SUBTYPING OF KLEBSIELLA BY BIOCHEMICAL FINGERPRINTING - A SIMPLE SYSTEM FOR EPIDEMIOLOGIC INVESTIGATIONS

Klebsiella and Enterobacter spp. are important nosocomial pathogens and may cause severe infections in neonates and in adult hospitalized patients. In nosocomial and other epidemiological investigations, simple methods for typing strains of these species are needed. A method for sybtyping strains belonging to Klebsiella and Enterobacter spp. was developed and evaluated. The method is based on the measurements of the kinetics of 32 selected metabolic reactions, performed in microtiter plates. Optical readings of reactions are directly transferred to a microcomputer which automatically calculates the similarities among all tested strains, clusters these data and finally prints out a list of phenotypes and a dendrogram. The method was compared to capsular antigen typing on 79 epidemiologically unrelated Klebsiella blood isolates. The present biochemical fingeprinting method yielded 100% typability whereas 90% of the isolates could be K typed. Also the number of distinct types was higher (62 biochemical phenotypes vs. 36 K types). This method for biochemical fingerprinting is reproducible, highly discriminating and very simple to use. It is therefore suitable for epidemiological and ecological investigations and may also be used for studies involving large numbers of isolates. © 1990.