The ability of Candida albicans and Candida spp. to adhere to inert polymeric surfaces may allow these organisms direct ingress into the human host. Biophysical characterization of this adherence shows that the forces responsible for such adherence are attractive London-van der Waals forces (or hydrophobic forces) and electrostatic forces. The hydrophobic affinity of yeasts was determined by (i) a water-hydrocarbon two-phase assay and by (ii) measurement of the contact angle (theta) of a liquid droplet on a monolayer of yeast cells. The hydrophobicity of the yeasts correlated with the tendency of yeasts to adhere to polystyrene and was reduced in the presence of Tween 20. The adherence of yeasts to polymers of increasing hydrophobicity (determined by the contact angle method) was directly proportional to theta. Yeast surface charges were altered by selectively blocking amino and carboxyl groups. The more positively charged yeasts adhered in greater numbers. Increasing the molarity of NaCl increased yeast adherence. These forces probably contribute to the negative cooperativity (determined by Scatchard and Hill plot) that characterizes the adherence of yeasts to polymers.

Fungal peritonitis is a rare complication in patients on continuous ambulatory peritoneal dialysis. We report five recent cases and their management. The fungi isolated were Candida albicans, C. parapsilosis, Exophiala jeanselmei, Drechslera spicifera, and a Fusarium species. Chemotherapy was attempted with various regimens including oral ketoconazole, intravenous or intraperitoneal amphotericin B, and oral flucytosine. Pharmacokinetic studies were done in two patients receiving treatment with one of these drugs. Three patients were cured of their fungal infection. Three patients whose Tenckhoff catheters were left in situ died, whereas two patients whose catheters were removed survived. Our experience suggests that removal of the peritoneal catheter should be considered once the diagnosis of fungal peritonitis is established.

The inhaled arthroconidia of Coccidioides immitis mature to form large (30-80 micron) endosporulating spherules. Each spherule releases hundreds of endospores, taxing immunologic reserves. Polymorphonuclear neutrophils (PMNs) are prominent in the lesions of coccidioidomycosis, but their effectiveness is questionable. Arthroconidia possess an antiphagocytic surface derived from the original hyphal outer wall layer. Only 20%-30% of arthroconidia or endospores that are ingested by PMNs are killed. PMNs can digest the outer wall layer of spherules but may not induce lethal injury. Cell-mediated immunity is central to host defense. Macrophages ingest arthroconidia and endospores but may be unable to kill them unless lymphokines stimulate phagolysosomal fusion. Whether spherules can be killed by macrophages is unclear. C. immitis is stimulated directly by serum levels of estradiol and progesterone achieved in pregnant women. This, together with the depressed cell-mediated immunity of pregnancy, may account for the virulent nature of coccidioidomycosis in pregnant women.

Athymic nude mice (nu/nu) were significantly more susceptible to pneumonia due to the agent of mouse pneumonitis (MoPn), Chlamydia trachomatis, than their heterozygous (nu/+) littermates, as judged both by a greater mortality and a decreased ability to rid their lungs of the infection. Nu/nu mice did not produce significant antibody to the MoPn agent, whereas nu/+ mice did. Thymic transplantation rendered nu/nu mice significantly more resistant to the MoPn agent than nu/nu controls. Resistance to the MoPn agent and production of specific antibody to the MoPn agent were dependent on thymus-derived cells.