Treatment of exogenous Candida endophthalmitis in rabbits with oral fluconazole

Clinical Practice Guideline for the Management of Candidiasis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Exogenous fungal endophthalmitis: an analysis of isolates and susceptibilities to antifungal agents over a 20-year period (1990-2010)

PURPOSE

To describe the isolates and susceptibilities to antifungal agents for patients with culture-proven exogenous fungal endophthalmitis.

DESIGN

Noncomparative case series.

METHODS

The clinical records of all patients treated for culture-proven exogenous fungal endophthalmitis at a university referral center from 1990 to 2010 were reviewed. Specimens initially used for diagnosis were recovered from the microbiology department and then underwent antifungal sensitivity analysis.

RESULTS

The antifungal susceptibilities of 47 fungal isolates from culture-positive fungal endophthalmitis are reported. Included are 14 isolates from yeast and 33 from mold. The mean (±standard deviation) minimum inhibitory concetrations (MICs) for amphotericin B (2.6 ± 3.5 μg/mL), fluconazole (36.9 ± 30.7 μg/mL), and voriconazole (1.9 ± 2.9 μg/mL) are reported. Presumed susceptibility to oral fluconazole, intravenous amphotericin B, intravitreal amphotericin B, oral voriconazole, and intravitreal voriconazole occurred in 34.8%-43.5%, 0-8.3%, 68.8%, 69.8%, and 100% of isolates, respectively.

CONCLUSIONS

Based on this laboratory study of isolates from exogenous fungal endophthalmitis, intravitreal voriconazole appears to provide the broadest spectrum of antifungal coverage and, as such, may be considered for empiric therapy of endophthalmitis caused by yeast or mold.

Vitrectomy with Fluconazole Infusion: Retinal Toxicity, Pharmacokinetics, and Efficacy in the Treatment of Experimental Candidal Endophthalmitis

The aim of this study was to determine the retinal toxicity and intraocular pharmacokinetics of vitrectomy with fluconazole infusion in rabbit eyes and to study its efficacy in the treatment of experimental candidal endophthalmitis. The right eyes of 13 New Zealand White (NZW) rabbits were vitrectomized and infused with 20 mL of 0.2 mg/mL, 1 mg/mL, or 2 mg/mL of fluconazole. An electroretinogram (ERG) was performed on both eyes of each rabbit at different time points. The right eyes of 26 different NZW rabbits were vitrectomized and infused with 20 mL of 2 mg/mL of fluconazole. These rabbits were sacrificed, and their right eyes were enucleated at hours 2, 4, 8, and 24 after the operation, and the concentration of fluconazole in the vitreous was measured by highpressure liquid chromatography. Experimental candidal endophthalmitis was induced in the right eye of 42 other NZW rabbits. Twenty-six (26) of the eyes were then vitrectomized and infused with 20 mL of 2 mg/mL of fluconazole, and the other 16 rabbits served as control. Severity of ocular infection was graded from 0-4 at different time intervals, using an indirect ophthalmoscope. In the first group, ERG showed no significant difference between the experimental eyes and the control eyes--in all concentrations of fluconazole--for up to 3 months. In the second group, the intraocular concentration of fluconazole declined so rapidly that, as of 8 hours after operation, there was none in the vitreous cavity. In the third group, significantly less vitreous opacity was found in the treated eyes on days 3 and 6. However, the difference ceased to be apparent on day 15. Our study suggests that there is no retinal toxicity resulting from vitrectomy with a 2 mg/mL fluconazole infusion, and that it is temporally effective in the treatment of experimental candidal endophthalmitis.

Efficacies of high-dose fluconazole plus amphotericin B and high-dose fluconazole plus 5-fluorocytosine versus amphotericin B, fluconazole, and 5-fluorocytosine monotherapies in treatment of experimental endocarditis, endophthalmitis, and pyelonephritis due to Candida albicans

We compared the efficacies of fluconazole (Flu), amphotericin B (AmB), and 5-fluorocytosine (5FC) monotherapies with the combination of Flu plus 5FC and Flu plus AmB in a rabbit model of Candida albicans endocarditis, endophthalmitis, and pyelonephritis. The dose of Flu used was that which resulted in an area under the concentration-time curve in rabbits equivalent to that seen in humans who receive Flu at 1,600 mg/day, the highest dose not associated with central nervous system toxicity in humans. Quantitative cultures of heart valve vegetations, the choroid-retina, vitreous humor, and kidney were conducted after 1, 5, 14, and 21 days of therapy. All untreated controls died within 6 days of infection; animals treated with 5FC monotherapy all died within 18 days. In contrast, 93% of animals in the other treatment groups appeared well and survived until they were sacrificed. At day 5, the relative decreases in CFU per gram in the vitreous humor were greater in groups that received Flu alone and in combination with 5FC or AmB than in groups receiving AmB or 5FC monotherapies (P < 0. 005) but were similar thereafter. In the choroid-retina, 5FC was the least-active drug. However, there were no differences in choroidal fungal densities between the other treatment groups. On days 5 and 14 of therapy, fungal densities in kidneys of AmB recipients were lower than those resulting from the other therapies (P < 0.001 and P < or = 0.038, respectively) and AmB-plus-Flu therapy was antagonistic; however, all therapies for fungal pyelonephritis were similar by treatment day 21. While fungal counts in cardiac valves of Flu recipients were similar to those of controls on day 5 of therapy and did not change from days 1 to 21, AmB therapy significantly decreased valvular CFUs versus Flu at days 5, 14, and 21 (P < 0.005 at each time point). 5FC plus Flu demonstrated enhanced killing in cardiac vegetations compared with Flu or 5FC as monotherapies (P < 0. 03). Similarly, the combination of AmB and Flu was more active than Flu in reducing the fungal density in cardiac vegetations (P < 0.03). However, as in the kidney, AmB plus Flu demonstrated antagonism versus AmB monotherapy in the treatment of C. albicans endocarditis (P < 0.05, P = 0.036, and P < 0.008 on days 5, 14, and 21, respectively).

