Efficacy of FK463, a new lipopeptide antifungal agent, in mouse models of disseminated candidiasis and aspergillosis

The efficacy of intravenous injection of FK463, a novel water-soluble lipopeptide, was evaluated in mouse models of disseminated candidiasis and aspergillosis and was compared with those of fluconazole (FLCZ) and amphotericin B (AMPH-B). In the candidiasis model, FK463 significantly prolonged the survival of intravenously infected mice at doses of 0.125 mg/kg of body weight or higher. In disseminated candidiasis caused by Candida species, including FLCZ-resistant Candida albicans, FK463 exhibited an efficacy 1.4 to 18 times inferior to that of AMPH-B, with 50% effective doses (ED(50)s) ranging from 0.21 to 1.00 mg/kg and 0.06 to 0.26 mg/kg, respectively, and was much more active than FLCZ. The protective effect of FK463 was not obviously influenced by the fungal inoculum size, the starting time of the treatment, or the immunosuppressed status of the host. The reduction in efficacy was less than that observed with FLCZ or AMPH-B. The efficacy of FK463 was also evaluated in the disseminated candidiasis target organ assay and was compared with those of FLCZ and AMPH-B. Efficacies were evaluated on the basis of a comparison between the mean log(10) CFU in kidneys in the groups treated with antifungal agents and that in control group. A single dose of FK463 at 0.5 mg/kg or higher significantly reduced the viable counts in kidneys compared with the numbers of yeast cells before treatment, and its efficacy was comparable to that of AMPH-B, while FLCZ at 4 mg/kg showed only a suppressive effect on the growth of C. albicans in the kidneys. In the disseminated aspergillosis model, FK463 given at doses of 0.5 mg/kg or higher significantly prolonged the survival of mice infected intravenously with Aspergillus fumigatus conidia. The efficacy of FK463 was about 2 times inferior to that of AMPH-B, with ED(50)s ranging from 0.25 to 0.50 mg/kg and 0.11 to 0.29 mg/kg, respectively. These results indicate that FK463 may be a potent parenterally administered therapeutic agent for disseminated candidiasis and aspergillosis.     

Efficacy, plasma pharmacokinetics, and safety of icofungipen, an inhibitor of Candida isoleucyl-tRNA synthetase, in treatment of experimental disseminated candidiasis in persistently neutropenic rabbits

Icofungipen (formerly PLD-118) is a synthetic derivative of the naturally occurring beta-amino acid cispentacin that blocks isoleucyl-tRNA synthetase, resulting in the inhibition of protein synthesis and growth of fungal cells. We investigated the efficacy, plasma pharmacokinetics, and safety of icofungipen in escalating dosages for the treatment of experimental subacute disseminated candidiasis in persistently neutropenic rabbits. Icofungipen was administered for 10 days starting 24 h after the intravenous inoculation of 10(3) Candida albicans blastoconidia. Study groups consisted of rabbits treated with icofungipen at 4 (ICO-4), 10 (ICO-10), and 25 (ICO-25) mg/kg of body weight/day in two divided dosages, rabbits treated with fluconazole at 10 mg/kg/day, rabbits treated with amphotericin B at 1 mg/kg/day, and untreated controls. Levels of icofungipen in plasma were derivatized by phthaldialdehyde and quantified by high-performance liquid chromatography with fluorescence detection. Rabbits treated with ICO-10 (P < 0.01) and ICO-25 (P < 0.001) showed significant dosage-dependent tissue clearance of C. albicans from the liver, spleen, kidney, brain, vitreous, vena cava, and lung in comparison to untreated controls. ICO-25 cleared C. albicans from all tissues and had activity comparable to that of amphotericin B versus untreated controls (P < 0.001). Pharmacokinetics of icofungipen in plasma approximated a dose-dependent relationship of the maximum concentration of drug in serum and the area under the concentration-time curve. There was no significant elevation of the levels of hepatic transaminases, alkaline phosphatase, bilirubin, urea nitrogen, or creatinine in icofungipen-treated rabbits. Icofungipen followed dose-dependent pharmacokinetics and was effective in the treatment of experimental disseminated candidiasis, including central nervous system infection, in persistently neutropenic rabbits.     

