Serum Carboxypeptidase Activity and Genotype-Stratified CA19-9 to Detect Early-Stage Pancreatic Cancer

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安徽及周边省份绵羊和山羊隐孢子虫分子特性分析

目的　调查安徽及周边省份绵羊和山羊隐孢子虫流行情况及分子特性。方法　选择安徽省及其周边的河南、江苏和山东部分地区的7个规模化绵羊场和10个规模化山羊场，分别采集832份和781份新鲜绵羊和山羊粪便样品，利用隐孢子虫SSU rDNA基因特异的巢氏PCR技术对所有样品进行检测，调查上述地区绵羊和山羊隐孢子虫感染和虫种分布；对获得的微小隐孢子虫和泛在隐孢子虫进行gp60基因扩增与分析，以鉴定其基因亚型。结果　安徽及周边省份绵羊和山羊隐孢子虫感染率分别为5.8%（48/832）和8.7%（68/781）。SSU rDNA基因分析显示，绵羊感染的隐孢子虫为肖氏隐孢子虫和泛在隐孢子虫，山羊感染的隐孢子虫为微小隐孢子虫。gp60基因分析显示，泛在隐孢子虫基因亚型均为XIIa亚型2，微小隐孢子虫基因亚型均为IIdA19G1。结论　人兽共患泛在隐孢子虫XIIa亚型2和微小隐孢子虫 IIdA19G1基因亚型的鉴定，提示绵羊和山羊可能为人隐孢子虫感染的潜在来源。     

Recommendations for accurate genotyping of SARS-CoV-2 using amplicon-based sequencing of clinical samples

ObjectivesGenotyping of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been instrumental in monitoring viral evolution and transmission during the pandemic. The quality of the sequence data obtained from these genotyping efforts depends on several factors, including the quantity/integrity of the input material, the technology, and laboratory-specific implementation. The current lack of guidelines for SARS-CoV-2 genotyping leads to inclusion of error-containing genome sequences in genomic epidemiology studies. We aimed to establish clear and broadly applicable recommendations for reliable virus genotyping.MethodsWe established and used a sequencing data analysis workflow that reliably identifies and removes technical artefacts; such artefacts can result in miscalls when using alternative pipelines to process clinical samples and synthetic viral genomes with an amplicon-based genotyping approach. We evaluated the impact of experimental factors, including viral load and sequencing depth, on correct sequence determination.ResultsWe found that at least 1000 viral genomes are necessary to confidently detect variants in the SARS-CoV-2 genome at frequencies of ≥10%. The broad applicability of our recommendations was validated in over 200 clinical samples from six independent laboratories. The genotypes we determined for clinical isolates with sufficient quality cluster by sampling location and period. Our analysis also supports the rise in frequencies of 20A.EU1 and 20A.EU2, two recently reported European strains whose dissemination was facilitated by travel during the summer of 2020.ConclusionsWe present much-needed recommendations for the reliable determination of SARS-CoV-2 genome sequences and demonstrate their broad applicability in a large cohort of clinical samples.     

In vitro activity of ibrexafungerp and comparators against Candida albicans genotypes from vaginal samples and blood cultures

