Combined bacteriophage and antibiotic therapy for refractory peritoneal dialysis-related peritonitis caused by Klebsiella pneumoniae

Phage therapy is emerging as a promising alternative to antibiotics for treating various infections. However, there have been no prior studies on using bacteriophages for peritonitis in patients undergoing peritoneal dialysis. This report presents the successful treatment of refractory peritonitis in a 71-year-old male peritoneal dialysis patient using bacteriophages combined with antibiotics. The patient has a history of refractory and repeat peritonitis caused by Staphylococcus haemolyticus, which was resolved through simultaneous catheter replacement (SCR). Subsequently, the patient experiences another episode of refractory peritonitis due to Klebsiella pneumoniae. Although this strain is found to be susceptible to amikacin and imipenem, a 14-day course of treatment with these antibiotics in the abdominal cavity fails to resolve the peritonitis. Combined with antibiotic therapy, the patient is successfully treated with intraperitoneal phage therapy targeting his bacterial isolate. We monitor the longitudinal progression of phage loads, phage-neutralizing antibodies, interleukin-6 levels, and lipopolysaccharide concentrations in the dialysate effluent during the bacteriophage therapy. The combination of a phage cocktail and imipenem (IPM) demonstrates a greater effect in killing bacteria than either treatment alone, which indicates that a synergistic effect exists between the phage cocktail and IPM. Intraperitoneal IPM is discontinued after a 3-week course of treatment. At the same time, oral fluconazole is given to prevent fungal infections. The patient is discharged without any antibiotics. After this round of treatment, the patient remains healthy during the one-month follow-up. Our study suggests that personalized phage therapy combined with sensitive antibiotics can play a significant role in managing refractory peritonitis in patients undergoing peritoneal dialysis, showing promise for future applications.