抑制幽门螺杆菌对胃粘膜黏附的天然活性物质研究概述

近年来,抑制幽门螺杆菌(Helicobacter pylori Hp)对胃粘膜黏附已经成为了治疗Hp引起疾病的又一个新的研究课题.本文对近几年国内外研究者利用天然可抑制Hp黏附的活性物质进行了概述,旨在为研究和开发幽门螺杆菌新的治疗方法提供理论参考.     

幽门螺杆菌与胃癌

幽门螺杆菌(Helicobacter pylori,Hp)是一种革兰阴性微需氧菌,世界上约50%的人群有Hp感染.感染通常发生在儿童时期,如不进行治疗,可终身定植于人的胃黏膜上皮,引起多种胃肠道疾病.     

幽门螺杆菌抗生素耐药机制研究进展

幽门螺杆菌(Helicobacter pylori,H.pylori)感染可引起消化性溃疡、胃粘膜相关淋巴组织淋巴瘤和胃癌。随着抗生素耐药性的问题越来越严重,耐药机制的研究也不断深入。分子检测方法,尤其是核酸检测技术,可高效、快速、准确地检测幽门螺杆菌抗生素耐药基因及突变,对幽门螺杆菌感染的临床治疗发挥重要的指导作用,同时也可对幽门螺杆菌抗生素耐药性进行大规模及时有效监控。本文讨论了关于幽门螺杆菌抗生素耐药机制并着重总结了相关耐药基因及突变。     

C57BL/6小鼠幽门螺杆菌感染动物模型的建立

目的：建立幽门螺杆菌（Helicobacter pylori,Hp）小鼠感染模型。方法：建立Hp经口感染SPF级小鼠的动物模型,取小鼠胃粘膜组织,利用PCR技术、尿素酶实验、细菌培养等方法检测接种小鼠,对结果进行判定。结果：Hp可感染C57BL／6小鼠并在小鼠胃部定植。     

全国中西医整合治疗幽门螺杆菌相关“病-证”共识

正幽门螺杆菌(Helicobacter pylori,H.pylori)与慢性胃炎、消化性溃疡、胃癌及胃黏膜相关淋巴组织(MALT)淋巴瘤的发生发展密切相关。1994年幽门螺杆菌被世界卫生组织列为胃癌发生的I类致癌因子,胃癌发生与幽门螺杆菌感染密切相关,根除幽门螺杆菌可降低胃癌的发生率。中国是幽门螺杆菌高感染率国家,同时也是胃癌高发国家,幽门螺杆菌感染不仅是一个临床问题,更是一个公     

胃溃疡、胃癌组织中幽门螺杆菌及真菌基因片段的扩增分析

探讨胃溃疡、胃癌组织中幽门螺杆菌(Helicobacter pylori,Hp)、真菌(Fungi)单纯感染及混合感染的可能性并进行验证。应用聚合酶链反应(PCR)技术,分别自4例胃溃疡和4例胃癌并伴单纯幽门螺杆菌、真菌及其混合感染病例石蜡包埋组织(FFPE)中扩增Hp及fungi基因特异片段并进行测序分析。成功提取了FF-PE胃组织基因组DNA,并扩增出Hp 16S rRNA及真菌内转录间隔区18S rDNA基因和28S rDNA之间的基因特异条带,测序大小分别为114 bp和357 bp,经在线BLAST比对分析表明所扩增基因与Hp及真菌核苷酸具有高度同源性。胃溃疡、胃癌组织中存在Hp和真菌单纯感染及混合感染。推测Hp与真菌混合感染可能是加重胃溃疡发展和诱发胃癌发生的又一致病因素。积极治疗Hp与真菌混合感染有助于提高胃溃疡的治愈率和减少胃癌的发生。     

口腔中幽门螺杆菌PCR检测方法的建立

全世界大约有50%的人口感染幽门螺杆菌(Helicobacter pylori, Hp),Hp感染容易造成慢性胃炎、消化性溃疡、低度恶性胃MALT淋巴瘤及胃癌,对人类造成严重的危害。为寻求一种简便、准确、非创伤性的方法用于口腔中Hp的检测,本研究建立了口腔中幽门螺杆菌的PCR检测方法,并对建立的PCR方法的敏感性、特异性进行分析,并应用于检测唾液样品和牙菌斑共50份。结果显示,50份样品中,阳性率为82%。结果表明,本研究建立的口腔中Hp的PCR检测方法特异性强、敏感性高,可以用于临床上Hp诊断的重要参考。     

