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

A randomized, double-blind comparative trial evaluating the safety of liposomal amphotericin B versus amphotericin B lipid complex in the empirical treatment of febrile neutropenia. L Amph/ABLC Collaborative Study Group

In this double-blind study to compare safety of 2 lipid formulations of amphotericin B, neutropenic patients with unresolved fever after 3 days of antibacterial therapy were randomized (1:1:1) to receive amphotericin B lipid complex (ABLC) at a dose of 5 mg/kg/d (n=78), liposomal amphotericin B (L Amph) at a dose of 3 mg/kg/d (n=85), or L Amph at a dose of 5 mg/kg/d (n=81). L Amph (3 mg/kg/d and 5 mg/kg/d) had lower rates of fever (23.5% and 19.8% vs. 57.7% on day 1; P<.001), chills/rigors (18.8% and 23.5% vs. 79.5% on day 1; P<.001), nephrotoxicity (14.1% and 14.8% vs. 42.3%; P<.01), and toxicity-related discontinuations of therapy (12.9% and 12.3% vs. 32.1%; P=.004). After day 1, infusional reactions were less frequent with ABLC, but chills/rigors were still higher (21.0% and 24.3% vs. 50.7%; P<.001). Therapeutic success was similar in all 3 groups.

Antifungal pharmacodynamics: review of the literature and clinical applications

Invasive fungal infections are seen with growing frequency, likely due to increases in numbers of patients at risk of infection. Optimal selection and dosing of antifungal agents are important, as these infections are often refractory to available therapy. In contrast to antibacterials, studies examining the pharmacodynamic properties of antifungals and their application in treating invasive disease often are lacking. Agents administered for invasive infections are amphotericin B, flucytosine, and azole antifungals. Several drugs are under investigation, such as posiconazole, voriconazole, and the echinocandins, and preliminary pharmacodynamic data likely will help shape dosing regimens. Clinical trials that investigated dosage and administration, as well as the potential benefits of combination and sequential therapy, are addressed. In addition, antifungal susceptibility and animal models of infection are discussed.

Fatal haemoptysis induced by invasive pulmonary aspergillosis in patients with acute leukaemia during bone marrow and clinical remission: report of two cases and review of the literature

We describe two patients with acute leukaemia who died of massive haemoptysis caused by invasive pulmonary aspergillosis (IPA). The fatal event occurred during the period of bone marrow remission which followed chemotherapy-induced neutropenia. This is a rare complication. We were able to find additional 17 similar cases in the English literature, which we review. Clinically, the picture consisted of unremitting fever with profound and prolonged neutropenia, cough and dyspnoea. Both our patients were treated with broad-spectrum antibiotics, fluconazole and amphotericin B. An upper lobe infiltrate in one case, and a progressive pleural effusion in the other, were late findings on chest radiographs during the period of bone marrow recovery. Both patients succumbed to sudden massive haemoptysis during the period of bone marrow and clinical improvement. In conclusion, patients with acute non-lymphoid leukaemia are at significant risk for IPA-induced fatal haemoptysis during bone marrow and clinical remission. A high index of suspicion should be sustained throughout the entire clinical course. In view of the potential fatal outcome, aggressive diagnostic and treatment efforts are mandatory.

Febrile neutropenia in allogeneic transplantation

Infections post allogeneic bone marrow transplant (BMT) are a major problem. Post BMT, three periods with infectious complications are discerned: pre-engraftment and early recovery, mid recovery and late recovery. In the first period mucosal damage and neutropenia are the major host defence deficits. Bacterial infections with Gram-positive and Gram-negative organisms, and fungal infections are seen in this period. In the mid recovery phase graft versus host and its treatment contribute to diminished host defences. Viral infections and fungal infections predominate. In the late recovery phase chronic graft versus host reaction impairs the monocyte macrophage function and CD4 counts are low. In this phase patients are at risk for infections with encapsulated bacteria, fungi, Pneumocystis carinii and Toxoplasma. Strategies for the management of febrile neutropenia are similar to those in 'high risk' neutropenic patients: immediate broad spectrum I.V. antibiotics (3rd or 4th generation cephalosporin+/-aminoglycoside or carbapenem) and early amphothericin B (lipid formulation) if fever persists beyond 5 days despite adequate I.V. antibiotics. Cytomegalovirus (CMV) prophylaxis or better preemptive therapy guided by viraemia is accepted practice. Prevention of infection measures, antimicrobial, antifungal and viral prophylaxis are generally accepted strategies but would differ from center to center. The post transplant infection history will change with different transplant techniques and evolving prophylactic and preemptive treatments.

Second early allogeneic stem cell transplantations for graft failure in acute leukaemia, chronic myeloid leukaemia and aplastic anaemia. French Society of Bone Marrow Transplantation

In this retrospective multicentre study, we analysed the results of 82 consecutive second early allogeneic transplants for primary (n = 28) or secondary ([n = 54) graft failures performed between 1985 and 1997 in patients with acute leukaemia (n = 33), aplastic anaemia (n = 29) or chronic myeloid leukaemia (n = 20). HLA-matched siblings were used in 64 cases. The same donors were used for both transplants in 56 cases and the first transplant was T-cell depleted in 30 cases. The median age at transplant was 25 years and the median intertransplant time interval was 2 months. Estimates of the 3-year overall survival and day 100 transplant-related mortality were 30% and 53% respectively. A recipient age < 34 years at transplant, an intertransplant time interval > or = 80 d and a positive recipient cytomegalovirus serology were predictors of a better outcome. The use of cyclosporin A (CsA) after second transplant had a dramatic impact on outcome, the best results being observed with CsA alone. The day 40 probability of neutrophil recovery was 73%. The use of peripheral blood progenitor cells (PBPCs) was associated with a higher and faster neutrophil recovery. Other factors associated with neutrophil recovery were an intertransplant time interval > or = 80 d and a positive recipient cytomegalovirus serology. Therefore, second early allogeneic transplantation for graft failure is an effective treatment, especially if patients can receive CsA for graft-versus-host disease prevention and are retransplanted more than 80 d from first transplant.

