Use of the DiversiLab® semiautomated repetitive-sequence–based polymerase chain reaction for epidemiologic analysis on Acinetobacter baumannii isolates in different Italian hospitals

Acinetobacter baumannii is typically a nosocomial pathogen. Epidemiologic tools that can rapidly trace the spread of hospital-associated infections due to this microorganism are essential. Currently, amplified fragment length polymorphism and pulsed-field gel electrophoresis using ApaI, a macrorestriction enzyme, are the molecular techniques most widely used to type this microorganism. Unfortunately, they are technically demanding, requiring also well-trained personnel, and are time consuming. The aims of this study are 1) to evaluate the usefulness of the semiautomated repetitive-sequence–based polymerase chain reaction (rep-PCR) for typing A. baumannii, comparing this method with another semiautomated technique, such as ribotyping, and 2) to acquire information about the incidence, the clinical significance, and the susceptibility patterns of this microorganism in 13 different Italian hospitals in a 4-week period (total study population, >14 000 beds). Twenty-eight A. baumannii were isolated in 7 different hospitals; 21 strains were analyzed with molecular methods. Automated ribotyping distinguished 6 different clusters of isolates, whereas rep-PCR appeared to be more discriminating, allowing us to distinguish 8 different clusters. Our study confirms the good discriminatory power of the semiautomated rep-PCR. Although expensive, this method is simple, fast, and reproducible, and in our opinion, it could be used in a hierarchic approach as a 1st-line typing tool if results of analysis are required in a short period or if a large number of isolates have to be analyzed.