Studio preliminare di persistenza di batteri non fermentanti in un reparto di terapia intensiva e rianimazione

A. baumannii, P. aeruginosa and S. maltophilia are important nosocomial pathogens, especially those collected from immunocomprimised patients and from intensive care units. In an attempt to define the epidemiology of non fermenting Gram negative bacteria, 87 P. aeruginosa, 50 A. baumannii and 22 S. maltophilia, isolated from the respiratory districts and blood cultures of patients in the intensive care unit of our hospital, were studied to verify their antimicrobial susceptibility patterns and their diffusion.These strains were typed using ID-GNB card (bioMérieux) and antimicrobial susceptibility patterns were determined using AST-GN09 card VITEK-2 (bioMérieux). Molecular typing methods, such as RAPD have emerged as most efficient tools for strain discrimination, because antibiotic supsceptibility and other phenotyping methods are not reliable for epidemiological studies. RAPD was performed on 15 P. aeruginosa, 12 S. maltophilia and 11 A. baumannii. The RAPD-PCR showed 7 different patterns in P. aeruginosa, 10 different patterns in S. maltophilia and the same profile in all strains of A. baumannii of patients admitted in intensive care units. Only two strains of A. baumannii of patients admitted in a thoracic surgical unit showed a different pattern in comparison to the other isolates.