FBPAII and rpoBC, the Two Novel Secreted Proteins Identified by the Proteomic Approach from a Comparative Study between Antibiotic-Sensitive and Antibiotic-Resistant Helicobacter pylori-Associated Gastritis Strains.

infection is the leading cause of chronic gastritis, which can develop into gastric cancer. Eliminating infection with antibiotics achieves the prevention of gastric cancer. Currently, the prevalence of resistance to clarithromycin and metronidazole, and the dual resistance to metronidazole and clarithromycin (C_R, M_R, and C/M_R, respectively), remains at a high level worldwide. As a means of exploring new candidate proteins for the management of infection, secreted proteins from antibiotic-susceptible and antibiotic-resistant -associated gastritis strains were obtained by in-solution tryptic digestion coupled with nano-liquid chromatography tandem mass spectrometry (nano-LC-MS/MS). A total of 583, 582, 590, and 578 differential expressed proteins were identified from C_R, M_R, C/M_R, and antibiotic-sensitive strain (S_S) samples, respectively. Of these, 23 overlapping proteins were found by Venn diagram analysis. Based on heat map analyses, the most and least differing protein expressions were observed from C/M_R strains and S_S strains, respectively. Of the proteins secreted by the S_S strain, only nine were found. After predicting the protein interaction with metronidazole and clarithromycin via the STITCH database, the two most interesting proteins were found to be rpoBC and FBPAII. After quantitative real-time reverse transcription PCR (qRT-PCR) analysis, a downregulation of from M_R strains was observed, suggesting a relationship of to metronidazole sensitivity. Inversely, an upregulation of from C_R, M_R, and C/M_R strains was noticed, suggesting the paradoxical expression of FBPAII and the gene. This report is the first to demonstrate the association of these two novel secreted proteins, namely, rpoBC and FBPAII, with antibiotic-sensitive associated gastritis strains.