Infection in immunodepressed patients. The approach to diagnosis and treatment.

Infection is an important cause of death in patients receiving cytostatic drugs or with any other impairment of host resistance. Such infections are frequently due to opportunist micro-organisms usually belonging to the endogenous flora of the patient. It is often difficult to obtain an exact diagnosis of the cause and localization of the infection. The problems associated with the prevention of infection are manifold. Exogenous infections can be prevented by proper isolation and a sterile diet. Endogenous infections can only be prevented by eradication of the patient's endogeous flora, so-called decontamination. Special attention should be given to treatment of foci of chronic infection and of the carrier state of certain microorganisms. However, the prophylactic use of antibiotics should be avoided. The curative use of antibiotics should be based on the most probable micro-organism. We consider the inventory of the patient's microflora, repeated weekly, of great help in the choice of antibiotics in cases of septicaemia of unknown aetiology. The initial therapy usually consists of a broad-spectrum combination of antibiotics, which should be bactericidal. When the causative bacteria have been isolated and the sensitivity is known, antibiotic therapy should be adjusted to the narrowest spectrum possible.