Regional dissemination of Salmonella enterica serovar Enteritidis is season dependent

Objective  To carry out epidemiological typing of clinical isolates of Salmonella enterica serovar Enteritidis by pulsed-field gel electrophoresis (PFGE), random amplified polymorphic DNA (RAPD) and analysis of their antibiotic resistance.
Methods  Over a 12-month period, 44 Salmonella Enteritidis isolates, recovered from 40 patients admitted to the University Hospital Center of Amiens, France and from three outpatients, were characterized by the analysis of phenotypic and genotypic traits and clinical data from medical reports.
Results  Forty nontyphoidal salmonellosis episodes were diagnosed in hospitalized patients (34 episodes of gastroenteritis, two episodes of bacteremia not affecting other organs, one episodes of bacteremia plus urinary infection, one episodes of bacteremia plus gastroenteritis, one episodes of chronic colitis plus gastroenteritis and one episode of peritonitis), and three carriers were observed in outpatients. By means of PFGE, RAPD and antibiotic susceptibility patterns 44 isolates were subdivided into 16 clonally related groups. Two of them were predominantly implicated in the course of these infections, being responsible for two successive waves of infection, while the others were encountered sporadically.     

Salmonella enterica serotype Virchow: epidemiology, resistance patterns and molecular characterisation of an invasive Salmonella serotype in Israel

This study outlines the unique epidemiology of Salmonella enterica serotype Virchow in Israel. Between 1997 and 2002, the overall incidence of non-typhoid Salmonella enterica (NTS) decreased from 69.3 to 53.3 infections/100,000 population, but the incidence of S. Virchow increased (from 7.2 to 9.1 infections/100,000). Since 2000, S. Virchow has become the second-ranking NTS isolate, accounting for 17% and 27% of all stool and blood NTS isolates, respectively. Infants aged < 1 year had the highest incidence of isolation from stools (92.8/100,000). The incidence of isolation from blood was highest for infants aged <1 year (4.4/100,000). Only 6% of isolates were susceptible to all ten antibiotic agents tested; 34% were resistant to one agent, 54% to one to three agents, and 40% to four to six agents. A high proportion of the tested isolates were resistant to nalidixic acid (89%), streptomycin (56%), tetracycline (43%), trimethoprim-sulphamethoxazole (38%) and chloramphenicol (28%), but none to ciprofloxacin or ceftriaxone. Pulsed-field gel electrophoresis revealed two closely related clusters, each containing a predominant pulsotype. Coupled with its invasive propensity, the increasing incidence of highly resistant S. Virchow in Israel is of real concern. Future research should focus on the sources of S. Virchow in the food chain in order to institute effective control measures.     

Characterisation of the first CTX-M-10-producing isolate of Salmonella enterica serotype Virchow

Microbiological analysis of a urine sample from an outpatient with symptoms of urinary infection detected >10(5) CFU/mL urine of Salmonella enterica serotype Virchow with resistance to cefotaxime. Molecular analysis demonstrated the presence of the gene encoding CTX-M-10 beta-lactamase in this clinical isolate. This is the first report of this enzyme in Salmonella spp.     

萘啶酸抗性甲型副伤寒病原菌的克隆扩散和遗传多样性

目的 认识肠沙门菌甲型副伤寒血清型(SPA)的克隆扩散和遗传多样性,建立并确定病原菌流行克隆的分型方法.方法 采用有对照的K-B纸片扩散技术对分离的3980株SPA进行抗微生物药物敏感性试验;经PCR扩增和基因测序检测15个萘啶酸抗性菌株喹诺酮抗性决定区的gyrA、gyrB、syrC和syrE基因;采用Spe Ⅰ和Xba Ⅰ消化染色体DNA脉冲场凝胶电泳(PFGE)对来自7个县的121个分离株进行分型和聚类分析.结果 萘啶酸敏感菌株在1999年占有优势,但2000年以后被萘啶酸抗性菌株替代;15个萘啶酸抗性菌株的PCR扩增和基因测序显示抗性机制是由gyrA基因的单点突变引起;121个菌株spe Ⅰ和Xba Ⅰ消化产物分别得出以Spe Ⅰ 01、spe Ⅰ 02或Xba Ⅰ 01型占优势的5种和4种PFGE型,Spe Ⅰ 01和Spe Ⅰ 02分别占37.2%和57.9%,或Xhn Ⅰ 01占95.0%.结论 在研究期间SPA分离株萘啶酸抗性率上升;PFGE型的SpeⅠ01和SpeⅠ 02或XbaⅠ01是玉溪流行的主要克隆;采用Spe Ⅰ和Xba Ⅰ的PFGE是鉴别SPA的一项有用技术.     

