Cerebrospinal fluid and plasma (1-->3)-beta-D-glucan as surrogate markers for detection and monitoring of therapeutic response in experimental hematogenous Candida meningoencephalitis

Antimicrob Agents Chemother. 2008 Nov;52(11):4121-9. doi: 10.1128/AAC.00674-08. Epub 2008 Sep 8.

Abstract

The treatment, diagnosis and therapeutic monitoring of hematogenous Candida meningoencephalitis (HCME) are not well understood. We therefore studied the expression of (1-->3)-beta-D-glucan (beta-glucan) in cerebrospinal fluid (CSF) and plasma in a nonneutropenic rabbit model of experimental HCME treated with micafungin and amphotericin B. Groups studied consisted of micafungin (0.5 to 32 mg/kg) and amphotericin B (1 mg/kg) treatment groups and the untreated controls (UC). Despite well-established infection in the cerebrum, cerebellum, choroid, vitreous humor (10(2) to 10(3) CFU/ml), spinal cord, and meninges (10 to 10(2) CFU/g), only 8.1% of UC CSF cultures were positive. By comparison, all 25 UC CSF samples tested for beta-glucan were positive (755 to 7,750 pg/ml) (P < 0.001). The therapeutic response in CNS tissue was site dependent, with significant decreases of the fungal burden in the cerebrum and cerebellum starting at 8 mg/kg, in the meninges at 2 mg/kg, and in the vitreous humor at 4 mg/kg. A dosage of 24 mg/kg was required to achieve a significant effect in the spinal cord and choroid. Clearance of Candida albicans from blood cultures was not predictive of eradication of organisms from the CNS; conversely, beta-glucan levels in CSF were predictive of the therapeutic response. A significant decrease of beta-glucan concentrations in CSF, in comparison to that for UC, started at 0.5 mg/kg (P < 0.001). Levels of plasma beta-glucan were lower than levels in simultaneously obtained CSF (P < 0.05). CSF beta-glucan levels correlated in a dose-dependent pattern with therapeutic responses and with Candida infection in cerebral tissue (r = 0.842). Micafungin demonstrated dose-dependent and site-dependent activity against HCME. CSF beta-glucan may be a useful biomarker for detection and monitoring of therapeutic response in HCME.

MeSH terms

  • Amphotericin B / administration & dosage
  • Amphotericin B / pharmacokinetics
  • Amphotericin B / therapeutic use
  • Animals
  • Antifungal Agents / administration & dosage
  • Antifungal Agents / pharmacokinetics
  • Antifungal Agents / therapeutic use
  • Biomarkers / blood
  • Biomarkers / cerebrospinal fluid
  • Candidiasis / blood*
  • Candidiasis / cerebrospinal fluid*
  • Candidiasis / drug therapy
  • Candidiasis / pathology
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Drug Monitoring
  • Echinocandins / administration & dosage
  • Echinocandins / pharmacokinetics
  • Echinocandins / therapeutic use
  • Female
  • Lipopeptides / administration & dosage
  • Lipopeptides / pharmacokinetics
  • Lipopeptides / therapeutic use
  • Meningitis, Fungal / blood*
  • Meningitis, Fungal / cerebrospinal fluid*
  • Meningitis, Fungal / drug therapy
  • Meningitis, Fungal / pathology
  • Meningoencephalitis / blood*
  • Meningoencephalitis / cerebrospinal fluid*
  • Meningoencephalitis / drug therapy
  • Meningoencephalitis / pathology
  • Micafungin
  • Rabbits
  • beta-Glucans / blood*
  • beta-Glucans / cerebrospinal fluid*

Substances

  • Antifungal Agents
  • Biomarkers
  • Echinocandins
  • Lipopeptides
  • beta-Glucans
  • Amphotericin B
  • Micafungin