Comparison of cryptococcal meningitis in HIV-negative patients with and without lung infections.

OBJECTIVE: To investigate the clinical features and outcomes of cryptococcal meningitis (CM) in HIV-negative patients with and without lung infections. METHODS: We retrospectively reviewed the medical records of HIV-negative patients with CM admitted to two university hospitals in Southwest China over the past 5 years. RESULTS: Seventy-one patients were included, of whom 35 (49.3%) had lung disease. Compared with patients without lung infection, CM patients with lung infection tended to be male and younger (≤30 years), experienced more fever, less vomiting and fewer central nervous system symptoms; more often had low white blood cell (WBC) counts (<20 × 106/L), and fewer often had ethmoid sinusitis, maxillary sinusitis, paranasal sinusitis, and otitis media. Cryptococcus neoformans isolates from these patients were sensitive to itraconazole, voriconazole, fluconazole, and amphotericin B but resistant to flucytosine. CM patients with lung infection had higher mortality at discharge compared with patients without lung infection (8.6% vs. 0%). Multivariable analyses showed that a WBC count <20 × 106/L was significantly associated with poor treatment outcome (odds ratio 0.01, 95% confidence interval 0-0.83). CONCLUSION: HIV-negative CM patients with lung infections tended to be male and younger. Fever, fewer central nervous system symptoms, and WBC counts <20 × 106/L were characteristic of this patient group.

Fluconazole plus flucytosine is a good alternative therapy for non-HIV and non-transplant-associated cryptococcal meningitis: A retrospective cohort study.

Cryptococcal meningitis (CM) carries a high risk of mortality with increasing incidences in immune competent hosts. Current treatments are not well tolerated, and evaluation of other treatments is needed. Fluconazole and 5-flucytosine in treating immune competent hosts have not been characterised. To evaluate the efficacy of fluconazole and 5-flucytosine in treating non-HIV- and non-transplant-associated CM. We performed a retrospective cohort study of the outcomes in immune competent patients with CM treated with fluconazole and 5-flucytosine or deoxycholate-amphotericin B and 5-flucytosine. The primary outcome was treatment response evaluated at the 12th week after initiation of antifungal therapy. A total of 43 and 47 patients received amphotericin B deoxycholate and 5-flucytosine or fluconazole and 5-flucytosine, respectively. A total of 38 (88.4%) patients cannot tolerate recommended doses of amphotericin B deoxycholate and 5-flucytosine (patients needed dose reduction during the treatment). Patients given fluconazole and 5-flucytosine had higher baseline cryptococcal burdens (median 3632 versus 900 cryptococci/mL, P = 0.008). No significant differences were seen in cryptococcus clearance (74.4% vs 70.2%, P = 0.814), treatment time (39 days, 20-69 days vs 21 days, 7-63 days, P = 0.107) and successful response (including complete and partial responses) rates (69.7% vs 72.3%, P = 0.820). Fluconazole and 5-flucytosine treatment had lower total adverse events (19.1% vs 90.7%, P < 0.001). Fluconazole and 5-flucytosine had relatively high efficacy with few adverse events in treating CM. Fluconazole and 5-flucytosine therapy is promising in patients that do not tolerate or are not suited for amphotericin B deoxycholate treatment.

Discovery of Carboline Derivatives as Potent Antifungal Agents for the Treatment of Cryptococcal Meningitis.

Clinical treatment of cryptococcal meningitis (CM) remains a significant challenge because of the lack of effective and safe drug therapies. Developing novel CM therapeutic agents with novel chemical scaffolds and new modes of action is of great importance. Herein, new ß-hexahydrocarboline derivatives are shown to possess potent anticryptococcal activities. In particular, compound A4 showed potent in vitro and in vivo anticryptococcal activity with good metabolic stability and blood-brain barrier permeability. Compound A4 was orally active and could significantly reduce brain fungal burdens in a murine model of CM. Moreover, compound A4 could inhibit several virulence factors of Cryptococcus neoformans and might act by a new mode of action. Preliminary mechanistic studies revealed that compound A4 induced DNA double-stranded breaks and cell cycle arrest at the G2 phase by acting on the Cdc25c/CDK1/cyclin B pathway. Taken together, ß-hexahydrocarboline A4 represents a promising lead compound for the development of next-generation CM therapeutic agents.

