Determination of optimal liquid medium for enzyme expression by Helicobacter pylori

Aims - To determine the best medium for the growth and enzyme expression of Helicobacter pylori. Methods - Twelve H pylori isolates from histologically confirmed infected patients were cultured on Brucella broth (BB), Brucella broth minus bisulphite (BLBB), and brain-heart infusion broth (BHIB), all supplemented with 5% (v/v) fetal calf serum. Growth rates and enzyme expressions of all H pylori isolates cultivated in these media were evaluated. Results - Although both BLBB and BHIB supported good growth of H pylori under microaerophilic conditions, the total protein content of H pylori detected was much higher with BHIB cultivation. Measurement of the specific activities of urease, phospholipase C, and sphingomyelinase for 12 H pylori isolates cultivated in these media, showed that BHIB supported the highest expression of these enzymes. Although BLBB supported better growth of H pylori than BB, it did not increase enzyme expression. Conclusions - Cultivation of H pylori in BHIB is recommended for studies on the physiology, metabolism, and enzyme-expression of the organism.