Skip to main content

Antibacterial Activity of Unconjugated and Conjugated Bile Salts on Staphylococcus aureus

 Thippeswamy H. Sannasiddappa1*†, Peter A. Lund2 and Simon R. Clarke1*

  • 1School of Biological Sciences, University of Reading, Reading, United Kingdom
  • 2Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom

Bile salts are potent antimicrobial agents and are an important component of innate defenses in the intestine, giving protection against invasive organisms. They play an important role in determining microbial ecology of the intestine and alterations in their levels can lead to increased colonization by pathogens. We have previously demonstrated survival of the opportunistic pathogen Staphylococcus aureus in the human colonic model. Thus investigating the interaction between S. aureus and bile salts is an important factor in understanding its ability to colonize in the host intestine. Harnessing bile salts may also give a new avenue to explore in the development of therapeutic strategies to control drug resistant bacteria. Despite this importance, the antibacterial activity of bile salts on S. aureus is poorly understood. In this study, we investigated the antibacterial effects of the major unconjugated and conjugated bile salts on S. aureus. Several concentration-dependent antibacterial mechanisms were found. Unconjugated bile salts at their minimum inhibitory concentration (cholic and deoxycholic acid at 20 and 1 mM, respectively) killed S. aureus, and this was associated with increased membrane disruption and leakage of cellular contents. Unconjugated bile salts (cholic and deoxycholic acid at 8 and 0.4 mM, respectively) and conjugated bile salts (glycocholic and taurocholic acid at 20 mM) at their sub inhibitory concentrations were still able to inhibit growth through disruption of the proton motive force and increased membrane permeability. We also demonstrated that unconjugated bile salts possess more potent antibacterial action on S. aureus than conjugated bile salts.


Read more

Comments

Post a Comment

Popular posts from this blog

Patrick Gut Environment

\ Keywords to use in further research, GALT, tight junction proteins, Mucin layer, microbiome in MECFS or Long Covid, Goblet cells.   It was great chatting with you the other day. I’ve put together this general overview, but as I mentioned, you’ll definitely want to do your own deeper research. This is a very complex, interactive environment, and you’ll naturally come across many different opinions about what’s happening. Most opinions tend to focus on single layers, but as I’ve discovered, these layers are highly interconnected and influence one another. I don’t want to oversimplify things, nor do I want to overcomplicate them. It takes time to truly understand the gut environment in its proper context. I’m also cautious about saying “do X and you’ll get Y,” because results are rarely that straightforward. When I introduce layered therapies, I look for subtle changes across a list of markers I track. That’s why I believe this should be approached with care and patience—though I’m ...
Post a Comment
Read more

Gut environment

 OK let's go back over the scenario Somebody gets a gut bug that could be viral or bacterial and we're going to put in the context of either long COVID or MECFS Let's discuss what exactly happens of how the body begins to adapt to this insult p — let’s build this cleanly, structurally, and without drama. This is the core terrain‑mechanics model of what happens when someone gets a gut bug (viral or bacterial) and then develops a long‑tail condition like long COVID or ME/CFS . This is the architecture that explains why the system never fully resets . I’ll walk you through it in chronological order , layer by layer, so you can see exactly how the body adapts — and why those adaptations become the trap. ⭐ 1. The Initial Insult Terrain layer: immune activation, epithelial irritation, redox stress A viral or bacterial gut infection does three things immediately: damages epithelial cells strips mucin spikes inflammatory cytokines This creates: redox collapse increased permeabil...
Post a Comment
Read more

Paneth Cells - guardians of the intestinal tract

  Click for the AI slideshow: https://sl.bing.net/hBioK3sTdDw From Google Gemini: Paneth Cells: The Guardians of the Gut Paneth cells are specialized epithelial cells found at the base of the intestinal crypts (small invaginations in the intestinal lining). They play a crucial role in maintaining the gut's health by acting as a first line of defense against harmful microorganisms. Key Functions: Antimicrobial Defense: Paneth cells produce and secrete a variety of antimicrobial peptides and proteins, such as lysozyme, defensins, and phospholipase A2. These substances help to kill bacteria, fungi, and other pathogens that may invade the intestinal tract. Regeneration of Intestinal Epithelium: Paneth cells contribute to the maintenance and regeneration of the intestinal lining by supporting the stem cells located nearby. Immune Regulation: These cells participate in regulating the immune response within the gut, helping to balance the body's reaction to both beneficial and ha...
Post a Comment
Read more