多聚酶链反应在细菌感染性疾病病原诊断中的应用

近年来,利用检测基因组中专一DNA序列进行遗传性疾病、肿瘤及感染性疾病的诊断日益增多,产生了一门新的学科分支——DNA诊断学。多聚酶链反应(PCR)技术以其操作简便、敏感性好、特异性强、快速等优点而广泛地应用于DNA诊断学,本文扼要阐述了PCR技术在细菌感染性疾病病原诊断中的应用。

血清C反应蛋白、降钙素原检测在血液病合并细菌感染中的诊断效果分析

目的研究血清C反应蛋白(CRP)、降钙素原(PCT)在检测血液病合并细菌感染中的效果。方法2015年1月-2019年6月期间选择我院80例血液病患者,合并细菌感染与非感染各40例,对两组分别采用CRP、PCT进行检测,研究此次检测的准确性、敏感性、特异性。结果经治疗后,PCT在血液病患者中的检测诊断准确性、敏感性、特异性均较CRP高,数据对比有统计学差异,P<0.05。结论PCT和CRP对血液病合并细菌感染的检测均有一定成效,但PCT的诊断效果更好,有应用价值。

克林霉素磷酸酯阴道凝胶与奥硝唑栓联用对细菌感染性阴道病患者的疗效与安全性评价

目的:评价克林霉素磷酸酯阴道凝胶与奥硝唑栓联用对细菌感染性阴道病患者的疗效与安全性。方法:选取2014年7月—2017年7月期间收治的细菌感染性阴道病患者108例资料,采用抽签法将其分为对照组与观察组(每组54例);对照组患者给予奥硝唑栓治疗,观察组患者在对照组基础上加用克林霉素磷酸酯阴道凝胶治疗,比较两组患者治疗后的总有效率和治疗期间不良反应的发生率及随访治疗后6月的复发率差异。结果:观察组患者治疗后的总有效率为92.59%高于对照组为75.93%(P<0.05),治疗期间不良反应的发生率为11.11%略高于对照组为7.41%,但经组间比较其差异无统计学意义(P>0.05),随访治疗后6月的复发率为3.70%低于对照组为16.67%(P<0.05)。结论:克林霉素磷酸酯阴道凝胶与奥硝唑栓联用治疗细菌感染性阴道病患者的疗效较为确切,且复发率较低。

口服酪酸梭菌散剂联合蒙脱石散治疗非细菌感染性婴幼儿腹泻的临床观察

目的观察口服酪酸梭菌散剂联合蒙脱石散治疗非细菌感染性婴幼儿腹泻的临床疗效。方法设口服酪酸梭菌散剂联合蒙脱石散治疗组和对照组,比较治疗后两组疗效。结果口服酪酸梭菌散剂联合蒙脱石散治疗组总有效率与对照组无显著差异(P>0.05)。口服酪酸梭菌散剂联合蒙脱石散治疗组显效率增加显著(P<0.01),腹泻时间、及恢复时间均比对照组明显缩短(P<0.01)。结论口服酪酸梭菌散剂联合蒙脱石散治疗非细菌感染性婴幼儿腹泻疗效显著。

阴道微环境与人乳头瘤病毒感染相关性的研究进展

近年,宫颈癌的发病率不但无下降趋势,而且发病年纪日趋年轻化,所以对于宫颈癌的预防不可忽略,早期的筛查和对宫颈癌前病变的干预可以使宫颈癌的发生率降低。宫颈癌及癌前病变的致病因素有很多,主要的致病原因是人乳头瘤病毒(HPV)感染,尤其是高危型人乳头瘤病毒(HP-HPV)的持续感染。对于人乳头瘤病毒感染,阴道微环境的改变与其有一定的相关性,本文对阴道微环境与人乳头瘤病毒(HPV)感染相关性的研究进展进行综述。

