Risk factors, aetiology, therapy and outcome in 123 episodes of breakthrough bacteraemia and fungaemia during antimicrobial prophylaxis and therapy in cancer patients.

One hundred and twenty-three breakthrough bacteraemias (BB) were defined during a 5-year period in a National Cancer Centre, among 9986 admissions and a total of 979 bacteraemic episodes analysed. Of 123 bacteraemias in 103 patients, 77 were polymicrobial and 116 of the 323 organisms isolated were resistant to currently administered antimicrobial agents. Sixty-seven of the bacteraemic episodes were catheter-associated, as confirmed by the isolation of the same organisms from both blood and catheter tip. The strains isolated most frequently were coagulase-negative staphylococci (30.5%), corynebacteria (10%), Pseudomonas aeruginosa (10%), Enterococcus faecalis (9%) and viridans streptococci (8.5%). Gram-positive aerobes accounted for two-thirds of all micro-organisms isolated during breakthrough bacteraemic and fungaemic episodes. Polymicrobial episodes were associated more frequently with vascular catheters and neutropenia, and had a less favourable outcome than monomicrobial infections. Relapse was associated more frequently with catheter-related episodes, but the overall mortality rate was similar and independent of catheter insertion. Breakthrough bacteraemic and fungaemic episodes were associated more frequently with acute leukaemia. Catheter removal, as an independent variable, and modification of antimicrobial therapy were essential for better outcome.