Cossio Alexandra, Jojoa Jimena, Castro María Del Mar, Castillo Ruth Mabel, Osorio Lyda, Shelite Thomas R, Gore Saravia Nancy, Melby Peter C, Travi Bruno L
Centro Internacional de Entrenamiento e Investigaciones Médicas, CIDEIM, Cali, Colombia.
Universidad Icesi, Cali, Colombia.
PLoS Negl Trop Dis. 2021 Apr 28;15(4):e0009291. doi: 10.1371/journal.pntd.0009291. eCollection 2021 Apr.
Control of cutaneous leishmaniasis by public health systems in the Americas relies on case identification and treatment. Point-of-care diagnostics that can be performed by health workers within or near affected communities could effectively bring the health system to the resource-limited sites providing early diagnosis and treatment, reducing morbidity and the burden of disease.
METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional study was undertaken to evaluate the diagnostic test performance of Isothermal Recombinase Polymerase Amplification (RPA) targeting Leishmania kinetoplast DNA, coupled with a lateral flow (LF) immunochromatographic strip, in a field setting and a laboratory reference center. Minimally invasive swab and FTA filter paper samples were obtained by community health workers and highly trained technicians from ulcerated lesions of > 2 weeks' evolution from 118 patients' ≥ 2 years of age in the municipality of Tumaco, Nariño. Extracted DNA was processed by RPA-LF at a reference center or in a primary health facility in the field. Evaluation was based on a composite "gold standard" that included microscopy, culture, biopsy and real-time polymerase chain reaction detection of Leishmania 18S rDNA. Standard of care routine diagnostic tests were explored as comparators. Sensitivity and specificity of RPA-LF in the reference lab scenario were 87% (95%CI 74-94) and 86% (95%CI 74-97), respectively. In the field scenario, the sensitivity was 75% (95%CI 65-84) and specificity 89% (95%CI 78-99). Positive likelihood ratios in both scenarios were higher than 6 while negative likelihood ratios ranged to 0.2-0.3 supporting the usefulness of RPA-LF to rule-in and potentially to rule-out infection.
CONCLUSIONS/SIGNIFICANCE: The low complexity requirements of RPA-LF combined with non-invasive sampling support the feasibility of its utilization by community health workers with the goal of strengthening the diagnostic capacity for cutaneous leishmaniasis in Colombia.
ClinicalTrials.gov NCT04500873.
美洲公共卫生系统对皮肤利什曼病的控制依赖于病例识别和治疗。由卫生工作者在受影响社区内或附近进行的即时诊断能够有效地将卫生系统延伸至资源有限的地区，实现早期诊断和治疗，从而降低发病率和疾病负担。
方法/主要发现：开展了一项横断面研究，以评估针对利什曼原虫动质体DNA的等温重组酶聚合酶扩增（RPA）结合侧向流动（LF）免疫层析试纸条在现场环境和实验室参考中心的诊断测试性能。社区卫生工作者和训练有素的技术人员从纳里尼奥省图马科市118名年龄≥2岁、溃疡病变超过2周的患者身上采集了微创拭子和FTA滤纸样本。提取的DNA在参考中心或现场的初级卫生设施中通过RPA-LF进行处理。评估基于包括显微镜检查、培养、活检和利什曼原虫18S rDNA实时聚合酶链反应检测在内的综合“金标准”。将常规护理诊断测试作为对照进行研究。在参考实验室环境中，RPA-LF的敏感性和特异性分别为87%（95%CI 74-94）和86%（95%CI 74-97）。在现场环境中，敏感性为75%（95%CI 65-84），特异性为89%（95%CI 78-99）。两种环境下的阳性似然比均高于6，而阴性似然比在0.2-0.3之间，这支持了RPA-LF用于确诊和潜在排除感染的有效性。
结论/意义：RPA-LF对复杂性要求较低，结合非侵入性采样，支持社区卫生工作者使用该方法的可行性，目的是加强哥伦比亚皮肤利什曼病的诊断能力。
ClinicalTrials.gov NCT04500873。
