Changing epidemiology of infections in patients with neutropenia and cancer: emphasis on gram-positive and resistant bacteria.

Over the past 3 decades, considerable changes have occurred in the types of bacteria causing infection in febrile patients with neutropenia and cancer. Twenty years ago, gram-negative bacteria caused approximately 70% of bloodstream infections. As a probable consequence of long-dwelling intravascular devices, fluoroquinolone prophylaxis, and high-dose chemotherapy-induced mucositis, there has been a shift toward gram-positive coccal bacteremia. In most centers today, approximately 70% of bacteremic isolates are gram-positive cocci. Of potential concern is that antimicrobial-resistant gram-positive organisms are becoming increasingly frequent in patients with neutropenia. Fluoroquinolone-resistant Escherichia coli are being isolated from several cancer centers. Several "new" organisms, such as Stomatococcus mucilaginosus, Bacillus cereus, Leuconostoc species, Corynebacterium jeikeium, Rhodococcus species, Stenotrophomonas maltophilia, Moraxella catarrhalis, Burkholderia cepacia, and Bartonella species, now cause infections in these patients. Careful application of infection-control principles, judicious prophylaxis, appropriate evaluation of new antibiotics, and prompt effective therapy will maximize benefits for these patients.