Repurposing and Reformulation of the Antiparasitic Agent Flubendazole for Treatment of Cryptococcal Meningoencephalitis, a Neglected Fungal Disease.

Current therapeutic options for cryptococcal meningitis are limited by toxicity, global supply, and emergence of resistance. There is an urgent need to develop additional antifungal agents that are fungicidal within the central nervous system and preferably orally bioavailable. The benzimidazoles have broad-spectrum antiparasitic activity but also have in vitro antifungal activity that includes Cryptococcus neoformans Flubendazole (a benzimidazole) has been reformulated by Janssen Pharmaceutica as an amorphous solid drug nanodispersion to develop an orally bioavailable medicine for the treatment of neglected tropical diseases such as onchocerciasis. We investigated the in vitro activity, the structure-activity-relationships, and both in vitro and in vivo pharmacodynamics of flubendazole for cryptococcal meningitis. Flubendazole has potent in vitro activity against Cryptococcus neoformans, with a modal MIC of 0.125 mg/liter using European Committee on Antimicrobial Susceptibility Testing (EUCAST) methodology. Computer models provided an insight into the residues responsible for the binding of flubendazole to cryptococcal ß-tubulin. Rapid fungicidal activity was evident in a hollow-fiber infection model of cryptococcal meningitis. The solid drug nanodispersion was orally bioavailable in mice with higher drug exposure in the cerebrum. The maximal dose of flubendazole (12 mg/kg of body weight/day) orally resulted in an ∼2 log10CFU/g reduction in fungal burden compared with that in vehicle-treated controls. Flubendazole was orally bioavailable in rabbits, but there were no quantifiable drug concentrations in the cerebrospinal fluid (CSF) or cerebrum and no antifungal activity was demonstrated in either CSF or cerebrum. These studies provide evidence for the further study and development of the benzimidazole scaffold for the treatment of cryptococcal meningitis.

Favorable Evolution of Cryptococcal Meningitis in the Context of Flucytosine Resistance.

Cryptococcal meningitis is a critical illness affecting 0.2% to 5% solid-organ transplant recipients with a 40% to 50% mortality. We report the case of a 48-year-old lung transplant recipient, who, 15 months after a right lung graft, kept parakeets and developed meningitis due to Cryptococcus neoformans. Immunosuppressive treatment was based on a quadruple sequential immunosuppressive therapy that included induction therapy with thymoglobulin, followed by corticosteroids, calcineurin inhibitors, and mycophenolate mofetil. Antifungal susceptibility testing of Cryptococcus neoformans showed resistance to flucytosine and intermediate sensitivity to fluconazole. Initial treatment adhered to international guidelines; however, the patient could not tolerate an effective double-antifungal therapy during the first 2 months of treatment. Despite this delayed treatment for an aggressive infection in an immunocompromised patient, the patient survived without relapse and received maintenance treatment with fluconazole during the course of 3 years. Administration of calcineurin inhibitors as immunosuppressive treatment may partly explain this outcome, as this therapeutic class is known to protect from severe forms of cryptococcal meningitis.

Experimental Models of Short Courses of Liposomal Amphotericin B for Induction Therapy for Cryptococcal Meningitis.

