**7. Problem statement**

108 Gastrointestinal Endoscopy

Currently, many research aims to evaluation of clarithromycin resistance in *H. pylori* were performed which showed variety of resistance rate around the world, due to 3 main reasons

Many investigators were assessed clarithromycin resistance rate in Europe in 1994 to 2009. In these studies, clarithromycin resistance was more prevalent in France. Also, Fontana et al by PCR-RFLP method showed that clarithromycin resistance was more divers between

In continent of America, clarithromycin resistance was varies between 9.8% in Brazil to 55% in USA. Less variety were observed in eastern Asia, by 20% to 27% resistance rate. In Iran (Middle East) with variety of customs, Kargar et al showed resistant rate of 23% and 36% in same geographic region in 2009 due to different methods including PCR-RFLP and real-time PCR assays respectively but, PCR-RFLP showed 22% and 23%resistance rate in 2007 and 2009 respectively. Also more variation was observed in 2 near region with different customs

Many studies aim to assessment of clarithromycin resistance rate were preformed around the world. This studies showed A2144G > A2142G > A2143G > A2142C > A2143C order for

**Researcher Country technique Mutations rate Ref** 

in Liquid Phase

PCR-DNA Enzyme Immunoassay

PCR

Matsuok Japan PCR-RFLP A2144G(80%)

Matsumura Japan Real-time PCR A2144G(55%)

Kargar Iran PCR-RFLP A2143G(68.3%)

A2144G(56%) A2143G(35%) A2143C(9%)

A2144G(48%) A2143G(24%) A2143C(3%)

A2144G(59%) A2143G(35%) A2143C(6%)

A2144G(87.5%)

A2144G(5.7%) A2143G(37.1%) A2142G(28.6%) A2143C(21.4%)

A2143G(12.5%) <sup>47</sup>

A2143G(20%) <sup>22</sup>

A2143G(5%) <sup>49</sup>

A2142G(15.8%) <sup>54</sup>

32

21

36

55

and economic level, with 36% in low economic level and 5% in high economic level.

including differences in i: methods, ii: region and iii: date (Table 2).

**6. Epidemiology of clarithromycin resistance mutations** 

**Pina France** Hybridization

Russman Germany FISH

Maeda Japan Seminested

Kargar Iran Real-time PCR

Table 3. Prevalence of clarithromycin resistance point mutations

clarithromycin resistance point mutations (Table 3).

Marais France

north (1.6%) and south (14%) of Italy in 2003.

Following the recognition of the important pathogenic role of *H. pylori* infection in the development of gastroduodenal diseases, there has been a continuous search for improved eradication therapy (Occhilini et al., 1997). *H. pylori* culture, as well as antimicrobial susceptibility studies is difficult to perform as well as labor intensive. Moreover, although the culture method allows antimicrobial susceptibility testing for several antibiotics, only the susceptibilities of macrolides and, in particular, of clarithromycin are really useful since the last is a major predictor of treatment failure. Therefore, detection of clarithromycinresistant *H. pylori* will facilitate the choice of an appropriate eradication regimen
