Brieuc Van Nieuwenhuyse1, Dimitri Van der Linden1,2, Olga Chatzis2, Cédric Lood3,4, Jeroen Wagemans3, Rob Lavigne4, Catherine de Magnée5, Étienne Sokal1,6, Hector Rodriguez-Villalobos7, Sarah Djebara8, Maya Merabishvili9, Patrick Soentjens8, Jean-Paul Pirnay9. 1Institute of Experimental and Clinical Research's Pediatric department, UCLouvain, Brussels, Belgium; 2Pediatric Infectious Diseases, General Pediatrics Department, Cliniques universitaires Saint-Luc, Brussels, Belgium; 3Department of Biosystems, Laboratory of Gene Technology, KULeuven, Leuven, Belgium; 4Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics, KULeuven, Leuven, Belgium; 5Pediatric and Transplantation Surgery, Cliniques universitaires Saint-Luc, Brussels, Belgium; 6Pediatric Hepatology and Gastro-enterology, Cliniques universitaires Saint-Luc, Brussels, Belgium; 7Department of Microbiology, Cliniques universitaires Saint-Luc, Brussels, Belgium; 8Center for Infectious Diseases, Queen Astrid Military Hospital, Brussels, Belgium; 9Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Brussels, Belgium A 14-month old boy undergoes a first liver transplantation (LT) (Day 0), from an ABO-incompatible living donor. On D+20, we detect a fecal carriage of an extensively drug-resistant (XDR) Pseudomonas aeruginosa (Pa) strain. Besides intermediate susceptibility to aztreonam and colistin and susceptibility to gentamycin, the strain is resistant to all other antibiotics. On D+53, the child enters a severe septic state due to a bacteremia with the same Pa strain. New antibiogram suggests a resistance to colistin. Liver bilomas' drainage material is cultured and grows the same Pa strain. Admission to the pediatric intensive care unit and adjunction of intravenous (IV) aztreonam, gentamycin, and colistin led to no improvement on the microbiological or clinical levels during the next four days. By collaborating with Queen Astrid Military Hospital (Brussels, Belgium), we initiated phage therapy (PT) on D+57 in accordance to the Article 37 of the Declaration of Helsinki and with the patient's parents' consent. PT is the use of lytic bacteriophage viruses to achieve antibacterial effect. Phage cocktail BFC1 contains two anti-Pa phages (PNM and 14/1) and one anti-Staphylococcus aureus phage (ISP). BFC1 was administered in situ by instillations through biliary catheter during six days, and in IV for 86 days (72 days until 2nd LT, 14 days afterwards), the longest described duration for IV PT in a child. Previous antibiotic therapy was pursued all along. Intraoperative PT was performed during 2nd LT by bathing the peritoneal cavity in phage solution during the anhepatic phase. To further our understanding of the case, seven Pa isolates, both bloodborne and liver-borne, were sequenced. Serum samples obtained before, during, and after phage therapy were analyzed through double agar overlay method to search for phage immune neutralization (PIN). Phage-induced virulence tradeoffs (PIVT) assays were performed in a Galleria mellonella model. In vitro phage-antibiotic interactions were evaluated with OmniLog® system. PT initiation was followed by immediate (<24 h) eradication of Pa from blood cultures. Reappearance of Pa in blood cultures after four days of PT led to a doubling of the PT dose, which was followed by eradication of Pa from bloodstream until 2nd LT. The child has known no further infectious episode since then. Sequencing confirmed the emergence of bacterial phage resistance (BPR) in four isolates. Such BPR did not lead to therapeutic failure, possibly thanks to PIVT. PIN against phage ISP was detected, but not against any anti-Pa phage. OmniLog® assays suggested synergistic properties between phage PNM and three antibiotics administered concomitantly to the patient. In conclusion, prolonged IV phage therapy combined with antibiotics led to the durable eradication of an XDR Pa sepsis in an immunosuppressed 14-month old boy, eventually allowing for 2nd LT. This possibly relied on synergy between phages and antibiotics. This combined therapy was safe.
Van Nieuwenhuyse, Brieuc ; van Der Linden, Dimitri ; Chatzis, Olga ; Lood, Cedric ; Wagemans, Jeroen ; et. al. Phage therapy to allow liver transplantation in a toddler infected by an extensively drug-resistant Pseudomonas aeruginosa.International Pediatric Transplant Association (Virtual Congress, du 26/03/2022 au 29/03/2022).