Cryptococcal meningoencephalitis is a rapidly lethal infection in immunocompromised patients. Induction regimens are usually administered for 2 weeks. The shortest effective period of induction therapy with liposomal amphotericin B (LAMB) is unknown. The pharmacodynamics of LAMB were studied in murine and rabbit models of cryptococcal meningoencephalitis. The concentrations of LAMB in the plasma and brains of mice were measured using high-performance liquid chromatography (HPLC). Histopathological changes were determined. The penetration of LAMB into the brain was determined by immunohistochemistry using an antibody directed to amphotericin B. A dose-dependent decline in fungal burden was observed in the brains of mice, with near-maximal efficacy achieved with LAMB at 10 to 20 mg/kg/day. The terminal elimination half-life in the brain was 133 h. The pharmacodynamics of a single dose of 20 mg/kg was the same as that of 20 mg/kg/day administered for 2 weeks. Changes in quantitative counts were reflected by histopathological changes in the brain. Three doses of LAMB at 5 mg/kg/day in rabbits were required to achieve fungicidal activity in cerebrospinal fluid (cumulative area under the concentration-time curve, 2,500 mg · h/liter). Amphotericin B was visible in the intra- and perivascular spaces, the leptomeninges, and the choroid plexus. The prolonged mean residence time of amphotericin B in the brain suggests that abbreviated induction regimens of LAMB are possible for cryptococcal meningoencephalitis.

Recent advances in AIDS-related cryptococcal meningitis treatment with an emphasis on resource limited settings.

INTRODUCTION: Recent advances in the treatment and prevention of cryptococcal meningitis have the potential to decrease AIDS-related deaths. Areas covered: Targeted screening for asymptomatic cryptococcal antigenemia in persons with AIDS is a cost effective method for reducing early mortality in patients on antiretroviral therapy. For persons with symptomatic cryptococcal meningitis, optimal initial management with amphotericin and flucytosine improves survival compared to alternative therapies; however, amphotsericin is difficult to administer and flucytosine has not been available in middle or low income countries, where cryptococcal meningitis is most prevalent. Expert commentary: Improved care for cryptococcal meningitis patients in resource-limited settings is possible, and new treatment possibilities are emerging.

Isavuconazole Is Effective for the Treatment of Experimental Cryptococcal Meningitis.

We evaluated the efficacy of isavuconazole against cryptococcal meningitis. Treatment with either oral isavuconazole (120 mg/kg and 240 mg/kg twice a day [BID]) or fluconazole as the positive control significantly improved survival in mice infected intracranially with either Cryptococcus neoformans USC1597 or H99 and significantly reduced brain fungal burdens for both isolates. Concentrations of isavuconazole in plasma and brain tissue also demonstrated that the greatest improvements in survival and fungal burden were associated with elevated exposures.

Toxicity of Amphotericin B Deoxycholate-Based Induction Therapy in Patients with HIV-Associated Cryptococcal Meningitis.

Amphotericin B deoxycholate (AmBd) is the recommended induction treatment for HIV-associated cryptococcal meningitis (CM). Its use is hampered by toxicities that include electrolyte abnormalities, nephrotoxicity, and anemia. Protocols to minimize toxicity are applied inconsistently. In a clinical trial cohort of AmBd-based CM induction treatment, a standardized protocol of preemptive hydration and electrolyte supplementation was applied. Changes in blood counts, electrolyte levels, and creatinine levels over 14 days were analyzed in relation to the AmBd dose, treatment duration (short course of 5 to 7 days or standard course of 14 days), addition of flucytosine (5FC), and outcome. In the 368 patients studied, the hemoglobin levels dropped by a mean of 1.5 g/dl (95% confidence interval [CI], 1.0 to 1.9 g/dl) following 7 days of AmBd and by a mean of 2.3 g/dl (95% CI, 1.1 to 3.6 g/dl) after 14 days. Serum creatinine levels increased by 37 µmol/liter (95% CI, 30 to 45 µmol/liter) by day 7 and by 49 µmol/liter (95% CI, 35 to 64µmol/liter) by day 14 of AmBd treatment. Overall, 33% of patients developed grade III/IV anemia, 5.6% developed grade III hypokalemia, 9.5% had creatinine levels that exceeded 220 µmol, and 6% discontinued AmBd prematurely. The addition of 5FC was associated with a slight increase in anemia but not neutropenia. Laboratory abnormalities stabilized or reversed during the second week in patients on short-course induction. Grade III/IV anemia (adjusted odds ratio [aOR], 2.2; 95% CI, 1.1 to 4.3; P = 0.028) and nephrotoxicity (aOR, 4.5; 95% CI, 1.8 to 11; P = 0.001) were risk factors for 10-week mortality. In summary, routine intravenous saline hydration and preemptive electrolyte replacement during AmBd-based induction regimens for HIV-associated CM minimized the incidence of hypokalemia and nephrotoxicity. Anemia remained a concerning adverse effect. The addition of flucytosine was not associated with increased neutropenia. Shorter AmBd courses were less toxic, with rapid reversibility.

