Antifungal chemoprophylaxis after blood and marrow transplantation

Application of Culture-Independent Rapid Diagnostic Tests in the Management of Invasive Candidiasis and Cryptococcosis

The diagnosis of invasive candidiasis (IC) and cryptococcosis is often complicated by slow and insensitive culture-based methods. Such delay results in poor outcomes due to the lack of timely therapeutic interventions. Advances in serological, biochemical, molecular and proteomic approaches have made a favorable impact on this process, improving the timeliness and accuracy of diagnosis with resultant improvements in outcome. This paper will serve as an overview of recent developments in the diagnostic approaches to infections due to these important yeast-fungi.

Preventing invasive fungal disease in patients with haematological malignancies and the recipients of haematopoietic stem cell transplantation: practical aspects

Invasive fungal disease (IFD), predominantly aspergillosis, is associated with significant morbidity and mortality in immunocompromised patients, especially those with haematological malignancies and recipients of allogeneic haematopoietic stem cell transplantation. There has been a great deal of scientific debate as to the effectiveness of antifungal prophylaxis in preventing infection in different patient groups and in which patients it is an appropriate management option. Deciding on an appropriate prophylaxis regimen for IFD is challenging as the incidence varies among different patient groups, due to the varied nature of their underlying haematological disease, and in different regions and centres. Attempts have been made to define risk factors and include them in treatment protocols. Impaired immune status of the patient, especially neutropenia, is a key risk factor for IFD and can sometimes be related to specific polymorphisms of genes controlling innate immunity. Risk factors also vary according to the type of fungal pathogen. Consequently, prophylaxis needs to be tailored to individual patient groups. Furthermore, the choice of antifungal agent for prophylaxis depends on the potential for drug-drug interactions with the patients' concomitant medications. Additional challenges are optimal timing of antifungal prophylaxis, when to change from prophylaxis to antifungal treatment and how to prevent recurrence of IFD. This article considers the use of antifungal prophylaxis for patients at risk of IFD in daily clinical practice, with clinical profiles that may be distinct from those covered by guidelines, and aims to provide practical advice for treatment of these patient groups.

Antifungal prophylaxis with micafungin in patients treated for childhood cancer

BACKGROUND

Invasive fungal infections (IFIs) remain a major cause of infectious morality in neutropenic patients receiving chemotherapy or hematopoietic stem cell transplantation (HSCT). Micafungin exhibits broad antifungal activity against both Aspergillus and Candida species. We performed a retrospective study to determine the efficacy and safety of prophylactic micafungin against IFI in pediatric neutropenic patients during chemotherapy or HSCT.

PROCEDURE

Forty patients were given micafungin (3 mg/kg/day) intravenously for neutropenia: 131 patient-cycles (39 patients) after chemotherapy and 15 patient-cycles (14 patients) after HSCT. Median duration of neutropenia and micafungin prophylaxis was 13 and 23 days after chemotherapy and HSCT, respectively.

RESULTS

Treatment success rate, defined as absence of proven, probable, possible, or suspected IFIs, was 93.9% (121/131) and 80.0% (12/15) for chemotherapy and HSCT, respectively. Proven or probable IFI was documented in only one patient after HSCT. No adverse events were observed that could be related to micafungin prophylaxis.

CONCLUSIONS

These results suggest that prophylactic micafungin is well tolerated and may prevent IFIs in pediatric patients with neutropenia receiving chemotherapy or HSCT.

Stem Cell Transplantation

Hematopoietic cell transplantation (HCT) is associated with profound compromises in host defenses. The patterns of immune compromise change over time. Infections are an important cause of serious morbidity and pose substantial threats to life. Thus, the challenges of infection facing the transplant clinician are both myriad and dynamic. Early after transplant, neutropenic infections are most important. Later herpesvirus and invasive fungal infections predominate. Even late after transplant, patients with chronic graft versus host disease remain susceptible to encapsulated bacterial, varicella zoster virus, and invasive fungal infections. Over time, with robust engraftment and control of GVHD, the risk of serious infections recedes with immune reconstitution.

Successfully treatedCandida kruseiinfection of the lumbar spine with combined caspofungin/posaconazole therapy

Candidal vertebral osteomyelitis represents an extremely rare invasive mycosis and can be difficult to treat due to poor drug penetration into bony tissue. We report on a case of vertebral osteomyelitis caused by Candida krusei in a patient who had neutropenia as a result of chemotherapy for acute myelogenous leukaemia. The patient received prophylactic liposomal amphotericin B during chemotherapy but became febrile and experienced severe lumbar pain. Magnetic resonance imaging revealed vertebral osteochondrosis. C. krusei was recovered from blood cultures and voriconazole monotherapy was initiated but proved unsuccessful. The patient was then started on caspofungin monotherapy, which was discontinued after Candida krusei was no longer recoverable from blood cultures. However, as lumbar pain increased and spinal biopsy confirmed the presence of Candida krusei, caspofungin therapy was resumed. Oral posaconazole was added to the regimen when the patient did not improve after 30 days of caspofungin therapy. Combined antimycotic therapy resulted in a successful outcome.

