Antibiotic resistance poses a grave challenge to many previously curable infectious diseases. At present, antibiotic resistance is proving to increase at a much faster rate compared to the development of new therapies.
For instance, according to a new study presented at UEG Week 2019 antibiotics used to treat a specific harmful bacterial species implicated in several stomach conditions are becoming ineffective due to the emergence of drug-resistant strains over just 20 years. UEG (United Europe Gastroenterology) is the largest European congress of gastroenterologists.
The impact of antibiotic resistance
Antibiotic resistance is the presence of one or more natural or acquired genetic traits that enables bacteria to resist or survive exposure to natural or synthetic chemicals that stop or slow their growth. There are many ways in which bacteria can become resistant, from expressing enzymes that break down the antibiotic to changing the shape of various cell wall receptors to which an antibiotic might otherwise bind, preventing its action on the bacterial cell.
The presence of antibiotic resistance causes more than 750,000 people to die of fatal bacterial infections each year. This is expected to rise steeply over the coming years, unless emergency action is taken to prevent it by limiting its occurrence and spread.
Antibiotic resistance in H. pylori
Helicobacter pylori (H. pylori) is a spiral bacterium that colonizes the gastric mucosal layer. It is found to be associated with gastric ulcer, stomach cancer and lymphoma. One of the most useful drugs against this pathogen was clarithromycin, but recently resistance to this agent was shown to have gone up from about 10% to 22% - over the period 1998 to 2018. Similar trends were shown in regard to levofloxacin and metronidazole.
Illustration of the helicobacter pyloris - Image Credit: Sebastian Kaulitzki / Shutterstock
H. pylori is a very common bacterial infection that affects about 50% (and some estimates say up to 66%) of human beings. This can cause the stomach lining to become inflamed, a condition called gastritis. Chronic gastric inflammation can result in severe chronic atrophic gastritis at the end – which is a risk factor for stomach cancer. However, in relative terms, only about 1% to 3% of H. pylori infections end in gastric cancer, though the absolute number is high in terms of the millions of infections that exist throughout the world. Even at present, it is difficult to treat H. pylori effectively, because the organism produces the enzyme urease which produces ammonia from urea, making the harsh acid environment of the stomach more alkaline around the bacterium. In addition, the organism takes shelter inside the mucus layer, and is also able to bind to the cells of the gastric mucosal lining.
H. pylori is able to evade immune recognition and attack by a range of mechanisms. Thus, common treatment regimens for this organism use multiple drugs to effectively eradicate it.
The current research focused on antibiotic resistance in H. pylori. Recently, more and more antibiotics are becoming ineffective against this bacterium, including clarithromycin. In response, the World Health Organization has recommended that the development of antibiotics against clarithromycin-resistant H. pylori should receive high priority in view of the worldwide threat of disease and death that it offers.
In addition, the current study found that the rate of primary clarithromycin resistance was highest in Southern Italy (approximately 40%), Croatia, and Greece (35% and 30% respectively). This was due to the overuse of antibiotics for such illnesses as flu and the common cold. This was aggravated by the lack of cooperation by medical institutions when it comes to limiting the use of antibiotics.
Other countries within the 18-member participant group with comparable rates of antibiotic resistance include Poland, Bulgaria, Ireland, Austria, France and Germany. Nations with the lowest rates of resistance include Denmark, at just 5%, Latvia, with about 7%, and Norway and Netherlands, at about 9% each.
Prior research showed that both Italy and Greece would probably have the highest mortality rates for antibiotic resistance among EU member countries, by 2017 – a prediction that agrees well with current findings.
If this infection is not controlled due to rising antibiotic resistance rates, it could mean that more cases of gastric cancer are likely to occur alongside increasing rates of gastric ulcer. Infection with this organism is also the cause of stomach cancer which ranks Number 7 among the list of cancer killers in Europe as well as in Third World countries. Explaining the situation, researcher Francis Megraud says, “With resistance rates to commonly used antibiotics such as clarithromycin increasing at an alarming rate of nearly 1% per year, treatment options for H. pylori will become progressively limited and ineffective if novel treatment strategies remain undeveloped.”
Reflecting on the findings, noted gastroenterologist Mario Dinis-Ribeiro remarks, “The increasing resistance of H. pylori to a number of commonly-used antibiotics may jeopardize prevention strategies.”
Megraud, F et al., 2019. European survey of Helicobacter pylori primary resistance to antibiotics - Evolution over the last 20 years. Presented at UEG Week Barcelona October 21, 2019