Liposomal amphotericin B for postoperative Aspergillus fumigatus endocarditis

Fungal mobile mass on echocardiogram: native mitral valve Aspergillus fumigatus endocarditis

The most common type of infective endocarditis is bacterial endocarditis. However, fungal infections have been seen more frequently, mostly in the immunocompromised population. We report a case of invasive Aspergillus fumigatus native mitral valve endocarditis. The patient received appropriate empiric antifungal treatment with a combination of liposomal amphotericin B and flucytosine, associated with surgical debridement, valve replacement and chordae tendineae repair. Despite receiving the standard treatment of Aspergillus endocarditis, and susceptibility of the microorganism to the antifungal regimen, the patient, unexpectedly, developed early-onset septic emboli. It is surprising to see that the patient had developed such complications early, despite attempts to eliminate the source of infection with surgical intervention.

Post-operative aspergillosis

While invasive aspergillosis occurs typically in severely immunocompromised patients, cases of surgical site infection have been reported in immunocompetent individuals. The Medline, LILACS and EMBASE databases were searched for descriptions of cases of post-operative aspergillosis, and references from relevant articles and conference abstracts were reviewed. More than 500 cases of post-operative aspergillosis were found. Cardiac surgery (n = 188), ophthalmological surgery (n > 90) and dental surgery (n > 100) were associated with the majority of cases. Other cases involved wound infections (n = 22), bronchial infections (n = 30), mediastinitis (n = 11), pleural aspergillosis (n = 1), infections following orthopaedic surgery (n = 42), vascular prosthetic surgery (n = 22), breast surgery (n = 5), abdominal surgery (n = 10) and neurosurgery (n = 25). In most patients, the source was presumed to be airborne infection during the surgical procedure. Prevention of these infections requires special care of the ventilation system in the operating room. Successful treatment requires rapid diagnosis, surgical debridement and antifungal therapy, often with voriconazole. In order to improve the outcome, better diagnostic methods are needed, particularly for cases of endocarditis and aortitis.

The invasive and saprophytic syndromes due to Aspergillus spp

Aspergillus spp. produce a wide range of invasive and sapropytic syndromes which may involve any tissue. Within a given tissue or organ the pathology and pathogenesis varies enormously, ranging from angioinvasive disease to noninvasive saprophytic disease. The individual invasive and saprophytic syndromes in which a causative role can be attributed to Aspergillus spp. are detailed specifically with reference to the underlying pathology and pathogenesis, the clinical setting and features, and the manner in which a diagnosis can be established.

Fungal endocarditis in neonates and children

Fungal endocarditis in the neonate and pediatric population is associated with a high degree of morbidity and mortality, with diagnosis in the majority of cases made postmortem. The aim of this article is to review published literature on fungal endocarditis in children and to discuss the incidence due to a wide range of fungi, primarily Aspergillus and Candida species, as well as its diagnosis, including the importance of molecular-based approaches and various treatment regimes.

Fungal endocarditis, 1995-2000

One hundred fifty-two cases of fungal endocarditis (FE) were identified in the English-language literature between January 1, 1995, and June 30, 2000. Although the median age of patients (44 years) was relatively young, injection drug use was identified as a risk factor in only 4.1% of cases. Other factors, including underlying cardiac abnormalities (47.3%), prosthetic valves (44.6%), and central venous catheters (30.4%), were more commonly identified as predisposing conditions and reflect the changing epidemiology of the syndrome. Unfortunately, mortality remains unacceptably high, particularly for patients with Aspergillus-related FE. Novel therapies are needed to improve patient outcomes.

Fungal infections in marrow transplant recipients under antifungal prophylaxis with fluconazole

Fungal infection is one of the most important causes of morbidity and mortality in bone marrow transplant (BMT) recipients. The growing incidence of these infections is related to several factors including prolonged granulocytopenia, use of broad-spectrum antibiotics, conditioning regimens, and use of immunosuppression to avoid graft-versus-host disease (GvHD). In the present series, we report five cases of invasive mold infections documented among 64 BMT recipients undergoing fluconazole antifungal prophylaxis: 1) A strain of Scedosporium prolificans was isolated from a skin lesion that developed on day +72 after BMT in a chronic myeloid leukemic patient. 2) Invasive pulmonary aspergillosis (Aspergillus fumigatus) was diagnosed on day +29 in a patient with a long period of hospitalization before being transplanted for severe aplastic anemia. 3) A tumoral lung lesion due to Rhizopus arrhizus (zygomycosis) was observed in a transplanted patient who presented severe chronic GvHD. 4) A tumoral lesion due to Aspergillus spp involving the 7th, 8th and 9th right ribs and local soft tissue was diagnosed in a BMT patient on day +110. 5) A patient with a history of Ph1-positive acute lymphocytic leukemia exhibited a cerebral lesion on day +477 after receiving a BMT during an episode of severe chronic GvHD. At that time, blood and spinal fluid cultures yielded Fusarium sp. Opportunistic infections due to fungi other than Candida spp are becoming a major problem among BMT patients receiving systemic antifungal prophylaxis with fluconazole.

Development of liposomal amphotericin B formulation

A considerable effort has been spent in the past three decades to investigate various aspects of liposomes as novel drug delivery systems. In 1990, the first amphotericin B (AmB) liposomal preparation (L-AmB) under the brand name AmBisome was introduced into the market by Vestar. The successful marketing of the product moved liposomes out of the stage of experimental obscurity to the realistic stage of clinical utility. The launch of AmBisome sparked off the introduction of other lipid-based AmB products marketed by Liposome Technology (Amphocil) and The Liposome Co. (Abelcet). The drive behind the development of a modified formulation of AmB was to improve the therapeutic index of this drug with respect to its major drawback associated with both acute and chronic toxic effects. In a 30-year-long experience with AmB, several reports were recorded in the literature of acute adverse effects, such as fever, rigors, vomiting, cardiotoxicity and hypotension occurring during infusion; while long-term therapy was reported to be associated with hypokalemia, renal dysfunction and hematological abnormalities. Another serious problem encountered with the drug had been the poor response obtained in immunocompromised patients like those with AIDS, neutropenia and cancer patients on chemotherapy. The encapsulation of amphotericin B in liposomal vesicles was hence targeted not only to obtain an improvement in the therapeutic index but also to see if it was useful in eradicating deep-seated fungal infections in immunocompromised patients. The liposomal AmB was found to have a better therapeutic index and lower toxicity than the commercial AmB preparations. The LD50 of AmBisome in mouse was 175 mg/kg compared with 3.7 mg/kg for Fungizone, the commercial preparation of AmB. Additionally, L-AmB has prolonged circulation time, and extravasates into the site of infection and delivers the drug directly to the site, with no nephrotoxicity and neurotoxicity as experienced with AmB. This review traces the course of development of L-AmB and discusses the rationale behind the development of its liposomal preparation. The results in in vitro, in vivo and clinical studies, mechanism of action, biodistribution, and formulation considerations of L-AmB are described. The clinical experience with the marketed preparation is reviewed.