Population Of Immunosuppressed Patients Research Articles

Clinical features and therapeutic interventions in 17 cases of Bacillus bacteremia in an immunosuppressed patient population.

We retrospectively examined episodes of Bacillus bacteremia at a hospital with a large proportion of immunosuppressed patients. Seventeen episodes in 9.5 years met our case definition: two of two bottles of one blood culture or one of two bottles of two or more separately obtained blood cultures drawn on the same date. During the same period, there were 59 additional episodes in which a single blood culture had only one of two bottles positive for Bacillus species. Only 2 of 59 such episodes resulted in recurrent bacteremia (3%), as compared with 5 of 17 episodes meeting our case definition (29%) (P = 0.004). In four of five episodes complicated by recurrent bacteremia and in which appropriate antibiotics were used, a Hickman-Broviac catheter was in place and was not removed. We suggest that our case definition permits the differentiation of infection from contamination based on outcome and that patients with Bacillus bacteremia have chronic venous catheters removed as well as receive antibiotic treatment.

Histoplasmosis in immunosuppressed patients

Infection with Histoplasma capsulatum in 58 patients whose immune responses were suppressed (Immunosuppressed patients) (16 from the present series and 42 described previously) was analyzed. The most common underlying diseases were Hodgkin's disease (29 per cent), chronic lymphocytic leukemia (19 per cent) and acute lymphocytic leukemia (17 per cent). Sixty-three per cent of the patients had received cytotoxic drugs, and 57 per cent had taken corticosteroids. Widely disseminated infection occurred in 88 per cent of the patients, with predominant involvement of lungs and organs of the reticuloendothelial system. Localized pulmonary infection was present in the remaining patients. The most useful diagnostic method was bone marrow biopsy with microscopic examination for the intracellular yeast form of H. capsulatum. Biopsy of oral lesions, lung, liver and lymph node also proved diagnostically helpful. Growth of H. capsulatum in culture was frequently too slow to be beneficial in diagnosing histoplasmosis in ill patients. Serologic methods were of little diagnostic help in this population of immunosuppressed patients. The response to amphotericin B therapy was excellent (6.7 per cent mortality rate) in those patients in whom the diagnosis was established early and in whom a full course of antifungal therapy could be given. In contrast, the mortality rate in patients who received no antifungal therapy or less than 1 g of amphotericin B was 100 per cent.

Bacillus Species Infection in Patients With Hematologic Neoplasia

THE USE of intensive chemotherapy for patients with hematologic neoplasia has produced a rapidly growing population of immunosuppressed patients at high risk for opportunistic infections. Until recently, only one case of infection with the aerobic, Gram-positive, spore-forming rods of the genus<i>Bacillus</i>has been reported in this group of patients.¹Since 1971, however,<i>Bacillus</i>species infection has been reported in three such patients,^2,3all with fatal outcome. None of these<i>Bacillus</i>species were<i>B anthracis</i>. The present report identifies two further cases of fatal<i>Bacillus</i>infection in patients with hematologic neoplasia and outlines some important clinical considerations when this organism is encountered. <h3>Report of Cases</h3><h3>Case 1.—</h3> A 56-year-old woman with leukemic reticuloendotheliosis was admitted to the Peter Bent Brigham Hospital because of a fever and cough of two days' duration. Current medications were cyclophosphamide and prednisone. On physical examination, her temperature was 38.6 C, she appeared dyspneic,