Comparison of bacteriophage typing, serotyping, and biotyping as aids in epidemiological surveillance of Klebsiella infections.

Bacteriophage typing was used to subdivide Klebsiella obtained from patients in a surgical intensive care unit during a 2-year period. The 15 phages employed to type the strains were propagated by a soft-agar layer technique. In all, 23 phage types were found among the 120 clinical strains. The phage types of repeat isolates were reproducible. Only 70% of the strains tested were phage typable, but when used in conjunction with capsular serotyping and biotyping, a much greater subdivision of the Klebsiella strains was achieved. The addition of phage typing to serobiotyping for epidemiological analysis suggested that the number of cross-infecting Klebsiella strains in the intensive care unit was few, but that these strains persisted in the unit for long periods of time and could infect different body sites.