Jean-Paul Pirnay and his team from the Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Brussels, Belgium, and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Non-traditional Antibacterial Therapy (ESGNTA), Basel, Switzerland, have presented a detailed analysis of personalized bacteriophage therapy (BT) outcomes. This retrospective observational study analyzed the first 100 consecutive cases of personalized BT for difficult-to-treat infections. The cases were facilitated by a Belgian consortium across 35 hospitals, 29 cities, and 12 countries between January 1, 2008, and April 30, 2022.
In contrast to the limited success observed in randomized controlled trials with non-personalized bacteriophage products, this study highlights promising outcomes for personalized approaches. The researchers evaluated general efficacy and conducted a regression analysis to explore functional relationships. Key findings include:
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Clinical Improvement: 77.2% of infections showed clinical improvement following personalized BT.
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Bacterial Eradication: Targeted bacteria were eradicated in 61.3% of infections.
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Impact of Concomitant Antibiotics: The absence of concomitant antibiotics reduced the likelihood of bacterial eradication by 70% (odds ratio = 0.3; 95% confidence interval = 0.127–0.749).
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Resistance and Synergy: In vivo selection of bacteriophage resistance was observed in 43.8% of evaluated patients, while in vitro bacteriophage–antibiotic synergy was documented in 90% of evaluated patients.
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Antibiotic Re-sensitization and Reduced Virulence: Bacteriophage-resistant bacterial isolates exhibited antibiotic re-sensitization and reduced virulence.
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Immune Neutralization: Bacteriophage immune neutralization was observed in 38.5% of screened patients.
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Adverse Events: The study reported 15 adverse events, including seven non-serious adverse drug reactions suspected to be linked to BT.
This analysis underscores the potential of personalized BT, particularly when used in combination with antibiotics, for treating difficult-to-treat infections. While limited by the uncontrolled nature of the data, the findings provide valuable insights for the design of future controlled clinical trials.
This study contributes to the growing body of evidence supporting personalized bacteriophage therapy as a promising avenue in addressing antibiotic-resistant infections.