Bacteriological method for detecting small intestinal hypomotility

Small intestinal hypomotility is an important cause of small intestinal bacterial overgrowth, yet assessment of small intestinal motility in this setting is problematic. This study was performed to investigate the validity of a bacteriological method for detecting small intestinal hypomotility.

Twenty-five subjects without previous gastric surgery were studied with (i) concurrent bacteriological analyses of fasting saliva and gastric and proximal small intestinal aspirates, (ii) measurement of gastric pH, and (iii) scintigraphic assessment of small intestinal transit rates of a liquid test meal. The reproducibility of bacteriological analyses of saliva and small intestinal secretions was determined in 12 subjects.

Serial bacteriological analyses of saliva and proximal small intestinal secretions yielded reproducible results over time periods of up to 1 month. Eleven subjects were deemed to harbor Enterobacteriaceae of nonsalivary origin in proximal small intestinal secretions. Orocaecal transit, but not gastric emptying, of a liquid test meal was significantly delayed in this group (p = 0.002 and p = 0.84, respectively), suggesting the presence of small intestinal hypomotility. Impaired gastric acidity unlikely confounded assessment of the origin of small intestinal Enterobacteriaceae in any instance.

The presence of Enterobacteriaceae of nonsalivary origin in proximal small intestinal secretions may be taken to reflect the presence of small intestinal hypomotility. The presence of impaired gastric acidity does not confound this approach. Because small intestinal intubation and culture of aspirate are required anyway to accurately diagnose small intestinal bacterial overgrowth, the simple addition of concurrent bacteriological analysis of saliva may allow small intestinal hypomotility to be detected at the same time as the presence or absence of small intestinal bacterial overgrowth itself is established, thus streamlining the investigation of subjects for this disorder and its possible causes.