Objective: Development of a new medium to culture and isolate Helicobacterpylori from faeces, could enable to eliminate in the future the gastric biopsy as the only way to obtain strains. The aim of the present study was to optimize mediums of culture to isolate H. pylori when it is present with other intestinal tract bacteria. Methods: Twenty-nine selective culture mediums were evaluated in several and consecutive assays. They were composed of 11 nutrient and component combinations; as well as by 14 antibiotic combinations (Amphotericin B, Cefalotin, Cefoperazona, Cefsulodin, Colistin, Polymixin B, Sulfamethoxazol, Trimethoprim and/or Vancomycin). We cultured between 2 and 13 H. pylori strains and 5 intestinal tract bacteria species (Et) isolated from clinical samples. Pylori agar (PA) was used as control of the selective medium, and Columbia agar with 5% sheep blood (both bioMí©rieux, Lyon, France) and the same nutrient combinations without antibiotics, were used as control of non-selective plates. Pure H. pylori and mixed (H. pylori + Et) suspensions were prepared, cultured and incubated at 37ordm;C on microaerophilia during 4 and 7 days. H. pylori growth was evaluated as pure and mixed suspensions, tacking into account the number of colony-forming units (CFU) on each plate and the colony visualization. Results: H. pylori was isolated on 3 selective mediums, in spite of there being 104 CFU Et/ml, where the number and visualization of H. pylori colonies were better with regard to the obtained on PA. The most selective antibiotic combination was Amphotericin B, Cefsulodin, Polymixin B, Trimethoprim and Vancomycin. The number and size of H. pylori colonies decreased in the presence of other bacteria species. Conclusions: The new culture mediums evaluated could be useful to isolate H. pylori from faeces, because increase number and visualization of H. pylori colonies with regard to commercial medium used to isolate H. pylori from gastric biopsies.
Full conference title:
16th European Congress of Clinical Microbiology and Infectious Diseases
- ECCMID 16th (2006)