Review of comparative studies between conventional and liposomal amphotericin B (Ambisome) in neutropenic patients with fever of unknown origin and patients with systemic mycosis

Fungal infections are an important cause of morbidity and mortality in immunocompromised patients. Treatment with amphotericin B is the main therapeutic approach. However, this treatment is limited by the substantial toxicity. We present the data of the first randomized prospective comparative trial in adults (134 patients with fever of unknown origin) with conventional amphotericin B and a liposomal formulation of amphotericin B (AmBisome, published in 1997 by Prentice et al. (Br. J. Haematol. 98, 711-718) and the data of adults with documented fungal infections (59 patients), treated in this trial. Patients received either conventional amphotericin B 1 mg kg-1 per day, liposomal amphotericin B 1 mg kg-1 per day or liposomal amphotericin B 3 mg kg-1 per day. Patients were entered if they had fever of unknown origin (FUO), defined as temperature of 38 degrees C or more, not responding to 96 h of systemic broad-spectrum antibiotic treatment, and neutropenia (< 0.5 x 10(9) l-1). Efficacy of treatment was assessed, with success defined as resolution of fever for three consecutive days (< 38 degrees C) in the group of patients with FUO and the freedom of clinical signs and/or the elimination of fungus in the group of patients with documented fungal infections. The safety of treatment and renal and hepatic toxicity of liposomal and conventional amphotericin B were compared. No statistically significant difference was found in the treatment efficacy in the three study arms. However, there is a tendency of better treatment results in the two groups of patients, who received liposomal amphotericin B. Thirty-five per cent of patients with documented fungal infections and 46% of patients with FUO responded to amphotericin B. In the patients group, that received 1 mg kg-1 liposomal amphotericin B it was 63 and 49%, in the group of patients that received 3 mg kg-1 liposomal amphotericin B it was 47 and 64%. Evidence of toxicity due to amphotericin B was seen in 50 patients (83%), toxicity due to liposomal amphotericin B, 1 mg kg-1, was seen in 35 patients (50%), and due to liposomal amphotericin B 3 mg kg-1 in 34 patients (54%). This was a statistically significant difference (P = 0.001). It was concluded that liposomal amphotericin B was safer than conventional amphotericin B, but both formulations are equivalent in treatment efficacy. The prophylactic use of amphotericin B in these immunocompromised patients is discussed.

Standard antifungal therapy in neutropenic patients

Fungal infections are life-threatening complications in patients with prolonged neutropenia. Amphotericin B, which is fungicidal and has a broad spectrum of antifungal activity, remains the current gold standard agent. However, because of its low therapeutic index, new lipid formulations of amphotericin B have been developed with better tolerance and less toxicity. The use of 5-fluorocytosine is waning because of the medullar toxicity of this agent. Fluconazole and itraconazole are both fungistatic and are more convenient for the treatment of fungal infections in haemodynamically stable patients.

Modifications of therapy

Rates of response to empirical therapy in the neutropenic patient with fever, range between 40 and 90%. Modifications of therapy are needed in patients who do not respond but may also be considered in patients who respond. In patients with unexplained fever and rapid defervescence, switch to oral therapy is an acceptable option and there is no need to continue the regimen until neutrophil recovery. Neutropenic patients with persistent undefined fever and those with progressive pneumonia benefit from the addition of antifungals while the empiric addition of a glycopeptide is unlikely to be effective. In patients with gram-negative bacterial infection initially treated with monotherapy, response may be increased after the addition of an aminoglycoside. In cases of a defined etiology, the institution of narrow-spectrum antimicrobials in a persistent neutropenic patient carries a substantial risk for superinfection and is not generally recommended. Improved diagnostic tools and sensitive clinical risk-assessment methods will allow selecting and targeting therapy modifications better.

Concepts in design of comparative clinical trials of antifungal therapy in neutropenic patients

Fundamental to the successful implementation of antifungal compounds in neutropenic patients is the appropriate design of comparative clinical trials investigating their safety and efficacy. The key elements of comparative clinical trial design include issues of enrollment, stratification, randomization, blinding, administration of study drugs, monitoring of drug toxicity, definitions, and key statistical elements of end points, sample size, and tools for data analysis. The initial selection of compounds and the timing of initiation of antifungal therapy in comparative clinical trials are predicated to a large degree on the in vitro and in vivo activities, plasma pharmacokinetics, profiles of safety and toxicity of the study drugs. Phase I and II studies have a critical role in designing comparative clinical trials of antifungal therapy by providing data on safety, tolerance, and plasma pharmacokinetics of the investigational agent. As new antifungal agents are developed in response to the challenge of invasive fungal infections in immunocompromised patients with cancer, thoughtfully designed and carefully implemented clinical trials will be essential in determining the future utility of these promising compounds.

Management of infection in children with bone marrow failure

The development of new and often more successful regimens of treatment for childhood blood and malignant diseases has usually been associated with a parallel increase in infectious problems. This is because these successes have often, in the absence of new effective drugs, been achieved by increasing drug dose intensity to new limits. This chapter is not intended to deal with every possible infection, but rather to be a practical guide to the current management of infection. The last few years have seen major improvements in the development of haematopoietic growth factors, new antifungal agents, new antibiotics and new ways to use aminoglycosides. Attempts are being made to identify good and poor risk factors for the outcome of infection in order to facilitate shorter courses and possibly home or day care use of antimicrobial agents. In addition the different needs of children are being recognized in view of the restricted use of quinolones in this group and the different organisms and types of infection that they experience.

Single-dose AmBisome (Liposomal amphotericin B) as prophylaxis for murine systemic candidiasis and histoplasmosis

AmBisome is a liposomal formulation of amphotericin B that has broad-spectrum antifungal activity and greatly reduced toxicity compared to the parent drug. In this study, amphotericin B deoxycholate (Fungizone) (1 mg/kg) and AmBisome (1 to 20 mg/kg) were tested as single-dose prophylactic agents in both immunocompetent and immunosuppressed C57BL/6 mice challenged with either Candida albicans or Histoplasma capsulatum. Prophylactic efficacy was based on survival and fungal burden in the target organ (kidneys or spleen). At 9 to 10 days after histoplasma challenge, 80 to 90% of both immunocompetent and immunosuppressed mice in the control and Fungizone groups had died. All AmBisome-treated mice survived, although in the AmBisome groups given 1 mg/kg, the mice became moribund by day 10 to 12. No spleen CFU were detected in the histoplasma-challenged mice given 10 or 20 mg of AmBisome per kg. By 23 to 24 days after histoplasma challenge, fungal growth and/or death had occurred in all immunosuppressed mice except for four mice receiving 20 mg of AmBisome per kg. There were still no detectable fungi in the spleens of immunocompetent mice given 10 or 20 mg of AmBisome per kg. In the C. albicans experiment at 7 days postchallenge, all animals in both untreated and treated groups were alive with culture-positive kidneys. The kidney fungal burdens in AmBisome groups given 5 to 20 mg/kg were at least 1 log unit lower than those in the Fungizone group and significantly lower than those in the untreated control group (P < 0.05). There was a trend toward decreasing fungal growth in the kidneys as the dose of AmBisome was increased. In conclusion, these results show that a single high dose of AmBisome (5 to 20 mg/kg) had prophylactic efficacy in immunocompetent and immunosuppressed murine H. capsulatum and C. albicans models.

