MOLECULAR TYPING OF KLEBSIELLA-PNEUMONIAE ISOLATES FROM A NEONATAL INTENSIVE-CARE UNIT

The epidemiological features of 60 multiresistant K. pneumoniae strain s isolated from 1991 to 1995 in a neonatal ward are described. Antibio tic susceptibility testing and plasmid profile analysis were used as s ubtyping procedures. Antibiotic susceptibility typing was not informat ive enough since discrimination among isolates was typically poor. Pla smid profile analysis demonstrated that 58 out of 60 strains harboured one or more plasmid DNA bands, of different molecular weights ranging between 1.8 and 150 Mda. Small plasmids were best visualized after th e alkaline lysis procedure, while large plasmids by the Kado and Liu m ethod. A combination of plasmid patterns obtained by the two extractio n procedures was used to define the final plasmid profile for each str ain. Thirteen different plasmid profiles were identified among the col lection of K. pneumoniae isolates from newborn patients of the same in tensive care unit. The investigation showed that the strains were not responsible for a single outbreak.