Gene fusion in Helicobacter pylori: making the ends meet

Microbial genomics: rhetoric or reality?

The availability of complete genome sequences of many bacterial species is facilitating numerous computational approaches for understanding bacterial genomes. One of the major incentives behind the genome sequencing of many pathogenic bacteria is the desire to better understand their diversity and to develop new approaches for controlling human diseases caused by these microorganisms. This task has become even more urgent with the rapid evolution of antibiotic resistance among many bacterial pathogens. Novel drug targets are required in order to design new antimicrobials against antibiotic-resistant pathogens. The complete genome sequences of an ever increasing number of pathogenic microbes constitute an invaluable resource and provide lead information on potential drug targets. This review focuses on in silico analyses of microbial genomes, their host-specific adaptations, with specific reference to genome architecture, design, evolution, and trends in computational identification of microbial drug targets. These trends underscore the utility of genomic data for systematic in silico drug target identification in the post-genomic era.

A novel gene associated with clarithromycin resistance of Helicobacter pylori

AIM: To investigate the mechanism of H. pylori resistance to clarithromycin in different concen-trations, and to look for a novel gene associated with clarithromycin resistance.

METHODS: H. pylori 26695 were used as the primary strain. Antibiotic selection pressure test, mutation by transponson (Tn5) containing chloromycetin marker and E-test were performed for the analysis of H. pylori resistance to clarithromycin in different concentrations.

RESULTS: After 12 generations, the 0.5 mg/L clarithromycin resistance strains remained resistant after the storage in -80 ℃ for 30 d. Clarithro-mycin-restant H. pylori which had been inserted by transponson showed a band of 700 bp. After culturing for 98-168 h, the resistant H. pylori from clarithromycin selection pressure test showed an elliptic inhibition ring. On the other hand, clarithromycin-resistant H. pylori inserted by trans-ponson showed no inhibition ring. After sequencing, the gene at the insertion site was homogenous with H. pylori1469, which coded Omp31.

CONCLUSION: The resistant H. pylori from lower concentrations of clarithromycin can be changed into higher concentration resistance strain through transponson insertion, indicating that the mechanism of H. pylori resistance to clarithromycin may be associated with Omp31 apart from 23S rRNA mutation.