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Background There are geographic variations in the genotypes of Helicobacter pylori (H. pylori) cagA, vacA, iceA, oipA and dupA. The aim of the study was to investigate the distribution of these genotypes among H. pylori strains from five regions of China and their association with clinical outcomes. Materials and methods Gastric biopsy specimens were obtained from 348 patients with different gastrointestinal diseases in the five regions of China. The regional distribution was 89 patients from Shandong, 91 from Guangxi, 57 from Hunan, 58 from Qinghai and 53 from Heilongjiang. The presence of cagA, vacA, iceA, oipA and dupA genotypes was determined by polymerase chain reaction (PCR) from H. pylori DNA. Results A total of 269 H. pylori isolates were obtained, of which 74 isolates were from Shandong, 78 from Guangxi, 46 from Hunan, 33 from Qinghai and 38 from Heilongjiang. The cagA-positive status was predominant in the five regions. The predominant vacA genotypes were s1c (73.4%), m2 (70.6%) and i1 (92.9%). In strains from Shandong, s1a and m1 were dominant. By contrast, s1c was dominant in Guangxi and i1 was dominant in Hunan and Heilongjiang. The prevalence of m2 subtype in Qinghai (78.8%) was significantly higher than that in other regions (P iceA genotype was iceA1 and the frequency of iceA1 was significantly more prevalent in Hunan than in other regions (P oipA status “on” gene was more frequent in Shandong (91.9%) and Guangxi (91%) than in Heilongjiang (71.7%) (P dupA-positive status was less than half in Shandong (31.1%) and Guangxi (15.4%), whereas it was 73.9% in Hunan and 81.8% in Qinghai (P cagA, vacA, iceA, oipA genotypes and clinical outcomes. The dupA-positive strains were more common in peptic ulcer disease (PUD) patients than in non-ulcer dyspepsia (NUD) patients in Shandong and Guangxi (P Conclusions There was significant geographic diversity of H. pylori genotypes in different regions of China and the presence of dupA gene can be considered as a marker for the development of gastroduodenal diseases. However, the cagA, iceA, vacA and oipA genes cannot be regarded for prediction of the clinical presentation of H. pylori infection in China.

Background The cytotoxin-associated gene A (cagA) is one of the most important virulence factors of Helicobacter pylori (H. pylori). There is a highly polymorphic Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region in the C-terminal of CagA protein. This repeat region is thought to play an important role in the pathogenesis of gastrointestinal diseases. The aim of this study was to investigate the diversity of cagA 3′ variable region and the amino acid polymorphisms in the EPIYA segments of the CagA C-terminal region of H. pylori, and their association with gastroduodenal diseases. Methods A total of 515 H. pylori strains from patients in 14 different geographical regions of China were collected. The genomic DNA from each strain was extracted and the cagA 3′ variable region was amplified by polymerase chain reaction (PCR). The PCR products were sequenced and analyzed using MEGA 7.0 software. Results A total of 503 (97.7%) H. pylori strains were cagA-positive and 1,587 EPIYA motifs were identified, including 12 types of EPIYA or EPIYA-like sequences. In addition to the four reported major segments, several rare segments (e.g., B′, B″ and D′) were defined and 20 different sequence types (e.g., ABD, ABC) were found in our study. A total of 481 (95.6%) strains carried the East Asian type CagA, and the ABD subtypes were most prevalent (82.1%). Only 22 strains carried the Western type CagA, which included AC, ABC, ABCC and ABCCCC subtypes. The CagA-ABD subtype had statistical difference in different geographical regions (P = 0.006). There were seven amino acid polymorphisms in the sequences surrounding the EPIYA motifs, among which amino acids 893 and 894 had a statistical difference with gastric cancer (P = 0.004). Conclusions In this study, 503 CagA sequences were studied and analyzed in depth. In Chinese population, most H. pylori strains were of the CagA-ABD subtype and its presence was associated with gastroduodenal diseases. Amino acid polymorphisms at residues 893 and 894 flanking the EPIYA motifs had a statistically significant association with gastric cancer.

