APPLICATION OF DNA PROBES TO ANALYSIS OF BACTERIOPHAGE DISTRIBUTION PATTERNS IN THE ENVIRONMENT

Radiolabeled bacteriophage DNA probes have been used in this study to determine the distribution of Pseudomonas aeruginosa-infecting bacteriophages in natural samples of lake water, sediment, soil, and sewage. The sensitivity of detection of bacteriophage with the DNA probes was between 10(3) and 10(4) PFU and 10(6) to 10(7) CFU of lysogenized bacteria detectable with a homologous phage DNA probe. Analyses of environmental samples suggest that up to 40% of P. aeruginosa in natural ecosystems contain DNA sequences homologous to phage genomes. By using different bacteriophage DNA probes, the diversity of the bacteriophage population in sewage was estimated to be higher than that in other natural samples. The indication that transducing phages and prophages are widely distributed in the Pseudomonas populations investigated has considerable implications for the frequency of natural gene transfer by transduction and of lysogenic conversion of host bacteria in natural ecosystems.