Effect of Amphotericin B and Micafungin Combination on Survival, Histopathology, and Fungal Burden in Experimental Aspergillosis in the p47 ^{phox − / −} Mouse Model of Chronic Granulomatous Disease

Abstract

Chronic granulomatous disease (CGD) is an inherited disorder of the NADPH oxidase characterized by recurrent life-threatening bacterial and fungal infections. We characterized the effects of single and combination antifungal therapy on survival, histopathology, and laboratory markers of fungal burden in experimental aspergillosis in the p47 phox؊/؊ knockout mouse model of CGD. CGD mice were highly susceptible to intratracheal Aspergillus fumigatus challenge, whereas wild-type mice were resistant. CGD mice were challenged intratracheally with a lethal inoculum ( Invasive aspergillosis is a major cause of morbidity and mortality in highly immunocompromised persons. Chronic granulomatous disease (CGD) is an inherited disorder of the NADPH oxidase complex in which phagocytes are defective in generating the reactive oxidant superoxide anion and its metabolites, hydrogen peroxide, hydroxyl anion, and hypohalous acid. Activation of preformed granular proteases is likely to be principally responsible for NADPH oxidase-mediated destruction of pathogens (25, 31). As a result of the defect in this key host defense pathway, CGD patients suffer from recurrent life-threatening bacterial and fungal infections. CGD patients are susceptible to a broad spectrum of opportunistic filamentous fungi, but Aspergillus infection is by far the most common. Invasive aspergillosis is the most important cause of mortality in CGD (10,(26)(27)(28). Genetically engineered CGD mice (Xlinked and p47 phoxϪ/Ϫ ) recapitulate the human disease and are highly susceptible to Aspergillus infection (5, 9, 24). p47phoxϪ/Ϫ mice were used in experimental pulmonary aspergillosis to evaluate single and combination antifungal regimens on the basis of survival, histopathology, and fungal burden in lungs. The following four treatment groups were evaluated: (i) vehicle, (ii) amphotericin B, (iii) micafungin, and (iv) amphotericin B plus micafungin. The combination of amphotericin B and micafungin was more effective than either agent alone in prolonging survival after Aspergillus fumigatus challenge. Our study also demonstrated unique features of the CGD mouse model that are distinct from other immunocompromised animal models of experimental aspergillosis.(Material in this paper was presented in abstract form at the 44th Interscience Conference on Antimicrobial Agents and Chemotherapy, Washington, D.C., October 2004 [abstr. M-232].) MATERIALS AND METHODS Mice. Mice with a targeted disruption of the p47phox gene have a defective NADPH oxidase, rendering phagocytes incapable of generating measurable superoxide (12). CGD mice were derived from C57BL/6 and 129 intercrosses, and mice used were backcrossed either 5 (N5) or 14 (N14) generations in the C57BL/6 background. In all experiments, treatment groups were matched with respect to age (16 to 24 weeks) and generation of backcrossing. Mice were bred

Liposomal Amphotericin B and Echinocandins as Monotherapy or Sequential or Concomitant Therapy in Murine Disseminated and Pulmonary Aspergillus fumigatus Infections

“…In fact, improved efficacy has been reported in mice with chronic granulomatous disease and pulmonary aspergillosis following administration of micafungin (Mycamine) and amphotericin B (17), as well as for murine systemic aspergillosis with a combination of caspofungin plus amphotericin B or amphotericin B-intralipid (2,47). In contrast, although there was no antagonism, Clemons and Stevens (10) reported no synergistic activity of micafungin and amphotericin B for pulmonary aspergillosis in immunosuppressed DBA/2 mice.…”

Anidulafungin in Combination with Amphotericin B against Aspergillus fumigatus

“…AFG combined with various AMB formulations against Aspergillus spp. Although two studies suggested that there were beneficial effects from combined therapies (i.e., caspofungin plus AMB and micafungin plus AMB) over the monotherapies (11,30), most studies showed that combinations did not enhance the effects of the most active single drug (8,9,13,15,18,31). We showed that neither single drugs nor combinations were active in brain tissues.…”

Infections fongiques et granulomatose septique chronique

“…Dans un modèle expérimental de CGD chez la souris, l'administration endotrachéale de doses sublétales d'Aspergillus fumigatus a entraîné la formation de pyogranulomes bien circonscrits, reconnus sur des coupes histologiques de tissu pulmonaire et se distinguant des images de nécrose observées lors de neutropénies [8]. Des lésions similaires sont retrouvées dans de nombreux organes (poumons et autres tissus) chez les patients, notamment lors d'infections fongiques [9].…”

“…Par ailleurs, la sensibilité des tests microbiologiques utilisés pour le diagnostic d'une infection fongique invasive n'est pas bien définie dans le cas des patients avec CGD, et le principal marqueur utilisé pour permettre un diagnostic précoce d'aspergillose invasive, la mesure du galactomannane sérique, est très peu sensible chez ces patients [23,33]. La raison en est probablement que, contrairement aux patients neutropéniques atteints d'hémopathie maligne [33], l'aspergillose invasive chez les patients CGD n'est habituellement pas associée à une angioinvasion mais plutôt à des granulomes bien circonscrits (Figure 3) [8,9]. Les nouvelles modalités diagnostiques, comme la mesure du taux sérique de 13-D-glucane, composant de la paroi de la majorité des champignons pathogènes sauf les mucorales et Cryptococcus spp., ou l'analyse par polymerase chain reaction (PCR) d'Aspergillus (dans le sérum ou le liquide de lavage bronchoalvéolaire) n'ont pas non plus été éva-luées spécifiquement dans cette population.…”