血清降钙素原检测在急性白血病化疗后粒细胞缺乏期合并细菌感染中的临床应用

目的分析血清降钙素原(PCT)在急性白血病化疗后粒细胞缺乏期合并细菌感染中的临床应用价值,为临床抗感染治疗及病情评估提供依据。方法对急性白血病化疗后粒细胞缺乏期合并感染患者68例进行血清PCT检测,根据血培养结果分为血培养阳性组、血培养阴性组、G^+菌感染组及G^-菌感染组,分析各组患者血清PCT水平。结果血培养阳性组血清PCT水平明显高于血培养阴性组,G^-菌感染组血清PCT水平明显高于G^+菌感染组,血培养阳性死亡组血清PCT水平明显高于生存组,差异均有统计学意义(P <0.05)。结论在急性白血病化疗后粒细胞缺乏期合并细菌感染中,血清PCT可作为判断患者的感染类型、感染严重程度及预测预后的指标,为抗生素的使用提供临床依据。

自身免疫病患者细菌感染的病原菌分布及耐药性研究

目的探讨自身免疫病(AD)患者细菌感染病原菌的种类、分布及耐药状况,为临床合理使用抗菌药物提供依据。方法应用ATB Expression自动细菌鉴定系统对病原菌进行鉴定,用K-B法进行药敏试验。结果428例AD患者并发细菌感染185例,感染率43.5%,例次感染率66.6%;共分离出病原菌285株,其中G+球菌86株(30.2%);MRSA和MRCNS分别占63.6%和70%;G-杆菌148株(51.9%);ESBLs的检出率分别为29.0%和30.8%;真菌43株(15.1%);结核杆菌8株(2.8%);万古霉素、替考拉宁对MRSA和MRCNS的抗菌活性高;粪肠球菌对替考拉宁、万古霉素、青霉素及氨苄西林等敏感性高;屎肠球菌仅对替考拉宁和万古霉素敏感;G-杆菌对亚胺培南、美罗培南及头孢哌酮/舒巴坦的耐药率最低;白色念珠菌对氟康唑、两性霉素B、制霉菌素及5-氟胞嘧啶的耐药率较低。结论AD患者并发细菌感染的临床表现无特异性,细菌谱及耐药性监测对控制细菌感染有重要意义,应尽早在药敏试验结果指导下进行抗感染治疗。

26株无芽胞厌氧菌分离

近年来,对厌氧菌的研究日趋深入,尤其对无芽胞厌氧菌的研究。细菌培养技术的提高以及抗生素的广泛应用,使患者免疫力下降。

Immunoproteome analysis of soluble and membrane proteins of Shigella flexneri 2457T

AIM: To profile the immunogenic proteins of Shigella flexneri (S. flexneri) expressed during human infection using a proteomic approach. METHODS: Soluble and membrane protein extractions of S. flexneri 2457T were separated by two-dimensional gel electrophoresis (2-DE). Proteins were transferred to PVDF membrane and immunoblotted with sera from shigellosis patients. Reactive protein spots were matched to Coomassie stained gels run in parallel, cut out and trypsin digested. Matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS) was used to determine the peptide mass fingerprints, which were searched in the MASCOT database to identify the protein. RESULTS: A total of 8 immunoreactive proteins were successfully identified from the Coomassie stained gels in three repeats. Six of these proteins have not previously been reported as immunogenic in S. flexneri. These proteins could be potential candidates for vaccine or attenuation studies. CONCLUSION: Soluble and membrane proteins of S. flexneri 2457T have been screened by 2-DE and immunoblotting with sera from shigellosis patients. Eight proteins are identified as immunogenic.

Third-line rescue therapy for Helicobacter pylori infection

H pylori gastric infection is one of the most prevalent infectious diseases worldwide. The discovery that most upper gastrointestinal diseases are related to Hpylori infection and therefore can be treated with antibiotics is an important medical advance. Currently, a first-line triple therapy based on proton pump inhibitor （PPI） or ranitidine bismuth citrate （RBC） plus two antibiotics （darithromycin and amoxicillin or nitroimidazole） is recommended by all consensus conferences and guidelines. Even with the correct use of this drug combination, infection can not be eradicated in up to 23% of patients. Therefore, several second line therapies have been recommended. A 7 d quadruple therapy based on PPI, bismuth, tetracycline and metronidazole is the more frequently accepted. However, with second-line therapy, bacterial eradication may fail in up to 40% of cases. When Hpylori eradication is striclly indicated the choice of further treatment is controversial. Currently, a standard third-line therapy is lacking and various protocols have been proposed. Even after two consecutive failures, the most recent literature data have demonsbated that Hpylori eradication can be achieved in almost all patients, even when antibiotic susceptibility is not tested. Different possibilities of empirical treatment exist and the available third-line strategies are herein reviewed.

