The fecal mycobiome in chronic pancreatitis is characterized by an increase in Candida species and Nakaseomyces.

Abstract

Introduction: The exocrine pancreas is an important determinant of the intestinal microbiome composition and stability. While chronic pancreatitis (CP) is known to severely affect the bacterial community, its impact on the intestinal mycobiome is currently unknown.

Methods: A total of 93 patients with clinical and imaging evidence of CP were prospectively recruited and compared with two equally sized matched control cohorts. One control group was matched for age, sex, body mass index, and smoking (Con-1), and the other additionally for exocrine pancreatic function (stool elastase) and diabetes (Con-2). Fecal samples were collected from all 279 individuals to determine the fecal mycobiome via internal transcribed spacer 2 (ITS2) sequencing.

Results: In CP patients, fungal reads were increased (3.7-fold and 2.0-fold) as compared to Con-1 and Con-2. In comparison with Con-1, CP patients demonstrated higher total abundance of Candida (4.5-fold, q=0.009) as well as higher mean relative abundance (11.4% vs. 1.0%, q=0.008) and presence (25.8% vs. 9.7%, q=0.025) of Nakaseomyces. In contrast to Con-2, CP patients showed higher Candida total abundance (1.9-fold, p=0.016) which was, however, not significant after correction for multiple testing (q=0.056).

Conclusions: Not only the microbiome, but also the mycobiome in CP patients is characterized by distinct changes, with higher abundances of Candida or Nakaseomyces. Exocrine pancreatic dysfunction in CP patients likely contributes to this observation. This may result in increased rates of fungal infections, chronic inflammation and could be contributing to the development of pancreatic cancer.