Epidemiological study of Acinetobacter species isolated from an intensive care unit

An epidemiological survey of the increase in Acinetobacter species isolates occurring in the intensive care unit of a Spanish teaching hospital during 1993 and 1994 was carried out. Different laboratory methods were used to find out, whether there was a genetic linkage. The isolates were divided into three main groups according to the resistance patterns to 11 drugs. Using API 20NE biotyping, eight different types were found. The two most common contained 20 and 11 isolates, respectively. Five different plasmid profile types were observed, although plasmids were only demonstrated in 40% of the isolates. Ribotyping with EcoRI, SalI and ClaI enzymes revealed 10, 9, and 8 different patterns, respectively. In total, 15 different ribotypes were identified using these three enzymes. Twenty-one isolates belonged to exactly the same ribotype, and 13 were associated with two highly related ribotypes. In the first ribotype, only five isolates harboured plasmids. The ribotyping method produced 100% typability and ribotypes were easy to compare; it also had taxonomic value. Ribotyping allowed us to determine the genetic linkage between Acinetobacter isolates recovered from ICU patients.