GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub Typhus

A point-of-care diagnostic for early and rapid diagnosis of scrub typhus caused by <i>Orientia tsutsugamushi</i> is required for prompt and proper treatment of patients presenting with undifferentiated febrile illnesses. In this study, an immunochromatographic antigen detection test kit...

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Main Authors: Nitaya Indrawattana, Pisinee Aiumurai, Nawannaporn Sae-lim, Watee Seesuay, Onrapak Reamtong, Manas Chongsa-nguan, Wanpen Chaicumpa, Nitat Sookrung
Format: Article
Language:English
Published: MDPI AG 2022-01-01
Series:Diagnostics
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Online Access:https://www.mdpi.com/2075-4418/12/1/136
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author Nitaya Indrawattana
Pisinee Aiumurai
Nawannaporn Sae-lim
Watee Seesuay
Onrapak Reamtong
Manas Chongsa-nguan
Wanpen Chaicumpa
Nitat Sookrung
author_facet Nitaya Indrawattana
Pisinee Aiumurai
Nawannaporn Sae-lim
Watee Seesuay
Onrapak Reamtong
Manas Chongsa-nguan
Wanpen Chaicumpa
Nitat Sookrung
author_sort Nitaya Indrawattana
collection DOAJ
description A point-of-care diagnostic for early and rapid diagnosis of scrub typhus caused by <i>Orientia tsutsugamushi</i> is required for prompt and proper treatment of patients presenting with undifferentiated febrile illnesses. In this study, an immunochromatographic antigen detection test kit (ICT AgTK) that targets the highly conserved <i>O. tsutsugamushi</i> 60 kDa GroEL chaperonin (heat shock protein 60) was developed. <i>E. coli</i>-derived recombinant GroEL expressed from DNA coding for the consensus sequence of 32 GroEL gene sequences extracted from the GenBank database was used to immunize rabbits and mice. Rabbit polyclonal antibodies (pAb) were used for preparing a gold-pAb conjugate, and the rGroEL-specific mouse monoclonal antibody was used as the antigen detection reagent at the ICT test line. In-house validation revealed that the ICT AgTK gave 85, 100 and 95% diagnostic sensitivity, specificity and accuracy, respectively, compared to the combined clinical features and standard IFA when tested on 40 frozen serum samples. The test kits correctly identified 10 scrub typhus samples out of 15 fresh plasma/buffy coat samples of patients with febrile illnesses. For independent laboratory validation, the ICT AgTK was sent to one provincial hospital. The ICT AgTK utilized by the hospital medical technologist correctly identified six scrub typhus samples out of 20 serum samples of patients with fever, as confirmed by specific IgM/IgG detection by IFA. The ICT AgTK is easy to perform with rapid turn-around time. It has the potential to be used as an important tool for on-site and early scrub typhus diagnosis by allowing testing of freshly collected samples (serum, plasma or buffy coat), especially in resource-limited healthcare settings.
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spelling doaj.art-79a603941e824acdab07217fa243818a2023-11-23T13:28:52ZengMDPI AGDiagnostics2075-44182022-01-0112113610.3390/diagnostics12010136GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub TyphusNitaya Indrawattana0Pisinee Aiumurai1Nawannaporn Sae-lim2Watee Seesuay3Onrapak Reamtong4Manas Chongsa-nguan5Wanpen Chaicumpa6Nitat Sookrung7Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, ThailandCenter of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitolgy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, ThailandCenter of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitolgy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, ThailandCenter of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitolgy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, ThailandDepartment of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, ThailandDepartment of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, ThailandCenter of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitolgy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, ThailandCenter of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitolgy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, ThailandA point-of-care diagnostic for early and rapid diagnosis of scrub typhus caused by <i>Orientia tsutsugamushi</i> is required for prompt and proper treatment of patients presenting with undifferentiated febrile illnesses. In this study, an immunochromatographic antigen detection test kit (ICT AgTK) that targets the highly conserved <i>O. tsutsugamushi</i> 60 kDa GroEL chaperonin (heat shock protein 60) was developed. <i>E. coli</i>-derived recombinant GroEL expressed from DNA coding for the consensus sequence of 32 GroEL gene sequences extracted from the GenBank database was used to immunize rabbits and mice. Rabbit polyclonal antibodies (pAb) were used for preparing a gold-pAb conjugate, and the rGroEL-specific mouse monoclonal antibody was used as the antigen detection reagent at the ICT test line. In-house validation revealed that the ICT AgTK gave 85, 100 and 95% diagnostic sensitivity, specificity and accuracy, respectively, compared to the combined clinical features and standard IFA when tested on 40 frozen serum samples. The test kits correctly identified 10 scrub typhus samples out of 15 fresh plasma/buffy coat samples of patients with febrile illnesses. For independent laboratory validation, the ICT AgTK was sent to one provincial hospital. The ICT AgTK utilized by the hospital medical technologist correctly identified six scrub typhus samples out of 20 serum samples of patients with fever, as confirmed by specific IgM/IgG detection by IFA. The ICT AgTK is easy to perform with rapid turn-around time. It has the potential to be used as an important tool for on-site and early scrub typhus diagnosis by allowing testing of freshly collected samples (serum, plasma or buffy coat), especially in resource-limited healthcare settings.https://www.mdpi.com/2075-4418/12/1/136antigen detection test kitscrub typhusGroEL chaperonin<i>Orientia tsutsugamushi</i>hybridomaimmunochromatography (ICT)
spellingShingle Nitaya Indrawattana
Pisinee Aiumurai
Nawannaporn Sae-lim
Watee Seesuay
Onrapak Reamtong
Manas Chongsa-nguan
Wanpen Chaicumpa
Nitat Sookrung
GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub Typhus
Diagnostics
antigen detection test kit
scrub typhus
GroEL chaperonin
<i>Orientia tsutsugamushi</i>
hybridoma
immunochromatography (ICT)
title GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub Typhus
title_full GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub Typhus
title_fullStr GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub Typhus
title_full_unstemmed GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub Typhus
title_short GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub Typhus
title_sort groel chaperonin based assay for early diagnosis of scrub typhus
topic antigen detection test kit
scrub typhus
GroEL chaperonin
<i>Orientia tsutsugamushi</i>
hybridoma
immunochromatography (ICT)
url https://www.mdpi.com/2075-4418/12/1/136
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