Preliminary investigation of suitable bacteria strains for the detection of bacteriophages in environmental polluted surface waters.

Different host-specific bacteriophages were monitored in several water systems together with the usual faecal contamination indicator bacteria (thermotolerant coliforms). The host bacteria used for the plaque assay were E. coli K12, E. coli K12 Hfr, E. coli CHfr and S. typhimurium LT2F+. S. typhimurium LT2F+ showed significantly lower phage counts than the three E. coli strains. The phages specific for E. coli K12 (somatic phages) were in high correlation (r = 0.86, r = 0.91; P less than 0.001) with other coliphages, but not with phages specific for S. typ. LT2F+ (r = 0.33; P less than 0.05). There was an high degree of correlation among phages of E. coli K12 Hfr, E. coli C Hfr and S. typhimurium LT2F+ (pilus F-carrying bacteria) (r = 0.96, r = 0.73, r = 0.75; P less than 0.001). Good correlation was seen between faecal coliforms and male-specific phages but not among faecal coliforms and E. coli K12-specific phages (r = 0.30; P less than 0.05). The relative suitability of host strains when using phages in the evaluation of faecal and viral pollution of aquatic environments is discussed.