Molecular methods

分子方法
  • 文章类型: Journal Article
    肉瘤的精确分类对于最佳临床治疗至关重要。在这个前景中,多中心,希腊肉瘤和罕见癌症组(HGSRC)内的观察性研究,我们评估了专家病理学审查的效果,加上分子诊断的应用,肉瘤患者的诊断和治疗。医生将新诊断的肉瘤患者交给HGSRC的两名肉瘤病理学家之一进行组织病理学诊断评估。使用靶向86个肉瘤基因融合体的平台对所有样品进行RNA下一代测序。根据专家病理学家的意见进行了其他分子方法。因此,专家病理学家根据组织病理学发现提供了最终诊断,必要时,分子测试。总的来说,对来自122名患者的128个样本进行了评估。在119例由非肉瘤病理学家初步诊断的病例中,肉瘤病理学家对诊断进行了37次修改(31.1%),导致17(14.2%)的管理变化。在进行分子检测的110例病例中,通过基因组结果,诊断有29次修改(26.4%),导致12(10.9%)的管理修改。我们的研究证实,专家病理学审查对于最佳的肉瘤诊断和治疗至关重要,在某些情况下应通过分子方法进行辅助。
    Precise classification of sarcomas is crucial to optimal clinical management. In this prospective, multicenter, observational study within the Hellenic Group of Sarcoma and Rare Cancers (HGSRC), we assessed the effect of expert pathology review, coupled with the application of molecular diagnostics, on the diagnosis and management of sarcoma patients. Newly diagnosed sarcoma patients were addressed by their physicians to one of the two sarcoma pathologists of HGSRC for histopathological diagnostic assessment. RNA next-generation sequencing was performed on all samples using a platform targeting 86 sarcoma gene fusions. Additional molecular methods were performed in the opinion of the expert pathologist. Therefore, the expert pathologist provided a final diagnosis based on the histopathological findings and, when necessary, molecular tests. In total, 128 specimens from 122 patients were assessed. Among the 119 cases in which there was a preliminary diagnosis by a non-sarcoma pathologist, there were 37 modifications in diagnosis (31.1%) by the sarcoma pathologist, resulting in 17 (14.2%) modifications in management. Among the 110 cases in which molecular tests were performed, there were 29 modifications in diagnosis (26.4%) through the genomic results, resulting in 12 (10.9%) modifications in management. Our study confirms that expert pathology review is of utmost importance for optimal sarcoma diagnosis and management and should be assisted by molecular methods in selected cases.
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  • 文章类型: Journal Article
    早发性败血症(EOS)是一个全球性的健康问题,被认为是新生儿死亡的主要原因之一。EOS的诊断具有挑战性,因为它的临床症状是非特异性的,和血液培养,这是当前的黄金标准诊断工具,灵敏度低。脓毒症诊断常用的生物标志物,包括C反应蛋白,降钙素原,和白细胞介素-6,缺乏对感染的特异性。由于血液培养和其他常见生物标志物的缺点,正在进行的努力旨在确定创新的分子方法来诊断有败血症风险的新生儿.这篇综述旨在收集这些新兴分子方法的知识和最新研究。基于PCR的技术和基于16SrRNA测序和16S-23SrRNA基因空间区域测序的非限制性技术提供了若干优点。尽管有潜力,由于一些限制,这些方法无法替代血液培养;然而,在新生儿败血症诊断中,它们可能被证明是有价值的补充测试。已经评估了几种microRNA,并提出将其作为EOS中的诊断生物标志物。T2磁共振和生物信息学分析提出了新生儿败血症的潜在生物标志物,尽管进一步的研究对于验证这些发现至关重要。
    Early-onset sepsis (EOS) is a global health issue, considered one of the primary causes of neonatal mortality. Diagnosis of EOS is challenging because its clinical signs are nonspecific, and blood culture, which is the current gold-standard diagnostic tool, has low sensitivity. Commonly used biomarkers for sepsis diagnosis, including C-reactive protein, procalcitonin, and interleukin-6, lack specificity for infection. Due to the disadvantages of blood culture and other common biomarkers, ongoing efforts are directed towards identifying innovative molecular approaches to diagnose neonates at risk of sepsis. This review aims to gather knowledge and recent research on these emerging molecular methods. PCR-based techniques and unrestricted techniques based on 16S rRNA sequencing and 16S-23S rRNA gene interspace region sequencing offer several advantages. Despite their potential, these approaches are not able to replace blood cultures due to several limitations; however, they may prove valuable as complementary tests in neonatal sepsis diagnosis. Several microRNAs have been evaluated and have been proposed as diagnostic biomarkers in EOS. T2 magnetic resonance and bioinformatic analysis have proposed potential biomarkers of neonatal sepsis, though further studies are essential to validate these findings.