Increased Antifungal Drug Resistance in Clinical Isolates of Cryptococcus neoformans in Uganda.

Cryptococcal antigen screening is recommended among people living with AIDS when entering HIV care with a CD4 count of <100 cells/µl, and preemptive fluconazole monotherapy treatment is recommended for those with subclinical cryptococcal antigenemia. Yet, knowledge is limited of current antimicrobial resistance in Africa. We examined antifungal drug susceptibility in 198 clinical isolates collected from Kampala, Uganda, between 2010 and 2014 using the CLSI broth microdilution assay. In comparison with two previous studies from 1998 to 1999 that reported an MIC50 of 4 µg/ml and an MIC90 of 8 µg/ml prior to widespread human fluconazole and agricultural azole fungicide usage, we report an upward shift in the fluconazole MIC50 to 8 µg/ml and an MIC90 value of 32 µg/ml, with 31% of isolates with a fluconazole MIC of ≥ 16 µg/ml. We observed an amphotericin B MIC50 of 0.5 µg/ml and an MIC90 of 1 µg/ml, of which 99.5% of isolates (197 of 198 isolates) were still susceptible. No correlation between MIC and clinical outcome was observed in the context of amphotericin B and fluconazole combination induction therapy. We also analyzed Cryptococcus susceptibility to sertraline, with an MIC50 of 4 µg/ml, suggesting that sertraline is a promising oral, low-cost, available, novel medication and a possible alternative to fluconazole. Although the CLSI broth microdilution assay is ideal to standardize results, limit human bias, and increase assay capacity, such assays are often inaccessible in low-income countries. Thus, we also developed and validated an assay that could easily be implemented in a resource-limited setting, with similar susceptibility results (P = 0.52).

Cryptoccocal meningitis in Yaoundé (Cameroon) HIV infected patients: Diagnosis, frequency and Cryptococcus neoformans isolates susceptibility study to fluconazole.

Cryptococcal meningitis is a mycosis encountered especially in patients with Acquired Immunodeficiency Syndrome and is fatal in the absence of treatment. Information on epidemiology, diagnosis and susceptibility profile to antifungal drugs, are scarce in Cameroon. Authors evaluated the diagnosis possibilities of the cryptococcal meningitis in Cameroon, and studied the antifungal susceptibility of isolated strains to fluconazole, used as first line treatment of the disease in Cameroon. Between December 2009 and July 2011, 146 cerebrospinal fluids obtained from HIV patients with suspicion of meningitis were analysed. The diagnosis procedure involved macroscopic and cyto-chemical analysis, India ink test, culture on Sabouraud chloramphenicol medium and antigen latex agglutination test. Antifungal susceptibility testing of isolated strains to fluconazole was done by the E-test(®) method. The diagnosis of cryptococcal meningitis gave 28.08% positive cases. Among these patients, 80% were at stages III and IV and 20% at stage I of the HIV infection, according to the WHO previous classification. Cyto-chemical analysis showed current findings in the case of cryptococcal meningitis. India ink test and latex agglutination test exhibited very high sensitivity and specificity (>94%). Fluconazole antifungal susceptibility testing gave MICs lower than 32µg/mL to 92.7% of isolated strains and MICs greater than this value to 7.3% of isolates. These results showed that cryptococcal meningitis remains a real problem among HIV infected patients in Yaoundé. The emergence of fluconazole reduced susceptibility strains is worrying. Nevertheless, efficacy of rapid detection tests is interesting because this will help in rapid diagnosis and treatment of patients.

