Helicobacter Pylori (cont.)
Charles Patrick Davis, MD, PhD
Charles Patrick Davis, MD, PhD
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
In this Article
Is H. pylori contagious?
Yes, H. pylori is contagious. However, sometimes there is a grey area between the terms contagious and colonized. Contagious usually implies a disease-causing agent is transferred from person to person, while colonization usually implies a non-disease-causing agent simply populates a body surface but does not cause disease, even when transferred from person to person. The grey area occurs when many people have the agent that causes disease in some of them, but not in many others. Some microbiologists consider such organisms as adapting to their human hosts by slowly changing from infecting humans to colonizing them. Although this is speculation, it seems to fit the ongoing situation with H. pylori. However, others think the bacteria become infecting agents when their genes and surrounding environment trigger H. pylori to produce and release enough toxic chemicals to cause the GI tract to become inflamed.
How is H. pylori infection diagnosed?
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Accurate and simple tests for the detection of H. pylori infection are available. They include blood antibody tests, urea breath tests, stool antigen tests, and endoscopic biopsies.
Blood tests for the presence of antibodies to H. pylori can be performed easily and rapidly. However, blood antibodies can persist for years after complete eradication of H. pylori with antibiotics. Therefore, blood antibody tests may be good for diagnosing infection, but they are not good for determining if antibiotics have successfully eradicated the bacterium.
The urea breath test (UBT) is a safe, easy, and accurate test for the presence of H. pylori in the stomach. The breath test relies on the ability of H. pylori to break down the naturally occurring chemical, urea, into carbon dioxide which is absorbed from the stomach and eliminated from the body in the breath. Ten to 20 minutes after swallowing a capsule containing a minute amount of radioactive urea, a breath sample is collected and analyzed for radioactive carbon dioxide. The presence of radioactive carbon dioxide in the breath (a positive test) means that there is active infection. The test becomes negative (there is no radioactive carbon dioxide in the breath) shortly after eradication of the bacterium from the stomach with antibiotics. Since some individuals are concerned about even minute amounts of radioactivity the breath test has been modified so that it also may be performed with urea that is not radioactive.
Endoscopy is an accurate test for diagnosing H. pylori as well as the inflammation and ulcers that it causes. For endoscopy, the doctor inserts a flexible viewing tube (endoscope) through the mouth, down the esophagus, and into the stomach and duodenum. During endoscopy, small tissue samples (biopsies) from the stomach lining can be removed. A biopsy specimen is placed on a special slide containing urea (for example, CLO test slides). If the urea is broken down by H. pylori in the biopsy, there is a change in color around the biopsy on the slide. This means that there is an infection with H. pylori in the stomach.
Biopsies also may be cultured in the bacteriology laboratory for the presence of H. pylori; however, this is done infrequently since other simpler tests are available.
A recently-developed test for H. pylori is a test in which the presence of the bacterium can be diagnosed with a sample of stool. The test uses an antibody to H. pylori to determine if H. pylori is present in the stool. If it is, it means that H. pylori is infecting the stomach. Like the urea breath test, in addition to diagnosing infection with H. pylori, the stool test can be used to determine if eradication has been effective shortly after treatment.
In 2012, the FDA gave approval for the urea breath test to be done in children aged 3 years to 17 years old.
Reviewed by Jay W. Marks, MD on 5/17/2012
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