Development of Burkholderia Cepacia Complex Targeted Clinical Registry and Phage Library

PurposeBurkholderia cepacia complex (BCC) are uncommon pathogens but associated with high morbidity/ mortality. Antibiotics are limited and phage therapy is being explored as a potential alternative. Our goal was to develop a phage library to target clinical BCC isolates for use in compassionate use protocols and clinical trials.MethodsWe developed an international, multicenter registry in which BCC-infected persons with CF were identified and entered into a coded dataset. Clinical isolates from patients (US, Canada) were sent to a central repository (JL, where bacteria were genotyped and stored) and then sent to a research laboratory (RH, where phage hunt was performed). Traditional methods of phage discovery were utilized to identify lytic phages. Phage characterization included determination of lytic activity, whole-genome sequencing, and host range determination. In addition to registry patients, additional BCC laboratory isolates were collected to assess phage coverage.ResultsFrom 7/1/2020- 9/30/2022, 56 patients were enrolled with baseline details noted in Table 1. BCC isolates consisted of B. cepacia (4), B. cenocepacia (14), B. multivorans (14), B. vietnamiensis (3), B. dolosa (3), B. gladioli (14), B. stabilis (1) and other (3). Additional 44 BCC laboratory isolates were added for total 100 BCC isolates. We identified 19 unique phages that were active against 80% of 35 tested isolates (work is ongoing) as noted in Table 2. Among these, 3 phages were active against 50% of the isolates. Among 6 patients that initiated compassionate use evaluation, phage(s) were found for 5. One patient was treated with phage prior to registry entry, two are awaiting clinical use, and two expired prior to phage use. Genetic sequencing of phages and phage-antibiotic synergy testing is ongoing.ConclusionWe developed a multicenter registry of BCC-infected patients and used clinical isolates to develop a targeted lytic phage library of 19 phages that covered 80% of isolates. Burkholderia cepacia complex (BCC) are uncommon pathogens but associated with high morbidity/ mortality. Antibiotics are limited and phage therapy is being explored as a potential alternative. Our goal was to develop a phage library to target clinical BCC isolates for use in compassionate use protocols and clinical trials. We developed an international, multicenter registry in which BCC-infected persons with CF were identified and entered into a coded dataset. Clinical isolates from patients (US, Canada) were sent to a central repository (JL, where bacteria were genotyped and stored) and then sent to a research laboratory (RH, where phage hunt was performed). Traditional methods of phage discovery were utilized to identify lytic phages. Phage characterization included determination of lytic activity, whole-genome sequencing, and host range determination. In addition to registry patients, additional BCC laboratory isolates were collected to assess phage coverage. From 7/1/2020- 9/30/2022, 56 patients were enrolled with baseline details noted in Table 1. BCC isolates consisted of B. cepacia (4), B. cenocepacia (14), B. multivorans (14), B. vietnamiensis (3), B. dolosa (3), B. gladioli (14), B. stabilis (1) and other (3). Additional 44 BCC laboratory isolates were added for total 100 BCC isolates. We identified 19 unique phages that were active against 80% of 35 tested isolates (work is ongoing) as noted in Table 2. Among these, 3 phages were active against 50% of the isolates. Among 6 patients that initiated compassionate use evaluation, phage(s) were found for 5. One patient was treated with phage prior to registry entry, two are awaiting clinical use, and two expired prior to phage use. Genetic sequencing of phages and phage-antibiotic synergy testing is ongoing. We developed a multicenter registry of BCC-infected patients and used clinical isolates to develop a targeted lytic phage library of 19 phages that covered 80% of isolates.