Multidrug-resistant bacteria isolated from patients hospitalised in Intensive Care Units

Surveys of the prevalence and susceptibility patterns of bacterial isolates are important in determining optimum empirical therapy for infections in critically ill patients. The aim of this study was to determine possible differences in the patterns of bacterial resistance in two Intensive Care Units (ICUs) depending on the patient profile. There was a high percentage of non-fermenting Gram-negative rods (NFGNR) among the bacterial isolates from both wards. NFGNR comprised 43.8% of all isolates from ICU-B and 38.9% from ICU-A. Extended-spectrum beta-lactamase production was detected in 40.0% of Gram-negative rods cultured from ICU-A compared with 26.7% from ICU-B; whilst imipenem-resistant strains of Acinetobacter baumannii constituted 17.1% of isolates from ICU-A and 9.6% from ICU-B. Emergence of A. baumannii strains resistant to imipenem was recorded, particularly among blood isolates. In both wards, multidrug-resistant (MDR) strains of Gram-negative bacilli were more prevalent among blood isolates than among strains cultured from other specimens. Longer stay in ICU-A promoted selection of MDR Gram-negative rods.