Bacteria Genomes - HELICOBACTER PYLORI

Helicobacter pylori is a spiral-shaped, Gram-negative rod approximately 0.5 x 3.0 micrometers in size. It is catalase-positive organism which has 4-6 sheathed flagella attached to one pole which allow for motility. It lives in the human stomach and duodenum.

H. pylori weakens the protective mucous coating of the stomach and duodenum, which allows acid to get through to the sensitive lining beneath. Both the acid and the bacteria irritate the lining and cause a sore, or ulcer.

H. pylori is able to survive in stomach acid because it secretes enzymes that neutralise the acid. This mechanism allows H. pylori to make its way to the "safe" area - the protective mucous lining. Once there, the bacterium's spiral shape helps it burrow through the lining.

Wilson's strain, known as J99, was the second H. pylori genome sequence published in the late 1990s. Wilson's unexpected return to hospital allowed researchers to document changes in the bacteria over time. For at least six years, his stomach had been a repository of H. pylori. With the patient's consent, doctors took additional biopsies and isolated 30 strains from different regions of his stomach. Those strains have now been analysed and compared to one another-and to the other two completely sequenced strains of H. pylori.

References:

Nature 388 (6642):539-47 1997
Nature 397 (6715):176-80 1999
http://www.niddk.nih.gov/health/digest/pubs/hpylori/hpylori.htm#2