OUTBREAK CAUSED BY 2 MULTIRESISTANT ACINETOBACTER-BAUMANNII CLONES INA BURNS UNIT - EMERGENCE OF RESISTANCE TO IMIPENEM

Since early 1992 an increased number of tobramycin- and imipenem-resis tant Acinetobacter spp. were observed causing colonization, wound infe ctions, and bacteraemias in a burns and plastic surgery unit. This rai sed the question of whether this outbreak was caused by a single or by multiple Acinetobacter spp. clones. To study this, 97 Acinetobacter s pp. isolates from clinical samples from different hospital units as we ll as isolates from the environment and the hands of the staff were ch aracterized by antibiogram, plasmid profile and ribotyping. Two domina nt multi-resistant ii. baumannii clones were identified; one of them w as sensitive to polymyxin B only. There was a close correlation betwee n the results obtained by plasmid profiling and ribotyping. No common environmental source or significant hand carriage, or spread of these strains outside the unit were detected. The burns patients were the mo st likely reservoir, and strain transmission occurred in spite of stri ct control measures.