Enterococcus as probiotics: what is the advantage?

Abstract

Enterococcus is a genus of lactic acid bacteria which normally colonize the intestines of mammals including humans [1]. Enterococci are among the first bacterial colonizers after birth and are able to proliferate in both the large and the small intestine. Enterococcus faecium and Enterococcus faecalis are the most common species of enterococcus found in human feces. However, enterococci can also cause serious infection including sepsis, pneumonia, ophthalmitis, nephritis and osteomyelitis, mainly as complications of various chronic conditions associated with intestinal dysbiosis such as cancer, AIDS or chronic renal failure [2]. Most clinical strains of enterococci belong to the two species E. faecium and E. faecalis, with vancomycin-resistant enterococcal strains (VRE) being the most common cause of lethal infection. Several virulence genes have been discovered in enterococci, allowing the identification of potentially hazardous strains [3]. At the same time, enterococci have a long history, being used as starters for making fermented food products from meat, milk or vegetables [4]. Many enterococcal strains (SF68, M74, LX, etc.) from that group of probiotic strains have been used for a long time as clinically effective probiotics. The current paper summarizes the probiotic effects of one Enterococcus faecium strain—E. faecium L3. This strain was originally isolated from starter culture used in the Russian food industry. The strain was fully characterized microbiologically and genetically and tested for the absence of virulence genes, safety in laboratory animals and it immunomodulatory features. E. faecium L3 has been used in Russia in several probiotic products such as Laminolakt and Bakfir for the last 20 years. The benefits of the strain have been shown in several randomized clinical studies, including some where it was used for the treatment of gastrointestinal diseases such as chronic gastritis, gastric ulcers, irritable bowel syndrome, pancreatitis and chronic hepatitis [5– 7]. In addition to other clinical effects such as anti-cancer properties, a significant cholesterol-lowering activity was also shown [8].