Voriconazole prophylaxis in lung transplant recipients

Increased mortality after pulmonary fungal infection within the first year after pediatric lung transplantation

BACKGROUND

Risk factors, morbidity and mortality from pulmonary fungal infections (PFIs) within the first year after pediatric lung transplant have not previously been characterized.

METHODS

A retrospective, multicenter study from 1988 to 2005 was conducted with institutional approval from the 12 participating centers in North America and Europe. Data were recorded for the first post-transplant year. The log-rank test assessed for the association between PFI and survival. Associations between time to PFI and risk factors were assessed by Cox proportional hazards models.

RESULTS

Of the 555 subjects transplanted, 58 (10.5%) had 62 proven (Candida, Aspergillus or other) or probable (Aspergillus or other) PFIs within the first year post-transplant. The mean age for PFI subjects was 14.0 years vs 11.4 years for non-PFI subjects (p < 0.01). Candida and Aspergillus species were recovered equally for proven disease. Comparing subjects with PFI (n = 58) vs those without (n = 404), pre-transplant colonization was associated with PFI (hazard ratio [HR] 2.0; 95% CI 0.95 to 4.3, p = 0.067). Cytomegalovirus (CMV) mismatch, tacrolimus-based regimen and age >15 years were associated with PFI (p < 0.05). PFI was associated with any prior rejection higher than Grade A2 (HR 2.1; 95% CI 1.2 to 3.6). Cystic fibrosis, induction therapy, transplant era and type of transplant were not associated with PFI. PFI was independently associated with decreased 12-month survival (HR 3.9, 95% CI 2.2 to 6.8).

CONCLUSIONS

Risk factors for PFI include Grade A2 rejection, repeated acute rejection, CMV-positive donor, tacrolimus-based regimen and pre-transplant colonization.

[Infection in lung transplantation]

Actualmente, el trasplante de pulmón se considera un tratamiento válido para un buen número de pacientes con insuficiencia respiratoria grave. De todas formas, las complicaciones son muy frecuentes y pueden llevar a fracaso del injerto a medio y largo plazo y menor supervivencia. De acuerdo con el registro de la International Society for Heart and Lung Transplantation, las tasas de supervivencia al primer, segundo y quinto año fueron, en 2006, del 74, 65 y 47%, respectivamente. El principal obstáculo para el éxito a largo plazo del trasplante de pulmón es el rechazo crónico, caracterizado histológicamente como bronquiolitis obliterante, que acontece en cerca de dos terceras partes de los pacientes. Uno de los factores más importantes para el desarrollo de bronquiolitis obliterante, además del número de rechazos agudos, es la infección y la enfermedad por citomegalovirus (CMV). Recientemente, se ha destacado el papel de la infección por diferentes virus respiratorios como factores de riesgo para el desarrollo de rechazo crónico en receptores de un trasplante de pulmón. Las complicaciones infecciosas son una causa frecuente de morbimortalidad en este tipo de pacientes, y la causa de muerte de cerca de la mitad de ellos. La infección bacteriana es la complicación más frecuente de un receptor de un trasplante de pulmón. Del total, el 35-66% son bacterianas y el 50-85% de los pacientes presentan como mínimo un episodio de infección bacteriana. La segunda causa más frecuente de infección, después de la bacteriana, es la infección por CMV. A pesar de utilizar diferentes estrategias de prevención, la incidencia sigue siendo elevada, y se sitúa alrededor del 7% el primer año postrasplante. Es el único tipo de trasplante de órgano sólido en el cual la etiología más frecuente de la infección fúngica es Aspergillus spp., a diferencia del resto, en que típicamente se deben a Candida spp. La incidencia de aspergilosis invasora se cifra en alrededor del 4%.

Evolving strategies in the management of aspergillosis

Aspergillus spp. remain the most common causes of invasive mould infections among patients with hematologic malignancies and recipients of solid-organ and hematopoietic stem-cell transplants. Despite advances in prevention and treatment, invasive aspergillosis continues to be a deadly disease. This paper reviews current approaches to treatment of aspergillosis in adults, including surgical and immune-based strategies, and developments in prophylaxis for aspergillosis in high-risk patient populations.

Aspergillus niger causing tracheobronchitis and invasive pulmonary aspergillosis in a lung transplant recipient: case report

A case of invasive aspergillosis caused by Aspergillus niger in a lung transplant recipient is described. The patient presented hyperglycemia starting postoperatively, with other complications such as cytomegalovirus infection. The associated predisposing factors and other implications are discussed. Aspergillus niger seems to be a fungal species of low virulence that requires the presence of a severely immunosuppressed host to cause invasive disease.

[Voriconazole for the therapy of mycoses in recipients of solid organ transplants]

Invasive fungal infections (IFI) are the third cause of infectious complications in recipients of solid organ transplants (SOT), showing an incidence of 5-42% depending of the trasplanted organ. Moreover, IFI account for significant morbility and mortality in SOT, ranging between 25-95% depending on the type of fungus and its organ localization. Different strategies (prophylaxis, preemptive treatment, treatment, antifungal combinations, routes of administration) have been tested to improve the prognosis of IFI in SOT. To reach this objective, it was essential to have access to new antifungals showing a higher spectrum of activity on the fungal pathogens, both classical and emerging, and showing improvements in pharmacokinetic and pharmacodynamic characteristics, ease of administration and acceptability and lower rates of adverse effects. Introduction of voriconazole in the therapeutic arsenal has facilitated to reach these goals due to its special pharmacological characteristics, its in vitro antifungal activity and the in vivo clinical efficacy demonstrated in different studies.

