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

Popular posts from this blog

Dementia Research

Disclaimer: I am not a doctor so I cannot diagnose or offer treatments, I am sharing this information that is considered educational. Much of the research on dementia/Alzheimer's is centered on what is referred to as Tight Junction Proteins. These are proteins that act like clamps that hold tissues together in terms of neurological, these "clamps" hold the blood vessels together. And when the tight junction proteins become damaged, the blood vessels begin to "leak".  Science refers the tight junction proteins as barrier as in the blood brain barrier. They will also refer to as barrier integrity. AI says this:  Tight junction proteins are vital for various physiological processes, including the formation of barriers in the brain (blood-brain barrier), intestines, and other tissues. They also play a role in disease mechanisms when their function is disrupted. The barrier function occurs in the blood vessels, and they think that when they leak, this is affecting co...

Microbiome SCFAs & AutoImmunity

  Does SCFA impact immune and inflammatory pathways? Show thinking Yes, absolutely! Short-Chain Fatty Acids (SCFAs) are major players in controlling immune and inflammatory pathways, both within the gut and systemically. This is one of the most significant and exciting areas of research on SCFAs. Here's how they exert their control: Interaction with G-Protein Coupled Receptors (GPCRs): GPR41 and GPR43: These are the most well-studied SCFA receptors, found on various cell types throughout the body, including immune cells (e.g., neutrophils, macrophages, T cells), gut epithelial cells, and adipocytes. When SCFAs (particularly acetate, propionate, and butyrate) bind to these receptors, they trigger intracellular signaling pathways that can influence immune cell function, cytokine production, and inflammatory responses. Histone Deacetylase (HDAC) Inhibition: Butyrate (and to a lesser extent propionate) are potent inhibitors of HDACs. HDACs are enzymes that modify histones, proteins aro...
You can buy most of this at Kroger's, I listed the pictures below. The idea is that you are targeting the gut, the microbiome to be exact. I am not going to list out all the studies but they have discovered that the right bacteria in the gut can change a lot of things including metabolic, neurological, immune responses, weight gain and many other things.  Increasing the good bacteria such as bifidobacteria etc. can also suppress the bad bacteria which have been linked to numerous problems.  There are products that you can buy on Amazon and these will also support the microbiome by giving the nutrients they need.  Kroger's has the ones in the pictures below, you will find the Cleveland Kraut in the refrigerated section and so is the Kefir. Both of these are live foods meaning they contain the good bacteria. Sauerkraut as canned does not work since there are no live organisms.  You will have to experiment with the doses; I do a couple of tablespoons of the kraut and ju...