Helicobacter pylori

Diagnosis

Today, doctors have various tools at their disposal to demonstrate Helicobacter pylori infection.

Among the non-invasive tests, a leading role is played by blood tests, through which anti-Helicobacter pylori antibodies are searched for in a very small blood sample.

»The Bacterium
»Epidemiology
»Pathogenicity
»Contagion and prevention
" Symptoms
»Diagnosis
" Treatment

After the infection, in fact, the organism begins to produce antibodies to defend itself from the infection and continues to produce them for a long time. Unfortunately, as happens in all antibody responses, the anti Helicobacter pylori immunoglobulins do not disappear following the eradication of the microorganism; consequently the antibody dosage is of no use in the case in which one wishes to evaluate the efficacy of the therapy undertaken. More useful, in this sense, is another non-invasive test, through which a search for the antigenic material of Helicobacter pylori in the feces is carried out.

The so-called breath test, or breath test, is also among the non-invasive tests. During this diagnostic procedure the patient is asked to drink a solution containing urea labeled with carbon 13 (a NON radioactive isotope of carbon) and citric acid (to slow gastric emptying). After ingestion, the urease activity of the possible colony of Helicobacter pylori splits the urea into ammonia and carbon dioxide (CO2). Therefore, by evaluating the concentration of carbon dioxide marked in the exhaled air thirty minutes after taking the urea meal, the doctor can confirm or deny the infection. In particular, the failure to increase the concentration of carbon 13 in the exhaled air, it indicates - depending on the context - the "absence of infection or" the eradication of the bacterium.

Non-invasive and highly sensitive and specific - both in the phase of digagnosis and in monitoring therapy - is the search for Helicobacter pylori antigens in the faeces.

The invasive methods are based on endoscopic techniques, such as the annoying gastroscopy, which allow a direct view of the stomach and any alterations such as gastritis, erosions and ulcers. Furthermore, during the examination, the doctor has the possibility of taking biopsy fragments of the gastric mucosa in the most

The tissue samples are then analyzed under the microscope (histology), with the aid of staining and culture techniques (useful for evaluating sensitivity to antimicrobial drugs; in particular, the antibiogram becomes very useful in the therapeutic setting when the first choice treatment failed to eradicate the infection).

The rapid urease test verifies the presence of Helicobacter pylori by adding biopsy fragments to a liquid medium or solid substrate, containing urea and a pH indicator. The presence of urease activity in the sample - typical of Helicobacter pylori - determines the production of ammonia and the consequent color change of the indicator. Although this is a sensitive test, there is a possibility of false negatives, especially in relation to the recent performance of antibiotic therapies by the patient.

Treatment

Helicobacter pylori eradication therapy aims on the one hand to eradicate the pathogen by means of one or more antibiotics and on the other to deprive it of the acid environment in which it lives through the use of proton pump inhibitors. In this regard, a "shock" treatment is generally used which consists in the joint administration, for 7-10 days, of a couple of antibiotics and a proton pump inhibitor. Among the most commonly used antibiotics are amoxicillin , clarithromycin, tinidazole, tetacycline and metronidazole, while the most widely used proton pump inhibitors include omeprazole, esomeprazole, lansoprazole and ranitidine bismuth citrate.

A few weeks after the end of the treatment, the doctor prescribes new diagnostic tests to ascertain the eradication of Helicobacter pylori.

Vaccines capable of preventing Helicobacter pylori infection, which have already shown good efficacy in mouse models and in the first phase I studies on human subjects, are also currently being tested.