[The microbiological diagnosis of chronic gastropathy associated with Campylobacter pylori]

The efficiency was studied, in experimental and practical conditions, of media for the isolation of C. pylori, as well as criteria for diagnosis and identification. The highest sensitivity was obtained with Columbia gelose, and a lower sensitivity was achieved with Campy I. C. gelose, and with heart-brain gelose, prepared as chocolate gelose, and Columbia gelose with integral blood. Both variants of the Mueller-Hinton gelose, even in the chocolate formula, gave negative results. Of the fluid media, supplemented with blood or with serum, only broth for I. C. blood cultures, and the heart-brain broth permitted the development of small cultures, while the soya-tripticase broth and the Mueller-Hinton broth remained sterile. None of the media, either solid or fluid, as such or supplemented with factors X, V, or X + V, did allow the development of C. pylori. In natural conditions, by inoculating 92 samples of gastric mucosa from patients with gastritis, with or without ulcers, confirmed histologically on Columbia chocolate gelose as such, or in a selective variant, 50 positive results were obtained with both variants, 9 positive results on the selective variant, and one positive result on the nonselective variant. The direct microscopic examination of samples from the mucosa disclosed the presence of C. pylori in all 60 samples that had also been confirmed by culture, as well as in another 21 samples from a total of 32 samples with negative cultures (88%). The direct urease test performed directly from the sample was done in 90 cases and was positive in 64 out of 79 samples that had been confirmed bacteriologically (77.2%), but in none of the 11 negative samples. The positive prediction index is thus of 100%, and the negative index is of 37.9%. Procedures for identification consisted in a definition of morphological characteristics, and in the cultivation, and biochemical features (including catalase and oxydase determination), which can define the Campylobacter genus, and the urease test, the sensitivity to cephalotine and the resistance to nalidixic acid for the differential species diagnosis. In conclusion cultivation of C. pylori presumes the use of media with superior quality peptones, supplemented with blood lactate in the gelose chocolate formula. The direct urease test is very useful as a procedure for diagnosis, and this can be done in the departments of gastroenterology.