D试验和多重PCR检测红霉素耐药葡萄球菌

目的了解红霉素耐药的葡萄球菌对克林霉素的耐药表型和基因型，指导临床合理使用抗生素。方法用NCCLS标准D试验检测红霉素和克林霉素的耐药表型，通过多重PCR检测耐药基因ermA、ermC和msrA。结果所有144株葡萄球菌中，84株（58．3％）对红霉素和克林霉素耐药（cMLS），27株（18．8％）对红霉素耐药对克林霉素敏感但D试验阳性（iMLS），33株（22．9％）对红霉素耐药，对克林霉素敏感但D试验阴性（MS）。在MS型耐药的菌株中均只检测到msrA基因，在cMLS和iMLS型耐药的菌株中，除了1株3种基因均阴性外，其他均检测到ermA或ermC基因。在金葡菌中iMLS型耐药的菌株以ermC基因稍多（3／5），而cMLS型耐药的菌株以ermA基因居多（56／62）；在凝固酶阴性葡萄球菌中iMLS型和cMLS型耐药的菌株均以ermC基因居多（分别为22／22和11／14）结论iMLS型耐药的葡萄球菌在临床比较多见，多重PCR和D试验均可对其鉴别，临床微生物实验室应常规进行D试验。     

标准化配置换药包预防骨科PICC导管相关性感染的研究

目的探讨标准化配置换药包对预防骨科PICC导管相关性感染的疗效。方法选择急诊收治的98例符合PICC中心静脉置管适应症的骨科患者为研究对象,随机将其分为对照组和观察组,各49例,置管过程中对照组使用常规换药包,观察组使用标准化配置换药包,对比分析两组导管相关性感染相关指标。结果观察组患者导管相关性血流感染率、出口部位感染发生率、感染发生率均低于对照组(P0.05);2组PICC置管术后在白细胞计数、抗生素使用时间、维护依从性及住院时间等方面比较,观察组均优于对照组(P0.05)。结论标准化配置换药包在预防骨科PICC导管相关性感染方面疗效确切,值得临床推广应用。     

New serological biomarkers of inflammatory bowel disease

Serological biomarkers in inflammatory bowel disease （IBD） are a rapidly expanding list of non-invasive tests for objective assessments of disease activity, early diagnosis, prognosis evaluation and surveillance. This review summarizes both old and new biomarkers in IBD, but focuses on the development and characterization of new serological biomarkers （identifi ed since 2007）. These include fi ve new anti-glycan antibodies, anti-chitobioside IgA （ACCA）, anti-laminaribioside IgG （ALCA）, anti-manobioside IgG （AMCA）, and antibodies against chemically synthesized （∑） two major oligomannose epitopes, Man α-1,3 Man α-1,2 Man （∑Man3） and Man α-1,3 Man α-1,2 Man α-1,2 Man （∑Man4）. These new biomarkers serve as valuable complementary tools to existing biomarkers not only in differentiating Crohn＇s disease （CD）, ulcerative colitis （UC）, normal and other non-IBD gut diseases, but also in predicting disease involvement （ileum vs colon）, IBD risk （as subclinical biomarkers）, and disease course （risk of complication and surgery）. Interestingly, the prevalence of the antiglycan antibodies, including anti-Saccharomyces cerevisiae antibodies （ASCA）, ALCA and AMCA, was found to be associated with single nucleotide polymorphisms （SNPs） of IBD susceptible genes such as NOD2/CARD15, NOD1/CARD4, toll-likereceptors （TLR） 2 and 4, and β-defensin-1. Further-more, a gene dosage effect was observed： anti-glycan positivity became more frequent as the number of NOD2/CARD15 SNPS increased. Other new serum/ plasma IBD biomarkers reviewed include ubiquitination factor E4A （UBE4A）, CXCL16 （a chemokine）, resistin, and apolipoprotein A-IV. This review also discusses the most recent studies in IBD biomarker discovery by the application of new technologies such as proteomics, fourier transform near-infrared spectroscopy, and multiplex enzyme-linked immunosorbent assay （ELISA）＇s （with an emphasis on cytokine/chemokine profiling）. Finally, the prospects o     

