Ventriculitis Due to Cryptococcus uniguttulatus

South Med J. 2001;94(1) 

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Fungal infections in humans due to non-neoformans cryptococci are rare. Two species, C albidus and C laurentii, have been reported as pathogens in humans and have been associated with fungemia, pneumonia, lung abscesses, and cutaneous infections.[2] Most of those infected persons had some form of underlying immune suppression, including high-dose corticosteroid therapy, neutropenia, or human immunodeficiency virus infection. Treatment of infections caused by non-neoformans cryptococci has consisted of systemic amphotericin B with or without 5-fluorocytosine, ketoconazole, and fluconazole.[2] Survival is similar after treatment with either amphotericin or the azoles, though limited information regarding susceptibility testing suggests that non-neoformans cryptococci are generally more sensitive to amphotericin than to the azoles.

We report what is, to our knowledge, the first case of human infection associated with the non-neoformans cryptococcus, C uniguttulatus. Using the database from the US National Library of Medicine, we were unable to find any other reports of this organism causing infections in humans. Cryptococcus uniguttulatus is a rarely encountered yeast. Like other Cryptococcus species, it has been isolated from the gastrointestinal tract and droppings of birds.[1] It has also been reported as a contaminant of bedding in animal care facilities housing rodents but has not been linked to disease in animals.[4] A single report notes that it was infrequently isolated from the vaginal flora of nonpregnant asymptomatic Nigerian women but was not associated with infection.[5]

We identified C uniguttulatus from the ventricular fluid of a patient who had had an invasive neurosurgical procedure. The presence of the organism likely represented true central nervous system infection rather than drain colonization, since it was detected in association with the clinical deterioration of the patient and an abnormal ventricular fluid. In addition, C uniguttulatus was isolated from multiple ventricular fluid samples obtained on different days and from two different drain sites. Disappearance of the organism from ventricular fluid occurred after the initiation of antifungal therapy and was concomitant with the patient's improvement.

We examined the in vitro sensitivity of C uniguttulatus to antifungal agents. Like other non-neoformans cryptococcal species, the organism had the lowest minimum inhibitory concentration (MIC) to amphotericin B. The MIC of the organism to itraconazole was also low, but MICs were significantly higher to fluconazole and 5-fluorocytosine. Based on clinical and laboratory data in our patient and those of other reports, it would appear that optimal therapy of infections due to C uniguttulatus and other non-neoformans cryptococci would include systemic treatment with amphotericin B.