Bacterial infections in cancer patients

The use of intensive chemotherapeutic regimens, hematopoietic stem cell transplantation, and other therapeutic modalities, has increased the remission and cure rates of many cancer patients. These modalities have also been associated with more severe myelosuppression and immunosuppression, increasing the frequency of severe, sometimes fatal, infection. Although substantial progress has been made in prevention, early diagnosis, and treatment of infections, the spectrum of organisms causing these infections undergoes periodic changes, new opportunistic pathogens emerge, and common organisms develop multiple mechanisms of resistance. Also, patients today are less restricted in their activities and may be exposed to human, plant, or animal pathogens more frequently than in the past, leading to an increasing proportion of infections originating outside the hospital. Additionally, the usual signs and symptoms of infection including fever may be minimal or absent, especially among severely neutropenic patients and those receiving adrenal corticosteroids. Consequently, patients must be monitored carefully, especially during periods of increased risk. The availability of sophisticated technology such as CT scan, antigen detection, and molecular techniques (PCR) have assisted in the diagnosis of some infections and offers promise for greater success in the future. Nevertheless, a specific diagnosis of infection is often not possible, and empiric therapy must be administered on the basis of local epidemiology and susceptibility/resistance patterns. In recent years, it has become possible to stratify patients into cate- gories such as high-risk and low-risk for the development of severe infections and associated complications. Treatment strategies such as early discharge, outpatient management, and orally administered drugs are now commonplace in low-risk patients.