Evaluation of a new method for routine in vitro cultivation of Giardia lamblia from human duodenal fluid.

Although a method for in vitro cultivation of Giardia lamblia was described as early as 1927, only a few clinical isolates were cultured in vitro due to the complexity of the techniques. We developed a method which allows for the routine isolation of Giardia trophozoites from human duodenal fluid and maintenance of the organisms in axenic culture. This study evaluates the method in 198 patients. Seventeen strains of Giardia were isolated and cultivated axenically. The method was more sensitive than the microscopic examination of aspirated fluid and examination of an impression of mucosal biopsy. Five patients, however, excreted cysts in the stool, although no trophozoites could be demonstrated in the duodenal fluid. G. lamblia were cultivated from one patient who did not excrete cysts. The method will enable the collection of G. lamblia strains from clinical material in large numbers and can offer an important advance in epidemiological, biochemical, immunological, and therapeutic investigations of giardiasis.