Prevalence of an Intestinal ST40 Enterococcus faecalis over Other E. faecalis Strains in the Gut Environment of Mice Fed Different High Fat Diets

Abstract

E. faecalis is a commensal bacterium with specific strains involved in opportunistic and nosocomial infections. Therefore, it is important to know how the strains of this species are selected in the gut. In this study, fifteen E. faecalis strains, isolated over twelve weeks from the faeces of mice fed standard chow or one of three high fat diets enriched with extra virgin olive oil, refined olive oil or butter were subjected to a genetic “Multilocus Sequence Typing” study that revealed the presence of mainly two genotypes, ST9 and ST40, the latter one prevailing at the end of the research. A V3–V5 sequence comparison of the predominant ST40 strain (12B3-5) in a metagenomic study showed that this sequence was the only E. faecalis present in the mouse cohort after twelve weeks. The strain was subjected to a comparative proteomic study with a ST9 strain by 2D electrophoresis and mass spectrometry. After comparing the results with a E. faecalis database, unshared entries were compared and 12B3-5 showed higher antimicrobial production as well as greater protection from environmental factors such as xenobiotics, oxidative stress and metabolite accumulation, which could be the reason for its ability to outcompete other possible rivals in an intestinal niche.

High fat diets induce early changes in gut microbiota that may serve as markers of ulterior altered physiological and biochemical parameters related to metabolic syndrome. Effect of virgin olive oil in comparison to butter

“…However, these two families did not show differences at six weeks yet. This could indicate that the bacterial adaptation to EVOO is not immediate, as we could also observe in a previous work on the fat-resilience of intestinal strains isolated from hosts fed different diets [21,22].…”

“…The results demonstrated a direct correlation between several variables involved in metabolic syndrome (insulin, diuresis, blood pressure, body weight) measured at 12 weeks, with bacterial taxa that at that time point were significantly increased under a butter enriched diet (BT) and decreased with an EVOO enriched diet [ 19 ]. The influence of these types of fat on the microbiota was also confirmed by culture-dependent methods, when a collection of enterococcal strains was isolated from faeces of mice after the diet intervention [ 21 , 22 ].…”

Intestinal microbiota modulation at the strain level by the olive oil polyphenols in the diet

“…If we add to this that these same EVOO strains have less resistance to antibiotics, a lower tendency to present virulence factors and that they do not participate in the dynamics of the other isolates to produce more biogenic amines over time, we can conclude that we are probably detecting a clear case of modulation of beneficial intestinal strains by diet. It is important to highlight that we are not talking about different genera, or sometimes not even different species ( 34 ) but about a much more subtle balance between genetically very close strains that, however, can make a difference in the health and the well-being of the host.…”

Study on the Mechanism of Lactobacillus Rhamnosus Probio-M9 Combined With Antibiotics on Staphylococcus Aureus Mastitis in Rat

“…Enterococcus is widely found in nature and is a normal ora in the intestinal tract of humans and animals. Enterococcus, as an important pathogen, can cause urinary tract infections, skin and soft tissue infections, and more serious abdominal infections, sepsis, meningitis and other diseases (Sánchez et al 2020). Escherichia coli, widely exists in the intestinal tract of humans and animals.…”