Isolation and characterization of soilborne virulent bacteriophages infecting the pathogen Rhodococcus equi

Aims To isolate and characterize a diversity of bacteriophages (phages) that infect the soilborne pathogen Rhodococcus equi. Methods and Results Twenty-seven phages were isolated from soil samples from geographically distinct locations using a range of R.equi bacterial strains, including clinical isolates. On the basis of host range, genomic DNA restriction profiles and virion protein profiles, the diversity of these phages was extensive, with phages being divided into 16 groupings. Conclusions Based on a range of criteria, these phages could be divided into 16 distinct groupings. The majority of the phages recovered from soil were Siphoviridae, adding to the limited number of Siphoviridae described to date for R.equi. One grouping consisted of phages belonging to the Myoviridae. Significance and Impact of the Study This represents the first study looking at the diversity of phages infecting the pathogen R.equi, including the first Myoviridae to be isolated and characterized for the genus Rhodococcus and for the nonmycobacterial actinomycetes. Given their diverse host range, including clinical isolates, this collection of phages offers the potential for the development of phage cocktails for use as a therapeutic or alternatively in the biocontrol of this pathogen in reservoirs of infection relating to animal husbandry.