Imipenen-resistant Ps. aeruginosa bacteraemia in cancer patients: risk factors, clinical features and outcome.

Ninety-nine patients with 101 bacteraemic episodes due to Pseudomonas aeruginosa (PA) within 6 years were divided into two groups according to their resistance to imipenem; of these 91 episodes were due to imipenem-sensitive (ISPA) and 10 due to imipenem-resistant (IRPA) strains. Risk factors, clinical course and outcome were evaluated and compared in the two groups. Acute leukaemia, long-lasting neutropenia, previous therapy with amikacin, third-generation cephalosporins, imipenem and prophylaxis with quinolones were significantly more frequently associated with IRPA than with ISPA. Imipenem-resistant PA bacteraemias were associated with a higher incidence of septic shock (40% vs 19.8%) p.1610.02) and death (33.3%) than were ISPA bacteraemias. Since 1992, when first IRPA appeared, the incidence of imipenem-resistance increased tenfold, and in 1994, up to 10% of the PA populations causing bloodstream infections in cancer patients in our centre were imipenem-resistant.