A sensitive and a rapid multiplex polymerase chain reaction for the identification of Candida species in concentrated oral rinse specimens in patients with diabetes

Objectives: Oral candidiasis is being frequently recognized in patients with diabetes, and is associated with multiple pathogens including Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis. The aim of this study was to evaluate a usefulness of a Multiplex Polymerase Chain Reaction as a rapid diagnostic tool for identification of four oral Candida pathogens in patients with diabetes.

Materials and methods: A multiplex PCR was optimized to identify four Candida species in concentrated oral rinse samples. Common reverse primer, ITS4 and four species-specific forward primers targeting ITS1 and ITS2 regions of yeast genome were used. Species-specific single amplicon were detected by agarose gel electrophoresis. Performance efficacy of multiplex PCR was compared with phenotypic identification.

Results: Out of 100 oral rinse samples, 72 were culture positive and of these 43 were at risk of oral Candida infection (>600cfu/ml). Multiple Candida species including C. albicans, C. parapsilosis and C. tropicalis were identified in 22 samples which had risk of oral Candida infection. In total, 85 patients were positive for Candida by multiplex PCR and of them 49 had multiple Candida species. All 43 colonized specimens were also positive by multiplex PCR. C. albicans was the most predominant organism (75/85) followed by C. parapsilosis (47/85), C. tropicalis (17/85) and C. glabrata (6/85). In specimens with multiple species, the two most common organisms were C. albicans and C. parapsilosis. Multiplex PCR yielded a sensitivity of 10 Candida cells/ml of oral rinse sample.

Conclusions: Multiplex PCR is found to be rapid, sensitive and specific than phenotypic identification methods in discriminating multiple Candida species in oral rinse specimens.     

Analysis of isodicentric Ph chromosomes in chronic myeloid leukemia blast crisis北大核心CSCD

Objective To explore the genetic and clinical characteristics of isodicentric Ph chromosomes [idic(Ph)] in lymphoid blast crisis of chronic myeloid leukemia (CML-BLC). Methods Bone marrow aspirates of 2 patients withCML-BLC were analyzed by R banding after 24 hours of culturing. Genomic copy number variations (CNV) wereanalyzed by single nucleotide polymorphism array (SNP array) in case 1. The results were confirmed withfluorescence in situ hybridization (FISH). Variations of acute lymphoblastic leukemia-related genes includingCDKN2A/AB and PAX5 were detected by multiplex ligation-dependent probe amplication (MLPA). Results Deletionsand duplications on derivative chromosome 9 detected by FISH were confirmed by SNP array analysis. Thedistances between the BCR/ ABL fusion signals on the idic(Ph) chromosomes in the two patients have differedgreatly. The idic(Ph) in the second patient was supposed to be formed by two Ph chromosomes joined at their qterminals, where as the idic(Ph) in the first patient have been shown to be fused at the satellite regions oftheir p arms. Conclusion The idic(Ph) chromosomes presented in CML-BLC may predict resistance to Imatinib andresponse to Dasatinib.     

Analysis of the cause of pregnancy failure with combined MLPA assay for subtelomeric regions and ultrasonography北大核心CSCD

Objective To explore the value of multiplex ligation-dependent probe amplification (MLPA) for thedetection of chromosome abnormalities in miscarriage tissues, and to correlate the result with ultrasoundfindings. Methods A total of 421 cases of spontaneous abortions and fetal deaths were detected with the MLPAmethod. Results Among the 421 samples, 232 (55. 11%) had an abnormal MLPA result. For the 286 cases derivedfrom < 13 weeks pregnancy, 206 (72.03%) were abnormal. For the 49 cases from 14 ~ 19 weeks pregnancy, 14(28. 57%) were abnormal. For the 86 cases derived after 20 weeks pregnancy, 12 (13. 95%) were abnormal. Amongthe 117 cases with abnormal ultrasound findings, 33 cases (28. 21%) had an abnormal MLPA result, 28 out of the33 cases were numerical chromosome abnormality, 4 cases were chromosome microdeletion and/or micro duplication, 1 case had both numerical abnormality and microduplication. For those with abnormal ultrasound findings for the neck region, fetal edematous syndrome, multiple malformations and digestive system, the detection rates forMLPA were 71. 4% , 58. 8% , 37. 8% , and 9.1% , respectively. For those with abnormal finding of cardiacsystem, nervous system, face, skeletal system and urinary system, none was found with positive results of MLPA. Conclusion Numerical chromosomal abnormalities account for the majority of cases with spontaneous abortion.With the increase of gestational age, the occurrence of chromosomal abnormalities gradually declines. Combinedultrasound and MLPA assay can improve the detection rate and accuracy for chromosomal abormalities.     

