Helicobacter pylori in culture: an ultrastructural study

Helicobacter pylori (H. pylori) is generally observed in the gastric mucus and on the epithelial cells in human, and is related to gastric disorders. Although many morphological studies have been performed on H. pylori, the precise ultrastructure of this organism has not been reported upon to the present. In this study, H. pylori (ATCC 43504) was cultured in a liquid medium for seven days and observed using scanning and transmission electron microscopic methods every day. The reproduction of the bacteria in culture was also examined daily, and the length and width of the organisms were measured with the use of Micro Computer Imaging Device (MCID) System. Spiral forms were dominant over the initial two days (the length and width: 2.04 +/- 1.12 microns and 0.49 +/- 0.12 micron on the 1st day, 1.71 +/- 0.96 microns and 0.38 +/- 0.12 micron on the 2nd day) respectively. Coccoid forms (diameter: 0.80 +/- 0.36 micron) were predominant on subsequent days. The bacterium had a cell wall membrane (15 nm thick) and a cytoplasmic membrane (10 nm thick). A hollow granule (0.15 +/- 0.06 micron in diameter) and a dense granule (0.12 +/- 0.04 micron in diameter) were observed in a cytoplasm filled with ribosomes. The flagella (51.1 +/- 6.6 nm total in diameter) with a sheath (12 nm thick) originated from a concave depression (less than 50 nm in depth) at the end of the organism which possessed a knob (less than 0.1 micron in diameter) at the distal end, which frequently attached to adjacent organisms. The coccoid form generally showed precariously membranous and intracytoplasmic ultrastructures with few flagella. A few of the coccoid forms possessed distinctive cellular ultrastructures with solid flagella similar to those found in the spiral forms.