Isolation for the Compromised Host

NOSOCOMIAL infection has become a serious problem in recent years. A substantial number of these infections are caused by Gram-negative bacilli.¹The emergence of these organisms as a major cause of infection in hospitalized patients is due, in part, to the control of streptococcal and staphylococcal infections with effective antibiotic therapy. Gram-negative bacillary infections are a special threat to patients with impaired hostdefense mechanisms. Most hospitals are populated with increasing numbers of these patients due to improvements in the management of a variety of chronic debilitating diseases. Agents such as adrenal corticosteroids, alkylating agents, and antimetabolites are being used extensively in the fields of organ transplantation, autoimmune disorders, hematological diseases, and metastatic malignancies. These agents contribute to the problem because their toxicity includes myelosuppression and impairment of immunological mechanisms. Reverse isolation has been an accepted technique for protecting compromised hosts from acquiring nosocomial infection. However, the effectiveness