Prevalence of clarithromycin resistance in H.pylori patients with failure of treatment
The H.pylori is a gram negative bacterium that colonizes the stomach has a high prevalence; more than 50 percent of the global population has H.pylori. It’s influenced by geography, age, gender, socioeconomic status, although it is decreasing in the developed world, it remains high in the developing world as there is less proper sanitation and hygiene, crowdedness, lack of safe water supply & poor diet, transmission is mainly oral-oral or feco-oral route(1,2,3) .The prevalence of H.pylori in 2011 in Egypt was 50% among children with age group 3 and about 90% among adult(3) .there is strong relation between H.pylori and a lot of gastro duodenal disorder. It has a rule in developing Acute and chronic gastritis, dyspepsia, peptic ulcers ,Atrophic gastritis, intestinal metaplasia &and gastric cancer(7) it is an important pathogen in the developing of gastro-duodenal ulcers(8’9) H.pylori triggers lymphoid infiltration and help in formation of Gastric MALT lymphoma(10) , although there is still controversy(11) but some studies shows a strong relation between H.pylori and GERD(12) the strongest known risk factor of H.pylori is the development of gastric adenocarcinoma. H. pylori strains that have the cag pathogenicity island induce more severe gastric injury and further augment the risk for developing cancer of the stomach (13). Iron deficiency enhances H. pylori virulence and represents a measurable biomarker to identify populations of infected persons at high risk for gastric cancer (14) .It can affect extra gastrointestinal organs as H. pylori can infect the skin, liver and heart (15). Effective treatment leads to eradication of H.pylori and thus prevent several gastro duodenal disease(16) ,it leads to ulcer healing, decrease relapse(17) .Eradication of Helicobacter pylori may result in complete regression of low-grade lymphoma of the gastric mucosa-associated lymphoid tissue (MALT)(18) ,it also leads to a significant reduction in gastric atrophy at the expense of increased esophagitis(19).Precancerous legions as gastric atrophy in antrum show more rapid progression in the case which were not treated with H.pylori infection compared to those who has H.pylori eradication(20)
Triple therapy including clarithromycin, proton pump inhibitor, amoxicillin or metronidazole is widely used worldwide. However recently it was found that it has lost some efficacy, H. pylori antibiotic resistance is increasing and it is the main factor affecting efficacy of current therapeutic regimens (21, 22, 23) In the case of clarithromycin resistance the rate of success of the clarithromycin-containing triple therapy is very low, in the range of 10-30%(18,24) .The first-line therapy should be tailored according to both clarithromycin and metronidazole resistance, In areas of low clarithromycin resistance, clarithromycin- containing treatments are recommended for first-line empirical treatment Bismuth-containing quadruple treatment is also an alternative. While in areas of high clarithromycin resistance, bismuth-containing quadruple treatments are recommended for first-line empirical treatment. If this regimen is not available sequential treatment or a non-bismuth quadruple treatment is recommended, PPI-clarithromycin-containing triple therapy without prior susceptibility testing should be abandoned when the clarithromycin resistance rate in the region is more than 15-20%(24) .
The antibacterial activity of clarithromycin is like other macrolides, but clarithromycin is better absorbed in the gastric mucus layer and is more acid-stable (25, 26). H. pylori resistance toward clarithromycin” the most powerful antibiotic currently available for infection is increasing worldwide and thus reducing success rate; levels of primary clarithromycin resistance was as high as 48.2-49.2% in 2010 in some European countries whilst...
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37. De Francesco V, Zullo A, Ierardi E, Giorgio F, Perna F, Hassan C, Morini S, Panella C, Vaira D. Phenotypic and genotypic Helicobacter pylori clarithromycin resistance and therapeutic outcome: benefits and limits. 2010
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41. Kim JM, Kim JS, Kim N, Kim YJ, Kim IY, Chee YJ, Lee CH, Jung HC. Gene mutations of 23S rRNA associated with clarithromycin resistance in Helicobacter pylori strains isolated from Korean patients. 2008
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