Management

The management of invasive fungal infection utilizes a variable multidisciplinary approach involving antifungals, appropriate surgery and immuno-correction. Conventional amphotericin B has been the mainstay of treatment but newer pathogens and poor outcomes has led to new formulations of this drug as well as to new and novel antifungals.

Unusual infections and novel therapy in the immunocompromised host

New methods of identification have led to an ever-increasing number of unusual pathogens causing infection in the immunocompromised host. Reports of antimicrobial-resistant organisms in this group of patients are also increasing, with the result that new treatments must be sought urgently. New agents and new strategies for the development of antimicrobial agents are critical for future progress in the treatment of resistant organisms.

Polyene antibiotics: relative degrees of in vitro cytotoxicity and potential effects on tubule phospholipid and ceramide content

Polyene antibiotic administration is limited by dose-dependent nephrotoxicity. The latter is believed to be mediated by polyene anchoring to plasma membrane cholesterol, resulting in pore formation, abnormal ion/solute flux, adenosine triphosphate (ATP) declines, and, ultimately, a loss of tubule viability. The relative nephrotoxicity of these agents and their liposomal preparations has remained poorly defined. Thus, freshly isolated mouse proximal tubules or cultured human proximal tubule (HK-2) cells were exposed to either nystatin, amphotericin B, or three different polyene liposomal preparations (Nyotran, AmBisome, or Abelcet; 4 to 64 microg/mL). The impact of these agents on (1) plasma membrane injury (sodium-driven ATP consumption, assessed by ATP-adenosine diphosphate [ADP] ratios); (2) cellular susceptibility to superimposed injury (chemical hypoxia or ferrous ammonium sulfate-mediated oxidative stress; assessed by lactate dehydrogenase release); and (3) membrane cholesterol, phospholipid, and ceramide expression was assessed. Amphotericin B was more cytotoxic than nystatin (approximately 25% to 50% greater ATP-ADP ratio declines). Most of this toxicity could be eliminated by polyene liposomal formulation. Nevertheless, the liposomal polyenes still fully sensitized tubule cells to superimposed chemical hypoxic (antimycin/deoxyglucose), but not oxidant, attack. Nystatin and amphotericin B caused acute increments in tubule sphingomyelin-phosphatidylcholine ratios and ceramide content (indicating an impact on the plasma membrane extending beyond the classic view of pore formation with ion flux). In conclusion, (1) nystatin is seemingly less cytotoxic than amphotericin B (in contrast to the prevailing clinical view); (2) liposomal formulation markedly decreases this cytotoxicity; (3) despite this reduced toxicity, liposomal polyenes are still able to render tubule cells more vulnerable to selected forms of superimposed injury; and (4) acute alterations in plasma membrane phospholipid and ceramide expression are previously unrecognized consequences and potential mediators of polyene-mediated tubular cell attack.

Supportive care in hematologic malignancies: hematopoietic growth factors, infections, transfusion therapy

A number of recent developments in the supportive care of hematological malignancies have been selected for critical discussion. The first section focuses on the role of evidence-based guidelines in influencing the use of hematopoietic growth factors in medical practice. The next section updates the current clinical status of amifostine (Ethyol, Alza Corp., Palo Alto CA, USA, and US Bioscience, West Conshohocken, PA, USA) the first broad-spectrum cytoprotective agent available. The management of invasive fungal infections and the use of liposomal antifungal agents are reviewed next. Finally, the current status of transfusion support is presented.

Invasive aspergillosis. Disease spectrum, treatment practices, and outcomes. I3 Aspergillus Study Group

A review of representative cases of invasive aspergillosis was conducted to describe current treatment practices and outcomes. Eighty-nine physicians experienced with aspergillosis completed case forms on 595 patients with proven or probable invasive aspergillosis diagnosed using modifications of the Mycoses Study Group criteria. Pulmonary disease was present in 56%, with disseminated infection in 19%. The major risk factors for aspergillosis were bone marrow transplantation (32%) and hematologic malignancy (29%), but patients had a variety of underlying conditions including solid organ transplants (9%), AIDS (8%), and pulmonary diseases (9%). Overall, high antifungal failure rates occurred (36%), and complete antifungal responses were noted in only 27%. Treatment practices revealed that amphotericin B alone (187 patients) was used in most severely immunosuppressed patients while itraconazole alone (58 patients) or sequential amphotericin B followed by itraconazole (93 patients) was used in patients who were less immunosuppressed than patients receiving amphotericin B alone. Response rate for patients receiving amphotericin B alone was poor, with complete responses noted in only 25% and death due to or with aspergillosis in 65%. In contrast, patients receiving itraconazole alone or following amphotericin B had death due to or with Aspergillus in 26% and 36%, respectively. These results confirm that mortality from invasive aspergillosis in severely immunosuppressed patients remains high even with standard amphotericin B. Improved responses were seen in the less immunosuppressed patients receiving sequential amphotericin B followed by itraconazole and those receiving itraconazole alone. New approaches and new therapies are needed to improve the outcome of invasive aspergillosis in high-risk patients.

Intensive intravenous amphotericin B for prophylaxis of systemic fungal infections. Results of a prospective controlled pilot study in acute leukemia patients

BACKGROUND

Invasive fungal infections are an increasing cause of morbidity in acute leukemia (AL) patients.

METHODS

In a prospective pilot trial, the safety and efficacy of antifungal prophylaxis with intravenous (i.v.) amphotericin B (AMB; 1 mg/kg every 48 h) was studied in 46 consecutive cycles. Prophylaxis with i.v. AMB was carried out in patients treated with intensive chemotherapy for AL and compared with a control of 49 cycles without prophylaxis.

RESULTS

Pulmonary infiltrates (5 vs. 23; p < 0.001) and fungal microabscesses in the liver or spleen (0 vs. 6; p = 0.014) occurred significantly less frequently in the prophylaxis group. While there were 3 deaths related to systemic fungal infections in the control group, there were none in the prophylaxis group. Escalation to conventional AMB (1.0 mg/kg/day) was significantly less frequent in the prophylaxis group (9 out of 46 cycles) compared with the control arm (29 out of 49 cycles; p = 0.001). A total of 695 mg of AMB per cycle was administered in the prophylaxis arm, compared with 634 mg/cycle for empirical treatment in the control group (p = 0.6). Infusion-related toxicity was documented in 29% of the cycles of prophylaxis compared with 55% of the cycles of empirical treatment with i.v. AMB in the control group. The nephrotoxicity of AMB prophylaxis was moderate, with >/= WHO degree II reported in 1 out of 46 cycles only.

CONCLUSION

Intensive i.v. AMB prophylaxis reduced invasive fungal infections and led to a reduction in fungal microabscesses in the liver or spleen, as well as pulmonary infiltrates, in patients treated for AL. The need for escalation to empirical i.v. AMB treatment was significantly reduced. Intensive AMB prophylaxis was feasible, with moderate adverse effects.