乙型肝炎肝硬化患者细菌感染诱发肝性脑病的临床治疗效果评价

探讨在为细菌感染诱发肝性脑病的乙型肝炎硬化患者治疗时联合应用恩替卡韦与阿德福韦酯的临床疗效。方法 选择我院2018年2月到2019年2月之间62名乙肝病毒感染致肝性脑病的病例,采用随机抽样方法,平均分配为两组,每组31名。阿德福韦酯用于对照组组,实验组则是在对照组基础上联合应用恩替卡韦进行治疗,实验组的治愈率为90.32%,实验组的疗效显著优于对照组的51.61%。结果 实验组疗效显著优于对照组(P<0.05)。结论 将恩替卡韦和阿德福韦酯结合用于乙肝硬化症引起的 HBV,临床治疗效果更明显。

Latest insights into the effects of Helicobacter pylori infection on gastric carcinogenesis

There appears to be the strong association between Helicobacter pylori （H pylori） and gastric cancer. We reviewed the latest evidences about the effects of H pylori infection on gastric carcinogenesis, classified into epidemiology, dynamics of gastric mucosal changes, DNA damages, virulence factors, host factors, and source of gastric malignancy. Through the considerable progress made in research into virulence factors resulting from differences between Hpylori strains, such as cagA positivity, as well as into host factors, such as gene polymorphisms, a diverse spectrum of H pyloriassociated diseases, including gastric cancer, is beginning to lend itself to elucidation. The impact of the novel hypothesis advanced by Houghton et al proposing bonemarrow derived stem cells （BMDC） as a potential source of gastric malignancy on evolving research remains to be seen with interest. Further progress in research into H pylori eradication as a viable prophylaxis of gastric cancer, as well as into the mechanisms of gastric carcinogenesis, is to be eagerly awaited for the current year and beyond.

Pathophysiology of increased intestinal permeability in obstructive jaundice

Despite advances in preoperative evaluation and postoperative care, intervention, especially surgery, for relief of obstructive jaundice still carries high morbidity and mortality rates, mainly due to sepsis and renal dysfunction. The key event in the pathophysiology of obstructive jaundice-associated complications is endotoxemia of gut origin because of intestinal barrier failure. This breakage of the gut barrier in obstructive jaundice is multi-factorial, involving disruption of the immunologic, biological and mechanical barrier. Experimental and clinical studies have shown that obstructive jaundice results in increased intestinal permeability. The mechanisms implicated in this phenomenon remain unresolved, but growing research interest during the last decade has shed light in our knowledge in the field. This review summarizes the current concepts in the pathophysiology of obstructive jaundice-induced gut barrier dysfunction, analyzing pivotal factors, such as altered intestinal tight junctions expression, oxidative stress and imbalance of enterocyte proliferation and apoptosis. Clinicians handling patients with obstructive jaundice should not neglect protecting the intestinal barrier function before, during and after intervention for the relief of this condition, which may improve their patients’ outcome.

H pylori recurrence after successful eradication

Recurrence of H pylori after eradication is rare in developed countries and more frequent in developing countries. Recrudescence (recolonization of the same strain within 12 mo after eradication) rather than reinfection (colonization with a new strain, more than 12 mo after eradication) is considered to be responsible for most of the cases. This observation was confirmed only in developed countries, while in developing countries a recent meta-analysis demonstrated a high rate of reinfection. The proportion of H pylori annual recurrence was 2.67% and 13.00% in developed and developing countries, respectively. Nested meta-analysis (only cases with a longer follow-up and a negative 13CUBT a year after eradication) revealed annual recurrence rate of 1.45% [relative risk (RR), 0.54] and 12.00% (RR, 0.92) in developed and developing countries, respectively. These findings support the notion that in developed countries many cases of recurrence are due to recrudescence within the first year after eradication, with a 46% drop in the recurrence rate after the first year post eradication, while in developing countries reinfection is more pronounced, and continue at the same rate since eradication. A different approach for follow-up after H pylori eradication is probably needed in patients of developing countries, since reinfection is highly prevalent.