[Status of fluconazole in the therapy of endogenous Candida endophthalmitis]

During the clinical course of invasive candidosis, endogenous Candida endophthalmitis (ECE) is associated with a higher mortality. In patients with candidemia, an ECE-incidence of 28 to 37% was reported. In i.v.-drug users, the incidence of Candida infections was 21%. Besides surgical procedures including vitrectomy and enucleation, early initiation of systemic antifungal therapy is decisive for the outcome. The clinical use of fluconazole in ECE is documented in 96 patients and in a minimum of 108 eyes. The mean duration of therapy was 6-8 weeks (maximum duration: lifelong) with an average dosage of 200-400 mg/d (maximum dosage: 800 mg/d and 14 mg/kg BW, resp.). The results reported in the literature show a good clinical efficacy of fluconazole in ECE: 90% response rate (19/21) in patients with/without concomitant vitrectomy and with/without concomitant use of other antifungals, complete disappearance of all eye lesions in 94% (15/16) non-neutropenic patients with candidemia and in 86% (6/7) ECE-patients addicted to heroin. With respect to these favorable results, fluconazole plays an important role in the standard therapy of ECE.

Comparison of fluconazole pharmacokinetics in serum, aqueous humor, vitreous humor, and cerebrospinal fluid following a single dose and at steady state

The objective of this study was to characterize the pharmacokinetic parameters and penetration of fluconazole following a single dose in the serum, aqueous humor, vitreous humor and cerebrospinal fluid (CSF) of non pigmented rabbits using serial sampling techniques and to determine if the pharmacokinetic parameters in the eye and CSF are similar. Twenty healthy male rabbits received intravenous fluconazole 20 mg/kg as a single dose or 20 mg/kg every 12 hours for 4 doses. Serum, aqueous humor, vitreous humor and CSF samples were taken 15 minutes after the initial intravenous injection and hourly thereafter for six hours. Fluconazole concentrations were determined by microbiological assay. Pharmacokinetic analyses were performed using a nonlinear least-square regression program. Fluconazole's penetration in all anatomical compartments was > 70% than in the serum. Similar elimination half-lives and time to reach maximum concentrations were noted in all compartments. While mean concentrations in each anatomical compartment were similar in animals receiving a single dose or among those at serum steady state, the mean concentrations achieved in the serum, aqueous and vitreous humors and CSF were between 1.82 and 2.17 times higher at serum steady state than following a single dose. At serum concentrations that are comparable to those in humans, the penetration of fluconazole into the noninflamed aqueous and vitreous humors and CSF were > or = 70%. The CSF and ocular pharmacokinetic parameters closely resembled each other, so that either could be used as a surrogate for the other.

Unexpected candidemia complicating ureteroscopy and urinary stenting

Two elderly patients with obstructive renal calculi who developed Candida albicans bloodstream infection within 12 h following ureteroscopy and ureteral stenting are described. Both patients were treated with prolonged courses of broad-spectrum antibiotics and were found to have urine cultures positive for Candida albicans prior to the urologic procedures. One patient also developed bilateral candidal endophthalmitis. The clinical presentation was indistinguishable from bacteremia complicating manipulation of the urinary tract. The patients were successfully treated with systemic antifungal therapy. Candiduria may present a risk for dissemination during invasive, relatively simple urologic procedures.

Multicenter randomized trial of fluconazole versus amphotericin B for treatment of candidemia in non-neutropenic patients. Canadian Candidemia Study Group

A randomized trial was conducted to compare the efficacy and safety of fluconazole versus that of amphotericin B in the treatment of candidemia in non-neutropenic adults. Enrollment was stratified by disease severity (APACHE II score). Patients were randomized (1:1) to receive amphotericin B 0.6 mg/kg/day (cumulative dose 8 mg/kg) or fluconazole 800 mg intravenous loading dose, then 400 mg daily for four weeks (intravenous for at least 10 days). Patients were monitored for six months. A total of 106 patients were enrolled. A protocol amendment implemented midway through the trial required patients to be removed from the study and treated with amphotericin B if species identification indicated candidemia due to Candida glabrata or Candida krusei. Baseline characteristics were similar for the two groups; 103 patients (fluconazole, 50; amphotericin B, 53) met the major enrollment criteria. The intention-to-treat analysis indicated successful therapy in 50% of fluconazole recipients compared to 58% of the amphotericin B group (p = 0.39; one-sided 95% CI, -8 to 24%). The efficacy analysis included 84 patients (fluconazole, 42; amphotericin B, 42); successful outcomes were observed in 57% and 62% of cases in the fluconazole and amphotericin B groups, respectively (p = 0.66: one-sided 95% CI, -12 to 22%). The mortality at day 14 for the fluconazole group was 26% and for the amphotericin B group 21% (p = 0.52; chi-square test) and remained similar throughout the course of follow-up, Drug-related adverse events were more frequent with amphotericin B than with fluconazole and prompted switching of therapy for two (4%) and zero cases, respectively. Fluconazole and amphotericin B were associated with similar clinical response rates and survival in the treatment of candidemia among non-neutropenic patients; however, drug-related adverse events were more frequent with amphotericin B.