Current trends of infectious complications following hematopoietic stem cell transplantation in a single center

This study was to analyze the infectious complications after hematopoietic stem cell transplantation (HSCT) according to the recent changes of HSCT. Medical records of 379 adult patients who underwent HSCT consecutively at Catholic HSCT Center from January 2001 to December 2002 were reviewed retrospectively. Allogeneic HSCT accounted for 75.7% (287/379) and autologous HSCT for 24.3% (92/379). During pre-engraftment period, bacterial infection was predominant, and E. coli was still the most common organism. After engraftment, viral infection was predominant. The incidence of invasive fungal infection showed bimodal distribution with peak correlated with neutropenia and graft-versus-host disease (GVHD). The overall mortality and infection-related mortality rates according to 3 periods were as follows; during pre-engraftment, 3.16% (12/379) and 1.8% (7/379); during midrecovery period, 7.9% (29/367) and 4.1% (15/367); during late-recovery period, 26.9% (91/338), and 15.9% (54/338). Risk factors for infection-related mortality were as follows; during pre-engraftment period, fungal infection and septic shock; during the mid-recovery period, hemorrhagic cystitis and delayed engraftment; during the late-recovery period, fungal infection, chronic GVHD, and relapse. In conclusion, infection was still one of the main complications after HSCT and highly contributes to mortality. The early diagnosis and the effective vaccination strategy are needed for control of infections.

Fluconazole for the management of invasive candidiasis: where do we stand after 15 years?

Candida spp. are responsible for most of the fungal infections in humans. Available since 1990, fluconazole is well established as a leading drug in the setting of prevention and treatment of mucosal and invasive candidiasis. Fluconazole displays predictable pharmacokinetics and an excellent tolerance profile in all groups, including the elderly and children. Fluconazole is a fungistatic drug against yeasts and lacks activity against moulds. Candida krusei is intrinsically resistant to fluconazole, and other species, notably Candida glabrata, often manifest reduced susceptibility. Emergence of azole-resistant strains as well as discovery of new antifungal drugs (new triazoles and echinocandins) have raised important questions about its use as a first line drug. The aim of this review is to summarize the main available data on the position of fluconazole in the prophylaxis or curative treatment of invasive Candida spp. infections. Fluconazole is still a major drug for antifungal prophylaxis in the setting of transplantation (solid organ and bone marrow), intensive care unit, and in neutropenic patients. Prophylactic fluconazole still has a place in HIV-positive patients in viro-immunological failure with recurrent mucosal candidiasis. Fluconazole can be used in adult neutropenic patients with systemic candidiasis, as long as the species identified is a priori susceptible. Among non-neutropenic patients with candidaemia fluconazole is one of the first line drugs for susceptible species. Cases reports and uncontrolled studies have also reported its efficacy in the setting of osteoarthritis, endophthalmitis, meningitis, endocarditis and peritonitis caused by Candida spp. among immunocompetent adults. In paediatrics, fluconazole is a well tolerated and major prophylactic drug for high-risk neonates, as well as an alternative treatment for neonatal candidiasis. Importantly 15 years after its introduction in the antifungal armamentarium, fluconazole is still a first line treatment option in several cases of invasive candidiasis. Its prophylactic use should however be limited to selected high-risk patients to limit the risk of emergence of azole-resistant strains.

A prospective study of real-time panfungal PCR for the early diagnosis of invasive fungal infection in haemato-oncology patients

A blinded prospective study was performed to determine whether screening of whole blood using a real-time, panfungal polymerase chain reaction (PCR) technique could predict the development of invasive fungal infection (IFI) in immunocompromised haemato-oncology patients. In all, 78 patients (125 treatment episodes) were screened twice weekly by real-time panfungal PCR using LightCyclertrade mark technology. IFI was documented in 19 treatment episodes (five proven, three probable and 11 possible), and in 12, PCR was sequentially positive. PCR positivity occurred in: 4/5 proven; 2/3 probable; 6/11 possible; and 29/106 with no IFI. In 8/12 with IFI and sequentially positive PCR results, PCR positivity occurred before (median 19.5 days) and in 4/12 (median 10.5 days) after the initiation of empirical antifungal therapy. Based on sequential positive results for proven/probable IFI sensitivity, specificity, positive predictive value and negative predictive value were 75, 70, 15 and 98%, respectively. Real-time panfungal PCR is a sensitive tool for the early diagnosis of IFI in immunocompromised haemato-oncology patients. It may be most useful as a screening method in high-risk patients, either to direct early pre-emptive antifungal therapy or to determine when empirical antifungal therapy can be withheld in patients with antibiotic--resistant neutropenic fever. However, these strategies require further assessment in comparative clinical trials.

