Simultaneous detection of somatic and F-specific coliphages in different settings by Escherichia coli strain CB390

Bacteriophages are increasingly being used as water quality indicators. Two groups of phages infecting Escherichia coli, somatic and F-specific coliphages, are being considered as indicators of fecal and viral contamination for several types of water around the world. However, some uncertainties remain regarding which coliphages to assess. Recently, E. coli strain CB390 has been reported to be suitable for simultaneous detection of both groups, which seems to be more informative than determining only one of the groups. Here, a significant number of samples from different settings, mostly those where F-specific phages have been reported to outnumber somatic coliphages, are analyzed for somatic coliphages, F-specific RNA phages by standardized methods and coliphages detected by host strain CB390. The results presented here confirm that the numbers of phages counted using CB390 are equivalent to the sum of the somatic and F-specific coliphages counted independently in all settings. Hence the usefulness of this strain for simultaneous detection of somatic and F-specific coliphages is confirmed. Also, sets of data on the presence of coliphages in reclaimed and groundwater are reported.