Evaluation of a selected lactic acid bacteria-based probiotic on Salmonella enterica serovar Enteritidis colonization and intestinal permeability in broiler chickens

Two experiments were conducted to evaluate the effect of a lactic acid bacteria-based probiotic (FloraMax-B11^®) against Salmonella enterica serovar Enteritidis intestinal colonization and intestinal permeability in broiler chickens. Experiment 1 consisted of two independent trials. In each trial, day-old broiler chicks were assigned to one of two groups: control?+?S. Enteritidis or probiotic?+?S. Enteritidis. At 72?h post-S. Enteritidis challenge, haematology and caecal content were evaluated for S. Enteritidis colonization. In Experiment 2, day-old broiler chicks were assigned to one of four groups: negative control; probiotic; control?+?S. Enteritidis; or probiotic?+?S. Enteritidis. At 72?h post-S. Enteritidis challenge, chickens in all groups were given an oral gavage dose of fluorescein isothiocyanate dextran (FITC-d). In both trials of Experiment 1, a significant reduction (P?S. Enteritidis in caecal content and a reduction in the incidence of S. Enteritidis enriched caecal samples were observed in probiotic?+?S. Enteritidis chickens. In addition, significant heterophilia and lymphopaenia were observed in control?+?S. Enteritidis chickens. In Experiment 2, a decrease in numbers of S. Enteritidis in caeca were observed in probiotic?+?S. Enteritidis chickens when compared to control?+?S. Enteritidis. Also, an increase in serum FITC-d concentration was detected in control?+?S. Enteritidis. These results suggest that early infection with S. Enteritidis can increase intestinal permeability, but the adverse effects can be prevented by the administration of the probiotic tested.     

Leukocytic response and composition of enteral microbiota in chickens fed a sage extract supplemented diet and infected with Salmonella Enteritidis PT4

The effects of sage on the enteral microbiota and leukocytic response of chickens challenged with Salmonella Enteritidis (SE) PT4 were studied. Chickens were divided into four groups: control, sage (S), SE and sage+S. Enteritidis (SSE). Groups S and SSE were fed sage extract (8.2 g kg^?1) for 21 days. Groups SE and SSE were challenged with SE (10⁸ CFU) on day 4. The administration of the sage extract to the SSE group confirmed the selective antibacterial activity on SE, and resulted in an increased number of leukocytes, lymphocytes, heterophils and phagocytic activity index at day 3 post-infection. In the early phase of the infection, there was a tendency to increase the numbers of CD3+, CD8+ and IgM+ cells in the SSE group. The later phase led to a decrease of IgM+, CD3+ and CD4+ cells, but an increase in influx of macrophages, which suggested their movement into inflammatory regions.     

Flagella-mediated bacterial motility accelerates but is not required for Salmonella serotype Enteritidis invasion of differentiated Caco-2 cells

The relative contributions of the flagellum and the flagella-associated bacterial motility in the invasion of Caco-2 cells by Salmonella serotype Enteritidis were investigated using an fliC mutant defective in flagellin production and a motA mutant that carries flagella but is non-motile. Infection assays demonstrated that, at 1 h of infection, both the fliC and the motA mutants were severely impaired in bacterial invasion compared to the parental strain. Infection assays at 3 h infection demonstrated virtually equal invasion levels for both non-motile mutants and the parental strain. Together these data suggest that flagella-mediated bacterial motility accelerates the invasion of Salmonella but is not required for the invasion event per se.     

Determination of in vivo toxicity and in vitro cytotoxicity of lipopolysaccharide isolated from Salmonella Enteritidis and its potential use for production of polyclonal antibody

In the present study, the effects of lipopolysaccharide (LPS) isolated from Salmonella Enteritidis were investigated by in vivo and in vitro methods. The mean lethal dose of 50% death (LD₅₀) was determined by a Probit test as 450-µg/mouse after 72 h post-treatment of LPS. Madin–Darby bovine kidney (MDBK), baby hamster kidney (BHK), mouse fibroblastic cell-lines (L929), and hybridoma cell lines were treated with different amounts of LPS (0–100 µg/ml) cultivated for 72 h in 24 well tissue culture plates. Morphological investigation was done with inverted microscope after Giemsa staining. The results suggested that MDBK, BHK, and L929 cell lines were resistant to LPS cytotoxicity due to lack of the specific membrane receptor unlike hybridoma cells. After immunisation, one priming and seven booster's diluted sera (1:100) antibody level was found to be 2.00 ± 0.06–2.41 ± 0.07 optical density (OD) by enzyme linked immunosorbent assay (ELISA) on day 142. This result indicated that the LPS, instead of whole bacteria, have potential application in the immunisation.     

