Microbiome of infected cysts, feces and saliva in patients with autosomal dominant polycystic kidney disease.

Cyst infection is a frequent and serious complication of autosomal dominant polycystic kidney disease (ADPKD). Hematogenous spread via bacterial translocation in the intestine is considered to be the main cause, so intestinal flora may be involved. However, the exact role of the intestinal flora in cyst infection in ADPKD is unknown. We report a 66-year-old woman and a 56-year-old man with ADPKD who had severe hepatic cyst infection. We analyzed the microbiome of infected cyst content, feces, and saliva in these two patients. The microbiome of patient 1 showed various bacteria in an infected cyst, whereas that of patient 2 showed only one bacterium. In both patients, the composition of the microbiome of the cyst content was quite different from those of feces and saliva, and the main bacteria in the infected cyst content represented a small proportion of those in feces and saliva. Lactobacilli were not almost detected in the infected cyst content though some lactobacilli are endemic in the gastrointestinal tract and the saliva. The association between bacteria in cysts and those in feces or saliva remains uncertain, and further research on this topic is needed.