A strategy for managing fungal infections in haematopoietic stem cell transplantation

As more indications continue to be found for allogeneic haematopoietic transplantation, more patients are at risk for invasive fungal infectious diseases (IFID), particularly candidiasis and aspergillosis. Risk factors for disease are becoming better defined and diagnostic methods have improved considerably. In addition, there is now international agreement that three elements form the basis for defining IFID (host factors, clinical evidence, and mycological results), that imaging is acceptable for diagnosing disease, and that indirect tests such as antigen detection are also adequate mycological proof of cause. There are also more drugs available and still more to come, offering the potential for selective prophylaxis as well as preemptive and specific therapy, as well as for flexible administration. Hence, all the elements are in place for designing and testing an effective and economically sound strategy for dealing with IFID.

Factors associated with severe manifestations of histoplasmosis in AIDS

We report factors associated with severe manifestations of histoplasmosis (such as shock, respiratory failure, and death) in patients with AIDS during an outbreak. Severe disease was present in 28 of 155 patients (17.9%). The following factors were associated with severe disease: black race (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.2-6.2); hemoglobin level <9.5 g/dL (OR, 2.7; 95% CI, 1.2-6.4), partial thromboplastin time >45 s (OR, 3.1; 95% CI, 1.1-9.3); alkaline phosphatase level >2.5 times normal (OR, 3.4; 95% CI, 1.3-8.7); aspartate aminotransferase level >2.5 times normal (OR, 4.2; 95% CI, 1.7-10.0); bilirubin level concentration >1.5 mg/dL (OR, 9.2; 95% CI, 2.5-34.3); creatinine concentration >2.1 mg/dL (OR, 8.3; 95% CI, 2.2-31.9); and albumin concentration <3.5 g/dL (OR, 4.6; 95% CI, 1.3-16.4). Zidovudine use was associated with decreased risk of severe disease (OR, 0.3; 95% CI, 0.1-0.7). Multivariate analysis showed that a creatinine value >2.1 mg/dL (OR, 9.5; 95% CI, 1.7-52) and an albumin value <3.5 g/dL (OR, 4.8; 95% CI, 1.0-22) were associated with an increased risk of severe disease, and zidovudine therapy remained associated with a decreased risk (OR, 0.2; 95% CI, 0.1-0.6). Findings associated with severe histoplasmosis should be recognized early and the cases managed aggressively.

Amphotericin B preparations: a maximum tolerated dose in severe invasive fungal infections?

Availability of lipid formulations of amphotericin B has opened up the possibility of treating invasive fungal infections in immunocompromised patients with high doses of this antifungal agent. Evidence is emerging to suggest that lipid formulations may have heightened efficacy compared to conventional amphotericin B. The issue of optimal dosage has been a neglected area. This article reviews published data accrued from clinical, open-label, salvage, and other studies, and finds little support that the use of high doses of lipid formulations are more efficacious than lower doses. The response rates for invasive fungal infection from most studies are predictably around 56%, irrespective of the lipid formulation and dose used. Animal models provide evidence that low doses of a lipid formulation are as successful in reducing fungal dissemination and in prolonging survival as higher doses, although concomitant tissue fungal eradication is not as effectively achieved by the lower doses (survival-mycologic eradication dissociation). Kinetic studies performed in the clinically relevant setting of critically ill patients give further support to the use of low doses, since levels of liposomal amphotericin B at all dosages between 1 and 4 mg/kg/day are similar and above maximum inhibitory concentrations for commonly encountered fungi. There has only been one prospective randomised study designed with the primary end-point of comparing two dosages of an amphotericin B lipid formulation on clinical response and survival. That European Organization for Research and Treatment of Cancer (EORTC) study concluded that liposomal amphotericin B given at 1 mg was as efficacious as 4 mg/kg/day in treating neutropenic patients with invasive pulmonary aspergillosis. There are a multitude of unanswered questions concerning dosing, and their answers are confounded by difficulties in performing clinical trials and the multiplicity of factors other than antifungal chemotherapy that influence outcome. Maximum tolerated dose studies using existing lipid formulations, or perhaps with the newer formulations such as pegylated immunoliposomal amphotericin B, could be performed to shed light on this difficult area.

Pharmacoeconomic analysis of liposomal amphotericin B versus conventional amphotericin B in the empirical treatment of persistently febrile neutropenic patients

PURPOSE

In a randomized, double-blind, comparative, multicenter trial, liposomal amphotericin B was equivalent to conventional amphotericin B for empirical antifungal therapy in febrile neutropenic patients, using a composite end point, but was more effective in reducing proven emergent fungal infections, infusion-related toxicities, and nephrotoxicity. The purpose of this study was to compare the pharmacoeconomics of liposomal versus conventional therapy.

PATIENTS AND METHODS

Itemized hospital billing data were collected on 414 patients from 19 of the 32 centers that participated in the trial. Hospital length of stay and costs from the first dose of study medication to the time of hospital discharge were assessed.

RESULTS

Hospital costs from the time of first dose to discharge were significantly higher for all patients who received liposomal amphotericin B ($48,962 v $43,183; P =.022). However, hospital costs were highly sensitive to the cost of study medication ($39,648 v $43,048 when drug costs were not included; P =.416). Using decision analysis models and sensitivity analyses to vary the cost of study medications and the risk of nephrotoxicity, the break-even points for the cost of liposomal therapy were calculated to range from $72 to $87 per 50 mg for all patients and $83 to $112 per 50 mg in allogeneic bone marrow transplant patients.

CONCLUSION

The cost of liposomal amphotericin B and patient risk for developing nephrotoxicity play large roles in determining whether liposomal amphotericin B is cost-effective as first-line empirical therapy in persistently febrile neutropenic patients.

Agents for treatment of invasive fungal infections

The incidence of fungal infections continues to rise as the population of immunocompromised individuals increases. Despite the enlarging numbers of infections, there are only a few antifungal agents for treatment of deep-seated, invasive infections. These agents include amphotericin B, flucytosine, terbinafine, and several azoles. Progress has been made in understanding the role of these agents in a variety of infections and this article examines in detail these agents and their prophylactic, empiric, and therapeutic uses in invasive mycoses. This article focuses on general concepts of antifungal therapies and provides a detailed review of each antifungal agent available for treatment of deep-seated mycoses.

