09.01.2019 change 09.01.2019

Scientists are looking for an answer to the increasing antibiotic resistance of H. pylori

Photo: Fotolia Photo: Fotolia

Growing bacterial resistance to commonly used antibiotics causes more and more problems in the treatment of, for example, Helicobacter pylori infections that cause gastric and duodenal ulcers and stomach cancer. According to specialists, only symptomatic infections, confirmed with diagnostic methods, should be treated with antibiotics.

Poland is among the countries with a high frequency of H. pylori infections - on average it is as high as 70 percent, says Prof. Magdalena Mikołajczyk-Chmiela from the Department of Immunology and Infectious Biology at the University of Lodz.

Researchers are looking for new biologically active compounds, for example of plant origin, with bactericidal activity against these bacteria. Such research is also conducted in the Department of Immunology and Infectious Biology of the University of Lodz.

H. pylori inhabits the mucosa of the stomach and duodenum. It belongs to the group of the most common human pathogens. It was first isolated in the early 1980s by two Australian researchers: Barry J. Marshall and J. Robin Warren. This achievement, for which they received the Nobel Prize in Physiology or Medicine, revolutionized the approach to the treatment of gastric and duodenal ulcer.

"It turned out that these bacteria were the etiological factor of gastritis, gastric and duodenal ulcers, and a further consequence of such infections could be the development of lymphoma originating from lymphocytes, or stomach cancer" - explains Prof. Mikołajczyk-Chmiela.

H. pylori infections are very common around the world. It is estimated that even half of the human population is infected, although there are differences depending on the region of the world and socio-economic status. In the United States, for example, the incidence of infection is 20-30 percent, but in Asian countries, such as China or Japan, it reaches 90 percent. Poland is considered to be a country with a high infection rate, which can reach 70 percent, although there are also differences depending on the region of the country.

In most cases, the infection is asymptomatic, or in the carrier form, but about 10-20 percent infected people develop so-called symptomatic infection, accompanied by symptoms of dyspepsia: reflux, heartburn or a feeling of heaviness after a meal. According to specialists, only this type of symptomatic infection should be treated after confirmation.

"The current consensus is that only people with symptomatic H. pylori infection, in whom it has been confirmed by a package of specific diagnostic methods, can be subjected to pharmacological treatment with the use of antibiotics. This protects against unnecessary use of antibiotics in people with asymptomatic infection and reduces the possibility of increasing antibiotic resistance" - emphasises Prof. Mikołajczyk-Chmiela.

Various tests are used in the diagnosis of such infections: histological methods and the rapid urease test determining the urease activity of these bacteria. These tests require gastroscopy and collecting stomach tissue samples. In contrast, non-invasive tests include: urea breath test with 13 C-labelled urea, tests designed to detect H. pylori antigens in faeces and serological methods to detect antibodies against antigens of these bacteria in serum.

Standard treatment lasts 7 to 10 days and two antibiotics are used simultaneously: clarithromycin or amoxicillin and metronidazole, plus a drug that reduces gastric juice acidity, which results in better stability of antibiotics. But the problem is the increasing resistance of H. pylori to currently used antibiotics.

"Resistance to clarithromycin and metronidazole is particularly common. Only amoxycycline remains an effective antibiotic. Therefore, other antibiotics, such as levofloxacin or fluoroquinolones, are introduced for treatment, but their use must also be approached with caution, because antibiotic resistance is increasing also in their case" - emphasises the expert from the University of Lodz.

The researcher admits that in some Asian countries, in connection with the risk of developing stomach cancer, there is an idea to treat all people infected with this bacterium, even people with asymptomatic infections. But the world medical and scientific community is against it, because it turns out that bacteria adapting to life in the host organism may have some beneficial effects.

"For example, they inhibit the development of oesophageal cancer. They also have certain properties consisting in modulating the activity of the immune system and, for example, there are data indicating that such activity of silencing certain immune mechanisms takes place in asthma. Therefore, universal treatment of asymptomatic infections is not approved by the scientific and medical community" - explains the expert.

On the other hand, more and more experimental and epidemiological studies point to the possible link between H. pylori infection and the development of systemic diseases, by stimulating a strong inflammatory response, which over time becomes chronic. This includes coronary artery disease and diabetes. "These are examples of systemic diseases in the development of which, to a certain extent, infection with this bacterium may be a risk factor" - admits the specialist.

Due to the common nature of H. pylori infections, serious health consequences of such infections, and the shrinking possibility of antibiotic use, researchers are looking for alternative therapies. "In our team at the Gastroimmunology Laboratory, we conduct research aimed at understanding the pathogenesis of these infections, in the context of understanding the causes of their different course" - says Prof. Mikołajczyk-Chmiela.

Researchers are also looking for new natural biologically active preparations of plant origin, mainly plant extracts and their specific components, which have a bactericidal effect or inhibit the growth of infectious agents, including H. Pylori.

"We are also looking for natural biological preparations that support the activity of the immune system and could thus contribute to combating such infections or preventing their development. Such preparations are also tested for enhancing the bactericidal activity of antibiotics" - explains Prof. Magdalena Mikołajczyk-Chmiel from the University of Lodz.

PAP - Science in Poland, Kamil Szubański

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