General composition of the faecal microbiota of untreated (white bars) and treated CD patients (grey bars) and healthy controls (black bars) as assessed by FISH and FCM. Data are expressed as proportions of bacterial cells hybridising with group-specific probes to total bacteria hybridising with EUB probe 338. Total Gram-negative bacteria and Gram-positive bacteria were calculated by adding the relative proportions of the corresponding groups detected by using group-specific probes. Median values and ranges are given. *Significant differences were established at P < 0.05 by applying the Mann-Whitney U-test.