Antigenemia immunoassay for point of care dianostic melioidosis

类鼻疽的实验室诊断现状目前，从多个身体部位培养是金 实验室诊断标准。培养需要有经验的人员，需要3-4天。水平 菌血症非常低（~ 1CFU/ml）。用于诊断类鼻疽的即时免疫测定可以极大地 因为高比例急性败血症患者在24-48小时内死亡， 经验性治疗败血症的抗生素对B无效。假鼻疽 由于在急性脓毒症的早期阶段缺乏抗体， 流行地区背景抗体水平高（6）。几项研究报道了PCR检测B。 假鼻疽，但报告的检测下限往往低于范围内的活菌 人类疾病期间的血液计数（118）。 类鼻疽免疫诊断的潜在抗原靶点细胞外 多糖已成功用于多种细菌感染。B有三种候选抗原。类鼻疽：胞外多糖（EPS）、荚膜多糖（CPS）和脂多糖（LPS）。EPS是重复四糖的无支链聚合物：[-3）-p-D-Galp 2Ac-（i-4）-a-D-Galp-（i-3）-p-D-Galp-（i-5）-|3-Kdo-（2-]（115）. CPS是[-3]-2-O-乙酰基-6-脱氧-β-D-甘露庚吡喃糖-（ i-]（120）。LPS是具有基本结构的二糖重复单元的无支链聚合物， 结构：[-3-）-|3-D-吡喃葡萄糖-（i-3）-6-脱氧-a-L-吡喃塔罗糖-（i-]（120）。类鼻疽患者产生EPS、CPS和LPS的抗体，表明这些抗原是在体内产生的。到目前为止，没有B。已经鉴定了类鼻疽假单胞菌蛋白作为类鼻疽病的抗原靶向诊断的候选物。所提出的InMAD工艺具有识别B的潜力。类鼻疽抗原在体内脱落，可以作为许多微生物威胁的快速广泛发现平台。

Status of laboratory diagnosis of melioidosis Currently, culture from multiple body sites is the gold standard for laboratory diagnosis. Culture requires experienced personnel and takes 3-4 days. Levels of bacteremia are very low (~ i CFU/ml). A point-of-care immunoassay for diagnosis of melioidosis could greatly impact patient outcome because a high percentage of patients with acute septicemia die within 24-48 h of admission, and the antibiotics used for empiric treatment of septicemia are not effective for B. pseudomallei. Assays for antibody have limited value due to an absence of antibody in the early stages of acute sepsis and a high level of background antibodies in endemic regions (6). Several studies reported PCR for detection of B. pseudomallei, but the reported lower limit of detection tends to fall above the range for the viable bacteria count in blood during human disease (118). Potential antigen targets for immunodiagnosis of melioidosis Detection of extracellular polysaccharides has been successful for a variety of bacterial infections. There are three candidate antigens for B. pseudomallei: the exopolysaccharide (EPS), the capsular polysaccharide (CPS), and the lipopolysaccharide (LPS). EPS is an unbranched polymer of a repeating tetrasaccharide: [-3)-p-D-Galp2Ac-(i-4)-a-D-Galp-(i-3)-p-D-Galp-(i-5)-|3-Kdo-(2-] (115). CPS is an unbranched homopolymer of [-3)-2-O-acetyl-6-deoxy-p-D-mannoheptopyranose-( i-] (120). LPS is an unbranched polymer of disaccharide repeating units having the basic structure: [-3-)-|3-D-glucopyranose-(i-3)-6-deoxy-a-L-talopyranose-(i-] (120). Melioidosis patients make antibodies to EPS, CPS and LPS, indicating that these antigens are produced in vivo. To date, no B. pseudomallei proteins have been identified as candidates for antigen-targeted diagnosis of melioidosis. The proposed InMAD process has the potential to identify B. pseudomallei antigens shed in vivo and may serve as a rapid broad discovery platform for many microbial threats.