Pharmacokinetics and pharmacodynamics of fluconazole for cryptococcal meningoencephalitis: implications for antifungal therapy and in vitro susceptibility breakpoints.

Fluconazole is frequently the only antifungal agent that is available for induction therapy for cryptococcal meningitis. There is relatively little understanding of the pharmacokinetics and pharmacodynamics (PK-PD) of fluconazole in this setting. PK-PD relationships were estimated with 4 clinical isolates of Cryptococcus neoformans. MICs were determined using Clinical and Laboratory Standards Institute (CLSI) methodology. A nonimmunosuppressed murine model of cryptococcal meningitis was used. Mice received two different doses of fluconazole (125 mg/kg of body weight/day and 250 mg/kg of body weight/day) orally for 9 days; a control group of mice was not given fluconazole. Fluconazole concentrations in plasma and in the cerebrum were determined using high-performance liquid chromatography (HPLC). The cryptococcal density in the brain was estimated using quantitative cultures. A mathematical model was fitted to the PK-PD data. The experimental results were extrapolated to humans (bridging study). The PK were linear. A dose-dependent decline in fungal burden was observed, with near-maximal activity evident with dosages of 250 mg/kg/day. The MIC was important for understanding the exposure-response relationships. The mean AUC/MIC ratio associated with stasis was 389. The results of the bridging study suggested that only 66.7% of patients receiving 1,200 mg/kg would achieve or exceed an AUC/MIC ratio of 389. The potential breakpoints for fluconazole against Cryptococcus neoformans follow: susceptible, ≤ 2 mg/liter; resistant, >2 mg/liter. Fluconazole may be an inferior agent for induction therapy because many patients cannot achieve the pharmacodynamic target. Clinical breakpoints are likely to be significantly lower than epidemiological cutoff values. The MIC may guide the appropriate use of fluconazole. If fluconazole is the only option for induction therapy, then the highest possible dose should be used.

Limited activity of miltefosine in murine models of cryptococcal meningoencephalitis and disseminated cryptococcosis.

Miltefosine is an alkyl phosphocholine with good oral bioavailability and in vitro activity against Cryptococcus species that has gained interest as an additional agent for cryptococcal infections. Our objective was to further evaluate the in vivo efficacy of miltefosine in experimental in vivo models of cryptococcal meningoencephalitis and disseminated cryptococcosis. Mice were infected intracranially or intravenously with either C. neoformans USC1597 or H99. Miltefosine treatment (1.8 to 45 mg/kg of body weight orally once daily) began at either 1 h or 1 day postinoculation. Fluconazole (10 mg/kg orally twice daily) or amphotericin B deoxycholate (3 mg/kg intraperitoneally once daily) served as positive controls. In our standard models, miltefosine did not result in significant improvements in survival or reductions in fungal burden against either C. neoformans isolate. There was a trend toward improved survival with miltefosine at 7.2 mg/kg against disseminated cryptococcosis with the H99 strain but only at a low infecting inoculum. In contrast, both fluconazole and amphotericin B significantly improved survival in mice with cryptococcal meningoencephalitis and disseminated cryptococcosis due to USC1597. Amphotericin B also improved survival against both cryptococcal infections caused by H99. Combination therapy with miltefosine demonstrated neither synergy nor antagonism in both models. These results demonstrate limited efficacy of miltefosine and suggest caution with the potential use of this agent for the treatment of C. neoformans infections.

Meningitis due to Cryptococcus neoformans: treatment with posaconazole.

