Bifunctional Enzyme SpoT Is Involved in Biofilm Formation of Helicobacter pylori with Multidrug Resistance by Upregulating Efflux Pump Hp1174 ( <i>gluP</i> )

Abstract

The drug resistance of <i>Helicobacter pylori</i> is gradually becoming a serious problem. Biofilm formation is an important factor that leads to multidrug resistance (MDR) in bacteria. The ability of <i>H. pylori</i> to form biofilms on the gastric mucosa is known. However, there are few studies on the regulatory mechanisms of <i>H. pylori</i> biofilm formation and multidrug resistance. Guanosine 3'-diphosphate 5'-triphosphate and guanosine 3',5'-bispyrophosphate [(p)ppGpp] are global regulatory factors and are synthesized in <i>H. pylori</i> by the bifunctional enzyme SpoT. It has been reported that (p)ppGpp is involved in the biofilm formation and multidrug resistance of various bacteria. In this study, we found that SpoT also plays an important role in <i>H. pylori</i> biofilm formation and multidrug resistance. Therefore, it was necessary to carry out some further studies regarding its regulatory mechanism. Considering that efflux pumps are of great importance in the biofilm formation and multidrug resistance of bacteria, we tried to determine whether efflux pumps controlled by SpoT participate in these activities. We found that Hp1174 (glucose/galactose transporter [<i>gluP</i>]), an efflux pump of the major facilitator superfamily (MFS), is highly expressed in biofilm-forming and multidrug-resistant (MDR) <i>H. pylori</i> strains and is upregulated by SpoT. Through further research, we determined that <i>gluP</i> is involved in <i>H. pylori</i> biofilm formation and multidrug resistance. Furthermore, the average expression level of <i>gluP</i> in the clinical MDR strains (C-MDR) was considerably higher than that in the clinical drug-sensitive strains (C-DSS). Taken together, our results revealed a novel molecular mechanism of <i>H. pylori</i> resistance to multidrug exposure.