The microflora of the postoperative stomach.

The microflora and pH have been assessed in gastric aspirates from 163 patients after gastric surgery and have been compared with 51 patients with gastro-oesophageal carcinoma, 152 unoperated patients with peptic ulceration, 72 of whom were receiving cimetidine, 3 patients with pernicious anaemia and 27 normal subjects. The total viable bacterial count was closely related to the pH of the aspirate and was independent of the cause of the hypochlorhydria; 90 per cent of aspirates of pH 1--2 were sterile, while 94 per cent of those of pH 4--8 contained bacteria. Escherichia coli was found significantly more frequently in the postoperative and cancer groups, and Clostridium spp. were significantly more common in patients with carcinoma. Elevated gastric juice nitrite concentrations were significantly more common in aspirates of pH 4--8 and this correlated well with the presence of nitrate-reducing bacteria. The pH of an aspirate is a good indicator of the presence of bacteria and may be useful in selecting patients requiring postoperative prophylactic antibiotic cover. Hypochlorhydric patients are exposed to increased concentrations of nitrite and there may be an increased risk of gastric cancer induced by N-nitrosocompounds.