ENTEROBACTER-CLOACAE CROSS-COLONIZATION IN NEONATES DEMONSTRATED BY RIBOTYPING

The intestinal colonization by Enterobacter cloacae strains with a der epressed cephalosporinase was studied in a paediatric ward between Feb ruary 1990 and January 1991. Environmental sampling was performed simu ltaneously. Fifty-two isolates mere recovered from 200 neonates (stool , blood) and 14 strains were isolated from the neonatal environment. A n epidemiological study based on the typing of 36 Enterobacter cloacae isolates was carried out using antibiotyping, biotyping and ribotypin g methods. The isolates selected were from 21 neonates (24 isolates), the neonatal ward environment (8 isolates) and from other wards (4 iso lates). Thirty-two isolates had the same antibiotic resistance pattern , corresponding to a derepressed cephalosporinase and resistance to th e following aminoglycosides: kanamycin, gentamicin, tobramycin and net ilmicin. No predominant biotyping pattern could be established. Riboty ping done with two endonucleases (EcoRI and BamHI) showed 28 Enterobac ter cloacae isolates to have a single pattern. Ribotyping was the most discriminating method used in this study, permitting identification o f cross-contamination with Enterobacter cloacae in the paediatric ward .