H pylori and host interactions that influence pathogenesis

H py/ori is probably the most prevalent human pathogen worldwide. Since it was initially suggested in 1983 by Marshall and Warren to be implicated in gastritis and peptic ulcer disease, H pylori has also been implicated in gastric carcinoma and was classified as a class I carcinogen. In the last two decades, a noteworthy body of research has revealed the multiple processes that this gram negative bacterium activates to cause gastroduodenal disease in humans. Most infections are acquired early in life and may persist for the life of the individual. While infected individuals mount an inflammatory response that becomes chronic, along with a detectable adaptive immune response, these responses are ineffective in clearing the infection. Hpylori has unique features that allow it to reside within the harsh conditions of the gastric environment, and also to evade the host immune response. In this review, we discuss the various virulence factors expressed by this bacterium and how they interact with the host epithelium to influence pathogenesis.

Gut flora and bacterial translocation in chronic liver disease

Increasing evidence suggests that derangement of gut flora is of substantial dinical relevance to patients with cirrhosis. Intestinal bacterial overgrowth and increased bacterial translocation of gut flora from the intestinal lumen, in particular, predispose to an increased potential for bacterial infection in this group. Recent studies suggest that, in addition to their role in the pathogenesis of overt infective episodes and the clinical consequences of sepsis, gut flora contributes to the pro-inflammatory state of cirrhosis even in the absence of overt infection. Furthermore, manipulation of gut flora to augment the intestinal content of lactic acid-type bacteria at the expense of other gut flora species with more pathogenic potential may favourably influence liver function in cirrhotic patients. Here we review current concepts of the various inter-relationships between gut flora, bacterial translocation, bacterial infection, pro-inflammatory cytokine production and liver function in this group.

Causal role of Helicobacter pylori infection and eradication therapy in gastric carcinogenesis

Many epidemiological reports indicate that Helicobacter pylori （H pylori） infection plays an important role in gastric carcinogenesis. Several genetic and epigenetic alterations contribute to the initiation, promotion, and progression of the cancer cells in a multi-step manner. H pylori is known to induce chronic inflammation in the gastric mucosa. Its products, including superoxides, participate in the DNA damage followed by initiation, and the inflammation-derived cytokines and growth factors contribute to the promotion of gastric carcinogenesis. By eradicating H pylori, gastric inflammation can be cured; the therapy diminishes the levels not only of inflammatory cell infiltration, but also atrophy/ intestinal metaplasia in part. A randomized controlled trial revealed that the eradication therapy diminished the gastric cancer prevalence in cases without precancerous conditions. In addition, recent epidemiological studies from Japanese groups demonstrated that the development of gastric cancer, especially of the intestinal type, was decreased by successful eradication therapy, although these were designed in a non- randomized manner. However, it should be mentioned that endoscopic detection is the only way to evaluate the degree of gastric carcinogenesis. We have reported that the endoscopic and histological morphologies could be modified by eradication therapy and it might contribute to the prevalence of gastric cancer development. Considering the biological nature of cancer cell proliferation, it is considered that a sufficiently long-term follow-up would be essential to discuss the anticancer effect of eradication therapy.

Effects of Helicobacter pylori infection on gastric epithelial cell kinetics in patients with chronic renal failure

AIM： To evaluate the effects of Helicobacter pylori infection on gastric epithelial cell kinetics in patients with chronic renal failure （CRF）. METHODS： Forty-four patients were enrolled in this study and divided into four groups with respect to their Helicobacter pylori （H pylori） and CRF status. Groups were labeled as follows： la： normal renal function, H pylori negative （n = 12）, lb： normal renal function, H pylori positive （n = 11）, 2a： CRF, H pylori negative （n = 10）, 2b： CRF, H pylori positive （n = 11）. Upper gastrointestinal endoscopy was done in all the patients involved in the study. During endoscopical investigation, antral biopsy specimens were taken from each patient. In order to evaluate the cell apoptosis and proliferation in gastric epithelial cells, Bax and proliferating cell nuclear antigen （PCNA） labeling indexes （LI） were assessed with immunohistochemical staining method. RESULTS： For groups la, lb, 2a, and 2b, mean Bax LI was identified as 34.4±13.7, 44.1±16.5, 46.3±20.5, 60.7±13.8, respectively and mean PCNA LI was identified as 36.2±17.2, 53.6±25.6, 59.5±25.6, 67.2±22, respectively. When the one-way ANOVA test was applied, statistically significant differences were detected between the groups for both Bax LI （P = 0.004 〈0.01） and PCNA LI （P = 0.009 〈0.01）. When groups were compared further in terms of Bax LI and PCNA LI with Tukey＇s HSD test for multiple pairwise comparisons, statistically significant difference was observed only between groups la and 2b （P = 0.006 〈0.01）.CONCLUSION： In gastric epithelial cells, expression of both the pre-apoptotic protein Bax and the proliferation marker PCNA increase with H pylori infection. This increase is more evident in patients with uremia. These findings suggest that uremia accelerates apoptosis and proliferation in gastric epithelial cells.