Safety, tolerability, and pharmacokinetics of Micafungin (FK463) in febrile neutropenic pediatric patients

Micafungin (FK463) is a new parenteral echinocandin. A multicenter, phase I, open-label, sequential-group dose escalation study was conducted to assess the safety, tolerability, and pharmacokinetics of micafungin in neutropenic pediatric patients. A total of 77 patients stratified by age (2 to 12 and 13 to 17 years) received micafungin. Therapy was initiated at 0.5 mg/kg per day and escalated to higher dose levels of 1.0, 1.5, 2.0, 3.0, and 4.0 mg/kg per day. Micafungin was administered within 24 h of initiating broad-spectrum antibacterial antibiotics for the new onset of fever and neutropenia. The most common overall adverse events in the study population were diarrhea (19.5%), epistaxis (18.2%), abdominal pain (16.9%), and headache (16.9%). Nine patients (12%) experienced adverse events considered by the investigator to be possibly related to the study drug. The most common related events were diarrhea, vomiting, and headache, all occurring in two patients each. There was no evidence of a dose-limiting toxicity as defined within the prespecified criteria of this clinical protocol. There was one death during the study due to septic shock. The pharmacokinetic profiles for micafungin over the 0.5- to 4.0-mg/kg dose range demonstrated dose linearity. Clearance, volume of distribution, and half-life remained relatively constant over the dose range and did not change with repeated administration. The overall plasma pharmacokinetic profile was similar to that observed in adults. However, there was an inverse relation between age and clearance. For patients 2 to 8 years old, clearance was approximately 1.35 times that of patients >/=9 years of age. In summary, micafungin over a dosage range between 0.5 and 4.0 mg/kg/day in 77 febrile neutropenic pediatric patients displayed linear pharmacokinetics and increased clearance as a function of decreasing age.     

Efficacy of intravenous itraconazole against invasive pulmonary aspergillosis in neutropenic mice

The efficacy of itraconazole (ITZ) solubilized in hydroxypropyl-β-cyclodextrin (ITZ-IV) was examined in a murine model of invasive pulmonary aspergillosis (IPA). Immunosuppressed mice were infected by the intratracheal inoculation of Aspergillus fumigatus conidia (2 × 10⁶ conidia/mouse). Their body weight rapidly decreased and they died within 6 days after infection. Intravenous administration of various doses of ITZ-IV was started 24 h after infection and was continued once a day for 4 days. ITZ-IV at daily doses of 10, 20, or 40 mg/kg was as effective as the intraperitoneal administration of amphotericin B (AMPH) at a dosage of 1 mg/kg daily in improving survival. ITZ-IV (20 mg/kg per day), as well as AMPH (1 mg/kg per day) significantly lowered the fungal burden in the pulmonary tissues. Histological improvement was seen within 2 days after the beginning of administration of ITZ-IV (20 mg/kg per day). In mice intravenously given a single dose of ITZ-IV (20 mg/kg), the blood level and pulmonary tissue level of ITZ plus its active metabolites, mainly hydroxyitraconazole (OH-ITZ), decreased gradually after the injection, but after 4 h their concentration was still between 1.4 μg/ml (ITZ) and 1.9 μg/ml (OH-ITZ), concentrations that were approximately 10 to 20 times greater than the minimum inhibitory concentration (MIC) of ITZ for challenging the strain of A. fumigatus (0.16 μg/ml). These results support the clinical usefulness of ITZ-IV for the treatment of IPA in immunocompromised patients.     

Efficacy, safety, and plasma pharmacokinetics of escalating dosages of intravenously administered ravuconazole lysine phosphoester for treatment of experimental pulmonary aspergillosis in persistently neutropenic rabbits

