Notably, a significant co-exclusion relationship between the relative abundances of Campylobacter taxa and NAPSB were present (both of our data sets, Fig. 2I; Additional file 2: Figure S7C), this pseudogene being found to be consistently significantly downregulated in GERD and MET when compared to NORM samples (Fig. 1E). Here, NAPSB is linked to gastroesophageal reflux disease.