幽门螺杆菌与胃黏膜相关淋巴瘤相关性研究

目的研究幽门螺杆菌(H.pylori)与胃黏膜相关淋巴瘤相关性。方法通过胃镜和相关辅助检查,对24例胃黏膜相关淋巴瘤病人胃内幽门螺杆菌进行动态观察。结果24例胃黏膜相关淋巴瘤病人中,18例出现H.pylori感染(75%);治疗后H.pylori感染例数减少(6/24,25%);1年后H.pylori病人感染又增加(11/24,46%)。结论抗H.pylori及胃黏膜相关淋巴瘤常规治疗方法有效,但易反复,可考虑辅以微生态调节剂治疗。     

幽门螺杆菌在牙菌斑及胃粘膜分布研究

目的:探讨幽门螺杆菌(Helicobacter pylori,Hp)在牙菌斑及胃粘膜分布状况。方法:采用聚合酶链式反应(polym erase chain reaction,PCR)技术对80 例慢性胃溃疡患者的牙菌斑及胃粘膜组织进行Hp 检测。结果:48 例胃粘膜Hp 阳性的患者中12 例牙菌斑Hp 阳性;胃粘膜Hp 阴性的患者无一例牙菌斑Hp 阳性;胃Hp 阳性检出率大于牙菌斑。结论:幽门螺杆菌不仅存在于胃粘膜组织中,也存在于口腔牙周组织中。提示牙菌斑可能是Hp 的重要寄居地。     

幽门螺杆菌检测技术研究进展及展望

幽门螺杆菌是(Helicobacter pylori,H. pylori)是导致人类多种胃肠疾病的主要病因,通过多种毒力因子导致各种疾病的发生和发展。鉴于目前幽门螺杆菌缺少商业化疫苗且多重耐药性问题日益严重,临床上对其根除效果不佳,因此,精准的检测技术是预防幽门螺杆菌感染的关键,也是评估感染后治疗效果的重要手段。幽门螺杆菌的检测方法主要包括尿素呼气试验、快速尿素酶试验、粪便抗原检测、血清学检查、内镜检查、组织学病理检查、聚合酶链式反应及细菌培养,每种方法在临床上皆存在优点与局限性。目前,对于幽门螺杆菌检测的“金标准”尚无统一定论,因此本文重点综述当前应用的幽门螺杆菌检测技术,分析其优点和局限性,并指明精准、快速且便捷的检测技术在流行病学调查等方面具备的优势,旨在为临床和研究提供科学的参考依据。     

益生菌在根除幽门螺杆菌中的应用

随着幽门螺杆菌耐药率的上升,幽门螺杆菌根除率逐渐下降,如何提高根除率是目前临床治疗上遇到的重要问题。益生菌不但能提高幽门螺杆菌根除率,还能降低根除幽门螺杆菌治疗的不良反应,益生菌在根除幽门螺杆菌中的应用越来越引起重视。     

Identification of a 23S rRNA Gene Mutation in Clarithromycin-Resistant Helicobacter pylori

Background Transition mutations (A-G) at residue 2143, cognate to position 2058 in the Escherichia coli 23S rRNA gene, have been shown to confer resistance to macrolides in Helicobacter pylori. This study reports the finding that transversion mutations (A-C) can occur at 2143 as well.
Materials and Methods. Three clarithromycin-resistant H. pylori isolated from three different patients after treatment with clarithromycin were analyzed for point mutations by cycle sequencing of a 163-bp amplified region surrounding residue 2143 within the conserved loop of the 23S rRNA gene.
Results. Nucelotide sequence comparisons of a 163-bp amplified product revealed that A-C transversion mutations occurred at position 2143. H. pylori isolated from the patients prior to treatment were susceptible to clarithromycin and displayed no polymorphism at 2143.
Conclusion. This is the first report to show that A-C transversion mutations at position 2143 can confer resistance to clarithromycin in H. pylori and further support the role that mutations at position 2143 play in conferring macrolide resistance in H. pylori.     

