The changing pattern of infection in neutropenic patients.

Over the past 20 years there has been a dramatic shift in the pattern of infection in neutropenic patients. During the 1970s Gram-negative organisms caused approximately 70% of all bacteraemias, but by the late 1980s the situation had reversed and approximately 70% of bacteraemias were due to Gram-positive organisms. The main contributors to this increase in Gram-positive infections have been the coagulase-negative staphylococci and the viridans streptococci. More recently, enterococci have emerged as significant pathogens in this patient group, and the development of glycopeptide resistance in the enterococci is of particular concern since this class of antibiotics is widely used in neutropenic patients. Among Gram-negative organisms, the emergence of resistance to fluoroquinolones, particularly in Escherichia coli, is a worrying feature which may lead to a reassessment of the use of quinolone prophylaxis in this setting.