Liposomal amphotericin B for empirical therapy in patients with persistent fever and neutropenia. National Institute of Allergy and Infectious Diseases Mycoses Study Group

Cryptococcal meningitis in renal transplant patients associated with environmental exposure

Fungal infections in renal transplant recipients are less common than bacterial infections; however, the morbidity from fungal infections is high. There is limited information in the literature concerning post-transplantation cryptococcal infection due to environmental exposure of patients living in high-risk areas. We report three patients who were diagnosed with cryptococcal meningitis after kidney transplantation. Cryptococcal titers prior to transplant surgery were negative in all three patients. These patients all lived in rural areas and demonstrated evidence of environmental exposure leading to subsequent cryptococcal meningitis. All patients had exposure to pigeon and chicken excreta and, after treatment, two patients are alive and well with excellent allograft function. The third patient has marginal renal function but is currently not on dialysis. Early diagnosis is essential for salvage from these potentially lethal infections. Intense headache was a prominent feature in the clinical presentation of our patients, and should signal the need for early sampling and culture of spinal fluid. Meningismus was not present in any of our patients, even when other systemic symptoms were identified. We recommend a high index of suspicion post-transplantation for all patients who may have environmental or occupational exposure to cryptococcus. If infection is detected quickly and treatment instituted promptly, patient recovery and allograft survival are possible. Long-term therapy with fluconazole, a non-nephrotoxic agent, should permit eradication of the infection with preservation of kidney function.

Treatment-related deaths during induction and first remission of acute myeloid leukaemia in children treated on the Tenth Medical Research Council acute myeloid leukaemia trial (MRC AML10). The MCR Childhood Leukaemia Working Party

Between 1988 and 1995, 341 children with acute myeloid leukaemia (AML) were treated on the Medical Research Council Acute Myeloid Leukaemia Trial (MRC AML10). The 5-year overall survival was 57%, much improved on previous trials. However, there were 47 deaths (13. 8%), 11 of which were associated with bone marrow transplantation (BMT). The treatment-related mortality was significant at 13.8%, but decreased in the latter half of the trial from 17.8% in 1998-91 to 9. 6% in 1992-95 (P = 0.03%). The main causes of death were infection (65.9%), haemorrhage (19.1%) and cardiac failure (19.1%). Fungal infection was a significant problem, causing 23% of all infective deaths. Haemorrhage occurred early in treatment, in children with initial white cell counts >100 x 109/l (P = 0.001), and was more common in those with M4 and M5 morphology. Cardiac failure only occurred from the third course of chemotherapy onwards, with 78% (7/9) in conjunction with sepsis as a terminal event. Some deaths could be prevented by identifying those most at risk, and with prompt recognition and aggressive management of complications of treatment. Future options include the prophylactic use of antifungal agents, and the use of cardioprotectants or alternatives to conventional anthracyclines to decrease cardiac toxicity.

Infection in the neutropenic and stem cell transplant patient

The spectrum of infectious complications in neutropenic patients after stem cell or bone marrow transplant is not very different from that seen in other neutropenic patients, with the possible exception of fungal infections. The prevention and therapy of these infections remain a major challenge. The management of neutropenic patients after stem cell or bone marrow transplant has markedly benefited from the development of new antiviral agents and the use of granulocyte/macrophage colony stimulating factors.

Unusual infections and novel therapy in the immunocompromised host

Many of the reports of infection in immunocompromised patients over the past year have been caused by unusual bacterial pathogens or fungi, which are often multiresistant and difficult to treat. Although many difficulties still remain some progress has been made over the past year in the development of new antimicrobial agents and alternative therapies.

Therapeutic Approach to Candida Sepsis

Serious infections due to Candida species are an emerging nosocomial problem. Therapy for culture-proven candidemia in nonneutropenic patients has been studied extensively, and these studies suggest that fluconazole and conventional amphotericin B are equivalent treatments under most circumstances. Empiric antifungal therapy for the seriously ill, febrile, nonneutropenic intensive care unit patient has been less well studied, but an understanding of the important risk factors for invasive candidiasis can help guide rational therapeutic choices. The important role of empiric antifungal therapy in the persistently febrile neutropenic host has been well established. The role of the lipid formulations of amphotericin B in the treatment of candidiasis remains unclear, but these compounds should be considered in any patient requiring amphotericin B with significant renal dysfunction. The trend towards nonalbicans Candida species as a cause of invasive candidiasis, together with an improved understanding of antifungal susceptibility data, should help clinicians and investigators devise new and better approaches to the treatment of this important nosocomial infection.

The challenge of invasive fungal infection

Systemic fungal infections cause almost 25% of the infection-related deaths in leukaemic patients. Particularly those with prolonged neutropenia are at risk but mycoses also feature in critically ill intensive care patients and in individuals who are treated for solid tumours and AIDS, or who received an organ transplant. The spread of AIDS and the more aggressive cytotoxic chemotherapy in combination with an improved management of haemorrhages and bacterial infections in leukaemic and other cancer patients facilitated the occurrence of these invasive fungal infections. These life-threatening complications remain both difficult to diagnose and to treat and therefore carry a poor prognosis. For many years, the only realistic option to treat systemic infections was amphotericin B, whose administration was known to be associated with numerous adverse effects. Now less toxic formulations of amphotericin have become available for clinical use, as well as several new triazoles that appear to provide an effective and less toxic alternative for the treatment of certain fungal infections.

Lipid-based amphotericin B formulations: from animals to man

Amphotericin B has been the mainstay of systemic antifungal therapy for over 30 years, despite its serious side-effects, and, although numerous alternative antifungal agents have been developed, none to date has matched the efficacy of amphotericin B. However, modern drug delivery technology has improved the safety of amphotericin B by incorporating it into lipid-based delivery systems, including liposomes. Three such formulations, based on the natural affinity of amphotericin B for lipids, are currently marketed. All increase the therapeutic index of amphotericin B, thereby allowing more aggressive treatment than is possible with the conventional product. However, they differ in structure, side-effect profiles and evidence of proven efficacy as discussed in this review.

Antiinfectives update: focus on treatment and prevention of viral and associated infections

OBJECTIVE

To review the clinically significant antiinfectives approved by the Food and Drug Administration (FDA) since 1996, with an emphasis on agents used for treatment, prevention, or suppression of infection in immunocompromised individuals.

DATA SOURCES

A MEDLINE search covering November 1994 to March 1998 was conducted to identify all antiinfectives (new medications and old medications with new indications) and the pertinent literature for review. The search was updated in August 1998 and supplemented with an FDA listing of approved drugs to enhance completeness.

STUDY SELECTION

Clinically relevant studies were selected to highlight specific points about each medication. Preclinical publications were used when sufficient information was not available from clinical trials and this information was needed for clinical practice.

CONCLUSIONS

Several new and promising antiretroviral agents (stavudine, lamivudine, saquinavir soft-gel capsules, nelfinavir, efavirenz) have been approved, which may allow more options to control HIV viremia. New options for treatment, prevention, and suppression of infections in immunocompromised individuals include azithromycin, cidofovir, famciclovir, valacyclovir, and itraconazole suspension. Liposomal-based amphotericin products may be associated with less toxicity than conventional amphotericin B; however, superior efficacy has not been proven.