血管细胞黏附分子-1增强人脑胶质瘤细胞系迁移和侵袭能力

目的探讨血管细胞黏附分子-1(VCAM-1)在脑胶质瘤细胞迁移侵袭能力中作用。方法用慢病毒p SGU6/GFP/Neo介导VCAM-1的shRNA、慢病毒EF1a-GFP/puro介导VCAM-1过表达载体、划痕迁移、Transwell侵袭、蛋白免疫印迹(Western blot)和细胞染色等实验技术和方法,观察了VCAM-1蛋白表达水平对人脑胶质瘤T98G和U251细胞系细胞迁移和侵袭能力的影响。其中,T98G细胞分为空白对照组、空载体对照组、乱序对照组和实验组(抑制VCAM-1蛋白表达水平组),U251细胞分为空白对照组、空载体对照组和实验组(过表达VCAM-1组),每组6个复孔。结果首先利用慢病毒介导VCAM-1的shRNA和过表达载体建立了稳定低表达VCAM-1的T98G细胞和稳定过表达VCAM-1的U251细胞。稳定低表达VCAM-1的T98G细胞划痕恢复能力(迁移能力)明显减弱(P0.01);而稳定过表达VCAM-1的U251细胞迁移能力明显提高(P0.05)。同样,稳定低表达VCAM-1的T98G细胞侵袭能力显著减弱(P0.05);而稳定过表达VCAM-1的U251细胞侵袭能力明显增强(P0.01)。结论VCAM-1可显著增强人脑胶质瘤细胞系细胞的迁移和侵袭能力。     

敲除EZH2抑制人宫颈癌细胞系迁移和侵袭

目的 研究zeste基因同源蛋白2(EZH2)对人宫颈癌细胞系迁移和侵袭的影响,并初步探讨其作用机制.方法 利用CRISPR/Cas9敲除人宫颈癌HeLa和人子宫颈鳞癌SiHa细胞系中EZH2的表达.划痕实验检测细胞迁移;Transwell小室法检测细胞体外迁移和侵袭;实时荧光定量PCR检测STAT3 mRNA水平;W...     

Combination of pulsed-field gel electrophoresis (PFGE) and single-enzyme amplified fragment length polymorphism (SAFLP) for differentiation of multiresistant Salmonella enterica serotype typhimurium

Objective   To assess the combined application of plasmid profile typing, pulsed-field gel electrophoresis (PFGE) and PCR-based single-enzyme amplified fragment length polymorphism ( S AFLP) for the differentiation of 18 multiresistant (MR) and one drug-sensitive strain of Salmonella enterica serotype typhimurium from humans and food animals.
Methods   Strains were phage typed and tested for resistance to a panel of antimicrobial agents. Strains were also tested for the ability to transfer resistance either directly or by mobilization to standard strains of Escherichia coli K12. Plasmid DNA was extracted from both drug-resistant donor strains and from drug-resistant exconjugants. Total genomic DNA was characterized by PFGE following digestion with the restriction endonuclease Xba I. The resultant patterns were categorized and analyzed by dendrogram analysis using the Dice coefficient and by data clustering using unweighted pair-group arithmetic averaging (UPGMA). Isolates were also characterized and categorized by SAFLP. The levels of discrimination achieved by each method were assessed individually and in combination.
Results   Plasmid DNA was detected in all of the 18 MR isolates but, not in the drug-sensitive isolate. Using PFGE, 19 different profiles were identified, falling into eight major categories. However, by SAFLP, only eight profiles were observed. Subsequent investigations have demonstrated epidemiologic relationships within at least one of these SAFLP profile groupings.
Conclusions   These studies have demonstrated that PFGE and SAFLP can be used independently for the differentiation of MR S. Typhimurium from humans and food animals. However, when used in combination, SAFLP can provide a format for broad epidemiologic groupings. These groupings can be further subdivided by PFGE to provide detailed information on putative strain relationships at the genotypic level.     

