Evaluation of a bacteriophage-typing scheme for Enterobacter cloacae.

A set of 25 Enterobacter cloacae typing phages was evaluated. Of 384 test strains, 93.8% were lysed by at least one phage; the mean number of reactions/strain was 7.3. Discrimination between strains was satisfactory within the most frequent O serotypes; 0.9 patterns/strain were found for strains of serotypes O3 and O8. Overall, 325 patterns were found. Phage patterns were completely reproducible when duplicates of strains were typed on the same day, but only 40% reproducible when repeated after 18 months. The combination of O serology and phage typing discriminated well between hospital isolates.