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  • 文章类型: Journal Article
    The Xpert MTB/RIF Ultra is a recent advancement in molecular diagnostics of tuberculosis (TB) with higher sensitivity compared to its predecessor, the Xpert MTB/RIF assay. Prospective studies evaluating the performance of Xpert MTB/RIF Ultra in children with suspected TB are lacking. In this study, we evaluated the Xpert MTB/RIF Ultra for detection of Mycobacterium tuberculosis in samples from 156 children, of which one was excluded from the analysis. Of the remaining 155 samples, 6·5% (10/155), 21·3% (33/155), 20% (31/155) and 21·9% (34/155) were positive by smear examination, MGIT culture, Xpert MTB/RIF and Xpert MTB/RIF Ultra, respectively. The Xpert MTB/RIF and Xpert MTB/RIF Ultra had a similar overall sensitivity of 81·8% (95% CI: 64·5-93) and 84·8% (95% CI: 68·1-94·9), respectively. In suspected pediatric TB patients, the Xpert MTB/RIF Ultra had higher sensitivity compared to the Xpert MTB/RIF (72·7 vs 63·6). The AUC (area under the curve) of 0·905 for the Xpert MTB/RIF and 0·893 for the Xpert MTB/RIF Ultra indicate similar and good overall performance. Both Xpert assays were found to be equally efficient, however Xpert MTB/RIF Ultra showed better detection rate in suspected TB cases.
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  • 文章类型: Journal Article
    The aim of this study was to evaluate the secondary resistance in Helicobacter pylori (Hp) infected patients who had failed a first-line therapy, and to compare the genotypic tests performed directly on gastric samples with phenotypic tests performed on culture media. The eradication rate of patients treated with bismuth quadruple therapy (BQT) is also evaluated. A total of 80 positive specimens were retrospectively examined. Antibiotic susceptibility testing of Hp strains was performed by E-test, whereas a molecular commercially available method was used for detecting the mutations involved in clarithromycin and levofloxacin resistance. High resistance levels to metronidazole and clarithromycin (61.6% and 35%, respectively) and worrying resistance levels to levofloxacin (15%) were found phenotypically. Multiple resistance to two or three antibiotics was observed as well. The polymorphism A2143G on clarithromycin 23S rRNA gene was found in 34/80 (42.5%) isolates including 10 mixed infections (29%), whereas 28/80 (35%) strains were resistant phenotypically. Levofloxacin resistance corresponded to 30% by PCR and 15% by E-test (statistically significant, p < 0.05). The knowledge of clarithromycin and levofloxacin resistance is crucial to establish an appropriate therapy in different geographical areas. The genetic methods were superior to phenotypic techniques in the absence of live bacteria or for identifying mixed infections that may lead to a resistance underestimation. The BQT eradication rate was effective (90%).
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  • 文章类型: Journal Article
    Applying a desirable disinfestation process is necessary to control the pathogenic microorganisms in the swimming pools and prevent both dermal and intestinal effects. Therefore, the present study was conducted to compare the bacterial community and diversity in the two swimming pools disinfected by the chlorine and ozone (O3)-chlorine processes. A total of 24 samples were taken from the two swimming pools in three distinct seasons to analyze the bacterial and physico-chemical indicators. Culture and molecular methods were used to evaluate the microbial quality. Two sets of sample taken from the pools with the maximum swimmer load in the summer were investigated by the next-generation sequencing (NGS) technique. In total, 410 and 406 bacterial species were identified in the chlorine- and ozone-chlorine-disinfected pools, respectively. Among the eight dominant bacterial species in each swimming pool, Pseudomonas alcaliphila, Pseudomonas stutzeri, and Pseudomonas acnes were common species between the two studied pools. Oleomonas sagaranensis (350 reads/18593), Staphylococcus caprae (302 reads /18593), and Anaerococcus octavius (110 reads/18593) were among the dominant bacteria in the chlorine-disinfected pool. Bacterial diversity was lower in the ozone-chlorine-disinfected pool than the other one, and the highest bacterial sequencing belonged to the genus Pseudomonas (85.79%). Results showed that water quality of in O3-chlorine-disinfected pool was more desirable than the chlorine-disinfected pool. Molecular methods along with conventional culture methods would be advantageous for microbial assessment in the swimming pools.