Aspergillosis in bone marrow transplant recipients

Invasive aspergillosis in bone marrow transplant recipient is associated with a high mortality. Diagnosis is often delayed because the inflammatory response is blunted by immunosuppression. The gold standard of tissue biopsy is often considered too in invasive as the procedure is often complicated by bleeding and secondary infection. Recent finding on non-invasive tests such as serial measurement of peripheral blood galactomannan antigen or DNA appears to be promising. However, the limited availability of such tests and requirement for expertise are still hampering their use in routine clinical management. More often than not, initiation of antifungal therapy is empirical and based on suggestive radiological changes. Amphotericin B remains the gold standard of therapy but liposconal preparation may prove to be less nephrotoxic and equally effective. Treatment outcome depends more on the acceleration of the recovery of the immune system and the reduction of anti-GVHD therapy than the antifungal agent followed by surgical resection. The efficacy of many reported anti-aspergillosis prophylactic regimen has not been proved in randomized control trials. Despite the absence of data, such policy should still be considered in transplant units with high incidence of aspergillus or undergoing renovation.

Fluconazole vs low-dose amphotericin B for the prevention of fungal infections in patients undergoing bone marrow transplantation: a study of the North American Marrow Transplant Group

Systemic fungal infections are a major problem in bone marrow transplant recipients who have prolonged neutropenia or who receive high-dose corticosteroids. Prophylaxis with Fluconazole or low-dose amphotericin B reduces, but does not eliminate these infections. To determine which prophylactic agent is better, we performed a prospective randomized study. Patients undergoing allogeneic (related or unrelated) or autologous marrow or peripheral stem cell transplantation were randomized to receive Fluconazole (400 mg/day p. o. or i.v.) or amphotericin B (0.2 mg/kg/day i.v.) beginning 1 day prior to stem cell transplantation and continuing until recovery of neutrophils to >500/microl. Patients were removed from their study drug for drug-associated toxicity, invasive fungal infection or suspected fungal infection (defined as the presence of fever >38 degrees C without positive culture while on broad-spectrum anti-bacterial antibiotics). Proven or suspected fungal infections were treated with high-dose amphotericin B (0.5-0.7 mg/kg/day). Patients were randomized at each institution and stratified for the type of transplant. The primary end-point of the study was prevention of documented fungal infection; secondary endpoints included fungal colonization, drug toxicity, duration of hospitalization, duration of fever, duration of neutropenia, duration and total dose of high-dose amphotericin B and overall survival to hospital discharge. From July 1992 to October 1994, a total of 355 patients entered into the trial with 159 patients randomized to amphotericin B and 196 to Fluconazole. Patient groups were comparable for diagnosis, age, sex, prior antibiotic or antifungal therapy, use of corticosteroids prior to transplantation and total duration of neutropenia. Amphotericin B was significantly more toxic than Fluconazole especially in related allogeneic transplantation where 19% of patients developed toxicity vs 0% of Fluconazole recipients (p < 0.05). Approximately 44% of all patients were removed from prophylaxis for presumed fungal infection. Proven fungal infections occurred in 4.1% and 7.5% of Fluconazole and amphotericin-treated patients, respectively. Proven fungal infections occurred in 9.1% and 14.3% of related allogeneic marrow recipients receiving Fluconazole or amphotericin B, respectively, and 2.1% and 5.6% of autologous marrow recipients receiving Fluconazole or amphotericin B, respectively (P > 0.05). In this prospective trial, low-dose amphotericin B prophylaxis was as effective as Fluconazole prophylaxis, but Fluconazole was significantly better tolerated.

Practice guidelines for the treatment of candidiasis. Infectious Diseases Society of America

Infections due to Candida species are the most common of the fungal infections. Candida species produce a broad range of infections, ranging from nonlife-threatening mucocutaneous illnesses to invasive process that may involve virtually any organ. Such a broad range of infections requires an equally broad range of diagnostic and therapeutic strategies. This document summarizes current knowledge about treatment of multiple forms of candidiasis and is the guideline of the Infectious Diseases Society of America (IDSA) for the treatment of candidiasis. Throughout this document, treatment recommendations are scored according to the standard scoring scheme used in other IDSA guidelines to illustrate the strength of the underlying data. The document covers 4 major topical areas. The role of the microbiology laboratory. To a greater extent than for other fungi, treatment of candidiasis can now be guided by in vitro susceptibility testing. The guidelines review the available information supporting current testing procedures and interpretive breakpoints and place these data into clinical context. Susceptibility testing is most helpful in dealing with infection due to non-albicans species of Candida. In this setting, especially if the patient has been treated previously with an azole antifungal agent, the possibility of microbiological resistance must be considered. Treatment of invasive candidiasis. In addition to acute hematogenous candidiasis, the guidelines review strategies for treatment of 15 other forms of invasive candidiasis. Extensive data from randomized trials are really available only for therapy of acute hematogenous candidiasis in the nonneutropenic adult. Choice of therapy for other forms of candidiasis is based on case series and anecdotal reports. In general, both amphotericin B and the azoles have a role to play in treatment. Choice of therapy is guided by weighing the greater activity of amphotericin B for some non-albicans species (e.g., Candida krusei) against the lesser toxicity and ease of administration of the azole antifungal agents. Flucytosine has activity against many isolates of Candida but is not often used. Treatment of mucocutaneous candidiasis. Therapy for mucosal infections is dominated by the azole antifungal agents. These drugs may be used topically or systemically and have been proven safe and efficacious. A significant problem with mucosal disease is the propensity for a small proportion of patients to suffer repeated relapses. In some situations, the explanation for such a relapse is obvious (e.g., relapsing oropharyngeal candidiasis in an individual with advanced and uncontrolled HIV infection), but in other patients the cause is cryptic (e.g., relapsing vaginitis in a healthy woman). Rational strategies for these situations are discussed in the guidelines and must consider the possibility of induction of resistance over time. Prevention of invasive candidiasis. Prophylactic strategies are useful if the risk of a target disease is sharply elevated in a readily identified group of patients. Selected patient groups undergoing therapy that produces prolonged neutropenia (e.g., some bone-marrow transplant recipients) or who receive a solid-organ transplant (e.g., some liver transplant recipients) have a sufficient risk of invasive candidiasis to warrant prophylaxis.

Tuftsin-bearing liposomes in treatment of macrophage-based infections

The use of liposomes as drug carriers in treatment of various diseases has been explored extensively for more than 20 years. 'Conventional' liposomes, when administered in vivo by a variety of routes, rapidly accumulate in the mononuclear phagocyte system (MPS). The inherent tendency of the liposomes to concentrate in MPS can be exploited in enhancing the non-specific host defence against infections by entrapping in them the macrophage modulators, and as carriers of antibiotics in treatment of intracellular infections that reside in MPS. This must further be enhanced by grafting on the liposome surface the ligands, e.g. tuftsin, that not only binds specifically to the MPS cells but also enhances their natural killer activity. Keeping this in view, we designed and developed tuftsin-bearing liposomes as drug carriers for the treatment of macrophage-based infections and outline these studies in this overview.