Background: There were geographical differences in the distribution of Helicobacter pylori (H. pylori) genotypes (cagA, vacA, iceA, oipA and dupA, et al). The population in different regions in China have grant different patterns of gastroduodenal diseases which are associated with these genotypes, but the geographical characteristics of H. pylori genotypes were still unknown. Materials and Methods: Gastric biopsy specimens were obtained from 348 patients from five regions in China. The regional distribution was 89 patients from Shandong, 91 from Guangxi, 57 from Hunan, 58 from Qinghai and 53 from Heilongjiang. DNA extracted from cultured isolates were analyzed by polymerase chain reaction (PCR) to determine the presence of cagA, vacA, iceA, oipA and dupA genotypes.Results: A total of 269 H. pylori isolates were obtained, of which 74 isolates were from Shandong, 78 from Guangxi, 46 from Hunan, 33 from Qinghai and 38 from Heilongjiang. The cagA gene was predominant in all the five regions (e.g. 100% in Hunan, Qinghai and Heilongjiang). The predominant vacA genotypes in the 269 isolates were s1a (88.1%) and m1(72.1%). vacA s1b was not detected in our study. In strains from Guangxi and Hunan, s1c was dominant; in contrast, s1a was dominant in Shandong, Qinghai and Heilongjiang. The prevalence of m1 strains in Heilongjiang (92.1%) was significantly higher (PoipA-positive strains were more prevalent in Guangxi (100%) and Hunan (100%) than in Qinghai (78.8%) (PdupA-positive strains were less than half in Guangxi (15.4%) and Shandong (32.4%), whereas it was 73.9% in Hunan and 81.8% in Qinghai (PConclusions: There are significant geographic differences in the distribution of H. pylori genotypes. These datas may be used to explain the gastroduodenal diseases patterns in different geographic regions of China.

HpaA as an outer membrane protein of Helicobacter pylori (H. pylori) plays a significant role in the adhesion to the human stomach, but the functional relation between HpaA and gastric epithelial cells is still not clear. To screen the interaction between HpaA and cellular proteins in gastric epithelial cells, the HpaA protein from H. pylori 26695 fused with a tag (6× His) was expressed and purified successfully, the secondary structure was estimated by the Circular Dichroism (CD) spectrum, and the purified recombinant protein was used to perform the pull-down assays with gastric cancer cell lines (AGS and SGC-7901) lysates, respectively. The pull-down proteins were identified by high-performance liquid chromatography tandem mass spectrometry system (HPLC-MS/MS). A total of 9 and 13 proteins related were analyzed from AGS and SGC-7901 cell lysates, respectively. ANXA2 was considered as putative HpaA functional partner discovered from lysates of both cell lines with high score and coverage. It is hypothesized that HpaA may be involved in the biological process of regulation of transcription and nucleic acid metabolism during the adhesion of H. pylori to human gastric epithelial cells, and HpaA-binding proteins also be used as targets for the development of antiadhesion drugs against H. pylori.

Some amoxicillin-resistant strains of H. pylori show a sharp decrease in amoxicillin resistance after freezing. In China, most clinical gastric mucosal specimens are frozen and transported for isolation and drug susceptibility testing for H. pylori, which may lead to an underestimation of the amoxicillin resistance. The objective of this study is to investigated reasons for the decreased amoxicillin resistance after cryopreservation. A high-level amoxicillin-resistant clone (NX24r) was obtained through amoxicillin pressure screening. After cryopreservation at −80 °C for 3 months, the minimum inhibitory concentration (MIC) of NX24r was reduced sharply. Mutations and changes of transcriptome were analyzed after amoxicillin screening and cryopreservation. Mutations in PBP1 (I370T, E428K, T556S) and HefC (M337K, L378F, D976V) were detected in NX24r, which may be the main reason for the induced amoxicillin resistance. No mutations were found in PBP1 or HefC after cryopreservation. However, transcriptome analysis showed that down-regulated genes in the cryopreserved clone were significantly enriched in plasma membrane (GO:0005886), including lepB, secD, gluP, hp0871 and hp1071. These plasma membrane genes are involved in the biosynthesis and transport function of the membrane. The decreased amoxicillin resistance after cryopreservation may be related to the down-regulation of genes involved in membrane structure and transport function.

Helicobacter pylori (H. pylori) adhesion to human gastric epithelial cells is closely linked with fucosylated glycans. Therefore, investigation of fucosylation in the interaction of gastric epithelial cells with H. pylori is critical. In this study we used lectin microarrays to detect the expression of fucosylated glycans in gastric epithelial cells (GES-1) infected with H. pylori strains isolated from patients with different diseases including chronic gastritis, duodenal ulcers, and gastric cancer (each containing two strains) at 4 h. In addition, we investigated the time-course expression of fucosyltransferase (FUT) 1–6 genes in GES-1 cells stimulated with H. pylori strains at 0.5–8 h. At 4 h post-infection, Lotus, AAA, BC2LCN, PA-IIL, CNL and ACG lectins had increased signals in H. pylori-infected GES-1 cells compared to uninfected cells. Higher expression of FUT1 and FUT2 was detected in all H. pylori-infected GES-1 cells within 2 h, regardless of the H. pylori strain. In particular, the expression of FUT2 was higher in H. pylori-infected GES-1 cells with a higher fold change in levels of BC2LCN lectin specific to α1-2 linked fucose (Fuc) at 4 h. The results suggest that the high levels of α1, 2-linked Fuc synthesized by FUT1/2, might play a role in the preliminary stage of H. pylori infection. This provides us with pivotal information to understand the adhesion of H. pylori to human gastric epithelial cells.