ObjectivesEmergence of azole resistance may contribute to recurrences of vulvovaginal candidiasis. Thus, new drugs are needed to improve the therapeutic options. We studied the in vitro activity of ibrexafungerp and comparators against Candida albicans isolates from vaginal samples and blood cultures. Furthermore, isolates were genotyped to study compartmentalization of genotypes and the relationship between genotype and antifungal susceptibility.MethodsCandida albicans unique patient isolates (n = 144) from patients with clinical suspicion of vulvovaginal candidiasis (n = 72 isolates) and from patients with candidaemia (n = 72) were studied. Antifungal susceptibility to amphotericin B, fluconazole, voriconazole, posaconazole, isavuconazole, clotrimazole, miconazole, micafungin, anidulafungin and ibrexafungerp was tested (EUCAST 7.3.2). Mutations in the erg11 gene were analysed and isolates genotyped.ResultsIbrexafungerp showed high activity (MICs from 0.03 mg/L to 0.25 mg/L) against the isolates, including those with reduced azole susceptibility, and regardless of their clinical source. Fluconazole resistance rate was 7% (n = 5/72) and 1.4% (n = 1/72) in vaginal and blood isolates, respectively. Some amino acid substitutions in the Erg11 protein were observed exclusively in phenotypically fluconazole non-wild type. Population structure analysis suggested two genotype populations, one mostly involving isolates from blood samples (66.3%) and the mostly from vaginal samples (69.8%). The latter group hosted all fluconazole non-wild-type isolates.DiscussionIbrexafungerp shows good in vitro activity against Candida albicans from vaginal samples including phenotypically fluconazole non-wild-type isolates. Furthermore, we found a certain population structure where some genotypes show reduced susceptibility to fluconazole.     

High within-host diversity found from direct genotyping on post-mortem tuberculosis specimens in a high-burden setting

ObjectivesTo characterize the clonal complexity in Mycobacterium tuberculosis (MTB) infections considering factors that help maximize the detection of coexisting strains/variants.MethodsGenotypic analysis by Mycobacterial Interspersed Repetitive-Unit–Variable-Number Tandem-Repeats (MIRU-VNTR) was performed directly on 70 biopsy specimens from two or more different tissues involving 28 tuberculosis cases diagnosed post-mortem in Mozambique, a country with a high tuberculosis burden.ResultsGenotypic data from isolates collected from two or more tissues were obtained for 23 of the 28 cases (82.1%), allowing the analysis of within-patient diversity. MIRU-VNTR analysis revealed clonal diversity in ten cases (35.7%). Five cases showed allelic differences in three or more loci, suggesting mixed infection with two different strains. In half of the cases showing within-host diversity, one of the specimens associated with clonal heterogeneity was brain tissue.ConclusionsDirect MTB genotyping from post-mortem tissue samples revealed a frequent within-host Mycobacterium tuberculosis diversity, including mixed and polyclonal infections. Most of this diversity would have been overlooked if only standard analysis of respiratory specimens had been performed.     

人类白细胞抗原新等位基因B*55:35的鉴定及家系调查

目的 鉴定人类白细胞抗原(human leukocyte antigen,HLA)基因B位点的1个新等位基因并调查其遗传情况.方法 应用聚合酶链反应-序列特异性寡核苷酸探针(polymerase chain reactionsequence specific oligonucleotide probe,PCR-SSOP) HLA分型技术发现1个疑似的新HLA等位基因,通过DNA测序鉴定其序列,并与同源性最高的HLA基因进行核苷酸序列比对,对携带者家系进行调查.结果应用PCR-SSOP进行HLA基因分型时,该样本HLA-B位点反应格局异常.DNA序列分析证实其为1个新HLA-B等位基因.与同源性最高的等位基因B*55:02比较,在第2外显子区域中有7个碱基发生改变,导致6个密码子发生了变化,造成2个氨基酸改变,即第69位的氨基酸由谷氨酸(Glu)变为甲硫氨酸(Met)、第70位的氨基酸由谷氨酸(Glu)变为丙氨酸(Ala).结论 发现并鉴定了HLA-B位点的1个新等位基因,GenBank注册号为FJ898284,被世界卫生组织HLA因子命名委员会正式命名为HLA-B* 55:35.     

Co-circulation of classic and novel astrovirus strains in patients with acute gastroenteritis in Germany

Objectives

In order to analyze the molecular epidemiology of human astroviruses (HAstV) in Germany, a retrospective long-term study was performed to characterize circulating human astrovirus in patients with acute gastroenteritis in Germany.