Ravuconazole is a new antifungal triazole with broad-spectrum activity and a long half-life in plasma. We studied the antifungal efficacy, safety, and pharmacokinetics of ravuconazole lysine phosphoester in escalating dosages for the treatment of invasive pulmonary aspergillosis due to Aspergillus fumigatus in persistently neutropenic rabbits. Treatment groups consisted of rabbits treated with ravuconazole at 2.5 (RVC2.5), 5 (RVC5), and 10 (RVC10) mg/kg of body weight/day, rabbits treated with amphotericin B (AMB) at 1 mg/kg/day, or untreated controls. There was a dose-dependent reduction of pulmonary residual fungal burden (CFU per gram) in RVC5-, RVC10-, and AMB-treated rabbits in comparison to untreated controls (P < 0.01, P < 0.001, and P < 0.01, respectively). These findings correlated with progressive galactomannan antigenemia in untreated controls and the RVC2.5-treated rabbits, a lower galactomannan index (GMI) in RVC5- and RVC10-treated rabbits, and a similarly low GMI in AMB-treated rabbits (P < 0.01). Rabbits treated with RVC5, RVC10, and AMB also showed a reduction of organism-mediated pulmonary injury, as measured by infarct scores and lung weights, in comparison to untreated controls (P < 0.001). These results were supported by decreased pulmonary infiltrates detected by computed tomography in RVC5- and RVC10-treated rabbits in comparison to untreated controls (P < 0.05). Survival throughout the entire study was achieved in 95% of RVC5-treated rabbits (P < 0.001), 85% of RVC10-treated rabbits (P < 0.001), and 50% of AMB-treated rabbits (P < 0.05) in comparison to none of the untreated controls. Ravuconazole showed linear plasma pharmacokinetics and a large volume of distribution while maintaining concentrations in plasma above the MIC throughout the dosing interval. There was no evidence of hepatotoxicity or nephrotoxicity among ravuconazole-treated animals. Intravenously administered ravuconazole lysine phosphoester showed dose-dependent efficacy and an excellent safety profile for the treatment of invasive pulmonary aspergillosis in persistently neutropenic rabbits.     

Efficacy of FK463, a new lipopeptide antifungal agent, in mouse models of pulmonary aspergillosis

The efficacy of FK463, a novel water-soluble lipopeptide, was evaluated in mouse models of pulmonary aspergillosis and was compared with that of amphotericin B (AMPH-B). In the pulmonary aspergillosis models induced by intranasal inoculation, FK463 exhibited good efficacy, with 50% effective doses in the range of 0. 26 to 0.51 mg/kg of body weight; these values were comparable to those of AMPH-B. In an Aspergillus target organ assay with immunosuppressed mice, under conditions of constant plasma levels of FK463, using a subcutaneously implanted osmotic pressure pump, a significant reduction in viable fungal cells was observed at plasma FK463 levels of 0.55 to 0.80 microgram/ml or higher. We conclude that FK463 is highly effective in the treatment of pulmonary aspergillosis in this animal model. These results indicate that FK463 may be a potent parenterally administered antifungal agent for pulmonary aspergillosis.     

Anidulafungin pharmacokinetics and microbial response in neutropenic mice with disseminated candidiasis

Candidemia is often fatal, especially in patients with persistent neutropenia. New therapies are needed. We performed 24-h pharmacodynamic studies to compare the efficacies of anidulafungin, fluconazole, and amphotericin B in neutropenic mice with disseminated candidiasis caused by one of three strains of Candida glabrata. Anidulafungin produced a maximal fungal kill (E(max)) of 1.4 to 1.9 log(10) CFU/g in kidneys and was not influenced by resistance to either fluconazole or amphotericin B. Fluconazole produced an E(max) of 1.3 log(10) CFU/g in mice infected with fluconazole-susceptible C. glabrata, but the E(max) was 0 for mice infected with a C. glabrata strain that had a fluconazole MIC of >/=32 mg/liter. Amphotericin B achieved an E(max) of 4.2 log(10) CFU/g in mice infected with amphotericin B-susceptible C. glabrata, but the E(max) was 0 for mice infected with a C. glabrata strain with an amphotericin B MIC of 2 mg/liter. In all instances, anidulafungin's maximal microbial kill was superior to that of fluconazole. Next, we performed a 96-h anidulafungin pharmacokinetic-pharmacodynamic study. Anidulafungin exhibited delayed peak concentrations in kidneys compared to those in serum, after which the concentrations declined, with a serum terminal half-life of 21.6 (+/-4.6) h. This was accompanied by a persistent 96-h decrease in the kidney fungal burden after treatment with a single anidulafungin dose of >/=8 mg/kg of body weight. This pharmacokinetic-pharmacodynamic picture of anidulafungin persistence in tissues and the resultant persistent fungal decline should be exploited to improve the efficacy of anidulafungin therapy for candidemia.     

