Bacteriologic analysis of mucosal biopsy specimens for detecting small-intestinal bacterial overgrowth

Although culture of luminal secretions is regarded as the most accurate diagnostic test for small-intestinal bacterial overgrowth, obtaining an aspirate is often difficult owing to the sparseness of luminal secretions present at the time of aspiration. Obtaining a mucosal biopsy specimen for bacteriologic analysis would overcome this problem.

Culture of small-intestinal and gastric aspirates and unwashed small-intestinal mucosal specimens was performed in 51 adult subjects investigated for small-intestinal overgrowth.

Highly significant (r = 0.85-0.90; p < 0.0005) correlations were found between viable bacterial counts in small-intestinal luminal secretions and biopsy specimens. Small-intestinal bacterial overgrowth was present in 60.8% of subjects. When specimens weighing 4.0-84.0 mg were suspended in diluent, total aerobic and/or anaerobic bacterial counts > or = 10(2) CFU/ml were found to have 90.3% sensitivity and 100% specificity for small-intestinal bacterial overgrowth.

Culture of an unwashed small-intestinal mucosal biopsy specimen is a useful alternative to culture of a small-intestinal aspirate for detecting subjects with small-intestinal bacterial overgrowth, especially when luminal secretions are scanty at the time of aspiration.