[Ribosomal DNA fingerprinting analysis of Enterobacter cloacae isolated from an outbreak of nosocomial infection].

16s and 23s ribosomal DNA (rDNA) genes were amplified form E. coli, labelled with [alpha- 32P] dATP by nick translation, and applied as conserved gene probes to detecting broad-spectrum rDNA. rDNA fingerprinting analysis of Enterobacter cloacae (E. cloacae) isolated form an outbreak of nosocomial infection and other hospital environmental sources was conducted with digestion by different restrictive endonuclease, such as Hind III, EcoRI, BamHI, Bgl I, et al. Results showed rDNA fingerprinting of E. cloacae strains isolated from 10 patients with nosocomial infection was the same as that from other sources. It suggested E. cloacae causing this outbreak was originated from one genetic clone, and its source of infection was the tubes and humidifying bottles for oxygenation. rDNA fingerprinting technique is accurate, reliable, specific and repeatable, and will plays important roles in identification and classification of bacteria, tracking the source of transmission of nosocomial infection.