DUOFAG® is a phage cocktail containing bacteriophages active against Staphylococcus aureus and Pseudomonas aeruginosa. It is an investigational medicinal product for the treatment of surgical site infections caused by S. aureus and P. aeruginosa.

The primary objective of the study is to demonstrate the safety of DUOFAG® and the clinical and microbiological change within 10 weeks after the start of treatment or until healing.

The study population will be recruited in two cohorts. The microbiological population of the wound will be evaluated to analyze the effect of the treatment. If the safety profile and treatment effect are going to be satisfactory, the recruitment will proceed with Cohort 2.

In both cohorts, the Investigational Medicinal Product (IMP) or placebo (the randomization ratio will be 1:1) will be applied twice a day for two weeks or until the commencement of healing.

Patients will receive the standard of care during the whole study duration. No concomitant treatment is planned during the treatment period.

The Adverse Events will be recorded on basis of an open interview without soliciting questions, and clinical observation. In case of occurrence of an adverse event (AE) with moderate or severe intensity possibly related to IMP, the treatment will be stopped, and the AE will be followed up until resolution.

Adverse Event descriptions, their severity (mild, moderate, or severe), duration and their perceived relationship to the study medication (probable, possible, unlikely, not related, and not sure) will be recorded.

The mLUMT (modified Leg Ulcer Measurement Tool) total score and individual item scores change since the baseline visit will be recorded.

Time from the start of the study treatment until the bacterial infection eradication - i. e. the swab sample is negative on S. aureus and/or P. aeruginosa will be recorded.

Time from the start of the study treatment until the wound is closed/healed (as assessed by investigator) will be recorded.

Inclusion Criteria:

• Patients with surgical wound infection and/or dehiscence
• Wound infected by S. aureus and/or P. aeruginosa according to wound swab.
• Wound in the groin or any other skin fold as per Investigator's discretion.
• Signed Informed Consent Form, approved by the ethical committee and competent authority.
• The age between 18 and 75 years.
• Patients able and willing to comply with study procedures.
• There are no contraindications for planned concomitant medication.
• Persisting symptoms of bacterial infection < 3 weeks since the surgery.
• Women of childbearing potential must take highly effective contraceptive measures since the study start and one month after the treatment administration at a minimum.

Exclusion Criteria:

• History of an organ or bone marrow transplantation.
• Any autoimmune disease.
• Uncompensated diabetes mellitus, confirmed by the concentration of HbA1c >60 mmol/mol (6%).
• Systematic immunosuppressive therapy.
• Malignancy treatment <1 year before the Baseline visit.
• COVID-19 infection <3 months before the Baseline visit, any signs of post-COVID syndrome.
• Pregnancy or planning to become pregnant during the study.
• Breastfeeding.
• Participation in another clinical study.
• Hypersensitivity to the IMP or placebo.