Letter: global emergence of Helicobacter pylori antibiotic resistance – unanswered questions

We read with great interest the article by Thung et al.,1 who discussed the important issue of Helicobacter pylori resistance to different antibiotics, and the alternative regimens to standard triple therapy (composed of a proton pump inhibitor, clarithromycin and amoxicillin/metronidazole). However, this review did not clarify some essential issues. Thung et al. declared furazolidone as a potential alternative antibiotic,1 but they did not state its resistance against H. pylori. This is a considerable problem due to its negative effect on the eradication rate. Studies in Asia show different prevalences of furazolidone resistance between countries during the last years, for instance 16.8% in China, 13.8% in India and 21.6% in Iran.2, 3 Resistance to furazolidone is possibly related to six mutations in porD and oorD genes on the chromosome of this bacterium.4 However, more surveys are widely needed in this regard. The authors also debated about multidrug resistance of H. pylori to several antibiotics.1 Studies indicate that resistance to three or more antibiotics has been developed in about 15% of clinical isolates of this bacterium. One of the reasons for multidrug resistance can be explained by over expression of efflux pump gene hefA. In fact, this genetic mechanism can probably decrease the minimum inhibitory concentrations of different antibiotics (such as amoxicillin and tetracycline) against H. pylori strains and cause a reduction in the eradication rate.5 In order to find new evidence for this topic, continuous investigations are necessary. Increasing resistance to H. pylori infection has enhanced concerns about a decline in the efficiency of the same antibiotics in treatment of other diseases (e.g. regarding clarithromycin as the second-line treatment of multidrug resistance tuberculosis). In addition, studies indicate that the pattern of antibiotic resistance can regionally change within countries.6 Therefore, we believe that the antibiotic resistance patterns of H. pylori can be extensible to infection with other bacterial strains and affect their efficacy in treatment of infectious diseases in an area. There are no reports about this issue and it is proposed that such studies be performed at local scales. Declaration of personal and funding interests: None.