CONTROL OF INFECTION WITH MULTIPLE ANTIBIOTIC-RESISTANT BACTERIA IN AHOSPITAL RENAL UNIT - THE VALUE OF PLASMID CHARACTERIZATION

An outbreak of infections due to multiple antibiotic-resistant bacteri a took place over a period of approximately 18 months in a renal unit. Strains of Escherichia coli, Enterobacter aerogenes, Klebsiella pneum oniae, Citrobacter spp. and Pseudomonas spp, were involved, and a vari ety of antibiotic resistances was encountered. Closely related plasmid s encoding resistance to aztreonam, ceftazidime and piperacillin, poss ibly derived from an archetypal plasmid of 105 kb were found in the ma jority of isolates examined. After limiting the use of aztreonam the i ncidence of new patient isolates of multiple-resistant organisms was g reatly reduced. This study demonstrated how molecular studies can cont ribute to the control of an outbreak situation in a hospital unit by p roviding an impetus to reduce the use of specific antibiotics.