Distribution of different species of the bacteroides fragilis group in individuals with japanese cedar pollinosis

We investigated associations of species of the Bacteroides fragilis group with Japanese cedar pollinosis (JCPsis). Cell numbers of Bacteroides fragilis and Bacteroides intestinalis were significantly higher in JCPsis subjects than in non-JCPsis subjects before the pollen season. They correlated positively with both symptom scores and JCPsis-specific immunoglobulin E levels.