DUODENAL BACTERIAL OVERGROWTH DURING TREATMENT IN OUTPATIENTS WITH OMEPRAZOLE

The extent of duodenal bacterial overgrowth during the pronounced inhi bition of acid secretion that occurs with omeprazole treatment is unkn own. The bacterial content of duodenal juice of patients treated with omeprazole was therefore examined in a controlled prospective study. D uodenal juice was obtained under sterile conditions during diagnostic upper endoscopy. Aspirates were plated quantitatively for anaerobic an d aerobic organisms. Twenty five outpatients with peptic ulcer disease were investigated after a 5.7 (0.5) weeks (mean (SEM)) treatment cour se with 20 mg (nine patients) or 40 mg (16 patients). The control grou p consisted of 15 outpatients referred for diagnostic endoscopy withou t prior antisecretory treatment. No patient in the control group had d uodenal bacterial overgrowth. In the omeprazole group bacterial overgr owth (greater than or equal to 10(5) cfu/ml) was found in 14 (56%) pat ients (p=0.0003). The number of bacteria (log(10)) in duodenal juice i n patients treated with omeprazole was distinctly higher (median 5.7; range <2-8.7) when compared with the control group (median <2; range < 2-5.0; p=0.0004). As well as orally derived bacteria, faecal type bact eria were found in seven of 14 and anaerobic bacteria in three of 14 p atients. Bacterial overgrowth was similar with the two doses of omepra zole. These results indicate that duodenal bacterial overgrowth of bot h oral and faecal type bacteria occurs often ii ambulatory patients tr eated with omeprazole. Further studies are needed to determine the cli nical significance of these findings, particularly in high risk groups during long term treatment with omeprazole.