用多重PCR技术检测小管福寿螺体内广州管圆线虫幼虫

目的建立一种多重PCR方法检测小管福寿螺体内的广州管圆线虫幼虫。方法根据广州管圆线虫核糖体小亚基rDNA基因序列(GenBank登录号为AY295804)设计特异性引物,并与小管福寿螺16srDNA的特异性引物组合,建立多重PCR检测方法。分别以阳性和阴性小管福寿螺DNA为模板进行多重PCR扩增,电泳鉴定并测序。用阴性小管福寿螺DNA倍比稀释200条广州管圆线虫Ⅲ期幼虫DNA模板,使之浓度分别为1200ng/μl、120ng/μl、12ng/μl、1200pg/μl、120pg/μl和12pg/μl,检测该方法的敏感性。野外采集小管福寿螺172只,肺检法检测后,进行多重PCR扩增,计算敏感性和特异性。结果电泳和测序结果证实该多重PCR检测方法能有效扩增出目的片段,小管福寿螺和广州管圆线虫的目的片段分别为550和405bp。该方法可检测出广州管圆线虫Ⅲ期幼虫DNA的最小浓度为120pg/μl。肺检法和多重PCR法检测均为阳性结果的45只,两法均为阴性的100只。肺检法为阴性、多重PCR法为阳性的24只,肺检法为阳性而多重PCR法检测为阴性的3只。多重PCR的敏感性和特异性分别为93.8%(45/48)和80.6%(100/124)。多重PCR法的阳性检出率为40.1%(69/172),肺检法阳性检出率为27.9%(48/172),差异具有统计学意义(χ2=14.8,P0.01)。结论建立了检测小管福寿螺体内广州管圆线虫的多重PCR方法。     

2种不同试剂检测血清免疫球蛋白结果的可比性及偏倚评估

目的进行2种不同免疫球蛋白诊断试剂对血清免疫球蛋白测定结果的可比性及偏倚评估研究,为血清免疫球蛋白测定的标准化和临床实验室认可提供实验数据。方法参考美国临床和实验室标准协会(CLSI)的EP9A2文件,分别用执诚试剂和优利特试剂在HITACHI7600-010全自动生化分析仪上测定免疫球蛋白IgG、IgA和IgM,以执诚试剂为对照组,优利特试剂为实验组。用线性回归统计法分析对照组(Y)和实验组(X)测定结果决定水平处的方法间误差,以美国临床实验室修正法规(CLIA′88)规定的室间质量评价允许误差范围的1/2为标准,判断不同试剂的临床可接受性。结果两种试剂对患者血清免疫球蛋白测定结果显示,方法内重复性良好,无离群点,除IgA在决定水平处的系统误差不能被接受外,其余项目测定结果的偏差临床可以接受。结论当同一实验室同一检验项目存在2个或以上的试剂时,应进行方法比对和偏差评估,判断其临床可接受性,以保证检验结果的可比性。     

Multiplex RT-PCR for rapid detection and differentiation of class I and class II Newcastle disease viruses

A multiplex RT-PCR was developed for detection and differentiation of class I and class II strains of Newcastle disease virus (NDV). The method was shown to have high specificity and sensitivity. The results obtained from the multiplex RT-PCR for a total of 67 NDV field isolates obtained in 2009 were consistent with those obtained by nucleotide sequencing and phylogenetic analysis. A phylogenetic tree based on the partial sequences of the F gene revealed that the 67 field isolates of NDV could be divided into two classes. Twenty-seven NDV isolates were grouped into class I, and two genotypes were identified. Most of the class I isolates were determined to be of genotype 3, with the exception of isolate NDV09-034, which belonged to genotype 2. Forty class II NDV isolates were divided into three genotypes, namely genotype VII (27 isolates), genotype I (2 isolates) and genotype II (11 isolates). Isolates of genotypes I and II in class II were shown to be related to commercial vaccine strains used commonly in China. All isolates of genotype VII were predicted to be virulent, on the basis of the sequence motif at the cleavage site of the F gene. This genotype has become predominantly responsible for most outbreaks of ND in China in recent years. In conclusion, this multiplex RT-PCR provides a new assay for rapid detection and differentiation of both classes of NDV isolates.     