Comparing triage algorithms using HPV DNA genotyping,HPV E7 mRNA detection and cytology in high-risk HPV DNA-positive women

BackgroundHigh-risk human papillomavirus (hrHPV) DNA positive women require triage testing to identify those with high-grade cervical intraepithelial neoplasia or cancer (≥CIN2).ObjectiveComparing three triage algorithms (1) E7 mRNA testing following HPV16/18/31/33/45/52/58 genotyping (E7 mRNA test), (2) HPV16/18 DNA genotyping and (3) cytology, for ≥CIN2 detection in hrHPV DNA-positive women.Study designhrHPV DNA-positive women aged 18–63 years visiting gynecology outpatient clinics were included in a prospective observational cohort study. From these women a cervical scrape and colposcopy-directed biopsies were obtained. Cervical scrapes were evaluated by cytology, HPV DNA genotyping by bead-based multiplex genotyping of GP5+6+-PCR-products, and presence of HPV16/18/31/33/45/52/58 E7 mRNA using nucleic acid sequence-based amplification (NASBA) in DNA positive women for respective HPV types. Sensitivities and specificities for ≥CIN2 were compared between E7 mRNA test and HPV16/18 DNA genotyping in the total group (n = 348), and E7 mRNA test and cytology in a subgroup of women referred for non-cervix-related gynecological complaints (n = 133).ResultsSensitivity for ≥CIN2 of the E7 mRNA test was slightly higher than that of HPV16/18 DNA genotyping (66.9% versus 60.9%; ratio 1.10, 95% CI: 1.0002–1.21), at similar specificity (54.8% versus 52.3%; ratio 1.05, 95% CI: 0.93–1.18). Neither sensitivity nor specificity of the E7 mRNA test differed significantly from that of cytology (sensitivity: 68.8% versus 75.0%; ratio 0.92, 95% CI: 0.72–1.17; specificity: 59.4% versus 65.3%; ratio 0.91, 95% CI: 0.75–1.10).ConclusionFor detection of ≥CIN2 in hrHPV DNA-positive women, an algorithm including E7 mRNA testing following HPV16/18/31/33/45/52/58 DNA genotyping performs similar to HPV16/18 DNA genotyping or cytology.     

The isolation and molecular characterization of Leishmania spp. from patients with American tegumentary leishmaniasis in northwest Argentina

American tegumentary leishmaniasis (ATL) is a group of zoonotic diseases caused by kinetoplastid flagellates of the genus Leishmania. A total of 66 patients diagnosed as positive ATL cases from northwest Argentina were included in this study. Leishmania stocks were isolated in vitro and analyzed over promastigote cultures sown on FTA through nested PCR and sequence of cytochrome b (cyt b). The molecular analysis resulted in the incrimination of L. (Viannia) braziliensis as the predominant species in the studied area, identifying two genotypes of L. (V.) braziliensis, 24 cases of Ab-1 cyt b and 41 cases of Ab-2 cyt b. One L. (V.) guyanensis strain was obtained from a traveler from the Brazilian Amazon. The prevalence of different genotypes was in agreement with previous studies, suggesting the necessity for new systems to study the genetic diversity in more detail. Most of the cases typified in this study were registered in the area of Zenta Valley (Orán, Hipólito Yrigoyen, and Pichanal cities), pointing a link between genotype and geographical origin of the sample. Sex and age distribution of the patients indicate that the transmission was predominantly associated with rural areas or rural activities, although the results might not exclude the possibility of peri-urban transmission. This work represents, so far, the largest isolation and molecular characterization of ATL cases in Argentina.     

不同类型样本用于HIV基因型耐药检测研究进展

随着艾滋病(AIDS)抗病毒治疗的推广,艾滋病死亡人数大幅度减少。然而抗病毒药物的压力促使病毒基因发生耐药性的突变,艾滋病病毒(HIV)耐药的检测已经成为HIV预防和治疗的一个重要方面。目前,用于基因型耐药检测的样本类型主要包括液体样本和滤纸片载体样本。液体样本包括全血、血浆、血清,滤纸片载体样本包括干血斑(DBS)、干浆斑(DPS)、干血清斑(DSS)。文章通过对以上样本类型用于检测的特点进行总结,比较它们之间的优缺点,综述各样本类型的使用范围及应用前景。