Bacteria-positive patient numbers. A: Normal subjects. B: Patients with reflux esophagitis. C: Patients with Barrett’s esophagus. Y axis shows the number of patients positive for each bacterium at the genus level. Streptococcus, Provotella and Helicobacter were prevalent in all patients. Veilonella, Neisseria and Fusobacterium were prevalent in patients with reflux esophagitis and Barrett’s esophagus, but were not found in patients with a normal esophagus.