A multicenter, randomized trial of fluconazole versus amphotericin B for empiric antifungal therapy of febrile neutropenic patients with cancer

PURPOSE

To compare the efficacy and safety of fluconazole and amphotericin B as empiric antifungal therapy of febrile neutropenic patients with cancer.

PATIENTS AND METHODS

A total of 317 neutropenic patients (<500 cells/mm3) with persistent or recrudescent fever despite 4 or more days of antibacterial therapy were randomly assigned to receive either fluconazole (400 mg intravenously once daily) or amphotericin B (0.5 mg/kg once daily). Patients were evaluated for the efficacy and safety of each drug by clinical criteria, frequent cultures and radiological procedures, and laboratory values. A response was classified as satisfactory at the end of therapy if the patient was afebrile, had no clinical or microbiological evidence of fungal infection, and did not require study termination due to lack of efficacy, drug toxicity, or death.

RESULTS

A satisfactory response occurred in 68% of the patients treated with fluconazole (107 of 158 patients) and in 67% of patients treated with amphotericin B (106 of 159 patients). Progressive or new fungal infections during therapy occurred in 13 (8%) patients treated with fluconazole (8 with Candida, 5 with Aspergillus) and in 10 (6%) patients treated with amphotericin B (5 with Candida, 3 with Aspergillus, 2 with other fungi). Adverse events related to study drug (especially fever, chills, renal insufficiency, electrolyte disturbances, and respiratory distress) occurred more often in patients treated with amphotericin B (128 [81%] of 159 patients) than patients treated with fluconazole (20 [13%] of 158 patients, P = 0.001). Eleven (7%) patients treated with amphotericin B but only 1 (1%) patient treated with fluconazole were terminated from the study owing to an adverse event (P = 0.005). Overall mortality (27 [17%] patients treated with fluconazole versus 34 [21%] patients treated with amphotericin B) and mortality from fungal infection (7 [4%] patients treated with fluconazole versus 5 [3%] patients treated with amphotericin B) were similar in each study group.

CONCLUSIONS

Intravenous fluconazole can be an effective and safe alternative to amphotericin B for empiric antifungal therapy in many febrile neutropenic patients. However, because fluconazole may be ineffective in the treatment of Aspergillus, patients at risk for that infection should be evaluated by chest radiograph, computed tomographic scanning, and cultures before the use of empiric fluconazole therapy.

Efficacy of liposomal amphotericin B with prolonged circulation in blood in treatment of severe pulmonary aspergillosis in leukopenic rats

The therapeutic efficacy of long-circulating polyethylene glycol-coated liposomal amphotericin B (AMB) (PEG-AMB-LIP) was compared with that of AMB desoxycholate (Fungizone) in a model of severe invasive pulmonary aspergillosis in persistently leukopenic rats as well as in temporarily leukopenic rats. PEG-AMB-LIP treatment (intravenous administration) consisted of a single, or double (every 72 h), or triple (every 72 h) dose of 10 mg of AMB/kg of body weight, a double dose (every 72 h) of 14 mg of AMB/kg, or a 5-day treatment (every 24 h) with 6 mg/kg/dose. AMB desoxycholate was administered for 10 consecutive days at 1 mg of AMB/kg/dose. Treatment was started 30 h after fungal inoculation, at which time mycelial growth was firmly established. Both persistently and temporarily leukopenic rats died between 4 and 9 days after Aspergillus fumigatus inoculation when they were left untreated or after treatment with a placebo. In persistently leukopenic rats, a single dose of PEG-AMB-LIP (10 mg/kg) was as effective as the 10-day treatment with AMB desoxycholate (at 1 mg/kg/dose) in significantly prolonging the survival of rats infected with A. fumigatus and in reducing the dissemination of A. fumigatus to the liver. Prolongation of PEG-AMB-LIP treatment (double or triple dose or 5-day treatment) did not further improve efficacy. For temporarily leukopenic rats no major advances in efficacy were achieved compared to those for persistently leukopenic rats, probably because the leukocyte numbers in blood were restored too late in the course of infection.

Pulmonary infection caused by Gymnascella hyalinospora in a patient with acute myelogenous leukemia

We report the first case of invasive pulmonary infection caused by the thermotolerant ascomycetous fungus Gymnascella hyalinospora in a 43-year-old female from the rural midwestern United States. The patient was diagnosed with acute myelogenous leukemia and treated with induction chemotherapy. She was discharged in stable condition with an absolute neutrophil count of 100 cells per microliter. Four days after discharge, she presented to the Cancer Clinic with fever and pancytopenia. A solitary pulmonary nodule was found in the right middle lobe which was resected by video-assisted thoracoscopy (VATHS). Histopathological examination revealed septate branching hyphae, suggesting a diagnosis of invasive aspergillosis; however, occasional yeast-like cells were also present. The culture grew a mold that appeared dull white with a slight brownish tint that failed to sporulate on standard media. The mold was found to be positive by the AccuProbe Blastomyces dermatitidis Culture ID Test (Gen-Probe Inc., San Diego, Calif.), but this result appeared to be incompatible with the morphology of the structures in tissue. The patient was removed from consideration for stem cell transplant and was treated for 6 weeks with amphotericin B (AmB), followed by itraconazole (Itr). A VATHS with biopsy performed 6 months later showed no evidence of mold infection. In vitro, the isolate appeared to be susceptible to AmB and resistant to fluconazole and 5-fluorocytosine. Results for Itr could not be obtained for the case isolate due to its failure to grow in polyethylene glycol used to solubilize the drug; however, MICs for a second isolate appeared to be elevated. The case isolate was subsequently identified as G. hyalinospora based on its formation of oblate, smooth-walled ascospores within yellow or yellow-green tufts of aerial hyphae on sporulation media. Repeat testing with the Blastomyces probe demonstrated false-positive results with the case isolate and a reference isolate of G. hyalinospora. This case demonstrates that both histopathologic and cultural features should be considered for the proper interpretation of this molecular test and extends the list of fungi recognized as a cause of human mycosis in immunocompromised patients.

Amphotericin B lipid soluble formulations vs amphotericin B in cancer patients with neutropenia

BACKGROUND

Patients with cancer who are treated with chemotherapy or receive a bone marrow transplant have an increased risk of acquiring fungal infections. Such infections can be life-threatening. Antifungal drugs are therefore often given prophylactically to such patients, or when they have a fever.

OBJECTIVES

To compare the effect and adverse effects of AmBisome and other lipid soluble formulations of amphotericin B with conventional amphotericin B in cancer patients with neutropenia.

SEARCH STRATEGY

MEDLINE and Cochrane Library. Unpublished trials from conference proceedings and contact to industry.

SELECTION CRITERIA

Randomised trials comparing lipid soluble formulations of amphotericin B with conventional amphotericin B.

DATA COLLECTION AND ANALYSIS

Data on mortality, invasive fungal infection, nephrotoxicity, serum creatinine and dropouts were extracted by both authors independently.

