Intra-individual diversity of bacteriophage susceptibility in Burkholderia cultured from cystic fibrosis sputum

The use of bacteriophage (phage) to treat bacterial infection of airways in persons with cystic fibrosis (CF) is gaining interest. However, phenotypic diversification of bacteria during chronic airway infection presents a potential challenge to this therapy. We recovered and subcultured two or three Burkholderia colonies from each of 12 CF sputum samples. All isolates were tested for their susceptibility to a panel of 65 Burkholderia-targeting phages. We observed that 9 (75%) of the 12 colony sets comprised mixtures of isolates that were sensitive or resistant to one or more of the phages tested. The occurrence of mixed populations of phage-sensitive and phage-resistant Burkholderia in individuals with CF needs to be considered in the development of phage therapy for this patient population.