Multiple mutations in or adjacent to the conserved penicillin-binding protein motifs of the penicillin-binding protein 1A confer amoxicillin resistance to Helicobacter pylori

BACKGROUND: Amoxicillin-based therapies are highly effective for the treatment of Helicobacter pylori infections, but the efficacy may decrease as the incidence of amoxicillin resistance is increasing. So far, the molecular mechanism underlying stable amoxicillin resistance has only been identified for a few naturally occurring amoxicillin-resistant (Amx) H. pylori isolates, and is mediated by mutations in penicillin-binding protein 1A (PBP1A). In this study the molecular mechanism underlying amoxicillin resistance of seven additional Amx H. pylori isolates has been established. METHODS: H. pylori strain 26695 (minimal inhibitory concentration (MIC) 0.125 mg/l) was naturally transformed with total DNA and pbp1A polymerase chain reaction (PCR) products from the seven Amx H. pylori isolates, and the MIC of amoxicillin and pbp1A gene sequence of the obtained Amx transformants were determined. RESULTS: Replacement of the wild-type pbp1A gene of H. pylori reference strain 26695 by the pbp1A gene of the Amx H. pylori isolates resulted in an increased MIC (0.5-1.0 mg/l). Sequence analysis of the smallest PBP1A fragments able to transfer the resistance indicated that several amino acid substitutions in or adjacent to the second (SKN402-404) and third (KTG555-557) conserved penicillin-binding protein motifs (PBP-motifs) mediate amoxicillin resistance in H. pylori. This was confirmed by site-directed mutagenesis using oligonucleotides that contained defined mutations in or adjacent to these PBP-motifs. CONCLUSION: In naturally occurring Amx H. pylori isolates, amoxicillin resistance is mediated by various mutational changes located in or adjacent to the second and third PBP-motifs of the PBP1A. Although we cannot exclude the role of the other genes in amoxicillin resistance, it is likely that multiple mutational changes in the PBP1A gene are the predominant cause of amoxicillin resistance in H. pylori. The findings of this study currently preclude the rapid detection of amoxicillin resistance in H. pylori by molecular tests.     

Helicobacter pylori in Pediatrics

This review summarizes important pediatric studies published from April 2011 up to March 2012. Proteomics profile of ulcerogenic Helicobacter pylori strains was defined in the most interesting study of the last year. The antigen stool test is becoming the "gold standard" in prevalence studies, and according to the last epidemiologic studies, the prevalence of H.?pylori infection in childhood is not decreasing any more in the developed world. The resistance rate of H.?pylori strains is high in children. Therefore, among other important issues concerning H.?pylori in pediatrics, guidelines published by ESPGHAN and NASPGHAN last year also recommended culture and susceptibility testing before first-line treatment in areas with high or unknown antibiotic resistance rates.     

Primary resistance of Helicobacter pylori to antimicrobial agents in Polish children

Helicobacter pylori resistance to antimicrobial agents is an important factor compromising the efficacy of treatment. Therefore the aims of our study were: to determine the prevalence of H. pylori resistance to clarithromycin, metronidazole, amoxycillin and tetracycline in children prior to eradication therapy, to compare different methods of susceptibility testing and to detect mutations responsible for clarithromycin resistance. During 1996-2000, 259 H. pylori strains were isolated from antral gastric biopsies. Susceptibility to antimicrobials was determined by the agar dilution method and the Etest. Mutations in the 23S rRNA gene associated with clarithromycin resistance were analysed by PCR-RFLP and direct sequencing. Overall, ninety-six strains (37%) were resistant to metronidazole, 50 strains (19.3%) were resistant to clarithromycin, and 20 strains (7.7%) were simultaneously resistant to both drugs. All cultured isolates were sensitive to amoxycillin and only one isolate (0.4%) was resistant to tetracycline. The agar dilution method and the Etest showed a perfect category correlation for clarithromycin and 4% discrepancies for metronidazole. Primary resistance to clarithromycin was mainly associated with an A2143G mutation in the 23S rRNA gene of H. pylori. The study highlights the high prevalence of H. pylori primary resistance to clarithromycin in Polish children, which implies a need for pretreatment susceptibility testing.     

Detection of high-level tetracycline resistance in clinical isolates of Helicobacter pylori using PCR-RFLP

Tetracycline is one of four antibiotics commonly used for the treatment of Helicobacter pylori infection, but its effectiveness is decreasing as the incidence of tetracycline resistance is increasing. In five Brazilian tetracycline-resistant (Tet(R)) H. pylori isolates, high-level tetracycline resistance is mediated by the triple-base-pair substitution AGA(926-928)-->TTC in both 16S rRNA genes, as was previously observed in two independent high-level Tet(R) H. pylori strains. A polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) assay was developed for the detection of the AGA(926-928)-->TTC substitution, and confirmed the presence of the aforementioned triple-base-pair substitution in all five Brazilian Tet(R) isolates. This PCR-RFLP-based approach distinguishes the high-level Tet(R) isolates from low-level Tet(R) and Tet(S) H. pylori strains and thus allows the direct detection of Tet(R) H. pylori isolates.     