Association of H pylori cagA and vacA genotypes and IL-8 gene polymorphisms with clinical outcome of infection in Iranian patients with gastrointestinal diseases

AIM： To find out if a functional promoter polymorphism in the IL-8 gene along with cagA status and polymorphisms in vacA gene influence the type of diseases in Iranian patients infected by Hpylori. METHODS： IL-8 -251 A/T polymorphism was genotyped by oligonucleotide allele specific PCR （ASO-PCR） in a sample of 233 patients with Hpylori infection undergoing upper gastrointestinal endoscopy. The presence of cagA gene and polymorphisms in vacA gene was also determined by PCR. Association of these genetic polymorphisms with the development of gastritis, peptic ulcers as well as gastric cancer was tested. RESULTS： When the patients with different clinical manifestations were compared according to the presence of cagA gene or various vacA genotypes, only the vacA genotypes were significantly different among gastritis, peptic ulcer and gastric cancer patients （χ^2= 17.8; P=0.001）. Furthermore, there was a significant difference in the frequency of IL-8 -251 A/T genotypes between patients with gastric cancer and benign diseases （χ^2=10.47;P=0.005） CONCLUSION： The IL-8 -251 A/T polymorphism and the polymorphisms in H pylor/ vacA gene are involved in limiting the infection outcome to gastritis and peptic ulcer or in favoring cancer onset in Iranian patients.

Role of dup A in virulence of Helicobacter pylori

Helicobacter pylori(H. pylori) is a gastric human pathogen associated with acute and chronic gastritis, 70% of all gastric ulcers, 85% of all duodenal ulcers, and both forms of stomach cancer, mucosal-associated lymphoid tissue(MALT) lymphoma and adenocarcinoma. Recently, attention has focused on possible relationship between presence of certain virulence factor and H. pylori-associated diseases. Some contradictory data between this bacterium and related disorders has been observed since not all the colonized individuals develop to severe disease. The reported diseases plausibility related to H. pylori specific virulence factors became an interesting story about this organism. Although a number of putative virulence factors have been identified including cytotoxin-associated gene a(cag A) and vac A, there are conflicting data about their actual participation as specific risk factor for H. pylori-related diseases. Duodenal ulcer promoting gene a(dup A) is a virulence factor of H. pylori that is highly associated with duodenal ulcer development and reduced risk of gastric cancer. The prevalence of dup A in H. pylori strains isolated from western countries is relatively higher than in H. pylori strains from Asian countries. Current confusing epidemiological reports will continue unless future sophisticated and molecular studies provide data on functional and complete dup A cluster in H. pylori infected individuals. This paper elucidates available knowledge concerning role of dup A in virulence of H. pylori after a decade of its discovery.

Human β-defensin-3 induction in H pylori-infected gastric mucosal tissues

AIM: To examine human β-defensin-3 (hBD-3) expression in inflamed gastric mucosal tissues or MKN45 gastric cancer cells with or without H pylori infection for better understanding the innate immune response to H pylori. METHODS: We used reverse transcription-polymerase chain reactions and immunohistochemistry to examine hBD-3 expression in inflamed gastric mucosal tissues or MKN45 gastric cancer cells with or without H pylori. Effects of hBD-3 against H pylori were also evaluated. RESULTS: The mean mRNA expression of hBD-3 in H pylori -positive specimens was significantly higher than that in H pylori-negative specimens (P = 0.0002, Mann-Whitney). In addition, unlike uninfected samples, 8 of 15 (53.33%) infected mucosal samples expressed hBD-3 protein. H pylori dose-dependently induced mRNA expression of hBD-3 in MKN45 cells, an effect inhibited by adding anti-toll-like receptor (TLR)-4 antibody. HBD-3 protein completely inhibited H pylori growth. CONCLUSION: Our results suggest that like hBD-2, hBD-3 may be involved in the pathophysiology of H pylori-induced gastritis.

H pylori infection and reflux oesophagitis: A case-control study

AIM： To examine the relationship between Hpylori and gastro-oesophageal reflux disease （GORD） in Iran. METHODS： In this study 51 GORD patients （referred to endoscopy at Taleghani hospital） were compared with 49 age-sex matched controls. Diagnosis of H pylori was made by gastric mucosal biopsy and rapid urease test （positive if the result of one or both diagnostic methods was positive）. Updated Sydney system was used to report histopathological changes. RESULTS： The frequency of H pylori infection based on rapid urease test and histology was 88.2% （45） in patients and 77.6% （38） in controls, which showed no significant difference. The frequency of H pylori infection was significantly higher in the antrum than in the corpus and cardia. The mean activity, inflammation, and gastritis scores were also higher in the antrum of patients than in the antrum of controls. The mean scores were significantly higher in the corpus of controls than in the corpus of patients. Diffuse active gastritis was observed in a significantly larger number of controls, while the frequency of diffuse chronic gastritis was higher in patients. There in the frequency of other patients and controls. was no significant difference histological findings between.CONCLUSION： H pylori infection cannot prevent GORD in this region.