Aspergillus infections in transplant recipients

Aspergillus infections are occurring with an increasing frequency in transplant recipients. Notable changes in the epidemiologic characteristics of this infection have occurred; these include a change in risk factors and later onset of infection. Management of invasive aspergillosis continues to be challenging, and the mortality rate, despite the use of newer antifungal agents, remains unacceptably high. Performing molecular studies to discern new targets for antifungal activity, identifying signaling pathways that may be amenable to immunologic interventions, assessing combination regimens of antifungal agents or combining antifungal agents with modulation of the host defense mechanisms, and devising diagnostic assays that can rapidly and reliably diagnose infections represent areas for future investigations that may lead to further improvement in outcomes.

Design Issues in a Prospective Randomized Double-Blinded Trial of Prophylaxis with Fluconazole versus Voriconazole after Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

Aspergillus infections pose the toughest infectious challenges to the clinician caring for hematopoietic cell transplant recipients. About 15% of patients become infected, with a case fatality rate of approximately 65%. To date, no effective prophylactic strategies have been developed.

METHODS

Voriconazole, a recently licensed extended-spectrum azole, with demonstrated efficacy against aspergillus, is currently being tested as a potential prophylactic agent against aspergillus and other invasive fungal infections. Logistic issues--such as patient selection, choice of comparator, blinding of study drugs, duration of study drug administration, and how to handle empirical amphotericin B for possible invasive fungal infections--and analytic concerns, including choice and definition of the primary end point and the potential confounding effect of informative censoring (as a result of noninfectious events), were considered in the design of the clinical trial.

RESULTS

The trial is now under way, with a projected 3-year enrollment period.

CONCLUSIONS

Each design decision shaped the trial in a way that permitted certain questions to be answered while not allowing others to be addressed. Once completed, the trial's results must be interpreted in light of these design details.

The Design of Clinical Trials That Evaluate Antifungal Prophylaxis and Combination Therapy: Introduction and Overview

On 8 February 2003, the second in a series of meetings in honor of John E. Bennett, M.D., was convened in New York City. A report from the previous meeting was published in 2003. The goal of this second meeting was to discuss the design of clinical trials in prophylaxis and combination therapy. This supplement presents 12 articles by leading clinicians who are currently active in trials in this area and presents a current view of the unmet needs and challenges.

A new era of antifungal therapy

Invasive fungal infections pose major management problems for clinicians caring for hematopoietic cell transplant patients. Two major fungal genera, Candida and Aspergillus, account for most fungal infections. Rates of systemic Candida infection range from 15% to 25%, mostly in the pre-engraftment period. Prophylaxis by fluconazole has dramatically reduced the frequency of early Candida infections. Caspofungin has recently been shown to offer an excellent alternative to amphotericin B (with less toxicity) or fluconazole (with a broader spectrum) for therapy of systemic Candida infections. Aspergillus infections occur in 15% to 20% of allogeneic hematopoietic cell transplant patients, most frequently in the post-engraftment period; they are associated with a severe diminution of cell-mediated immune responses by graft-versus-host disease and prolonged corticosteroid use. Voriconazole, a recently introduced broad-spectrum azole, has excellent activity against Aspergillus and is generally well tolerated. Voriconazole currently offers the best prospect for success and tolerance as a first-line treatment for aspergillosis. Second-line therapies include lipid formulations of amphotericin B, caspofungin, or intravenous itraconazole. Unfortunately, early initiation of therapy for aspergillosis is frequently not possible because of inaccurate diagnostics. One new diagnostic, the galactomannan assay, has recently been approved, and others are in development; these offer promise for earlier diagnosis without the need for invasive procedures. It is hoped that these new therapies and new diagnostics will usher in a new era of antifungal therapy.

Infectious complications and outcomes after allogeneic hematopoietic stem cell transplantation in Korea

We reviewed 242 allogeneic hematopoietic stem cell transplantation (HSCT) recipients retrospectively over a 2-year period (January 1998-December 1999) in order to analyze the characteristics and assess the outcomes of infectious complications in patients after HSCT in Korea. Bacteria were the major pathogens before engraftment, and viral and fungal infections predominated during the post-engraftment period. Varicella zoster virus was the most common viral pathogen after engraftment. Cytomegalovirus disease occurred mainly in the late-recovery phase. The frequency of mold infection was higher than that of yeast. There was a relatively high incidence of tuberculosis (3.0%) and Pneumocystis carinii pneumonia (6.5%). One case of death by measles confirmed by autopsy was also noted. Overall, cumulative mortality was 43% (104/242), and 59.6% of these deaths (62/104) were infection-related. Allogeneic HSCT recipients from unrelated donors were prone to infectious complication and higher mortality than those from matched sibling (17/39 (43.6%) vs 45/203 (22.2%), respectively; P<0.01; odd ratio 2.5; 95% confidence interval 1.2-5.1). As infection was the main post-HSCT complication in our data, more attention should be given to the management of infections in HSCT recipients.