多重实时荧光定量PCR对9种常见呼吸道病原体检测

目的探讨多重实时荧光定量PCR(MRT-PCR)检测9种常见呼吸道病原体的临床应用价值。方法采用Primer Express3.0(ABI)和Primer3 Input 4.0设计引物和探针建立MRT-PCR法,通过构建质粒标准品分析该方法的最低检出限和特异性。并对204例临床标本中副流感病毒1、2、3型、肺炎支原体、肺炎衣原体、呼吸道合胞病毒、腺病毒、甲型流感病毒、乙型流感病毒进行回顾性检测。结果 MRT-PCR法检测病原体的最低检出限达103copies/m L,特异性达100%,无交叉反应。204例咽拭子标本中,MRT-PCR检出呼吸道合胞病毒23例,副流感病毒1、2、3型13例,腺病毒15例,肺炎支原体15例,肺炎衣原体3例,甲型流感病毒13例与乙型流感病毒6例。该结果与其他试剂报告结果完全一致。结论多重实时荧光定量PCR具有快速、准确、特异性强等特点,在呼吸道病原体检测方面有重要价值。     

多重PCR快速检测3种食源性致病菌

目的建立一种能同时检测金黄色葡萄球菌、产单核李斯特菌和沙门菌3种致病菌的多重PCR检测方法。方法采用LB培养液对金黄色葡萄球菌、产单核李斯特菌和沙门菌标准菌株进行增菌。根据金黄色葡萄球菌的nuc基因、产单核李斯特氏菌的hlvA基因、沙门氏菌的invA基因设计引物,通过多重聚合酶链反应（PCR）对上述3种食源性致病菌的目的基因进行扩增,同时对反应体系进行优化。结果对平均浓度为5cfu／ml的金黄色葡萄球菌、产单核李斯特菌和沙门氏菌在LB培养液中进行8h振荡培养,可以检出阳性结果;把金黄色葡萄球菌、产单核李斯特菌、沙门菌、志贺菌、蜡样芽孢杆菌、大肠埃希菌0157、阪崎肠杆菌7种菌混合在一起提取混合基因组DNA进行PCR扩增,显示出很好的特异性结果。结论建立的多重PCR检测方法适用于金黄色葡萄球菌、产单核李斯特菌和沙门菌的快速检测,具有快速、简便、灵敏的特点,可广泛应用于食品卫生检测、食物中毒应急处理和临床检验等领域。     

fliC基因在快速分型鉴定伤寒沙门菌和甲型副伤寒沙门菌的应用

目的:探讨沙门菌1相鞭毛蛋白抗原fliC基因在快速分型鉴定伤寒沙门菌和甲型副伤寒沙门菌的应用。方法:根据伤寒沙门菌和甲型副伤寒沙门菌1相鞭毛蛋白fliC-d和fliC-a基因以及菌体抗原rfbS基因的核酸序列,设计针对fliC-d、fliC-a及rfbS基因的3对特异性引物,采用多重PCR法进行检测。结果:实验结果显示,伤寒沙门菌和甲型副伤寒沙门菌分别在750 bp和329 bp处扩增出2条特异性目的条带,在258 bp处扩增出1条相同条带,非伤寒沙门菌株和甲型副伤寒沙门菌株均为阴性。结论:fliC基因检测可用于伤寒沙门菌和甲型副伤寒沙门菌的分型鉴定,而rfbS基因则无助于分型鉴定。     

