Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America.
Department of Mathematics and Statistics, Northern Arizona University, Flagstaff, Arizona, United States of America.
PLoS Negl Trop Dis. 2023 Feb 8;17(2):e0011067. doi: 10.1371/journal.pntd.0011067. eCollection 2023 Feb.
Melioidosis is a disease caused by the bacterium Burkholderia pseudomallei, infecting humans and non-human primates (NHP) through contaminated soil or water. World-wide there are an estimated 165,000 human melioidosis cases each year, but recordings of NHP cases are sporadic. Clinical detection of melioidosis in humans is primarily by culturing B. pseudomallei, and there are no standardized detection protocols for NHP. NHP are an important animal model for melioidosis research including clinical trials and development of biodefense countermeasures.
METHODOLOGY/PRINCIPLE FINDINGS: We evaluated the diagnostic potential of the multiple antigen serological assay, BurkPx, in NHP using two sera sets: (i) 115 B. pseudomallei-challenged serum samples from 80 NHP collected each week post-exposure (n = 52) and at euthanasia (n = 47), and (ii) 126 B. pseudomallei-naïve/negative serum samples. We observed early IgM antibody responses to carbohydrate antigens followed by IgG antibody recognition to multiple B. pseudomallei protein antigens during the second week of infection. B. pseudomallei negative serum samples had low to intermediate antibody cross reactivity to the antigens in this assay. Infection time was predicted as the determining factor in the variation of antibody responses, with 77.67% of variation explained by the first component of the principal component analysis. A multiple antigen model generated a binary prediction metric ([Formula: see text]), which when applied to all data resulted in 100% specificity and 63.48% sensitivity. Removal of week 1 B. pseudomallei challenged serum samples increased the sensitivity of the model to 95%.
CONCLUSION/SIGNIFICANCE: We employed a previously standardized assay for humans, the BurkPx assay, and assessed its diagnostic potential for detection of B. pseudomallei exposure in NHP. The assay is expected to be useful for surveillance in NHP colonies, in investigations of suspected accidental releases or exposures, and for identifying vaccine correlates of protection.
类鼻疽病是由伯克霍尔德氏菌引起的疾病，通过受污染的土壤或水感染人类和非人类灵长类动物（NHP）。全球每年估计有 165,000 例人类类鼻疽病病例，但 NHP 病例的记录较为零散。人类类鼻疽病的临床检测主要通过培养伯克霍尔德氏菌来实现，而 NHP 则没有标准化的检测方案。NHP 是类鼻疽病研究的重要动物模型，包括临床试验和生物防御对策的开发。
方法/原理发现：我们使用两个血清集评估了多抗原血清学检测法（BurkPx）在 NHP 中的诊断潜力：（i）从 80 只暴露后每周（n = 52）和安乐死（n = 47）时采集的 115 份受 Burkholderia pseudomallei 挑战的 NHP 血清样本，以及（ii）126 份 Burkholderia pseudomallei 阴性/阴性血清样本。我们观察到在感染后的第二周内，针对碳水化合物抗原的早期 IgM 抗体反应，随后是针对多种 Burkholderia pseudomallei 蛋白抗原的 IgG 抗体识别。在该检测法中，Burkholderia pseudomallei 阴性血清样本的抗原抗体交叉反应性较低或中等。感染时间是决定抗体反应变化的因素，主成分分析的第一成分解释了 77.67%的变异。多抗原模型生成了一个二元预测指标（[公式：见文本]），将其应用于所有数据可实现 100%的特异性和 63.48%的灵敏度。去除第 1 周的 Burkholderia pseudomallei 挑战血清样本后，该模型的灵敏度提高到 95%。
结论/意义：我们使用了以前标准化的人类检测法，即 BurkPx 检测法，并评估了其在 NHP 中检测 Burkholderia pseudomallei 暴露的诊断潜力。该检测法有望用于 NHP 群体的监测，调查疑似意外释放或暴露事件，并识别疫苗保护相关因素。