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  • 文章类型: Journal Article
    恶性疟原虫具有复杂的生命周期,涉及与人类和蚊子宿主内部的多种组织相互作用。临床开发疟疾控制和根除工具迫切需要在恶性疟原虫生命周期的所有不同阶段鉴定必需基因。然而,恶性疟原虫的研究受到目前可用的遗传工具无法在其整个生命周期中对寄生虫进行遗传修饰的限制。这里,我们描述了在整个生命周期中表达雷帕霉素诱导的Cre重组酶的新的无标记恶性疟原虫寄生虫系的详细表征。利用这个寄生虫线,我们首次能够在三个不同的发育阶段有条件地删除必需的入侵配体AMA1。我们通过靶向非必需激酶FIKK7.1进一步证实了有效的基因缺失。重要性研究恶性疟原虫的主要限制之一是到目前为止,只有无性阶段才能进行快速条件遗传修饰。最有希望的药物靶点和候选疫苗,然而,由于它们在血液阶段或在蚊子媒介中传播是必不可少的,因此对遗传修饰是难以理解的。这在我们对大多数生命周期阶段的寄生虫蛋白的理解上留下了很大的差距,并阻碍了药物和疫苗靶标的遗传验证。这里,我们首次描述了一种支持恶性疟原虫生命周期中条件性基因缺失的方法。我们通过删除不同寄生虫阶段的必需和非必需基因来证明其潜力,这为疟疾和药物开发的研究开辟了全新的途径。它还可以允许使用减毒的寄生虫实现新的疫苗接种策略。
    Plasmodium falciparum has a complex life cycle that involves interaction with multiple tissues inside the human and mosquito hosts. Identification of essential genes at all different stages of the P. falciparum life cycle is urgently required for clinical development of tools for malaria control and eradication. However, the study of P. falciparum is limited by the inability to genetically modify the parasite throughout its life cycle with the currently available genetic tools. Here, we describe the detailed characterization of a new marker-free P. falciparum parasite line that expresses rapamycin-inducible Cre recombinase across the full life cycle. Using this parasite line, we were able to conditionally delete the essential invasion ligand AMA1 in three different developmental stages for the first time. We further confirm efficient gene deletion by targeting the nonessential kinase FIKK7.1.IMPORTANCE One of the major limitations in studying P. falciparum is that so far only asexual stages are amenable to rapid conditional genetic modification. The most promising drug targets and vaccine candidates, however, have been refractory to genetic modification because they are essential during the blood stage or for transmission in the mosquito vector. This leaves a major gap in our understanding of parasite proteins in most life cycle stages and hinders genetic validation of drug and vaccine targets. Here, we describe a method that supports conditional gene deletion across the P. falciparum life cycle for the first time. We demonstrate its potential by deleting essential and nonessential genes at different parasite stages, which opens up completely new avenues for the study of malaria and drug development. It may also allow the realization of novel vaccination strategies using attenuated parasites.
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  • 文章类型: Journal Article
    Clinical and Laboratory Standards Institute (CLSI) conditions for testing the susceptibilities of pathogenic Sporothrix species to antifungal agents are based on a collaborative study that evaluated five clinically relevant isolates of Sporothrixschenckii sensu lato and some antifungal agents. With the advent of molecular identification, there are two basic needs: to confirm the suitability of these testing conditions for all agents and Sporothrix species and to establish species-specific epidemiologic cutoff values (ECVs) or breakpoints (BPs) for the species. We collected available CLSI MICs/minimal effective concentrations (MECs) of amphotericin B, five triazoles, terbinafine, flucytosine, and caspofungin for 301 Sporothrix schenckii sensu stricto, 486 S. brasiliensis, 75 S. globosa, and 13 S. mexicana molecularly identified isolates. Data were obtained in 17 independent laboratories (Australia, Europe, India, South Africa, and South and North America) using conidial inoculum suspensions and 48 to 72 h of incubation at 35°C. Sufficient and suitable data (modal MICs within 2-fold concentrations) allowed the proposal of the following ECVs for S. schenckii and S. brasiliensis, respectively: amphotericin B, 4 and 4 μg/ml; itraconazole, 2 and 2 μg/ml; posaconazole, 2 and 2 μg/ml; and voriconazole, 64 and 32 μg/ml. Ketoconazole and terbinafine ECVs for S. brasiliensis were 2 and 0.12 μg/ml, respectively. Insufficient or unsuitable data precluded the calculation of ketoconazole and terbinafine (or any other antifungal agent) ECVs for S. schenckii, as well as ECVs for S. globosa and S. mexicana These ECVs could aid the clinician in identifying potentially resistant isolates (non-wild type) less likely to respond to therapy.