耐甲氧西林金黄色葡萄球菌SCCmec基因分型及耐药谱分析

目的 研究耐甲氧西林金黄色葡萄球菌(MRSA) SCCmec基因分型情况,并对其耐药谱进行分析.方法 收集从临床标本分离出的MRSA 91株,应用多重PCR法对MRSA进行SCCmec基因分型,采用MicroScanWalk-Away-40全自动微生物鉴定药敏分析仪进行细菌的鉴定及药敏试验,部分药敏试验采用K-B法.结果 91株MRSA中SCCmecⅡ型72株,占79.1％,SCCmecⅢ型16株,占17.6％,未分型3株,占3.3％,未见SCCmec Ⅰ型及SCCmecⅣ型;ICU中MRSA所占比例最多,为SCCmecⅡ型51.4％、SCCmecⅢ型37.5％,2种SCCmec基因型的MRSA对万古霉素、磺胺甲噁唑/甲氧苄啶、利奈唑胺、喹奴普汀/达福普汀的耐药率为0,对氯霉素的耐药率分别为11.1％和12.5％,对利福平的耐药率分别为8.3％和37.5％,其余均呈高水平耐药,2种SCCmec基因型的MRSA均表现为多药耐药.结论 临床分离的MRSA以SCCmecⅡ型为主,且对抗菌药物呈多药耐药.     

Multiplex ARMS PCR to Detect 8 Common Mutations of ATP7B Gene in Patients With Wilson Disease

Background

Wilson disease is a rare disorder of copper metabolism due to mutation in ATP7B gene. Proper counseling of patients with Wilson disease, and their families necessitates finding mutation in ATP7B gene. Finding mutations in ATP7B gene with 21 exons, and more than 500 mutations is expensive and time-consuming.

Objectives

The aim of this study was to provide a simple multiplex amplification refractory mutation system PCR (M-ARMS-PCR) for screening eight common mutations in ATP7B gene.

Patients and Methods

Two sets of ARMS mutant and normal specific primer pairs were designed for genotyping of p.R778L, p.R969Q, p.H1069Q, and p.3400delC mutations as Set 1 and p.W779G, c.3061-1G > A, p.I1102T, and p.N1270S mutations as Set 2. The Multiplex ARMS assay was then subsequently tested in 65 patients with Wilson disease with known and unknown ATP7B mutations.

Results

Using these two sets, we identified H1069Q mutation in four patients, c.2335T > G mutation in three, c.3061-1G > A splice site mutation in five, c.3305T > C mutation in one, and c.3809A > G mutation in two patients.

Conclusions

The Multiplex ARMS assay used in this study can be an efficient, reliable, and cost effective method as a primary screen for patients with Wilson disease.     

多重PCR-SSCP检测人瘢痕疙瘩Fas基因突变

目的　建立多重PCR -SSCP反应体系 ,以筛选瘢痕疙瘩Fas基因突变。方法　按照多重PCR引物设计原则设计相应引物 ,经分析、实验得到理想的多重PCR扩增条件 ,以此条件扩增目的基因 ;将所得PCR反应产物在单基因对照下进行银染多重SSCP分析 ,进而筛选基因突变。结果　外显子 6 ,8,9的单一PCR反应产物及多重PCR反应产物经琼脂糖凝胶电泳 ,各条带清晰 ,无非特异性扩增 ,且产量较高 ,产物的长度与理论值相符 ;经银染多重SSCP分析 ,正常皮肤组织和增生性瘢痕中均未检出突变 ,在 2 3例瘢痕疙瘩标本中 ,18例出现异常电泳带。结论　本实验建立了用以分析瘢痕疙瘩Fas基因突变的多重PCR -SSCP方法 ,分析结果提示 :瘢痕疙瘩组织中Fas基因的突变可能与该病的发生有密切关系 ;多重PCR -SSCP是检测基因点突变的一种快速、敏感、有效的方法