Trichosporon montevideense Isolated from the Descending Colon of a Patient with Active Severe Crohn’s Disease: A Case Report
This case report presents a detailed account of a 13-year-old girl with severe Crohn’s disease (CD) who was found to have Trichosporon montevideense in her descending colon. The patient, hailing from Shandong Province, was transferred to an inflammatory bowel disease (IBD) center in April 2013. Three months prior to her admission, she had presented with hematochezia and fever, which did not respond to antibiotic treatment. Upon admission, a colonoscopy revealed segmental lesions, cobblestoning, and stricture in the descending colon. Initial diagnostic tests excluded cytomegalovirus, Epstein-Barr virus, Clostridium difficile, and amoebae as potential causes. Additionally, there were no indications of Behcet disease, systemic vasculitis, or other autoimmune diseases. The patient was diagnosed with active severe CD (Vienna typing, A1L3B2).
Given the difficulty in excluding intestinal tuberculosis, the patient was initially treated with glucocorticoids to induce remission, alongside antituberculosis therapy. However, this approach proved ineffective, prompting a switch to infliximab. After three doses of infliximab (administered at weeks 0, 2, and 6), a follow-up colonoscopy showed no improvement in the lesions. A biopsy was then sent for culture to rule out specific infections, and the culture unexpectedly yielded a fungus, later identified as Trichosporon montevideense through sequence analysis of internal transcribed spacers and intergenic spacer regions. Despite this finding, T. montevideense was initially considered unrelated to the patient’s symptoms, as this genus is commonly found in the normal intestinal microbiota.
After three months of infliximab therapy, the patient’s abdominal pain and general well-being showed no improvement. She subsequently underwent emergency surgery for intestinal bleeding, which included a total colectomy and ileostomy. Postoperatively, the patient developed a high fever (39°C). Considering her prolonged use of glucocorticoids and infliximab, she was treated with a combination of antibiotics (meropenem, teicoplanin, and caspofungin acetate). However, her fever persisted after 72 hours, and blood and peritoneal lavage cultures showed no pathogens. Additionally, the (1,3)-β-D-glucan test and galactomannan test were negative. The persistence of the fever posed a significant risk to the patient’s health.
Given that the majority of yeast isolates from the intensive care unit were from the genus Candida, and considering the rarity of pathogenic fungi such as Cryptococcus and Trichosporon, the medical team speculated that Trichosporon sp. might be the cause of the patient’s symptoms. This hypothesis was supported by several factors: T. montevideense had previously been cultured from the patient’s colon mucosa, Trichosporon sp. is the second most common cause of basidiomycetous yeast infections in humans, and gut translocation is a major source of infection. Furthermore, Trichosporon sp. is naturally resistant to caspofungin acetate. Consequently, the patient was started on voriconazole, to which Trichosporon sp. is susceptible. Encouragingly, the patient’s temperature began to decrease within 24 hours and returned to near normal after three days. Three months later, the patient had recovered sufficiently to be discharged. Immunofluorescence staining of colon tissue also revealed the presence of yeast, further supporting the likelihood that Trichosporon sp. was the pathogen responsible for the fever.
The role of T. montevideense in colitis remains unclear, although there is a known association between gut mycobiota and inflammatory bowel disease. For instance, Candida albicans and Malassezia spp. can exacerbate colitis, whereas Saccharomyces boulardii can alleviate it. The presence of antibodies against Saccharomyces cerevisiae is also a marker for susceptibility to IBD. Additionally, caspase recruitment domain 9 (Card9) is a key regulator of immunity to fungi, and certain Card9 polymorphisms are associated with IBD.
Previous studies have reported the presence of Trichosporon spp. in the intestinal mucosa of patients with CD. Research by Iliev et al. found increased amounts of Trichosporon spp. during colitis in mice, suggesting that these fungi may be adapted to the inflammatory environment. To further investigate the potential role of T. montevideense in colitis, the clinical isolate (BMU 07526) was tested in a mouse model of colitis induced by dextran sodium sulfate (DSS). The experimental mice received a daily gavage of 10^8 T. montevideense cells. The results indicated that T. montevideense had no effect on the control (non-colitis) group but exacerbated colitis in the DSS group. Mice treated with the yeast exhibited greater weight loss, shorter colon lengths, higher disease activity scores, and higher histopathology scores compared to control mice. Additionally, Trichosporon spp. were detected in the colon mucosa of mice that received the yeast gavage.
These findings suggest that Trichosporon spp. are capable of gut colonization, can cause invasive infections, and can exacerbate the symptoms of colitis. Clinicians should consider the possibility of intestinal colonization by fungi, particularly Trichosporon spp., in patients with CD who present with fever, hematochezia, and colon biopsy cultures positive for fungi.
In conclusion, this case highlights the potential role of Trichosporon montevideense in exacerbating colitis in patients with Crohn’s disease. The patient’s clinical course, combined with experimental evidence from a mouse model, underscores the importance of considering fungal infections in the management of severe IBD cases. Further research is needed to elucidate the mechanisms by which Trichosporon spp. contribute to the pathogenesis of colitis and to explore potential therapeutic strategies.
doi.org/10.1097/CM9.0000000000000793
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