Development of an Immunochromatographic Test for Rapid Serodiagnosis of Human Pythiosis

Abstract

Human pythiosis is an emerging and life-threatening infectious disease caused by the fungus-like organism Pythium insidiosum. High rates of morbidity and mortality for patients with pythiosis are exacerbated by the lack of early diagnosis and an effective treatment. Here, we developed and evaluated an immunochromatographic test (ICT) for the diagnosis of human pythiosis, in comparison to a standard serological test of immunodiffusion (ID). Culture filtrate antigen of P. insidiosum was used to detect human anti-P. insidiosum antibody. Sheep anti-human immunoglobulin G-colloidal gold conjugate was used to generate an ICT signal. Thirty-three sera from patients with vascular (n ‫؍‬ 27), ocular (n ‫؍‬ 4), and cutaneous (n ‫؍‬ 2) pythiosis and 181 control sera from healthy blood donors (n ‫؍‬ 100), as well as patients with a variety of infectious (n ‫؍‬ 56) and noninfectious (n ‫؍‬ 25) diseases, were included in the test evaluation. The turnaround time for generating a result by the ICT was less than 30 min, while that for ID was ϳ24 h. Based on the results for all sera of pythiosis patients and the control groups, the ICT showed 88% sensitivity and 100% specificity and ID showed 61% sensitivity and 100% specificity. By both tests, false-negative results for sera from all ocular pythiosis patients were obtained. In addition, the ID test yielded false-negative results for sera from eight patients with vascular pythiosis and one patient with cutaneous pythiosis. It was concluded that the ICT is a rapid, user-friendly, and reliable serological test for the early diagnosis of vascular and cutaneous pythiosis.

Hemagglutination Test for Rapid Serodiagnosis of Human Pythiosis

“…The ID test gave false-negative test results for nine proven cases of vascular and cutaneous pythiosis, while the HA test correctly detected these cases. Our work confirmed the results of previous studies showing that the ID test has poor sensitivity (11,12). The assay turnaround time for the HA test (1 h) was significantly shorter than that for the ID test (24 h).…”

“…Serodiagnosis of pythiosis commonly relies on an immunodiffusion (ID) test. Although the ID test is highly specific, it has very poor sensitivity (11,12,21,25). Subsequently, other diagnostic methods, such as an in-house enzyme-linked immunosorbent assay (ELISA), an immunochromatographic test (ICT), a Western blot assay, and a PCR assay, were developed and have good specificity and sensitivity (11-13, 20, 22, 32).…”

An ultrasensitive competitive immunochromatographic assay (ICA) based on surface-enhanced Raman scattering (SERS) for direct detection of 3-amino-5-methylmorpholino-2-oxazolidinone (AMOZ) in tissue and urine samples

“…The main features of the GNPs-based ICA are the user-friendly operation, quickly obtained results, less interference due to chromatographic separation, a relatively low cost, and fairly good shelf life [21]. ICA has been widely used for rapid detection of toxic or harmful substances in many fields such as food safety monitoring and point-of-care diagnostics [22][23][24][25][26][27]. Although the conventional qualitative analysis can meet the needs of detection some analytes (e.g., pregnancy testing), it is not suitable in some cases when the quantitative level of an analyte is important [28].…”

Development of an Anti-Elicitin Antibody-Based Immunohistochemical Assay for Diagnosis of Pythiosis

“…The current diagnostic modalities, including culture identification (9)(10)(11), serodiagnosis (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22), and molecular-based detection (22)(23)(24)(25)(26)(27), are fraught with problems. For example, culture identification is time-consuming and often fails to grow and to identify the organism.…”