Therapeutic efficacy of posaconazole against isolates ofCandida albicanswith different susceptibilities to fluconazole in a vaginal model

The in vitro and in vivo efficacy of fluconazole in combination with farnesol against Candida albicans isolates using a murine vulvovaginitis model

Farnesol is a quorum-sensing molecule that inhibits biofilm formation in Candida albicans. Previous in vitro data suggest that, in combination with certain antifungals, farnesol may have an adjuvant anti-biofilm agent. However, the in vivo efficacy of farnesol is very questionable. Therefore, the in vitro and in vivo activity of fluconazole combined with farnesol was evaluated against C. albicans biofilms using fractional inhibitory concentration index (FICI) determination, time-kill experiments and a murine vulvovaginitis model. The median biofilm MICs of fluconazole-sensitive C. albicans isolates ranged between 4 -> 512 mg/L and 150-300 μM for fluconazole and farnesol, respectively. These values were 512 -> 512 mg/L and > 300 μM for fluconazole-resistant clinical isolates. Farnesol decreased the median MICs of fluconazole by 2-64-fold for biofilms. Based on FICI, synergistic interaction was observed only in the case of the sessile SC5314 reference strain (FICIs: 0.16-0.27). In time-kill studies, only the 512 mg/L fluconazole and 512 mg/L fluconazole + 75 μM farnesol reduced biofilm mass significantly at each time point in the case of all isolates. The combination reduced the metabolic activity of biofilms for all isolates in a concentration- and time-dependent manner. Our findings revealed that farnesol alone was not protective in a murine vulvovaginitis model. Farnesol was not beneficial in combination with fluconazole for fluconazole-susceptible isolates, but partially increased fluconazole activity against one fluconazole-resistant isolate, but not the other one.

Efficacy of ravuconazole in a murine model of vaginitis by Candida albicans

BACKGROUND

The incidence of vulvovaginal candidiasis, a common infection among healthy women primarily caused by the yeast Candida albicans, has increased significantly in recent years.

AIMS

The purpose of this study was to compare the efficacy of ravuconazole (RVC) and fluconazole (FLC) in the treatment of experimental C. albicans vaginitis.

METHODS

Forty isolates of C. albicans were screened for their in vitro susceptibility to RVC and FLC. A strain of C. albicans that was resistant to FLC (minimum inhibitory concentration [MIC] of >64 μg/ml) was selected for the in vivo study. Treatment regimens for the murine vaginal infection model were (1) 1, 5, 10, and 20 mg/kg RVC once daily, (2) 20 mg/kg RVC twice daily, (3) 20 mg/kg FLC once daily, and (4) 20 mg/kg FLC twice daily.

RESULTS

The geometric means of the MIC values at 48 h for all isolates tested were 0.05 and 0.5 μg/ml for RVC and FLC, respectively. Regimens of either RVC or FLC at 20 mg/kg twice daily were more effective to reduce the load of FLC-resistant C. albicans than single dose administration.

CONCLUSIONS

Complete eradication of C. albicans from the vagina was not observed with RVC or FLC treatment in the animal model, although RVC treatment showed a lower fungal concentration 14 days after drug administration.

Therapeutic efficacy of posaconazole against Candida glabrata in a murine model of vaginitis

The frequency of mucosal infections caused by Candida glabrata has increased significantly. Candida glabrata infections are often resistant to many azole antifungal agents, especially fluconazole. The purpose of this study was to compare the efficacies of posaconazole (PSC) and fluconazole (FLC) in the treatment of experimental C. glabrata vaginitis caused by isolates with different FLC susceptibilities. A battery of 36 vaginal isolates of C. glabrata was tested against PSC and FLC to determine their in vitro susceptibilities. The 48-h geometric mean MICs for all isolates tested were 0.156 and 4.238 μg ml(-1) for PSC and FLC respectively. Two strains of C. glabrata for which FLC MICs were different were selected for in vivo study. The treatment regimens for the vaginal murine infection model were PSC or FLC at 10 or 20 mg kg(-1) of body weight/day and 20 mg kg(-1) twice a day. Regimens with PSC at 20 mg kg(-1) once or twice a day were effective in reducing the load of both the FLC-susceptible and -resistant isolates of C. glabrata. FLC at 20 mg kg(-1) twice a day was effective in reducing the load of both the isolates of C. glabrata. PSC displayed a more effective in vivo activity than FLC in the treatment of murine C. glabrata vaginitis.

Efficacy of albaconazole against Candida albicans in a vaginitis model

The efficacy of albaconazole (ABC) was evaluated using a murine model of vaginal Candida albicans infection. Both ABC and fluconazole (FLC) were effective in reducing the fungal load from vaginas of infected mice; however, ABC demonstrated encouraging activities against an FLC-resistant strain, with trends toward superiority over FLC in some treatment groups.

Therapeutic efficacy of voriconazole against a fluconazole-resistant Candida albicans isolate in a vaginal model

BACKGROUND

The purpose of this study was to assess the therapeutic efficacy of oral versus intravaginal voriconazole and compare it with fluconazole for the treatment of experimental vaginitis caused by a fluconazole-resistant Candida albicans isolate.

METHODS

Mice were treated with voriconazole at 5, 10 and 20 mg/kg once a day and 20 mg/kg twice a day or with fluconazole at 20 mg/kg once or twice a day orally. Intravaginal treatments were evaluated with voriconazole and fluconazole at 0.5, 1 and 5 mg/kg once a day. All treatment regimens were given on days 1-5 post-challenge. One day 6, the vaginas were swabbed to assess treatment effects.

RESULTS

Mice treated orally with voriconazole at >or=10 mg/kg and fluconazole at >or=20 mg/kg showed significantly reduced fungal counts over controls (P = 0.0002-0.007). Significant differences were found between the groups that received voriconazole at 20 mg/kg once or twice daily and those that received fluconazole at 20 mg/kg once or twice daily, orally (P = 0.010 and 0.001, respectively). Mice treated with voriconazole or fluconazole administered intravaginally at >or=0.5 mg/kg exhibited a reduced fungal burden when compared with the control group (P = 0.0002-0.007). There was no statistically significant difference in fungal burden between topical treatment with doses of 0.5, 1 and 5 mg/kg once daily of voriconazole or fluconazole. Sterilization of vaginas was not observed with voriconazole and fluconazole without taking into consideration the therapeutic modality.

CONCLUSIONS

Voriconazole could emerge as a new alternative for treatment of vaginal candidosis.