BACKGROUND: Central nervous system infections caused by Cryptococcus neoformans remain to be opportunistic infections with high mortality in severely immunocompromised patients such as patients with AIDS. Amphotericin B deoxycholate and fluconazole remain to be the drugs of choice; however, in consideration of the intolerance to amphotericin B deoxycholate and the possible resistance to fluconazole, it is necessary to evaluate other azoles, such as posaconazole, that have demonstrated lower adverse events. The objective of this study was to describe the characteristics and clinical and microbiological response of the use of posaconazole in patients with CNS infections caused by C. neoformans. METHODS: We designed a case study that included eight patients diagnosed with AIDS and cryptococcal meningitis. Seven patients were treated with 800 mg of posaconazole orally for 28 days. RESULTS: During the second week of treatment, a cerebrospinal fluid (CSF) culture was performed and was negative for the development of C. neoformans. The patients showed an improvement in signs and symptoms of impairment of the CNS such as reduction of cephalea, fever, visual disturbances such as double vision, meningism and papilledema, and improved alertness and environmental awareness. CONCLUSIONS: CNS fungal infections usually occur in immunocompromised patients. The use of systemic antifungal agents contributes to the development of fungal resistance. The results of this study suggest that posaconazole is a good alternative in the treatment of fungal CNS infection due to C. neoformans.

Efficacy of intrathecal administration of liposomal amphotericin B combined with voriconazole in a murine model of cryptococcal meningitis.

Meningitis is one of the most fatal manifestations of cryptococcosis, even with specific treatment. Combination of a prompt diagnosis and appropriate therapy are critical to reduce the fungal load and the inflammatory response effects of the proliferation of yeast into the central nervous system (CNS). Mice with experimental acute meningitis caused by Cryptococcus neoformans were treated with liposomal amphotericin B (L-AmB) administered intrathecally (i.t.c.) at 0.006 mg/kg weekly or intravenously (i.v.) at 10 mg/kg daily or with voriconazole (VCZ) administered orally at 30 mg/kg per dose twice daily or with combinations of both drugs, i.e. L-AmB i.t.c.+VCZ or L-AmB i.v.+VCZ at the same doses as used in the monotherapies. All treatments significantly increased the survival of animals in comparison with the control group, with VCZ being less effective in comparison with all other treatments (P ≤ 0.012). All treatments, with the exception of VCZ (P=0.533), reduced fungal burdens in the brain in comparison with controls. The combination of L-AmB i.t.c.+VCZ showed a synergistic effect in the reduction of fungal load that was significantly superior to any tested therapy (P ≤ 0.039). Histologically, untreated animals showed a marked inflammatory response with massive fungal cells in the meninges, whilst treated animals showed a variable number of fungal cells in the CNS, with the exception of animals receiving L-AmB i.t.c.+VCZ in which neither yeasts nor inflammation were observed.

Correlation of susceptibility of Cryptococcus neoformans to amphotericin B with clinical outcome.

Testing of Cryptococcus neoformans for susceptibility to antifungal drugs by standard microtiter methods has not been shown to correlate with clinical outcomes. This report describes a modified quantitative broth macrodilution susceptibility method showing a correlation with both the patient's quantitative biological response in the cerebrospinal fluid (CSF) and the survival of 85 patients treated with amphotericin B (AMB). The Spearman rank correlation between the quantitative in vitro measure of susceptibility and the quantitative measure of the number of organisms in the patient's CSF was 0.37 (P < 0.01; 95% confidence interval [95% CI], 0.20, 0.60) for the first susceptibility test replicate and 0.46 (P < 0.001; 95% CI, 0.21, 0.62) for the second susceptibility test replicate. The median in vitro estimated response (defined as the fungal burden after AMB treatment) at 1.5 mg/liter AMB for patients alive at day 14 was 5 CFU (95% CI, 3, 8), compared to 57 CFU (95% CI, 4, 832) for those who died before day 14. These exploratory results suggest that patients whose isolates show a quantitative in vitro susceptibility response below 10 CFU/ml were more likely to survive beyond day 14.

Oral versus intravenous flucytosine in patients with human immunodeficiency virus-associated cryptococcal meningitis.