Efficacy of single-dose liposomal amphotericin B or micafungin prophylaxis in a neutropenic murine model of invasive pulmonary aspergillosis

In a neutropenic murine model of invasive pulmonary aspergillosis, prophylaxis with single doses of liposomal amphotericin B or micafungin at ≥5 mg/kg of body weight improved animal survival and suppressed the lung fungal burden for up to 7 days after infection, demonstrating the potential utility of infrequent dosing with these antifungals.     

Caspofungin: antifungal activity in vitro, pharmacokinetics, and effects on fungal load and animal survival in neutropenic rats with invasive pulmonary aspergillosis

OBJECTIVES: Evaluation of the potential of caspofungin, in relation to pharmacokinetics, in order to optimize its use in the treatment of filamentous fungal infections. METHODS: The in vitro antifungal activity, pharmacokinetics and therapeutic efficacy of caspofungin versus amphotericin B was investigated in vitro as well as in a model of aerogenic Aspergillus fumigatus infection in neutropenic rats, using rat survival and decrease in fungal burden as parameters for therapeutic efficacy. RESULTS: In contrast to amphotericin B, caspofungin shows a concentration-dependent gradual decrease in fungal growth in vitro, which makes it difficult to perform visual readings of antifungal activity (CLSI guidelines). The quantitative XTT [2,3-bis(2-methoxy-4-nitro-5-[(sulphenylamino) carbonyl]-2H-tetrazolium-hydroxide] assay measuring a decrease in fungal metabolic activity seems more appropriate for caspofungin susceptibility testing. Using this assay, in vitro caspofungin was 4-fold less active than amphotericin B. In the infection model, therapy was started 16 h after fungal inoculation, and continued once daily for 10 days. Caspofungin was administered intraperitoneally at 1, 2, 3 or 4 mg/kg/day (CAS 1, 2, 3 or 4), amphotericin B at 1 mg/kg/day (AMB 1). Treatment with CAS 1 or AMB 1 provided modest prolongation of animal survival. The combination of caspofungin and amphotericin B did not show additive effects. Increasing the dosage of caspofungin to 2, 3 or 4 mg/kg/day resulted in a dose-dependent significant increase in efficacy. There was 100% survival among rats in the CAS 4 group, which was correlated with a significant decrease in fungal burden, based on the concentration of A. fumigatus galactomannan in serum and lung tissue and quantification of A. fumigatus DNA in lung tissue. Pharmacokinetic analysis suggested that the CAS 4 dose in rats produced drug exposure comparable to the human situation, visualized by similar 24 h AUC and trough concentrations. CONCLUSIONS: The therapeutic efficacy of caspofungin is superior to amphotericin B, which seemed to be discrepant with their in vitro antifungal activity.     

In vivo activity of micafungin in a persistently neutropenic murine model of disseminated infection caused by Candida tropicalis

Micafungin is a new echinocandin with broad-spectrum in vitro and in vivo antifungal activity against both Aspergillus and Candida species. We compared the activity of micafungin with that of amphotericin B and fluconazole in a persistently immunocompromised murine model of disseminated candidiasis against a strain of Candida tropicalis that was resistant to amphotericin B and fluconazole in vitro. Mice were rendered persistently neutropenic with multiple doses of cyclophosphamide and infected intravenously with C. tropicalis. Mice were treated with either intraperitoneal amphotericin B (0.5-5 mg/kg per dose), oral fluconazole (50 mg/kg twice a day), intravenous micafungin (1-10 mg/kg per dose) or solvent control for 7 days. Mice were killed at 11 days post-infection and kidneys, lungs, brain and liver removed for quantitative culture. Overall mortality in the model was low, with rates varying between 10% and 25% in treatment groups. Micafungin at doses between 2 and 10 mg/kg were the only regimes able to reduce cfu below the level of detection of tissues infected with C. tropicalis. Micafungin was well tolerated by the mice and was much more effective than amphotericin B or fluconazole against an amphotericin B- and fluconazole-resistant C. tropicalis.     

SCH-39304 in prevention and treatment of disseminated candidiasis in persistently granulocytopenic rabbits.

