Helicobacter pylori: Properties of the Bacteria

Helicobacter pylori

The association of H. pylori with gastritis, peptic ulcer, gastric adenocarcinoma and gastric mucosa-associated lymphoid type (MALT), and B-cell lymphoma is recognized worldwide.

Properties of the Bacteria

◗ Morphology

H. pylori shows following morphological features:

·            H. pylori is a curved, spiral, or S-shaped Gram-negative bacil-lus measuring 3 mm in length and 0.5–0.9 mm in breadth.

·           The organism is highly motile and shows cork screw motility due to presence of a unipolar tuft of lophotrichous flagella.

·           It is nonsporing.

◗ Culture

H. pylori is microaerophilic and grows in the presence ofdecreased oxygen concentration (5%) and increased carbon dioxide concentration (10%) in a temperature range between 30 and 37°C. The bacteria do not grow anaerobically, grow poorly at 42°C, and do not grow at all at 25°C. H. pylori grows well on freshly prepared chocolate agar and Skirrow’s campylobacter media. H. pyloriproduces circular, convex, and translucent col-onies on these media, after incubation of 3–5 days.

◗ Biochemical reactions

pylori shows following biochemical reactions:

·           H. pylori produces the enzyme urease, which is almost 100times more active than that produced by Proteus vulgaris.

·           Urease production is the most important feature of H. pylori.

·           H. pylori is catalase and oxidase positive.

·           These are biochemically inactive and do not ferment or oxi-dize sugars, although they can metabolize amino acids by fermentative pathways.