In a randomized controlled trial of amphotericin B-based therapy for human immunodeficiency virus (HIV)-associated cryptococcal meningitis in Thailand, we also compared the mycological efficacy, toxicity, and pharmacokinetics of oral versus intravenous flucytosine at 100 mg/kg of body weight/day for the initial 2 weeks. Half of 32 patients assigned to the two arms containing flucytosine were randomized to oral and half to intravenous flucytosine. Early fungicidal activity was determined from serial quantitative cultures of cerebrospinal fluid (CSF), and toxicity was assessed by clinical and laboratory monitoring. Flucytosine and fluorouracil concentrations in plasma and CSF were measured by high-performance liquid chromatography. No significant bone marrow or hepatotoxicity was seen, there was no detectable difference in bone marrow toxicity between patients on intravenous and those on oral formulation, and no patients discontinued treatment. In patients receiving intravenous flucytosine, the median 24-h area under the concentration-time curve was significantly higher than in the oral group. Despite this difference, there was no difference in early fungicidal activity between patients on intravenous compared with patients on oral flucytosine. The results suggest that either formulation can be used safely at this dosage in a developing country setting, without drug concentration monitoring. The bioavailability of the oral formulation may be reduced in late-stage HIV-infected patients in Thailand. Concentrations of flucytosine with intravenous formulation at 100 mg/kg/day may be in excess of those required for maximal fungicidal activity.

Amphotericin B and fluconazole, a potent combination therapy for cryptococcal meningitis.

We evaluated the antifungal activities of amphotericin B, fluconazole, and flucytosine, alone and in combination, in a murine model of cryptococcal meningitis. The objectives were to determine the greatest antifungal effects achievable with these drugs alone or in combination. Meningitis was established in male BALB/c mice weighing 23 to 25 g by intracerebral injection of Cryptococcus neoformans. Treatment was started on day 2. Amphotericin B was tested at 0.3 to 1.3 mg/kg of body weight/day by slow intravenous injection. Fluconazole at 10 to 40 mg/kg/day and flucytosine at 20 to 105 mg/kg/day were administered in the sole source of drinking water. The mice were killed at 16 days, and the numbers of fungal colonies in the brain were quantified. The association between the response and the dose combination was evaluated by local nonparametric response surface methods; 99% confidence intervals were used to evaluate the antifungal effects. Ninety-five percent of the mice treated with amphotericin B at 0.5 mg/kg survived to the end of the experiment, regardless of the fluconazole or flucytosine dose used. The greatest activity was seen with amphotericin B plus fluconazole with or without flucytosine. However, the addition of flucytosine did not increase the antifungal activity. Given the widespread availability of amphotericin B and fluconazole and the relative safety profile of fluconazole compared to that of flucytosine, the full potential of this two-drug combination deserves further evaluation.

In vitro and in vivo efficacies of the new triazole albaconazole against Cryptococcus neoformans.

The activity of albaconazole (UR-9825; J. Uriach & Cía. S.A., Barcelona, Spain) was compared to that of fluconazole against 12 isolates of Cryptococcus neoformans in vitro and against 1 isolate in vivo in a rabbit model of cryptococcal meningitis. Albaconazole was 100-fold more potent in vitro than fluconazole on a per-weight basis and was fungicidal at potentially relevant concentrations for two isolates. MICs ranged from

Effects of fluconazole singly and in combination with 5-fluorocytosine or amphotericin B in the treatment of cryptococcal meningoencephalitis in an intracranial murine model.

In this study we developed a highly reproducible intracranial murine model of cryptococcosis. Mice (Balb/c, 5-7 weeks old) were challenged intracranially and treated with intermediate (30 mg/kg) or high (90 mg/kg) dose fluconazole, and amphotericin B (0.75 mg/kg), administered singly or in combination with flucytosine (100 mg/kg). Survival and brain CFU analyses were performed. Effect of fluconazole prophylaxis was also determined. Our data show that the developed model mimics clinical signs of cryptococcal meningitis. In single treatment, fluconazole (30 mg/kg) was more efficacious than amphotericin B or flucytosine (P < 0.0001). Combination treatment led to significantly increased anticryptococcal activity, which was highest for high dose fluconazole + flucytosine (P < 0.0001). However, no significant difference was observed between high dose fluconazole treatment with and without flucytosine (P >0.05). Fluconazole prophylaxis led to a significant decrease in brain CFU. In conclusion, high dose fluconazole administered post-infection, or as prophylaxis, may be highly efficacious in the treatment and prevention of meningoencephalitis.