Biofilm on ventriculo-peritoneal shunt tubing as a cause of treatment failure in coccidioidal meningitis

Abstract

We describe a case of recurrent coccidioidal meningitis in which a fungal biofilm on the tip of ventriculo-peritoneal shunt tubing was likely responsible for a 4-year persistence of Coccidioides immitis, despite the patient's taking an adequate dosage of fluconazole. Fungal biofilms should be considered as a cause for treatment failure and fungal persistence, especially when artificial prostheses or indwelling catheters are present.

Figure 1

Coccidioides immitis hyphae dislodged from the tip of the ventriculo-peritoneal catheter tip, fixed in formalin and stained with Calcofluor. Stained barrel-shaped arthroconidia (arrows) are seen, along with empty cells (x400). The upper left image shows a section from the tip of the shunt tubing stained with SYTOX Green nucleic acid stain and examined by scanning confocal microscopy with argon-ion laser light source. This specific staining for nucleic acids clearly shows the presence of a biofilm and some 4- to 6-μm cells. The upper right image shows an unstained, transmitted light microscopic image of the same area of the edge of the tubing. The bottom right image shows a recombined image with the nucleic acid stain colocalized with the transmitted light image. The recombined image shows that a substantial (~30 μm) biofilm composed of 4- to 6-μm cells has colonized the “scalloped” surface of this tubing. (x630 total magnification mosaic)

Figure 2

A. Scanning electron microscopy shows the presence of leukocytes and red blood cells on the tip of the ventriculo-peritoneal mass, within which coccoid cells can be visualized. The enclosing matrix material has condensed by dehydration, but the outline of the 4- to 6-μm coccoid cells (arrow), similar to those of C. immitis, can be resolved within the mass (x4,000). B. Scanning electron microscopy of the surface of the ventriculo-peritoneal shunt, showing complete colonization of the surface by a matrix-enclosed biofilm formed by the cells of C. immitis. Within the dehydration-condensed matrix of this biofilm, a hyphal element (arrow) and coccoid cells (4-6 μm) of the pathogen can be discerned (x5,000).

Figure 3

A. Scanning electron microscopy shows the presence of leukocytes and red blood cells on the tip of the ventriculo-peritoneal mass, within which coccoid cells can be visualized. The enclosing matrix material has condensed by dehydration, but the outline of the 4- to 6-µm coccoid cells (arrow), similar to those of C. immitis, can be resolved within the mass (x4,000). B. Scanning electron microscopy of the surface of the ventriculo-peritoneal shunt, showing complete colonization of the surface by a matrix-enclosed biofilm formed by the cells of C. immitis. Within the dehydration-condensed matrix of this biofilm, a hyphal element (arrow) and coccoid cells (4-6 µm) of the pathogen can be discerned (x5,000).