Multiplex high resolution melting assay for estimation of Porcine Endogenous Retrovirus (PERV) relative gene dosage in pigs and detection of PERV infection in xenograft recipients

Porcine Endogenous Retrovirus (PERV) poses an infectious risk in the field of xenotransplantation. This risk may be mitigated by breeding selectively animals bearing favorable PERV genetic characteristics including pigs with low levels of PERV integrated in the genome. A real-time quantitative polymerase chain reaction (PCR) assay employing the Roche High Resolution Melting (HRM) Master was used to estimate the relative gene dosage of PERV pol integrated within the pig genome. When assessed across 99 pigs of the Auckland Island breed numerous animals bearing low gene dosage were identified. The assay was adapted further to perform multiplex PCR for the detection of PERV infection within xenograft recipients. Besides PERV, amplification targets for the multiplex PCR include a pig cell marker for the determination of microchimerism and an internal amplification control (IAC) to assess the efficiency of nucleic acid isolation and effects of PCR inhibition. When 12 patients who had received porcine islet transplants were tested no evidence of PERV infection was found. The assay was shown to be specific, highly reproducible with superior performance over conventional nested PCR. This assay can be used as both a screening tool for PERV proviral levels within donor pigs and as a diagnostic tool to examine PERV transmission in human patients treated with porcine xenotransplantation material.     

Triplex PCR‐based detection of enterotoxigenic Bacillus cereus ATCC 14579 in nonfat dry milk

Although many strains of Bacillaceae are considered nonpathogenic, Bacillus cereus is recognized worldwide as a bacterial pathogen in a variety of foods. The ability of B. cereus to cause gastroenteritis following ingestion of contaminated food is due to the production of enterotoxins. The ubiquity of this genus makes it a persistent problem for quality assurance in food processing environments. The primary objective of this study was to develop and apply a multiplex real‐time PCR‐based assay for rapid and sensitive detection of enterotoxigenic B. cereus. Template DNA was separately extracted from tryptic soy broth (TSB)‐grown and 2.5% Nonfat Dry Milk (NFDM)‐grown B. cereus using a commercial system. Three enterotoxin gene fragments (hblC, nheA, and hblA) were simultaneously amplified in real‐time followed by melting curve analysis to confirm amplicon identity. Resolution of melting curves (characteristic T_m) was achieved for each amplicon (hblC = 74.5 °C; nheA = 78 °C; and hblA = 85.5 °C in TSB and 84 °C in NFDM) with an assay sensitivities of 10¹ CFU/ml for both TSB and NFDM‐grown B. cereus compared to 10⁴ CFU/ml in either matrix using gel electrophoresis. The results demonstrate the potential sensitivity of real‐time bacterial detection methods in a heterogenous food matrix using real‐time PCR. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Do we know all there is to know about Familial Adenomatous Polyposis?

Familial Adenomatous Polyposis (FAP) and Attenuated FAP (AFAP) are caused by a germline mutation in the Adenomatous polyposis coli (APC) gene. Recently, a new pathway characterized by a biallelic mutation in the MYH gene, with a recessive model of inheritance was discovered for this inherited syndrome. This report describes a Tunisian patient with an attenuated FAP phenotype, presenting seven colon polyps and an adenocarcinoma but no detectable germline mutations in the FAP target genes. A well known somatic mutation was found in the APC mutation cluster region (MCR). This case shows that further studies are needed to fully understand all the pathways of the FAP syndrome.