Helicobacter pylori infection in Turkish children: comparison of diagnostic tests, evaluation of eradication rate, and changes in symptoms after eradication

BACKGROUND: Helicobacter pylori infection is most frequently acquired in childhood. After this organism is eradicated, the rate of reinfection is low. Thus, it is very important to diagnose and treat the disease appropriately in childhood, and to be able to assess eradication with certainty. Eradication of H. pylori infection is reported to reduce or eliminate abdominal pain and dyspeptic symptoms in children. PATIENTS AND METHODS: The study involved 102 children who had already been diagnosed with symptomatic H. pylori infection based on gastric histopathological examination, urea breath test, rapid urease test, serology and culture. Each patient's symptoms and family history of gastrointestinal problems were recorded. Using histology as the gold standard for identifying H. pylori infection, we determined the diagnostic sensitivity of each of the other methods. Omeprazole or lansoprazole, amoxicillin and clarithromycin were administered as eradication treatment, and each patient was re-evaluated by urea breath test 8 weeks later. Each child was re-interviewed about symptoms after treatment. These answers and the results of drug sensitivity testing were recorded. Cases of failed eradication were re-treated with a quadruple-drug regimen of tetracycline, metronidazole, bismuth subsalicylate and omeprazole. RESULTS: The most frequent symptom was abdominal pain (89.2%). Fifty-four per cent of the subjects had a family history of dyspeptic symptoms. Sixty-six patients (64.7%) exhibited nodularity in the antral mucosa. The sensitivities of the diagnostic tests in histologically proven cases were as follows: urea breath test 100%, rapid urease test 89.2%, serology 71.9%, and culture 54.9%. Metronidazole had the highest frequency of resistance (36.4%) and the rate of clarithromycin resistance was 18.2%. The eradication rate after first-line therapy was 75.5%, and abdominal pain and dyspeptic symptoms were reduced or completely resolved in 75.7% of the successful-eradication cases. The proportion of failed-eradication cases that responded well to quadruple-drug therapy was 93.8%. CONCLUSION: Symptomatic H. pylori infection in a child should always be treated. The urea breath test is an accurate and reliable way to identify H. pylori-positive patients and to determine the response to treatment. Triple-agent therapy is effective for eradicating H. pylori infection in children and usually helps reduce or eliminate dyspeptic symptoms. The level of H. pylori resistance to metronidazole is high in our region. The significant rate of resistance to clarithromycin (18.1%) may explain the treatment failure observed in this study.     

Antibacterial effect of Kampo herbal formulation Hochu-ekki-to (Bu-Zhong-Yi-Qi-Tang) on Helicobacter pylori infection in mice

Because Helicobacter pylori (H. pylori) infection is a major cause of gastroduodenal diseases in humans, the eradication of H. pylori using antibiotics is very effective for the treatment of gastroduodenal diseases. However, it has recently been reported that resistance to these antibiotics is developing. In the present study, the antibacterial effect of a Kampo (traditional Japanese medicine) herbal formulation, Hochu-ekki-to (RET; Formula repletionis animalis et supletionis medii), against H. pylori was examined in vitro and in vivo. HET inhibited the growth of antibiotic-resistant strains of H. pylori as well as antibiotic-sensitive strains at a dose of 2.5 mg/ml in vitro. When 1,000 mg/kg of HET was administered orally to C57BL/6 mice for 7 days before or after inoculation with H. pylori, H. pylori in the stomach was significantly reduced in the HET-pre-treatment group compared with the control group. Furthermore, HET in combination with antibiotics completely eradicated the bacteria in mice. The expression of interferon (IFN)-gamma was induced in the gastric mucosa of the mice pre-treated with HET. There were no significant differences between the colonization of H. pylori in the control and HET treatment groups in IFN-gamma gene-deficient mice. These results suggest that the antibacterial effect of HET may be partly due to IFN-gamma induction, and that HET may be clinically useful for treatment of H. pylori infection.