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16-05-2012 | Gastroenterology | Article

Antibacterial resistance testing necessary before H. pylori treatment


Free abstract

MedWire News: Susceptibility testing is crucial before treatment for Helicobacter pylori infection in European patients, say researchers who found that antibacterial resistance in this setting is linked to outpatient use of antibiotics.

"The knowledge of antibiotic consumption in a given region may provide a simple tool to predict the susceptibility of H. pylori to quinolones and macrolides, and to adapt the treatment strategies in settings where diagnostic laboratory facilities are not available," say Francis Megraud (Université de Bordeaux, France) and co-authors in Gut.

The team determined primary antibiotic resistance rates ‑ the major cause of H. pylori treatment failure ‑ in 18 European countries between April 2008 and June 2009. Data for 2204 patients including 311 children were examined.

H. pylori resistance was reported for 17.5% of adult patients given clarithromycin, 14.1% given levofloxacin, and 34.9% treated with metronidazole, while less than 1% of patients had strains resistant to amoxicillin, tetracycline, or rifabutin.

The pattern of resistance was significantly different among children, with over 30% carrying strains resistant to clarithromycin, and 25.7% and 2.5% carrying strains resistance to metronidazole and levofloxacin, respectively.

The rate of resistance also varied significantly between western, central and southern European countries, affecting over 20% of patients, compared with northern Europe where less than 10% of patients had resistance.

Other factors affecting likelihood of antibiotic resistance included endoscopic diagnosis of ulcer disease, age, female gender, and birth outside of Europe.

In all, 51.2% of bacterial strains had no drug resistance, 36.8% were resistant to one class of antibiotics, 12.0% to two classes, and 2.0% to three classes. Three strains were found to be resistant to four antibiotic classes.

Clarithromycin plus metronidazole resistance was found in 7.8% of strains overall, and made up more than 10% of strains detected in Hungry, Austria, Poland, and France, the researchers note.

Of concern, there was a significant and positive correlation in countries between greater outpatient use of quinolones and the proportion of patients with strains resistant to levofloxacin. A similar pattern was also detected between long-acting macrolides and clarithromycin resistance.

Megraud et al say that their results have "major implications" for first-line treatment for H. pylori infection, commenting that "clarithromycin-based regimens can no longer be recommended without previous susceptibility testing in countries from Central and Southern Europe where more than 20% of the patients are infected with a macrolide-resistant strain."

"The increasing resistance to levofloxacin in several countries in Europe is also of concern because it precludes its empirical use in anti-H. pylori rescue regimens without prior susceptibility testing," they add.

The team recommends in Gut that local national resistance surveys representative of the general population be performed for individual countries, so to improve the effectiveness of H. pylori treatment.

By Lynda Williams

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