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  • 文章类型: Evaluation Study
    There is a need for improved methods for the study of the impacts of climatic and livestock management change on the epidemiology of production-limiting helminth parasitic diseases. In this study we report the application of molecular methods to describe the natural history of the small lancet fluke, Dicrocoelium dendriticum on Machair pastures on the Inner Hebridean Isle of Coll. Our results build upon those of the only previous historic field study of D. dendriticum in the British Isles that had been undertaken on the same study site. We demonstrate the value of combining conventional parasitological methods with PCR amplification of a mitochondrial DNA fragment for the detection of D. dendriticum in ants and snails, and PCR amplification of ITS2 and 28S ribosomal DNA fragments to support the species identity of the intermediate hosts, to improving understanding of the epidemiology of D. dendriticum. We report the presence of D. dendriticum infection in cattle, sheep and rabbits grazing on Machair pastures. D. dendriticum infection was identified in a high percentage of the snails, identified as Cochlicella acuta and Cernuella virgata, and in a high percentage of Formica fusca and Myrmica ruginoides ants that were collected from, or clinging to, the tops of flowers. We have identified the involvement of different intermediate host species and higher prevalences of snail and ant infection than previously reported, in part reflecting differences between the sensitivity and specificity of morphological and molecular speciation methods. Overall, our results highlight the complex life history of dicrocoeliosis and illustrate the parasite\'s generalist host strategy that confers potential to exploit new niches created by climatic change or grazing management for habitat conservation.
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  • DOI:
    文章类型: Journal Article
    OBJECTIVE: The US Environmental Protection Agency has suggested faecal enterococci as the primary bacterial indicators. Of more importance is their direct correlation with swimmer-associated gastroenteritis in recreation water quality monitoring. In contrast to other seawater bodies with 3.5% salinity, the recreational waters in the southern coast of the Caspian Sea possess its own salinity (about 1% w/v) and thus require further investigations to determine the capacity of Enterococcus faecalis as the sole primary microbial index in this unique aquatic environment.
    METHODS: The survey of the presence and survival of E. faecalis as a microbial index in the recreational waters of the southern Caspian Sea was carried out using a microcosm as an experimental model. The concentration of E. faecalis cells in samples of seawater were estimated by a standard membrane filtration method using m-Enterococcus agar as the selective culture medium. As the current standard culture-based methods are not reliable enough for the detection of non-growing, damaged and under-tension bacteria, PCR was used to identify the possible VBNC form of the bacterium after disappearance of the culturable cells.
    CONCLUSIONS: A continuous decline in the number of culturable E. faecalis cells resulted in apparent elimination of the bacteria from seawater in a defined period. Detection of intact DNA was possible in the following 60 days. The salinity of about 1% and the self-purification properties of the Caspian Sea make the conditions feasible for the use of this microorganism as a measure of water quality throughout the region. The results confirmed the presence of damaged bacterial cells, namely VBNC forms, indicating the necessity of examining of the sea water samples by using molecular approaches or repair procedures.
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  • 文章类型: Journal Article
    BACKGROUND: In 2013-2014 Greece experienced a resurgence of severe influenza cases, coincidental with a shift to H1N1pdm09 predominance. We sought to estimate Vaccine Effectiveness (VE) for this season using available surveillance data from hospitals (including both inpatients and outpatients).
    METHODS: Swab samples were sent by hospital physicians to one of three laboratories, covering the entire country, to be tested for influenza using RT-PCR. The test-negative design was employed, with patients testing positive serving as cases and those testing negative serving as controls. VE was estimated using logistic regression, adjusted for age group, sex, region and calendar time, with further adjustment for unknown vaccination status using inverse response propensity weights. Additional age group stratified estimates and subgroup estimates of VE against H1N1pdm09 and H3N2 were calculated.
    RESULTS: Out of 1310 patients with known vaccination status, 124 (9.5%) were vaccinated, and 543 patients (41.5%) tested positive for influenza. Adjusted VE was 34.5% (95% CI: 4.1-55.3%) against any influenza, and 56.7% (95% CI: 22.8-75.7%) against H1N1pdm09. VE estimates appeared to be higher for people aged 60 and older, while in those under 60 there was limited evidence of effectiveness. Isolated circulating strains were genetically close to the vaccine strain, with limited evidence of antigenic drift.
    CONCLUSIONS: These results suggest a moderate protective effect of the 2013-2014 influenza vaccine, mainly against H1N1pdm09 and in people aged 60 and over. Vaccine coverage was very low in Greece, even among groups targeted for vaccination, and substantial efforts should be made to improve it. VE can and should be routinely monitored, and the results taken into account when deciding on influenza vaccine composition for next season.
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