SURVEILLANCE OF AN ADULT INTENSIVE-CARE UNIT FOR LONG-TERM PERSISTENCE OF A MULTIRESISTANT STRAIN OF ACINETOBACTER-BAUMANNII

Sporadic infections with Acinetobacter spp., punctuated with prolonged outbreaks of infection involving larger numbers of patients and a par ticular epidemic strain of Acinetobacter baumannii, have occurred in t he adult intensive care unit (ICU) of Nottingham University Hospital s ince 1985. The aim of this study was to screen patients admitted to th e ICU for three or more days during a non-outbreak period in 1994-1995 and to use DNA fingerprinting techniques to compare any isolates of A cinetobacter spp. with isolates obtained from the same ICU during the previous ten years. In the present study, almost 20% of the ICU patien ts screened during 1994-1995 became colonized with Acinetobacter spp. The commonest species isolated from patients was Acinetobacter baumann ii; five different strains were identified by random amplified polymor phic DNA fingerprinting, including the epidemic strain responsible for outbreaks of infection in 1985-1986 and 1992-1993. Environmental samp ling yielded Acinetobacter spp. from one or more samples on four occas ions; Acinetobacter radioresistens was the commonest species isolated, and Acinetobacter baumannii (not the epidemic strain) was isolated on only one occasion from the environment. The long-term persistence of a potentially epidemic strain in the ICU, even during a non-outbreak p eriod, indicates a need for continued vigilance. Consequently, periodi c patient and environmental surveillance, combined with typing of isol ates, is recommended for ICUs where significant outbreaks of Acinetoba cter infection have occurred in the past.