Public Health Wales Microbiology Cardiff, University Hospital of Wales, Heath Park, Cardiff, UK.
Department of Infection, Immunity and Biochemistry, Cardiff University, University Hospital of Wales, Heath Park, Cardiff, UK.
J Med Microbiol. 2014 Sep;63(Pt 9):1160-1166. doi: 10.1099/jmm.0.076315-0. Epub 2014 Jul 1.
Invasive aspergillosis is a significant cause of morbidity and mortality within at-risk groups. Directed antifungal chemotherapy, guided by effective screening algorithms that incorporate reliable and validated molecular assays, reduces the morbidity associated with empirical administration and allows earlier diagnosis. The efficient extraction of nucleic acid from Aspergillus fumigatus is the main limiting factor for successful Aspergillus PCR from clinical specimens. With the integration of automated extraction platforms, assessment of the suitability of these platforms for specific targets is of paramount importance. In this study, four extraction robots (Applied Biosystems MagMAX, bioMérieux easyMAG, Qiagen EZ1 and Roche MagNA Pure LC) were evaluated for their ability to extract clinically significant levels of A. fumigatus from blood. All of the platforms could detect 10(1) c.f.u. ml(-1) from EDTA whole blood, although only the easyMAG, EZ1 and MagNA Pure had 100 % reproducibility at this level. Despite good analytical sensitivity, contamination associated with the easyMAG platform excluded its use for diagnostic Aspergillus PCR. The EZ1 and MagNA Pure platforms demonstrated equivalent high sensitivity and negative predictive values (97.4-100 %), essential for screening assays.
侵袭性曲霉菌病是高危人群发病和死亡的重要原因。通过有效的筛查算法指导使用靶向抗真菌化疗，这些算法纳入了可靠和经过验证的分子检测，可减少经验性治疗相关的发病率，并有助于更早诊断。从临床标本中成功进行曲霉 PCR 的主要限制因素是从烟曲霉中有效提取核酸。随着自动化提取平台的整合，评估这些平台针对特定靶标的适用性至关重要。在这项研究中，评估了四个提取机器人（Applied Biosystems MagMAX、bioMérieux easyMAG、Qiagen EZ1 和 Roche MagNA Pure LC）从血液中提取临床相关水平烟曲霉的能力。所有平台都能够从 EDTA 全血中检测到 10(1) c.f.u. ml(-1)，尽管只有 easyMAG、EZ1 和 MagNA Pure 在该水平上具有 100%的重现性。尽管具有良好的分析灵敏度，但与 easyMAG 平台相关的污染排除了其用于诊断性曲霉 PCR 的应用。EZ1 和 MagNA Pure 平台表现出等效的高灵敏度和阴性预测值（97.4-100%），这对筛选检测很重要。
