[Plasmid profile and toxicity of Klebsiella pneumoniae strains isolated at a neonatal department].

The authors tested the plasmid profile of 11 and the toxicity of 16 strains of K. pneumoniae isolated in a neonatal department. Based on examination of the plasmid profile it may be assumed that very probably a nosocomial spread of the strains was involved. This is suggested by the identical plasmid profile of all strains isolated in the environment and five strains isolated from neonates. On investigation of the enterotoxicity of culture filtrates of the investigated strains the authors did not reveal the presence of a thermolabile or thermostable enterotoxin. In the skin test on rabbits 93.8% of the tested samples were positive. Morphological changes on Vero cells after 48 hours action were produced by four culture filtrates. Only two strains caused haemolysis of agar with 6% sheep and rabbit blood after incubation at 37 degrees C. Another 14 strains caused lightening of the agar with rabbit blood after subsequent incubation at 4 degrees C.