Why does aspirin increase the susceptibility of Helicobacter pylori to antimicrobials?

Resent studies reported that aspirin inhibited the growth of H. pylori in a dose-dependent manner and significantly affected the activity of virulence factors of H. pylori. In addition, aspirin increased the susceptibility of H. pylori to antimicrlbials including metronidazole, clarithromycin and amoxicillin. However, the mechanisms remained unknown.

A research team led by Prof. Wang from Peking University First Hospital of China addressed this issue and their results will be published on February 28, 2009 in the World Journal of Gastroenterology.

H. pylori reference strain 26695 and two metronidazole-resistant isolates of H. pylori were included in this study. The effect of aspirin on the permeability of the outer membrane of H. pylori was determined using [7-3H] tetracycline. The effects of aspirin on the expression of OMPs of H. pylori were also determined. Taqman-based real-time quantitative PCR was used to analyze the influence of aspirin on the expression of the related OMPs genes.

They found that the mutations in rdxA gene did not change in metronidazole resistant isolates treated with aspirin. The radioactivity of H. pylori increased when treated with aspirin, indicating that aspirin improved the permeability of the outer membrane of H. pylori. However, the expression of two OMP bands between 55 kDa and 72 kDa altered in the presence of aspirin. The expression of the mRNA of hopA, hopB, hopC, hopD, hopE and hefA, hefB, hefC of H. pylori did not change when treated with aspirin.

Their results indicated that although aspirin increases the susceptibility of H. pylori to metronidazole, it has no effect on the mutations of rdxA gene of H. pylori. Aspirin increases endocellular concentrations of antimicrobials and probably by altering the expression of the outer membrane proteins (OMP) of H. pylori. Their study will help understand the mechanisms of the resistance of H. pylori to antibiotics more intensively and discover a more effective eradication regimen in clinical practice.

Reference: Zhang XP, Wang WH, Tian Y, Gao W, Li J. Aspirin increases susceptibility of Helicobacter pylori to metronidazole by augmenting endocellular concentrations of antimicrobials. World J Gastroenterol 2009; 15(8): 919-926 http://www.wjgnet.com/1007-9327/15/919.asp

Correspondence to: Wei-Hong Wang, Department of Gastroenterology, Peking University First Hospital, Beijing 100034, China. wangweihong@medmail.com.cn

World Journal of Gastroenterology (WJG), a leading international journal in gastroenterology and hepatology, has established a reputation for publishing first class research on esophageal cancer, gastric cancer, liver cancer, viral hepatitis, colorectal cancer, and H. pylori infection and provides a forum for both clinicians and scientists. WJG has been indexed and abstracted in Current Contents/Clinical Medicine, Science Citation Index Expanded (also known as SciSearch) and Journal Citation Reports/Science Edition, Index Medicus, MEDLINE and PubMed, Chemical Abstracts, EMBASE/Excerpta Medica, Abstracts Journals, Nature Clinical Practice Gastroenterology and Hepatology, CAB Abstracts and Global Health. ISI JCR 2003-2000 IF: 3.318, 2.532, 1.445 and 0.993. WJG is a weekly journal published by WJG Press. The publication dates are the 7th, 14th, 21st, and 28th day of every month. WJG is supported by The National Natural Science Foundation of China, No. 30224801 and No. 30424812, and was founded with the name of China National Journal of New Gastroenterology on October 1, 1995, and renamed WJG on January 25, 1998.

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