To investigate the potential use of SCH-39304 for the prevention and treatment of disseminated candidiasis in granulocytopenic patients, we studied its in vivo antifungal activity as preventive, early, and late treatments in three models (acute, subacute, and chronic) of disseminated candidiasis in persistently granulocytopenic rabbits. SCH-39304 was an effective as amphotericin B alone and fluconazole alone for the prevention of disseminated candidiasis. SCH-39304 alone and fluconazole alone were as effective as amphotericin B plus flucytosine for early treatment of subacute disseminated candidiasis. When treatment was delayed for 5 days to establish chronic disseminated candidiasis, SCH-39304 was less effective than amphotericin B plus flucytosine. In comparison with different treatment regimens, SCH-39304 was more effective in early and preventive treatment. Thus, SCH-39304 was comparable to treatment control regimens in prevention and early treatment of subacute disseminated candidiasis. SCH-39304 also was most effective in granulocytopenic rabbits with disseminated candidiasis when used for prevention or early treatment.     

In vitro antifungal activity of Micafungin (FK463) against dimorphic fungi: comparison of yeast-like and mycelial forms

The characteristics of in vitro micafungin (FK463) antifungal activity against six species of dimorphic fungi were investigated in accordance with the NCCLS M27-A microdilution methods. MICs of micafungin, amphotericin B, itraconazole, and fluconazole for Histoplasma capsulatum var. capsulatum, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Penicillium marneffei, and Sporothrix schenckii were determined both for the yeast-like form and mycelial form. Coccidioides immitis was tested only in its mycelial form. We have clearly demonstrated that the in vitro activity of micafungin depends considerably on the growth form of dimorphic fungi. Micafungin exhibited potent activity against the mycelial forms of H. capsulatum, B. dermatitidis, and C. immitis (MIC range, 0.0078 to 0.0625 micro g/ml), while it was very weakly active against their yeast-like forms (MIC range, 32 to >64 micro g/ml). Micafungin was also more active against the mycelial forms than the yeast-like forms of Paracoccidioides brasiliensis, Penicillium marneffei, and S. schenckii. The MICs of amphotericin B were 2 to 5 dilutions lower for the mycelial forms than for the yeast-like forms of B. dermatitidis and Paracoccidioides brasiliensis. There was no apparent difference in the activity of itraconazole between the two forms. The MICs of fluconazole for the yeast-like forms were generally lower than those for the mycelial forms, and considerably so for B. dermatitidis. These results suggest that the growth form employed in antifungal susceptibility testing of dimorphic fungi can considerably influence the interpretation of results. At present, it cannot be judged whether micafungin has clinical usefulness for dimorphic fungus infections, since for most fungi it remains uncertain which growth form correlates better with therapeutic outcome. However, the results of this study warrant further investigations of micafungin as a therapeutic agent for infections caused by dimorphic fungi.     

In vitro activities of a new lipopeptide antifungal agent, FK463, against a variety of clinically important fungi

The in vitro antifungal activity and spectrum of FK463 were compared with those of amphotericin B, fluconazole, and itraconazole by using a broth microdilution method specified by National Committee for Clinical Laboratory Standards document M27-A (National Committee for Clinical Laboratory Standards, Wayne, Pa., 1997). FK463 exhibited broad-spectrum activity against clinically important pathogens including Candida species (MIC range, <==0.0039 to 2 microg/ml) and Aspergillus species (MIC range, <==0.0039 to 0.0313 microg/ml), and its MICs for such fungi were lower than those of the other antifungal agents tested. FK463 was also potently active against azole-resistant Candida albicans as well as azole-susceptible strains, and there was no cross-resistance with azoles. FK463 showed fungicidal activity against C. albicans, i.e., a 99% reduction in viability after a 24-h exposure at concentrations above 0.0156 microg/ml. The minimum fungicidal concentration (MFC) assays indicated that FK463 was fungicidal against most isolates of Candida species. In contrast, the MFCs of FK463 for A. fumigatus isolates were much higher than the MICs, indicating that its action is fungistatic against this species. FK463 had no activity against Cryptococcus neoformans, Trichosporon species, or Fusarium solani. Neither the test medium (kind and pH) nor the inoculum size greatly affected the MICs of FK463, while the addition of 4% human serum albumin increased the MICs for Candida species and A. fumigatus more than 32 times. Results from preclinical in vitro evaluations performed thus far indicate that FK463 should be a potent parenteral antifungal agent.     

