HefA Plays An Important Role In Multidrug Resistance Of Helicobacter ...

Tag : resistance

A research group investigated the susceptibility to antibiotics ofH pylori isolates, and they found that Efflux pump gene hefA playsan important role in multidrug resistance of H pylori and itcontains an active multidrug efflux mechanism in H pylori; hefABCgene was found in all of the strains.
Three RND efflux systems had been identified in H pylori, namelyhefABC, hefDEF, and hefGHI, each of which consisted of atranslocase, an accessory protein. But the contribution of effluxproteins to antibiotic resistance is not well established. 27putative translocases also had been identified in the H pylori26695 genome, but only four putative H pylori OEPs or TolC homologswere identified. While they could not quantitate the operonsexpression levels of the efflux systems in multidrug resistancestrains of H pylori.
A new research article addresses this question. The research teamled by Prof. Zheng from Zhengzhou University used fluorescencereal-time quantitative PCR to study the levels of mRNA expressionof hefA in MDR strains and its parent strains. To futher evaluatethe contribution of hefA in multidrug resistance of H pylori, thearticle also constructed an H pylori mutant strain (△H.pylori LZ1026), and detected the susceptibility to 10antimicrobials of the △H pylori LZ1026 with a more sensitivemethod of twofold agar dilution tests.
Six multidrug-resistant strains (including 5 clinical isolates andH pylori NCTC11637) were selected, and their MICs showed asignificant (≥ 4-fold) increase than their parent strains. Theexpression levels of hefA gene in the MDR strains weresignificantly higher compared with their parent strains (P =0.033). An H pylori LZ1026 mutant was successfully constructed andthe △H pylori LZ1026 was more susceptible to four of the 10antibiotics. All 20 strains displayed transcripts for hefA thatconfirmed the in vitro expression of these genes.
The results revealed that the relative expression of hefA in theinduced multidrug resistant strains were higher than those in theirwild susceptible isolates. It has shown that similar to othergram-negative organisms, the H pylori hefA mutant displayedincreased susceptibilities to antibiotics. It confirmed that highexpression of the hefA plays an important role inmultidrug-resistance of H pylori. H pylori contains an activemultidrug efflux mechanism and therefore compound efflux needs tobe taken into account when determining resistance mechanisms inthis organism.
Journal reference : Liu et al. Efflux pump gene hefA of Helicobacter pylori plays an importantrole in multidrug resistance . World Journal of Gastroenterology , 2008; 14 (33): 5217 DOI: 10.3748/wjg.14.5217