Invasive aspergillosis: epidemiology, diagnosis and management in immunocompromised patients

Morbidity and mortality caused by invasive Aspergillus infections are increasing. This is because of the higher number of patients with malignancies treated with intensive immunosuppressive therapy regimens as well as their improved survival from formerly fatal bacterial infections, and the rising number of patients undergoing allogeneic haematopoietic stem cell or organ transplantation. Early initiation of effective systemic antifungal treatment is essential for a successful clinical outcome in these patients; however, clinical clues for diagnosis are sparse and early microbiological proof of invasive aspergillosis (IA) is rare. Clinical diagnosis is based on pulmonary CT scan findings and non-culture based diagnostic techniques such as galactomannan or DNA detection in blood or bronchoalveolar lavage samples. Most promising outcomes can be expected in patients at high risk for aspergillosis in whom antifungal treatment has been started pre-emptively, backed up by laboratory and imaging findings. The gold standard of systemic antifungal treatment is voriconazole, which has been proven to be significantly superior to conventional amphotericin B and has led to a profound improvement of survival rates in patients with cerebral aspergillosis. Liposomal amphotericin B at standard dosages appears to be a suitable alternative for primary treatment, while caspofungin, amphotericin B lipid complex or posaconazole have shown partial or complete response in patients who had been refractory to or intolerant of primary antifungal therapy. Combination therapy with two antifungal compounds may be a promising future strategy for first-line treatment. Lung resection helps to prevent fatal haemorrhage in single patients with pulmonary lesions located in close proximity to larger blood vessels, but is primarily considered for reducing the risk of relapse during subsequent periods of severe immunosuppression. Strict reverse isolation appears to reduce the incidence of aspergillosis in allogeneic stem cell transplant recipients and patients with acute myeloid leukaemia undergoing aggressive anticancer therapy. Well designed, prospective randomised studies on infection control measures effective to prevent aspergillosis are lacking. Prophylactic systemic antifungal treatment with posaconazole significantly improves survival and reduces IA in acute myeloid leukaemia patients and reduces aspergillosis incidence rates in patients with intermediate-to-severe graft-versus-host reaction emerging after allogeneic haematopoietic stem cell transplantation. Voriconazole prophylaxis may be suitable for prevention of IA as well; however, the results of large clinical trials are still awaited.

Safety of aerosolized amphotericin B

Aerosolized delivery of a number of antimicrobial agents has been studied. Despite a theoretical soundness behind this strategy, full consideration of the potential toxicities associated with this mode of administration is imperative. Aerosolized amphotericin B, as both deoxycholate and lipid formulations, has been studied in a variety of high-risk patient populations for prophylaxis and treatment against fungal infections. Although available data remain inconclusive regarding the clinical efficacy of this therapy, variability among results may be due to lack of standardization of administration methods and doses. Akin to the lack of clinical consensus, data regarding the tolerability of this means of amphotericin B delivery are conflicting. This variability may again be accounted for by the lack of standardized means for aerosolized administration. Owing to uncertain clinical benefit and concern for pulmonary toxicities, the use of aerosolized amphotericin B should be limited to clinical investigations at this time.

Invasive fungal infections and antifungal therapies in solid organ transplant recipients

This manuscript will review the risk factors, prevalence, clinical presentation, and management of invasive fungal infections (IFIs) in solid organ transplant (SOT) recipients. Primary literature was obtained via MEDLINE (1966-April 2007) and EMBASE. Abstracts were obtained from scientific meetings or pharmaceutical manufacturers and included in the analysis. All studies and abstracts evaluating IFIs and/or antifungal therapies, with a primary focus on solid organ transplantation, were considered for inclusion. English-language literature was selected for inclusion, but was limited to those consisting of human subjects. Infectious complications following SOT are common. IFIs are associated with high morbidity and mortality rates in this patient population. Determining the best course of therapy is difficult due to the limited availability of data in SOT recipients. Well-designed clinical studies are infrequent and much of the available information is often based on case-reports or retrospective analyses. Transplant practitioners must remain aware of their therapeutic options and the advantages and disadvantages associated with the available treatment alternatives.

Fungal infections in solid organ transplantation

Fungal infections in solid organ transplant recipients continue to be a significant cause of morbidity and mortality. Candida spp. and Aspergillus spp. account for most invasive fungal infections. The incidence of fungal infection varies with type of solid organ transplant. Liver transplant recipients have highest reported incidence of candida infections while lung transplant recipients have highest rate of Aspergillus infections. Recent epidemiological studies suggest the emergence of resistant strains of candida as well as mycelial fungi other than Aspergillus in these patients. The current review incorporates the recent changes in the epidemiology of fungal infections in solid organ transplant recipients and highlights the newer data on the diagnosis, prophylaxis and treatment of fungal infections in these patients.