Efficacy of the echinocandin caspofungin against disseminated aspergillosis and candidiasis in cyclophosphamide-induced immunosuppressed mice

The in vivo efficacy of the echinocandin antifungal caspofungin acetate (caspofungin; MK-0991) was evaluated in models of disseminated aspergillosis and candidiasis in mice with cyclophosphamide (CY)-induced immunosuppression. Caspofungin is a 1, 3-beta-D-glucan synthesis inhibitor efficacious against a number of clinically relevant fungi including Aspergillus and Candida species. Models of CY-induced transient or chronic leukopenia were used with once daily administration of therapy initiated 24 h after microbial challenge. Caspofungin was effective in treating disseminated aspergillosis in mice that were transiently leukopenic (significant prolongation of survival at doses of > or =0.125 mg/kg of body weight and a 50% protective dose [PD(50)] of 0.245 mg/kg/day at 28 days after challenge) or chronically leukopenic (50 to 100% survival at doses of > or =0.5 mg/kg and PD(50)s ranging from 0.173 to 0.400 mg/kg/day). Caspofungin was effective in the treatment and sterilization of Candida infections in mice with transient leukopenia with a 99% effective dose based on reduction in log(10) CFU of Candida albicans/gram of kidneys of 0.119 mg/kg and 80 to 100% of the caspofungin-treated mice having sterile kidneys at caspofungin doses from 0.25 to 2.0 mg/kg. In Candida-infected mice with chronic leukopenia, caspofungin was effective at all dose levels tested (0.25 to 1.0 mg/kg), with the log(10) CFU of C. albicans/gram of kidneys of caspofungin-treated mice being significantly lower (>99% reduction) than that of sham-treated mice from day 4 to day 28 after challenge. Also, 70 to 100% of the caspofungin-treated, chronic leukopenic mice had sterile kidneys at caspofungin doses of 0.5 to 1.0 mg/kg from day 8 to 28 after challenge. Sterilization of Candida infections by caspofungin in the absence of host leukocytes provides compelling in vivo evidence for fungicidal activity against C. albicans. Further human clinical trials with caspofungin against serious fungal infections are in progress.     

Effect of the growth medium on the in vitro antifungal activity of micafungin (FK-463) against clinical isolates of Candida dubliniensis.

Micafungin (FK-463), a member of the new candin family of antifungal agents, was highly active against clinical isolates of Candida albicans and Candida dubliniensis. The in vitro activity of micafungin suggested that it was more potent than fluconazole, flucytosine, amphotericin B or voriconazole against C. albicans, and comparable or moderately less effective against C. dubliniensis isolates when high-resolution medium (HR) was used. Lower MICs of micafungin were recorded when RPMI 2% or AM3 2% media were used, indicating an influence of the growth medium on the MIC.     

Activity of micafungin (FK463) against an itraconazole-resistant strain of Aspergillus fumigatus and a strain of Aspergillus terreus demonstrating in vivo resistance to amphotericin B

We compared the activity of four doses of micafungin (FK463) with that of amphotericin B, liposomal amphotericin B and itraconazole in a murine model of disseminated aspergillosis. Temporarily neutropenic mice were infected with a lethal dose of either an itraconazole-resistant Aspergillus fumigatus isolate or Aspergillus terreus, a species that is less susceptible to amphotericin B. Treatment was started 24 h after infection and lasted for 7 days. Mice were treated with either amphotericin B (0.5 or 5 mg/kg), liposomal amphotericin (5 or 25 mg/kg), itraconazole (25 or 75 mg/kg) or FK463 (either 1, 2, 5 or 10 mg/kg). Treatment of the A. fumigatus model with either amphotericin B, liposomal amphotericin or FK463 prolonged survival. Doses of FK463 5 and 10 mg/kg had a 100% survival. Treatment of A. terreus infection with either itraconazole or FK463, but not amphotericin B, also prolonged survival. Doses of liposomal amphotericin of 5 and 25 mg/kg were ineffective against A. terreus infection. No treatment regime was able to totally clear the liver or kidneys in either model. The data indicate that FK463 may have a clinical role in the treatment of life-threatening invasive aspergillosis.     

