: 10.1128/spectrum.01836-22
• COBISS.SI-ID: 128780803
• Publication date in RUL: 17.01.2024

Record is a part of a journal

• Title: Microbiology spectrum
• Shortened title: Microbiol. spectr.
• Publisher: ASM Press
• ISSN: 2165-0497
• COBISS.SI-ID: 4526968

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: probiotiki, socialne interakcije, patogeni mikroorganizmi, biofilm