Abstracts
1999 Digestive Disease Week

# 4674 SUPPRESSION OF GASTRIC ACID SECRETION IN PATIENTS WITH GERD RESULTS IN BACTERIAL OVERGROWTH AND DECONJUGATION OF BILE SALTS
Joerg Theisen, Univ of Southern CA, Los Angeles, CA; D Nehra, Univ Hosp of Wales, Cardiff United Kingdom; D Citron, Univ of Southern CA Microbiology Res Lab, Los Angeles, CA; M Hashemi, Univ of Southern CA Dept of Surg, Los Angeles, CA; J A Hagen, S R DeMeester, Univ of Southern CA, Los Angeles, CA; G.M. R. Campos, L F Sillin, Univ of Southern CA Dept of Surg, Los Angeles, CA; Cedric G Bremner, Univ of Southern CA, Los Angeles, CA; J Johansson, Univ of Southern CA Dept of Surg, Los Angeles, CA; David J Bowrey, Univ of Southern CA, Los Angeles, CA; J H Peters, Univ of Southern CA Dept of Surg, Los Angeles, CA

Objective: The effect of chronic acid suppression therapy on gastric bacterial overgrowth and its potential impact on bile salt deconjugation in patients with gastro-esophageal-reflux disease (GERD) is unknown. These drug-induced changes may contribute significantly to the composition of the refluxate. Our aim was to study the effect of bacterial overgrowth on bile salt composition and deconjugation in patients on acid suppression therapy. Methods: Thirty consecutive patients with GERD and abnormal 24h-esophageal pH exposure were treated with 20-40 mg omeprazole for at least 3 months. Ten patients with GERD not taking omeprazole for at least 2 weeks represent the control group. At time of endoscopy 5 to 10 ml of gastric juice were aspirated and the pH was determined with a glass probe after precalibration and plated for bacterial growth. Type and conjugation status of bile salts was assessed and quantified with HPLC. A bacterial count > 103/ml was considered abnormal overgrowth. Results: Bacterial overgrowth was found in 11/30 patients taking omeprazole and in 1/10 patient in the control group. Bacterial overgrowth only occurred when the pH was >3.8. The ratio of conjugated:unconjugated bile salts dramatically changed, even reversed in the bacterial positive specimen. Conclusion: Chronic acid suppression therapy results in both bacterial overgrowth and bile salt deconjugation in approximately 30% of the patients. Given that deconjugated bile salts are more toxic their reflux may amplify esophageal mucosal injury. This study demonstrates for the first time deconjugation of bile salts in the foregut secondary to bacterial overgrowth.

control		Omeprazole
	(n=10)	bact- (n=19)	bact+ (n=11)	p value
pH	3.5[2.4-4]	2.5[2.1-3.2]	5.3*[4.2-6.3]	*<0.05
Total bile salt	92.5	68.0	69.0	n.s.
concentration (mmol)	[0-327]	[22-154]	[0-256]
conjugates:unconjugates	3:1	4:1	1:3*	*<0.05
Values are expressed as medians and interquartile ranges [IQR].

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