PERSISTENCE OF A MULTIRESISTANT CLONE OF STAPHYLOCOCCUS-EPIDERMIDIS IN A NEONATAL INTENSIVE-CARE-UNIT FOR A 4-YEAR PERIOD

A cluster of cases of Staphylococcus epidermidis bacteremia in a neona tal intensive-care unit (NICU) during 1991 raised the question of whet her these infections were caused by a single strain. Sixty-seven isola tes of S, epidermidis from blood cultures of 56 neonates treated in th e NICU between 1986 and 1992 and 54 control strains from other patient s with bacteremia were characterized by three typing methods: antibiog ram, plasmid profile, and ribotype. Plasmid profiles and ribotype patt erns indicated that 11 (16%) of the 67 episodes of S, epidermidis bact eremia in the NICU were caused by a single strain, Although this epide mic strain did not account entirely for the increase in the incidence of bacteremia in the NICU, it did persist for 4 years during the study period. Other clones responsible for smaller outbreaks were also foun d. These results suggest that S. epidermidis cross-infections are very common in the NICU setting.