Choices aplenty: antifungal prophylaxis in hematopoietic stem cell transplant recipients

The incidence of invasive fungal infection (IFIs) in hematopoietic stem cell transplantation (HSCT) recipients ranges from 10 to 25% with an overall case fatality rate of up to 70-90%. Candida and Aspergillus genera remain the two most common pathogens. Although fluconazole prophylaxis in this population has been moderately effective in reducing mortality due to invasive candidiasis, this agent does not have activity against invasive aspergillosis (IA) and other mould. Several new agents such as voriconazole and caspofungin have enhanced potency and broad-spectrum antifungal activity and show promising results against yeasts and filamentous fungi when given as therapy and as chemoprophylaxis. Further, new diagnostic tools to detect circulating fungal antigens in biological fluids and PCR-based methods to detect species or genus-specific DNA or RNA have been developed. Incorporating these techniques along with clinical criteria appear to improve the accuracy of preclinical diagnosis of IFIs. Such approaches may alter the current treatment strategy from prophylaxis to pre-emptive therapy, thereby potentially decreasing cost and toxicity in high-risk patients.

Invasive fungal infections are responsible for one-fifth of the infectious deaths in children with ALL

The following report will discuss in detail all lethal invasive fungal infections (IFI) that occurred in a group of 2021 children with acute lymphoblasic leukaemia (ALL). The German ALL-Berlin-Frankfurt-Muenster (BFM) study group is one of the largest cooperation for the treatment of childhood ALL. Between 1995 and 2000, 2021 children with ALL received chemotherapy according to the German BFM 95 protocols (ALL-BFM 95). This population was retrospectively screened, whether a lethal fungal infection occurred: totally, in this group, 43 of 2021 (2.1%) children died because of infections. Nine of 43 (21%) patients died in the context of an IFI: six fatal Aspergillus infections and three fatal yeast infections were reported. The following report will focus on the nine children with ALL who died from IFI. The underlying risk factors (RF) included neutropenia (seven of nine patients) and steroid medication (nine of nine patients). Seven of nine children had additional medical complications (e.g. liver failure, haemolytic uraemic syndrome and acute renal failure). In six of nine children the fungal infection was progressive despite intravenous antimycotic therapy, three patients received no antifungal therapy, as IFI was not considered. The progression of IFI despite antimycotic therapy illustrates the inherent problems of diagnosis and the need for innovative therapeutic modalities. The high percentage (21%) of death from IFI among lethal infections in paediatric ALL patients illustrates the relevance of fungi in this group of patients. On the contrary, the total number of IFI in paediatric ALL patients remains to be determined, as only lethal infections were included in this report.

In vitro activities of voriconazole, posaconazole, and four licensed systemic antifungal agents against Candida species infrequently isolated from blood

We determined the in vitro susceptibilities of 314 strains of Candida spp., representing 13 species rarely isolated from blood, to posaconazole and voriconazole as well as four licensed systemic antifungal agents (amphotericin B, flucytosine, fluconazole, and itraconazole). The organisms included 153 isolates of C. krusei, 67 isolates of C. lusitaniae, 48 isolates of C. guilliermondii, 10 isolates of C. famata, 10 isolates of C. kefyr, 6 isolates of C. pelliculosa, 5 isolates of C. rugosa, 4 isolates of C. lipolytica, 3 isolates of C. dubliniensis, 3 isolates of C. inconspicua, 2 isolates of C. sake, and 1 isolate each of C. lambica, C. norvegensis, and C. zeylanoides. MIC determinations were made by the National Committee for Clinical Laboratory Standards reference broth microdilution method and Etest (amphotericin B). Resistance to both amphotericin B and fluconazole was observed in strains of C. krusei, C. lusitaniae, C. guilliermondii, C. inconspicua, and C. sake. Resistance to amphotericin B, but not to fluconazole, was also observed among isolates of C. kefyr and C. rugosa. Posaconazole and voriconazole were active (MIC, < or = 1 micro g/ml) against 94 to 100% of these isolates. In contrast to the more common species of Candida causing bloodstream infection, these rare species appear to be less susceptible to the currently licensed systemic antifungal agents, with the exception of voriconazole. Continued surveillance will be necessary to detect the emergence of these species as more prevalent, resistant pathogens. The new triazoles appear to offer acceptable coverage of uncommon Candida sp. bloodstream infections.