异丙酚下调PKM2抑制人肺腺癌细胞系增殖、迁移和侵袭

目的探讨异丙酚对肺腺癌细胞增殖、迁移和侵袭的影响。方法 MTT法检测异丙酚(60、100、120μmol/L)处理的人肺腺癌细胞系A549、Anip973的抑制率或增殖;将si-NC组(转染si-NC)、si-PKM2(丙酮酸激酶M2)组(转染si-PKM2)、pc DNA3. 1组(转染pc DNA3. 1)、pc DNA3. 1-PKM2组(转染pc DNA3. 1-PKM2)用脂质体法转染至Anip973细胞,部分组用120μmol/L异丙酚处理;Transwell小室法检测细胞迁移和侵袭;RT-qPCR检测细胞中PKM2的mRNA的表达;Western blot检测细胞中PKM2、E-cadherin、MMP-2的蛋白表达。结果异丙酚(60、100和120μmol/L)呈浓度依赖性抑制人肺腺癌细胞A549、Anip973增殖(P <0. 05),Anip973细胞对异丙酚的敏感性较强,最适浓度为120μmol/L;异丙酚可抑制Anip973细胞迁移和侵袭,并下调PKM2、MMP-2蛋白表达,上调E-cadherin蛋白表达;敲减PKM2具有与异丙酚相同的抑制Anip973细胞的增殖、迁移和侵袭作用,下调MMP-2蛋白表达,上调E-cadherin蛋白表达的作用;过表达PKM2可减轻异丙酚对Anip973细胞增殖、迁移和侵袭及E-cadherin、MMP-2蛋白表达。结论异丙酚可抑制肺腺癌细胞系的增殖、迁移和侵袭,其机制与下调PKM2表达相关。     

Requirement of cyclooxygenase-2 expression and prostaglandins for human prostate cancer cell invasion

The PC-3 Low Invasive cells and the PC-3 High Invasive cells were used to investigate the correlation of the COX-2 expression and its arachidonic acid metabolites, prostaglandins, with their invasiveness through Matrigel using a Boyden chamber assay. The COX-2 expression in PC-3 High Invasive cells was approximately 3-fold higher than in PC-3 Low Invasive cells while the COX-1 expression was similar in both cell sublines. When incubated with arachidonic acid, PGE2 was the major prostaglandin produced by these cells. PC-3 High Invasive cells produced PGE2 approximately 2.5-fold higher than PC-3 Low Invasive cells. PGD2 was the second most abundant prostaglandin produced by these cells. Both indomethacin (a nonspecific COX inhibitor) and NS-398 (a specific COX-2 inhibitor) inhibited the production of prostaglandins and the cell invasion. PGE2 alone did not induce the cell invasion of PC-3 Low Invasive cells. However, PGE2 reversed the inhibition of cell invasion by NS-398 and enhanced the cell invasion of the PC-3 High Invasive cells. In contrast, PGD2 slightly inhibited the cell invasion. These results suggest that in the PC-3 Low Invasive cells, COX-2-derived PGE2 may not be sufficient to induce cell invasion while in the PC-3 High Invasive cells, PGE2 may be sufficient to act as an enhancer for the cell invasion. Further, PGD2 may represent a weak inhibitor and counteracts the effect of PGE2 in the cell invasion.     

Characterization of ''adult-type'' mast cells derived from human bone marrow CD34+ cells cultured in the presence of stem cell factor and interleukin-6. Interleukin-4 is not required for constitutive expression of CD54, FcεRIα and chymase, and CD13 expression is reduced during differentiation

BACKGROUND: In vitro-derived human mast cells exhibit different properties, depending in part on the source of progenitor cells. Most investigations have used fetal liver, cord blood or peripheral blood. Few have used adult bone marrow. OBJECTIVE: Human mast cells derived in vitro from the CD34(+) progenitors in bone marrow and cord blood that had been cultured with recombinant human stem cell factor (rhSCF) and recombinant human interleukin-6 (rhIL-6) were compared. METHODS AND RESULTS: After 12 weeks of culture, nearly all of the cells were mast cells, and nearly all of these had cytoplasmic granules containing both tryptase and chymase (MCTC type), stained metachromatically with acidic toluidine blue, and expressed CD117 on the cell surface. Both tryptase protein and mRNA were detected by two weeks of culture. Chymase mRNA and protein were detected at 4 weeks but not at 2 weeks of culture. By 12 weeks, chymase content per cell, measured by ELISA, was significantly higher (P < 0.05) in human bone marrow-derived mast cells (HBMMC) (5.6 +/- 0.9 pg) than in cord blood-derived mast cells (CBMC) (2.4 +/- 0.9 pg), whereas histamine and tryptase levels were not significantly different. Of the cluster designations tested, CD29, CD49d, CD51 and CD61 were strongly expressed on HBMMC. CD54 and Fc epsilon RI alpha also were expressed constitutively. Approximately half of CD34-sorted cells at day 0 were CD13(+) and this diminished as mast cell maturation occurred. Electron microscopy revealed that 12-week-old HBMMC had many secretory granules that contained spherical electron dense cores surrounded by electron lucent space, consistent with previous reports of immature MCTC cells developing in vivo. CONCLUSIONS: CD34(+) progenitors of human bone marrow are a rich source of mast cell progenitors capable of expressing granule and surface markers of mature mast cells in the presence of rhSCF and rhIL-6.