Isolation of Malassezia yeasts from dogs with gastrointestinal disease undergoing duodenal endoscopy

Objectives: To culture Malassezia and other fungi from the duodenum of dogs with gastrointestinal signs undergoing routine endoscopic examination. Materials and Methods: Quantitative microbial culture was performed on duodenal juice aspirated from dogs with suspected enteropathy during routine upper gastrointestinal endoscopy; samples were cultured on Sabouraud's dextrose agar (30, 32 and 37°C) and modified Dixon agar (32°C) for 14 days. Isolates were identified phenotypically and by matrix-assisted laser desorption ionisation-time of flight, and internal transcribed spacer sequencing. Yeast presence was also evaluated by cytological and histopathological examination of smears and biopsy specimens. Results: Forty-five dogs were recruited with chronic inflammatory enteropathy (n=38), granulomatous colitis (n=2), gastric adenocarcinoma (n=2), duodenal small cell lymphoma (n=1) and idiopathic severe gastrointestinal haemorrhage (n=2). Fungi were cultured from 14 dogs: Malassezia pachydermatis was isolated from eight [chronic inflammatory enteropathy (n=7) (along with Candida albicans n=1); granulomatous colitis (n=1)] and Malassezia sympodialis from another (gastric adenocarcinoma). Five dogs with chronic inflammatory enteropathy yielded other yeasts (C. albicans, Candida glabrata, Kazachstania slooffiae, Kazachstania telluris, Pichia kudriavzevii [syn. C. krusei]). Yeasts were never observed in histopathological specimens. Fluorescent microscopical examination of cytological specimens showed yeast in only one case, from which K. slooffiae was subsequently isolated. Clinical Significance: Based on a literature search, this is the first report of isolation of M. pachydermatis, M. sympodialis, K. slooffiae and K. telluris from the canine duodenum. Further studies are needed to determine whether these are resident or transient fungi in the canine duodenum and whether their presence has a pathogenic effect on the host.