Comparison of Fluconazole and Itraconazole in a Rabbit Model of Coccidioidal Meningitis

Abstract

ABSTRACT Coccidioidal meningitis is a devastating disease that requires long-term therapy with little hope of cure. A rabbit model of coccidioidal meningitis was used to compare the therapeutic efficacies of fluconazole (FCZ) and itraconazole (ITZ). Hydrocortisone-treated male New Zealand white rabbits were infected intracisternally with 5.0 × 10 4 to 5.4 × 10 4 arthroconidia of Coccidioides immitis . Oral treatment with polyethylene glycol 200 (PEG) ( n = 9), FCZ ( n = 8; 80 mg/kg of body weight/day), or ITZ ( n = 8; 80 mg/kg/day) began 5 days after infection and continued for 28 consecutive days. Both FCZ and ITZ reduced the number of CFU of C. immitis organisms in the spinal cord and brain compared with the number in PEG-treated animals ( P ≤ 0.003), but the results for FCZ and ITZ were not different from each other. Histopathologic severity (semiquantitative scoring system by an observer blinded to treatment) was equally reduced in both FCZ and ITZ treatment groups compared with that in controls ( P ≤ 0.0004). Both treatments resulted in lower cerebrospinal fluid (CSF) protein concentrations and leukocyte counts and faster clearing of C. immitis from CSF compared with the results for PEG-treated controls. Neither drug affected CSF glucose levels. Both compounds were effective at reducing neurological and systemic signs and extending survival ( P ≤ 0.014). FCZ was more effective at reducing head and body shakes, posture changes, and incontinence; ITZ was more effective at reducing continuous fever. Mean levels of FCZ and ITZ in the serum and CSF were determined by bioassay; at 17 to 26 h postdosing, levels were 28.1 to 40.0 and 22.4 to 29.9 μg/ml, respectively, for FCZ and 0.77 to 2.51 and 0 μg/ml, respectively, for ITZ. The sera of most animals developed antibody to C. immitis , but azole treatment attenuated antibody development in CSF and its titer. In conclusion, both FCZ and ITZ were efficacious, but neither was curative in a rabbit model of coccidioidal meningitis.