Staphylococcus aureus undergoes major transcriptional reorganization during growth with Enterococcus faecalis in milk. (August 2018)

• Record Type: Journal Article
• Authors: Viçosa, Gabriela Nogueira; Botta, Cristian; Ferrocino, Ilario; Bertolino, Marta; Ventura, Marco; Nero, Luís Augusto; Cocolin, Luca
• Is Part Of: Food microbiology. Volume 73(2018)
• Page Start: 17
• Page End: 28
• Publication Date: 2018-08
• Subjects: Staphylococcus aureus -- Enterococcus faecalis -- RNA sequencing -- Co-culture -- Skimmed milk; Food Microbiology -- Periodicals; Aliments -- Microbiologie -- Périodiques; Food -- Microbiology; Periodicals; Food -- Microbiology -- Periodicals; Food contamination -- Periodicals; 664.001579
• DOI: 10.1016/j.fm.2018.01.007
• Languages: English
• ISSNs: 0740-0020

Abstract

Abstract: Previous studies have demonstrated the antagonistic potential of lactic acid bacteria (LAB) present in raw milk microbiota over Staphylococcus aureus, albeit the molecular mechanisms underlying this inhibitory effect are not fully understood. In this study, we compared the behavior of S. aureus ATCC 29213 alone and in the presence of a cheese-isolated LAB strain, Enterococcus faecalis 41FL1 in skimmed milk at 30 °C for 24 h using phenotypical and molecular approaches. Phenotypic analysis showed the absence of classical staphylococcal enterotoxins in co-culture with a 1.2-log decrease in S. aureus final population compared to single culture. Transcriptional activity of several exotoxins and global regulators, including agr, was negatively impacted in co-culture, contrasting with the accumulation of transcripts coding for surface proteins. After 24 h, the number of transcripts coding for several metabolite responsive elements, as well as enzymes involved in glycolysis and acetoin metabolism was increased in co-culture. The present study discusses the complexity of the transcriptomic mechanisms possibly leading to S. aureus attenuated virulence in the presence of E. faecalis and provides insights into this interspecies interaction in a simulated food context. Highlights: S. aureus grew less in co-culture with E. faecalis compared to single culture. Staphylococcal enterotoxins were not detected in co-culture. S. aureus transcriptomic response in co-culture revealed significant alterations. Expression of stress and virulence related genes was the most altered in co-culture.