New waterborne bacteriophages active on Yersinia enterocolitica.

Seven bacteriophages active on Yersinia enterocolitica (YE) were isolated from surface water samples collected in Granada, Spain. A comparison of the respective host ranges of these new phages and of reference phages used for YE phage typing showed that YE strains belonging to various phage types, grown at either 37 or 25 degrees C, expressed susceptibility to reference sewage water phages whereas susceptibility to new waterborne phages, as well as to reference phages from lysogenic YE, was only demonstrated in YE strains grown at 25 degrees C. A YE strain isolated by stool culture from a pig was lysogenic for a bacteriophage which behaved like waterborne phages and reference phages from lysogenic YE strains. The possibility that the isolation of waterborne bacteriophages might, in certain circumstances, reflect the presence of lysogenic YE was raised.