Modern medicine increasingly faces challenges that force us to reconsider established treatment methods. One of the most pressing is the rapid growth of antibiotic resistance, especially among opportunistic pathogens. One such pathogen is Enterococcus faecalis , a bacterium capable of rapidly changing its behavior from a benign inhabitant of the intestines to an aggressive pathogen that causes severe diseases.

Enterococcus faecalis: a familiar inhabitant or a potential threat?

Enterococcus faecalis is a gram-positive, spherical bacterium that is typically part of the normal microflora of the human gastrointestinal tract. However, under certain circumstances, this microorganism can become a real health threat. This is especially true for people with weakened immune systems, chronic diseases, or those undergoing invasive medical procedures.

Most commonly, Enterococcus faecalis causes:

• Urinary tract infections (cystitis, pyelonephritis);

• Endocarditis is an inflammation of the inner lining of the heart;

• Wound infections;

• Intra-abdominal infections;

• Sepsis is a life-threatening condition of systemic inflammation.

The problem is compounded by the fact that the bacteria is easily transmitted in hospital settings. It is particularly common in catheterized patients or after prolonged antibiotic treatment. Infection can occur through contaminated medical instruments, staff hands, and the fecal-oral route due to poor hygiene.

Why is Enterococcus faecalis so difficult to treat?

In recent years, bacteria have developed widespread resistance to antibiotics. Specifically, this includes resistance to:

• penicillins;

• vancomycin ( VRE — vancomycin-resistant enterococci);

• aminoglycosides;

• cephalosporins.

Resistant strains often cause relapses, complications, and can lead to prolonged hospitalizations. Worse still, treatment options are becoming increasingly limited, forcing doctors to use toxic antibiotics or combinations of them, which can affect liver and kidney function and significantly impair patients' quality of life.

Bacteriophages: Our Allies in the Fight Against Enterococcus faecalis

In clinical practice, phage therapy against infections caused by Enterococcus faecalis is used depending on the type of lesion:

• For urinary tract infections (such as chronic cystitis or urethritis), phages are injected through a catheter directly into the affected area, ensuring direct contact with bacteria and highly effective cleansing.

• For enterocolitis or dysbiosis caused by Enterococcus faecalis, oral bacteriophages are prescribed in the form of liquid solutions or capsules. Phages pass through the gastrointestinal tract and specifically attack pathogens without harming beneficial flora.

• For wound infections or post-operative lesions, phage preparations are used locally - in the form of gels, ointments or impregnated dressings that are applied directly to the affected area.

• For the treatment of gynecological infections, including bacterial vaginosis associated with enterococci, intravaginal administration of solutions or swabs with phages is used.

• In case of systemic complications such as sepsis or endocarditis, intravenous administration of phages may be possible according to individual protocols, especially in the context of clinical trials or in complex cases of multidrug-resistant forms.

Before starting therapy, laboratory diagnostics are performed to identify the Enterococcus faecalis strain and test its sensitivity to specific phages. In some situations, customized phage cocktails—mixtures of several bacteriophages—are created to maximize pathogen coverage and reduce the risk of resistance development.

Unlike antibiotics, phages do not cause allergies, do not suppress beneficial bacteria, and do not harm the liver or kidneys. Furthermore, when bacteria develop resistance, phages can evolve alongside them—unlike chemical drugs.

Phage therapy studies against Enterococcus faecalis

Global and Ukrainian research shows that phage therapy can be effective even in cases where traditional antibiotics prove ineffective.

• Successful treatment of diabetic foot infected with multidrug-resistant bacterial strains, including Enterococcus faecalis.
  https://bacteriophages.info/ua/4doctors/klinichniy-vipadok-fagoterapiya-infikovanoi-diabetichnoi-stopi/

• Bacteriophages in the Treatment of Alcoholic Liver Disease: This study examines the role of E. faecalis, specifically cytolysin-producing strains, in the development of alcoholic liver disease. Experiments in mice have shown that phage therapy may be effective in reducing liver damage caused by these strains.
  https://bacteriophages.info/ua/news/bakteriofagi-v-likuvanni-alkogolnoi-hvorobi-pechinki/

• A clinical case of chronic bacterial prostatitis treated with multidrug-resistant strains, including E. faecalis. The patient underwent several courses of phage therapy, which resulted in significant improvement.
  https://bacteriophages.info/ua/news/fagoterapiya-bacterialnogo-prostatitu/

• A combination of phages and antibiotics: synergy between bacteriophages and antibiotics in the fight against E. faecalis is being explored . Specifically, mutations in the epaR gene can reduce the bacteria's susceptibility to phages while simultaneously increasing its susceptibility to certain antibiotics, such as daptomycin.
  https://bacteriophages.info/ua/news/kombinatsiya-fagiv-i-antibiotikiv-yaki-perevagi/

• The study assessed the efficacy of phage preparations against clinical isolates of E. faecalis. The results demonstrated specific activity of these preparations against enterococci.
  https://bacteriophages.info/ua/news/vivchennya-chutlivosti-klinichnih-shtamiv-spektru-umovno-patogennih-ta-patogennih-mikroorganizmiv-do-preparativ-na-osnovi-bakteriofagiv/

• A case of phage therapy in a sea turtle with an E. faecalis infection is described . Treatment resulted in symptom relief and a reduction in the bacterial load.
  https://bacteriophages.info/ua/news/fagoterapiya-ryatue-ridkisnih-tvarin/

Despite the aggressive nature of Enterococcus faecalis and its ability to rapidly develop resistance, phage therapy opens a new dimension in the treatment of such infections. Thanks to their precision, safety, and flexibility, bacteriophages are becoming not only an alternative but also a strategic tool for the medicine of the future. Real-life patient stories demonstrate that phages work, often where other methods fail.