米卡芬净单药及联合两性霉素B对小鼠侵袭性肺曲霉病的治疗作用

目的 评价米卡芬净单药及联合两性霉素B对小鼠侵袭性肺曲霉病(IPA)的治疗作用.方法 采用环磷酰胺骨髓抑制、烟曲霉孢子滴鼻接种构建中性粒细胞减少小鼠IPA模型.实验动物随机分为为4组:模型对照组(NS+5%Gs,A组)、米卡芬净治疗组[5 mg/(kg·d),B组]、两性霉素B治疗组[1 mg/(kg·d),C组]和米卡芬净[5 mg/(kg·d)]加两性霉素B[1mg/(kg·d)]治疗组(D组),治疗从接种第2天开始,每天1次,共7 d.①动物生存期观察:每组15～16只小鼠,接种后每天观察1次至第21天.共进行2批次实验.分别给予2×105和6×106个孢子/小鼠.②肺的真菌负荷:每组9只小鼠,给予1.5×104个孢子/小鼠.治疗结束后取肺,匀浆后梯度稀释培养,记取菌落数并计算肺的真菌负荷量.结果 ①生存分析:第1批次,米卡芬净、两性霉素B单药及联合用药治疗均能延长小鼠生存期.但3种治疗方案在延长生存期方面差异无显著性(B组、C组分别与A组比较均有P<0.05.D组与A组比较P<0.01).第2批次,联合用药组生存期长于其它各组.米卡芬净及两性霉素B单药治疗组与模型组比较差异无显著性(D组与A组比较P<0.01:D组分别与B组及C组比较均有P<0.05).②肺的真菌负荷:两性霉素B单药及联合用药均能降低肺的真菌负荷,米卡芬净单药不降低肺的真菌负荷(C组与A组比较P<0.01;D组与A组比较P<0.05;B组与C组比较P<0.05;B组与D组比较P<0.01).结论 单独应用米卡芬净或两性霉素B及联合用药均能够延长中性粒细胞减少IPA小鼠生存期,当孢子接种量为6×106/小鼠时,联合用药优于单独应用米卡芬净或两性霉素B.单独应用米卡芬净不降低肺的真菌负荷,联合用药或两性霉素B单药在降低肺的真菌负荷方面均优于对照组及米卡芬净组.     

米卡芬净单药及联合两性霉素B对小鼠侵袭性肺曲霉病的治疗作用

目的评价米卡芬净单药及联合两性霉素B对小鼠侵袭性肺曲霉病(IPA)的治疗作用。方法采用环磷酰胺骨髓抑制、烟曲霉孢子滴鼻接种构建中性粒细胞减少小鼠IPA模型。实验动物随机分为为4组:模型对照组(NS+5%GS,A组)、米卡芬净治疗组[5 mg/(kg.d),B组]、两性霉素B治疗组[1 mg/(kg.d),C组]和米卡芬净[5 mg/(kg.d)]加两性霉素B[1mg/(kg.d)]治疗组(D组),治疗从接种第2天开始,每天1次,共7 d。①动物生存期观察:每组15~16只小鼠,接种后每天观察1次至第21天。共进行2批次实验,分别给予2×105和6×106个孢子/小鼠。②肺的真菌负荷:每组9只小鼠,给予1.5×104个孢子/小鼠。治疗结束后取肺,匀浆后梯度稀释培养,记取菌落数并计算肺的真菌负荷量。结果①生存分析:第1批次,米卡芬净、两性霉素B单药及联合用药治疗均能延长小鼠生存期,但3种治疗方案在延长生存期方面差异无显著性(B组、C组分别与A组比较均有P<0.05,D组与A组比较P<0.01)。第2批次,联合用药组生存期长于其它各组,米卡芬净及两性霉素B单药治疗组与模型组比较差异无显著性(D组与A组比较P<0.01;D组分别与B组及C组比较均有P<0.05)。②肺的真菌负荷:两性霉素B单药及联合用药均能降低肺的真菌负荷,米卡芬净单药不降低肺的真菌负荷(C组与A组比较P<0.01;D组与A组比较P<0.05;B组与C组比较P<0.05;B组与D组比较P<0.01)。结论单独应用米卡芬净或两性霉素B及联合用药均能够延长中性粒细胞减少IPA小鼠生存期,当孢子接种量为6×106/小鼠时,联合用药优于单独应用米卡芬净或两性霉素B。单独应用米卡芬净不降低肺的真菌负荷,联合用药或两性霉素B单药在降低肺的真菌负荷方面均优于对照组及米卡芬净组。