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.

Lethal effect and apoptotic DNA fragmentation in response of D-GalN-treated mice to bacterial LPS can be suppressed by pre-exposure to minute amount of bacterial LPS: Dual role of TNF receptor 1

AIM: To investigate whether induction of tolerance of mice to lipopolysaccharide (LPS) was able to inhibit apoptotic reaction in terms of characteristic DNA fragmentation and protect mice from lethal effect. METHODS: Experimental groups of mice were pretreated with non-lethal amount of LPS (0.05 μg). Both control and experimental groups simultaneously were challenged with LPS plus D-GaIN for 6-7 h. The evaluations of both DNA fragmentations from the livers and the protection efficacy against lethality to mice through induction of tolerance to LPS were conducted. RESULTS: In the naive mice challenge with LPS plus D-GaIN resulted in complete death in 24 h, whereas a characteristic apoptotic DNA fragmentation was exclusively seen in the livers of mice receiving LPS in combination with D-GaIN. The mortality in the affected mice was closely correlated to the onset of DNA fragmentation. By contrast, in the mice pre-exposed to LPS, both lethal effect and apoptotic DNA fragmentation were suppressed when challenged with LPS/D-GalN. In addition to LPS, the induction of mouse tolerance to TNF also enabled mice to cross-react against death and apoptotic DNA fragmentation when challenged with TNF and/or LPS in the presence of D-GaIN. Moreover, this protection effect by LPS could last up to 24 h. TNFR1 rather than TNFR2 played a dual role in signaling pathway of either induction of tolerance to LPS for the protection of mice from mortality or inducing morbidity leading to the death of mice. CONCLUSION: The mortality of D-GalN-treated mice in response to LPS was exceedingly correlated to the onset of apoptosis in the liver, which can be effectively suppressed by brief exposure of mice to a minute amount of LPS. The induced tolerance status was mediated not only by LPS but also by TNF. The developed tolerance to either LPS or TNF can be reciprocally cross-reacted between LPS and TNF challenges, whereas the signaling of induction of tolerance and promotion of apoptosis was through TNFR1, rather than TNFR2.

Lymphocytic colitis: A clue to bacterial etiology

AIM： To find out the role of bacteria as a possible etiological factor in lymphocytic colitis. METHODS： Twenty patients with histopathological diagnosis of lymphocytic colitis and 10 normal controls were included in this study. Colonoscopic biopsies were obtained from three sites （hepatic and splenic flexures and rectosigmoid region）. Each biopsy was divided into two parts. A fresh part was incubated on special cultures for bacterial growth. The other part was used for the preparation of histologic tissue sections that were examined for the presence of bacteria with the help of Giemsa stain. RESULTS： Culture of tissue biopsies revealed bacterial growth in 18 out of 20 patients with lymphocytic colitis mostly Escherichia coil （14/18）, which was found in all rectosigmoid specimens （14/14）, but only in 8/14 and 6/14 of splenic and hepatic flexure specimens respectively. In two of these cases, E coli was associated with proteus. Proteus was found only in one case, Klebsiella in two cases, and Staphylococcus aureus in one case. In the control group, only 2 out of 10 controls showed the growth of E coli in their biopsy cultures. Histopathology showed rod-shaped bacilli in the tissue sections of 12 out of 14 cases with positive E coli in their specimen＇s culture. None of the controls showed these bacteria in histopathological sections. CONCLUSION： This preliminary study reports an association between E coli and lymphocytic colitis, based on histological and culture observations. Serotyping and molecular studies are in process to assess the role of E coli in the pathogenesis of lymphocytic colitis.

