Epidemiologic typing of international collections of Klebsiella spp.: computerized biochemical fingerprinting compared with serotyping, phage typing and pulsed-field gel electrophoresis.

Objective: The Phene Plate (PhP) biochemical fingerprinting system is based on measurements of the kinetics of selected biochemical reactions performed in microtiter plates, and computerized data-processing. This study compared the performance of the PhP system as an epidemiologic tool with other commonly used typing systems.

Methods: PhP typing was applied to 107 nosocomial Klebsiella spp. isolates from 10 collections, mostly representing outbreaks. The results were compared with those obtained by capsular (K) serotyping, phage typing and, for a subset of isolates (n=33), pulsed-field gel electrophoresis (PFGE).

Results: Clusters of identical or closely related isolates based on serotype, phage type, PhP type and PFGE type were found in most collections. The typeability was 100%, 95%, 94% and 68% for PhP, K, PFGE and phage typing, respectively. The agreement between the typing methods was high (88-96%). The discriminatory power was high for PhP and PFGE (diversity index 0.95 and 0.97, respectively), but lower for phage typing (diversity index 0.91) and K typing (diversity index 0.87).

Conclusions: Like serotyping and PFGE, PhP typing is useful in studies of the nosocomial epidemiology of Klebsiella spp. Combining PhP typing with PFGE or K typing rarely yielded additional information when comparing isolates within each collection, but PFGE sometimes discriminated between isolates of similar PhP type derived from different collections.