Evaluation of "CLO-test" to detect Campylobacter pyloridis in gastric mucosa.

Campylobacter pyloridis is strongly associated with the presence of histological gastritis,1 2 but its role in the aetiology of peptic ulcer disease and non-ulcer dyspepsia has yet to be determined. Its detection in antral mucosal biopsy specimens usually entails histo-logical or microbiological methods that may require several days for a result. In a previous study3 we found that direct examination of biopsy specimens by phase contrast microscopy was a rapid and reliable screening method. It has the disadvantage, however, that the necessary equipment is not always readily available. As Cpyloridis produces abundant urease4 5 this fact has been used for the rapid detection of its presence in human gastric antral biopsy specimens.67 We prospectively evaluated a commercial urease test, CLO-test (Delta West Ltd, Canning Vale, Western Australia 6155) by comparing it with microscopy and culture for C pyloridis in gastric antral mucosa. Patients and methods Gastric biopsy specimens were taken from 80 consecutive patients undergoing routine upper gastro-intestinal endoscopy. Nineteen of these patients were taking part in two other ongoing trials. Three endo-scopic biopsy specimens were obtained from the gastric antral mucosa within a 5 cm radius of the pylorus. One specimen was immediately inserted in the CLO-test, which was held at room temperature for up to 24 hours. It was examined frequently for any colour change from yellow (negative) to orange or bright pink (positive). The two other biopsy specimens were collected in 0-25 ml sterile saline (0 85%) for transport to the laboratory and were processed within three hours. Phase contrast microscopy, Gram stain, and culture were performed as previously described.3 The Gram stain was done retrospectively if only one other test was positive for C pyloridis. The number of Campylobacter like organisms seen on microscopy was scored from + to + + +. Isolates were considered to be C pyloridis if they grew as 0 5-1 mm translucent greyish colonies after three days on chocolate (horse) blood agar, and were Gram negative, curved, or S shaped rods which were positive for oxidase, catalase, and rapid urease (Oxoid CM7 1). Growth occurred under micro-aerophilic conditions, but not in air. Results Eighty antral biopsy specimens were examined by phase contrast microscopy, culture, and CLO-test. Gram stain was also done on 10 specimens when only one of the other tests was positive. The rapid urease test was positive for 47 specimens, two of which were orange at 24 hours rather …