New plate medium for growth and detection of urease activity of Helicobacter pylori.

A new medium for detection of urease activity and isolation of Helicobacter pylori is proposed. This medium, containing Columbia Agar Base, was supplemented with IsoVitaleX, hemin, urea, and phenol red (nonselective medium [NSM]). Both bacterial growth and color change were evaluated and compared with growth in the same medium supplemented with cefsulodin, vancomycin, polymyxin B sulfate, and amphotericin B (selective medium [SM]). Twenty-five recent clinical isolates and antral biopsy specimens from 33 patients who underwent endoscopy were examined. The isolates showed a rapid color change and good growth at 5 days of incubation with NSM and SM. H. pylori-positive biopsies revealed a color change within 36 h, and bacterial growth was better appreciated in NSM, but with more contaminating flora than in SM.