Matti Ylänne

Yersinia enterocolitica causes yersiniosis, the third most common gastrointestinal infection in humans throughout Europe. The emergence of multidrug resistance and the lack of effective new antibiotics have drawn attention to phage therapy as a treatment option. Here, we report the complete genome sequence of phage fMtkYen3-01, which infects Y. enterocolitica serotype O:3 strains. This phage has a genome 40,415 bp in length with 45.1% GC content and 49 predicted genes. fMtkYen3-01 infected 9.5% of the 42 Y. enterocolitica strains tested and showed stability at 25–40 °C, as well as pH 5.0–10.0. These results suggest the therapeutic potential of this phage.

Background: Intravascular stent infections are often associated with high risks of morbidity and mortality. We report here a case of a patient with an arterial stent and recurrent Pseudomonas septicaemias successfully treated with phage–meropenem combination therapy. Methods: A 75-year-old female with arteriosclerosis and comorbidities went through a femoropopliteal bypass with prosthesis in the right inguinal area. After the bypass, she developed a recurring Pseudomonas aeruginosa infection and also neutropenia during different antibiotics. A rapidly growing pseudoaneurysm in the right inguinal area led to an emergency intra-arterial stent placement during blood stream infection, later suspected to host a P. aeruginosa biofilm. Removing the stent was deemed precarious, and phage therapy was considered as a compassionate treatment option. A three-phage cocktail infecting the P. aeruginosa strain was prepared and administered intravenously together with meropenem for two weeks, after which, a ten-month follow-up was carried out. Results: No adverse reactions occurred during the phage therapy treatment, while infection markers were normalized. In addition, recovery was seen in a PET-CT scan. During the 10-month follow-up, no further P. aeruginosa septicaemias occurred. Conclusions: Phage–meropenem combination therapy was thus found safe and effective in the treatment of recurrent Pseudomonas septicaemia in a patient with an arterial stent.