Increasing antimicrobial resistance and medical device-related infections have led to a renewed interest in phage therapy as an alternative or adjunct to conventional antimicrobials. Expanded access and compassionate use cases have risen exponentially but have varied widely in approach, methodology, clinical situations in which phage therapy might be considered, dosing, route of administration, and outcomes. Large gaps in knowledge contribute to a heterogeneity in approach and lack of clear consensus in many important clinical areas. Here, the Antibacterial Resistance Leadership Group (ARLG) has convened a panel of experts in phage therapy, clinical microbiology, infectious diseases, and pharmacology, who worked with regulatory experts and a funding agency to identify questions based on a clinical framework and divided them into three themes: potential clinical situations in which phage therapy might be considered, and laboratory testing and pharmacokinetic considerations. Suggestions are provided as answers to a series of questions intended to inform clinicians considering experimental phage therapy for patients in their clinical practices.

The therapeutic value of phage as an alternative to antibiotics for the treatment of bacterial infections is being considered in the wake of mounting antibiotic resistance. In this study, the pharmacokinetic properties of Staphylococcus aureus phage K following intravenous and intra-articular administration were investigated in a rabbit model. Using a traditional plaque assay and a novel quantitative PCR assay to measure phage levels in specimens over time, it was found that intra-articularly administered phage enters the systemic circulation; that phage may be detected in synovial fluid up to 24 h following the intra-articular, but not intravenous, administration; and that qPCR-based enumeration is generally more sensitive than plaque enumeration, with fair to moderate correlation between the two methods. Findings presented should inform the design of phage therapy experiments and therapeutic drug monitoring in preclinical and human phage studies.

A Corrigendum on Pharmacokinetic assessment of staphylococcal phage K following parenteral and intra-articular administration in rabbits