Isolation of Helicobacter pylori after transport from a regional laboratory of gastric biopsy specimens in saline, Portagerm pylori or cultured on chocolate agar.

Multiple gastric biopsies were taken from 288 patients in Port Lincoln, South Australia. One biopsy was used for a CLOtest and the other three were transported to a central laboratory in Adelaide in physiological saline, Portagerm pylori transport medium or after culture on a chocolate agar plate which was placed in a Biobag. Helicobacter pylori was isolated from 18.3% of patients. There was a 95.7% concordance between culture results and the CLOtest result. Recovery rates after transport on chocolate agar, Portagerm pylori and in saline were 90.2, 90.2 and 84.3%, respectively.

Comparison of culture, histopathology and urease testing for the diagnosis of Helicobacter pylori gastritis and susceptibility to amoxycillin, clarithromycin, metronidazole and tetracycline.

Gastric biopsy specimens were taken from 737 patients undergoing upper gastrointestinal endoscopy and assessed for Helicobacter pylori infection. The diagnostic utilities of H. pylori culture (733 patients), detection of urease production (724 patients) and histopathological examination (469 patients) were compared. Since each of these techniques may fail to diagnose patients infected with H. pylori, an attempt was made to estimate the true rate of infection using a mathematical approach that combined the results of culture, histopathology and urease testing; 34% of the 733 patients were thought to be infected. Using this figure as a benchmark, the sensitivity, specificity, positive predictive value and negative predictive value of H. pylori culture were 73.2%, 100%, 100% and 86.3%, respectively, compared with 58.7%, 100%, 100% and 89.6%, respectively for urease production and 77.0%, 100%, 100% and 82.4%, respectively for histopathology. Thus, histopathological examination was the single most reliable test. A combination of histopathological examination and H. pylori culture diagnosed 99.5% of patients that were estimated to be truly infected. The minimum inhibitory concentrations of a number of antibiotics were measured for 135 isolates of H. pylori. All isolates were susceptible to amoxycillin and tetracycline whereas 5.2% were resistant to clarithromycin and 60% were resistant to metronidazole.