OUTBREAK OF MULTIPLY RESISTANT ENTEROBACTERIACEAE IN AN INTENSIVE-CARE UNIT - EPIDEMIOLOGY AND RISK-FACTORS FOR ACQUISITION

A prospective study was initiated in an intensive care unit (ICU) wher e extended-spectrum beta-lactamase-producing enterobacteriaceae (ESBLP E) were endemic. From July 1990 to July 1991, patients hospitalized fo r greater than or equal to 5 days were screened for ESBLPE acquisition by means of weekly rectal sampling and clinical cultures. Baseline ch aracteristics and various ICU procedures in 62 cases of ESBLPE were co mpared with those for 205 patients without ESBLPE, with use of Cox's m odel. Risk for acquiring ESBLPE (Klebsiella pneumoniae in most cases) increased during the ICU stay, from 4.28 in the first week to 24%in th e fourth week, Baseline characteristics were not different between the two groups. Urinary catheterization (P =.04) and arterial catheteriza tion (P =.03) were independent risk factors for acquiring ESBLPE and p robably reflected frequency of health care manipulations. The first si te of ESBLPE acquisition was the digestive tract in 58 of the 62 patie nts; 28 infections developed in 22 patients, and these followed or occ urred simultaneously with rectal colonization in 18 of those 22. DNA m acrorestriction analysis suggested that the same strain was responsibl e for most cases. In conclusion, ESBLPE acquisition depends on length of stay in the ICU and the use of invasive procedures. Colonization is a prerequisite for infection.