MAIN RESULTS

AmBisome vs conventional amphotericin B (3 trials, 1149 patients): AmBisome tended to be more effective than conventional amphotericin B for invasive fungal infection (relative risk 0.63, 95% confidence interval 0.39 to 1.01, P=0.053) whereas there was no significant difference in mortality (relative risk 0.74, 95% CI 0.52 to 1.07). AmBisome decreased significantly the incidence of nephrotoxicity, defined as a 100% increase in serum creatinine (relative risk 0.51, 95% CI 0.40 to 0.64). Fewer patients dropped out on AmBisome but the difference was not significant (relative risk 0.78, 95% CI 0.56 to 1. 08). Amphotericin B in Intralipid vs conventional amphotericin B (4 trials, 145 patients): There were no significant differences in clinical effect whereas the patients treated with the lipid soluble formulation experienced significantly less nephrotoxicity (relative risk 0.34, 95% CI 0.15 to 0.75) and smaller increases in serum creatinine (weighted mean difference 32 micromol/l, 95% CI 21 to 43 micromol/l). Amphotericin B colloidal dispersion (ABCD) vs conventional amphotericin B (1 trial, 213 patients): There was lower nephrotoxicity with ABCD (relative risk 0.38, 95% CI 0.25 to 0.59).

REVIEWER'S CONCLUSIONS

AmBisome is a better drug than conventional amphotericin B but its high cost prohibits routine use in most settings. Furthermore, the advantages of AmBisome may be smaller than indicated in our review if conventional amphotericin B is administered under optimal circumstances. It is not clear whether other lipid formulations of amphotericin B could offer a worthwhile advantage compared to conventional amphotericin B.

Antimicrobial therapy for infants and children: guidelines for the inpatient and outpatient practice of pediatriac infectious diseases

In this article, we discuss antimicrobial regimens for both outpatient and inpatient use in infants and children. A substantial number of pediatric patient visits annually result in the prescribing of antimicrobial drugs. The emergence of bacteria resistant to commonly used antimicrobial agents is a growing concern. Information on newer drugs such as meropenem, which is active against penicillin-resistant Streptococcus pneumoniae and gram-negative bacilli, and cefepime, which has activity against gram-negative bacilli including Pseudomonas aeruginosa and against gram-positive cocci is also presented. Management of patients with congenital or acquired immunodeficiencies continues to be challenging in regard to the use of antimicrobial drugs to treat various fungal and viral infections. New formulations of older drugs such as aerosolized tobramycin and amphotericin B lipid complex are available. New antiviral agents have been approved, most of which are antiretroviral agents. Childhood tuberculosis is an ongoing concern, and regimens to treat Mycobacterium tuberculosis in children are discussed.

Fungal infections in patients undergoing blood and marrow transplantation

Fungal infections are currently a leading cause of infectious morbidity and mortality in patients undergoing allogeneic blood and marrow transplantation (BMT). Although the introduction of azole antifungals for prophylaxis has had a significant impact on the incidence of candidal infections (especially those caused by C. albicans and C. tropicalis), invasive aspergillosis has increased in incidence in many centers worldwide. Given the long risk period corresponding with graft-versus-host disease, and the toxicities of currently available mold-active antifungals, the development of a prevention strategy for these angioinvasive molds remains a challenge. The introduction of new antifungal drugs and adjunctive therapy to improve immune function may be beneficial in decreasing mortality associated with these infections in the future. Most importantly, a greater understanding of the pathogenesis of fungal disease and specific host risks is necessary to impact this increasingly important infection in immunocompromised hosts.

Advances in antimicrobial therapy

Despite several decades of improved therapy and prevention of infectious diseases, infectious pathogens remain major causes of morbidity and mortality in humans worldwide. Among the most complex and daunting problems facing medical science is the evolution of antibiotic resistance among many common and once easily-treated infectious agents. This review summarizes the status of newer antimicrobial agents that have utility against pathogens infecting the central nervous system.

Amphotericin B and its new formulations: pharmacologic characteristics, clinical efficacy, and tolerability

Amphotericin B (amB) remains the gold standard for the treatment of invasive fungal infections. However, the efficacy is limited, with response rates from 10% to 80%. Moreover, amB is toxic, especially for the kidneys. New formulations have been developed in an attempt to improve both efficacy and tolerability. In an attempt to reduce toxicity, a number of investigators have reconstituted amB in a lipid emulsion, but few data are available on efficacy in documented infections. An improvement in immediate and renal tolerance was obtained with equivalent daily dose regimens, but the therapeutic index does not appear to be improved. This approach cannot be recommended at present. Three lipid formulations have been developed and are now available in most countries: amB colloidal dispersion (ABCD), amB lipid complex (ABLC), and liposomal amB (AmBisome). The efficacy of ABCD on various fungal infections has been assessed in open trials, with a response rate of 49% in aspergillosis, 70% in candidiasis, and 67% in mucormycosis. In two randomized trials comparing ABCD with amB in invasive aspergillosis and in persistent febrile neutropenia, the response rates were equivalent. ABCD was less nephrotoxic. In contrast, immediate reactions to ABCD were as frequent and severe as with amB. These immediate effects are more frequent during the first infusions and lessen as treatment continues. The recommended dose is 3-4 mg/kg/day. ABLC appeared to be effective as rescue therapy in various types of invasive mycoses, with a response rate of 42% in aspergillosis, 67% in candidiasis, and 82% in fusariosis. Efficacy identical to that of amB was demonstrated in a comparative randomized trial involving patients with invasive candidiasis. General and renal tolerability is improved compared with amB. The recommended dose regimen is 5 mg/kg/day. Liposomal amB (AmBisome) is the only truly liposomal formulation. The response rates in preliminary trials were 66% in aspergillosis and 81% in candidiasis. Several comparative studies have confirmed that this formulation has similar or superior efficacy relative to amB in various fungal infections and also in the empirical treatment of febrile neutropenia. Renal and general tolerability is excellent. The optimal dosing remains unclear but is generally between 3 and 5 mg/kg/day. A double-blind trial comparing the tolerance of liposomal amB and ABLC demonstrated that both infusion-related events and nephrotoxicity were significantly lower for liposomal amB. In sum, the new lipid formulations of amB are effective in various invasive fungal infections. The three formulations exhibit reduced nephrotoxicity compared with conventional amB. Large-scale comparative clinical trials may clarify issues of relative efficacy in various forms of mycotic infections.