Drug utilization of clarithromycin for gastrointestinal disease treatment

AIM： To evaluate the patterns of use of clarithromycin for gastrointestinal disease treatment and promote its rational use.METHODS： Using a structured pro forma, we conducted a two-month survey of the electronic prescriptions containing immediate-release （IR） or sustained-release （SR） product of clarithromycin for outpatients with gastrointestinal diseases in a 2200-bed general hospital. Suitability of the prescription was audited retrospectively. RESULTS： One hundred and sixty-four prescriptions of SR product and 110 prescriptions of IR product were prescribed for gastrointestinal disease treatment. Among prescriptions for anti-Helicobacter pylori （H pylori） therapy, triple therapy take the dominant position （91.8%）, followed by quadruple therapy （4.3%） and dual therapy （3.9%）. Amoxicillin was the most frequently co-prescribed antibiotic.Furazolidone and levofloxacin are used more widely than metronidazole or tinidazole. Clarithromycin SR was administered at inappropriate time points in all prescriptions. Fifty percent of all prescriptions of clarithromycin SR, and 6.4% of prescriptions of clarithromycin IR, were prescribed at inappropriate dosing intervals. Surprisingly, disconcordance between diagnoses and indications was observed in all prescriptions of clarithromycin SR which has not been approved for treating Hpy/ori infection although off-label use for this purpose was reported in literature. On the contrary, only one prescription （0.9%） of clarithromycin IR was prescribed for unapproved indication （i.e. gastro-oesophageal reflux disease）. 1.4% of prescriptions for chronic gastritis or peptic ulcer treatment were irrational in that clarithromycin was not co-prescribed with gastric acid inhibitors. Clinical significant CYP3A based drug interactions with clarithromycin were identified. CONCLUSION： There is a great scope to improve the quality of clarithromycin prescribing in patients with gastrointestinal disease, especially with regard to administration schedule, concordance between indications and diagnoses and management of drug interactions.

Evaluation of the role of H pylori infection in pathogenesis of gastric cancer by immunoblot assay

AIM： To elucidate the different serological reactions to H pylori using the immunoblotting technique for further understanding of its pathogenic role in gastric cancer. METHODS： A total of 54 patients were divided into two groups after upper gastrointestinal endoscopy： normal control group （25 patients） and gastric cancer group （29 patients）. Both groups were further divided into Hpylori （＋） and H pylori （-） subgroups based on the results of CLO test, Giemsa staining and culture. Sera were further analyzed with the immunoblotting technique （HelicoBIot 2.0, Genelabs Diagnostics, Singapore）. RESULTS： The positive rate of the immunoblotting test was as high as 88.9% in the H pylori （-） gastric cancer group and only 14.3% in the H pylori （-） normal control group with a statistically significant difference. CONCLUSION： The prevalence of H pylori infection is higher in gastric cancer patients than in the normal controls, suggesting that H pylori may play a role in the pathogenesis of gastric cancer.

Effects of probiotic bacteria on gastrointestinal motility in guinea-pig isolated tissue

AIM: To evaluate the intestinal motility changes evoked by 8 bacterial strains belonging to Bifidobacterium , Lactobacillus and Streptococcus genera within the probiotic preparation VSL#3. METHODS: Ileum and proximal colon segments isolated from guinea-pigs were used as a study model. Entire cells and cell fractions (cell debris, cell wall fraction, cytoplasmatic fraction, proteinaceous and non- proteinaceous cytoplasmatic components) of VSL#3 strains and, as controls, Escherichia coli, Salmonella aboni and Bacillus licheniformis were tested in this in vitro model. RESULTS: Among the bacterial cell fractions tested, only the cytoplasmatic fraction modified intestinal motility. Lactobacillus strains stimulated the contraction of ileum segment, whereas all probiotic strains tested induced proximal colon relaxation response. The non-proteinaceous cytoplasmatic components were responsible for the colon relaxation. CONCLUSION: The results obtained in this study suggest that the proximal colon relaxation activity showed by the probiotic bacteria could be one of the possible mechanisms of action by which probiotics exert their positive effects in regulating intestinal motility.