The Bifunctional Enzyme SpoT Is Involved in the Clarithromycin Tolerance of Helicobacter pylori by Upregulating the Transporters HP0939, HP1017, HP0497, and HP0471.

Clarithromycin (CLA) is a commonly recommended drug for eradication. However, the prevalence of CLA-resistant is increasing. Although point mutations in the 23S rRNA are key factors for CLA resistance, other factors, including efflux pumps and regulation genes, are also involved in the resistance of to CLA. Guanosine 3'-diphosphate 5'-triphosphate and guanosine 3',5'-bispyrophosphate [(p)ppGpp)], which are synthesized by the bifunctional enzyme SpoT in , play an important role for some bacteria to adapt to antibiotic pressure. Nevertheless, no related research involving has been reported. In addition, transporters have been found to be related to bacterial drug resistance. Therefore, this study investigated the function of SpoT in resistance to CLA by examining the shifts in the expression of transporters and explored the role of transporters in the CLA resistance of A Δ strain was constructed in this study, and it was shown that SpoT is involved in tolerance of CLA by upregulating the transporters HP0939, HP1017, HP0497, and HP0471. This was assessed using a series of molecular and biochemical experiments and a cDNA microarray. Additionally, the knockout of genes , , and in the resistant strains caused a reduction or loss (the latter in the Δ strain) of resistance to CLA. Furthermore, the average expression levels of these four transporters in clinical CLA-resistant strains were considerably higher than those in clinical CLA-sensitive strains. Taken together, our results revealed a novel molecular mechanism of adaption to CLA stress.