Antifungal prophylaxis in neutropenia

Despite the widespread prophylactic use of antifungal agents in neutropenic patients, invasive fungal infections continue to emerge as major causes of morbidity and mortality. With the exception of fluconazole prophylaxis in allogeneic marrow transplant recipients, no firm conclusions can be drawn due to the lack of reliable, randomized trials. At the present time, it seems that antifungal chemoprophylaxis is more a matter of faith rather than science. Earlier diagnosis based on noninvasive diagnostic techniques and pre-emptive strategies may offer more promise than a liberal prophylactic approach.

Clinical significance of nephrotoxicity in patients treated with amphotericin B for suspected or proven aspergillosis

The records of 239 immunosuppressed patients receiving amphotericin B for suspected or proven aspergillosis were reviewed to determine rates of nephrotoxicity, dialysis, and fatality. The mean and median durations of treatment were 20.4 and 15.0 days, respectively. The creatinine level doubled in 53% of patients and exceeded 2.5 mg/dL in 29%; 14.5% underwent dialysis; and 60% died. A multivariate Cox proportional hazards analysis showed that patients whose creatinine level exceeded 2.5 mg/dL (hazard ratio [HR], 42.02; P<.001), allogeneic bone marrow transplantation (BMT) patients (HR, 6.34; P<. 001), and autologous BMT patients (HR, 5.06; P=.024) were at greatest risk for requiring hemodialysis. Use of hemodialysis (HR, 3. 089; P<.001), duration of amphotericin B use (HR, 1.03 per day; P=. 015), and use of nephrotoxic agents (HR, 1.96; P=.017) were associated with greater risk of death, whereas patients undergoing solid organ transplantation were at lowest risk (HR, 0.46; P=.002). These data indicate that elevated creatinine levels during amphotericin B treatment are associated with a substantial risk for hemodialysis and a higher mortality rate, but the risks vary in different patient groups.

Safety and toxicokinetics of intravenous liposomal amphotericin B (AmBisome) in beagle dogs

PURPOSE

Amphotericin B (AmB) in small, unilamellar liposomes (AmBisome) has an improved therapeutic index, and altered pharmacokinetics. The repeat-dose safety and toxicokinetic profiles of AmBisome were studied at clinically relevant doses.

METHODS

Beagle dogs (5/sex/group) received intravenous AmBisome (0.25, 1, 4, 8, and 16 mg/kg/day), empty liposomes or vehicle for 30 days. AmB was determined in plasma on days 1, 14, and 30, and in tissues on day 31. Safety parameters included body weight, clinical chemistry, hematology and microscopic pathology.

RESULTS

Seventeen of twenty animals receiving 8 and 16 mg/kg were sacrificed early due to weight loss caused by reduced food intake. Dose-dependent renal tubular nephrosis, and other effects characteristic of conventional AmB occurred at 1 mg/kg/day or higher. Although empty liposomes and AmBisome increased plasma cholesterol, no toxicities unique to AmBisome were revealed. Plasma ultrafiltrates contained no AmB. AmBisome achieved plasma levels 100-fold higher than other AmB formulations. AmBisome kinetics were non-linear, with clearance and distribution volumes decreasing with increasing dose. This, and nonlinear tissue uptake, suggest AmBisome disposition was saturable.

CONCLUSIONS

AmBisome has the same toxic effects as conventional AmB, but they appear at much higher plasma exposures. AmBisome's non-linear pharmacokinetics are not associated with increased risk, as toxicity increases linearly with dosage. Dogs tolerated AmBisome with minimal to moderate changes in renal function at doses (4 mg/kg/day) producing peak plasma concentrations of 18-94 microg/mL.

Emerging Issues in Nosocomial Fungal Infections

Nosocomial fungal infections remain a serious cause of morbidity and mortality. As immunodeficient populations increase, the incidence of nosocomial fungal infections continues to rise. Although a wide variety of new and emerging fungi can cause nosocomial infections, Candida species remain the major etiologic agent. Candida species vary in their epidemiology and therapy. New diagnostic, epidemiologic, and therapeutic tools have been developed and are discussed in this review. They include the use of polymerase chain reaction-based diagnostic methods, recent advances in antifungal susceptibility testing, and comparative therapeutic and prophylactic trials. As advances in prevention, diagnosis, and therapy continue, nosocomial fungal infections and the morbidity and mortality associated with them can be reduced.

Safety and efficacy of multilamellar liposomal nystatin against disseminated candidiasis in persistently neutropenic rabbits

The activity of liposomal nystatin (L-Nys) against subacute disseminated candidiasis was investigated in persistently neutropenic rabbits. Antifungal therapy was administered for 10 days starting 24 h after intravenous inoculation of 10(3) blastoconidia of Candida albicans. Responses to treatment were assessed by the quantitative clearance of the organism from blood and tissues. Treatments consisted of L-Nys at dosages of 2 and 4 mg/kg of body weight/day (L-Nys2 and L-Nys4, respectively) amphotericin B deoxycholate at 1 mg/kg/day (D-AmB), and fluconazole at 10 mg/kg/day (Flu). All treatments were given intravenously once daily. Compared to the results for untreated but infected control animals, treatment with L-Nys2, L-Nys4, D-AmB, and Flu resulted in a significant clearance of the residual burden of C. albicans from the kidney, liver, spleen, lung, and brain (P < 0.0001 by analysis of variance). When the proportion of animals infected at at least one of the five tissue sites studied was evaluated, a dose-dependent response to treatment with L-Nys was found (P < 0.05). Compared to D-AmB-treated rabbits, mean serum creatinine and blood urea nitrogen levels at the end of therapy were significantly lower in animals treated with L-Nys2 (P < 0.001) and L-Nys4 (P < 0.001 and P < 0.01, respectively). L-Nys was less nephrotoxic than conventional amphotericin B and had dose-dependent activity comparable to that of amphotericin B for the early treatment of subacute disseminated candidiasis in persistently neutropenic rabbits.

Systemic fungal infections in patients with hematologic malignancies: indications and limitations of the antifungal armamentarium

The rates of fungal infections have increased substantially in Europe as well as in North America. Most frequently Aspergillus spp. and Candida spp. are isolated. Despite the recent introduction of new azoles and lipid-based formulations of amphotericin B, there are relatively few randomized, controlled studies on the use of antifungal drugs in patients with hematological malignancies and invasive fungal infections. Conventional amphotericin B is considered the gold standard for the treatment of invasive fungal infections; however, adverse events limit conventional amphotericin B treatment. The newer azoles, fluconazole and itraconazole, are well tolerated; however, fluconazole has no activity against Aspergillus spp. An additional serious problem is the emerging resistance of nonalbicans Candida spp. to fluconazole. In this situation, lipid formulations of amphotericin B seem to be attractive, since the use of these drugs has been shown to be safe and effective. Considerably higher medical costs limit broader application of lipid formulations of amphotericin B. Because of the rapidly increasing incidence of serious fungal infections, we have reviewed current strategies and the role of newer antifungal drugs for the treatment of deep-organ infections.