Development of a New Genus-Specific Quantitative Real-Time PCR Assay for the Diagnosis of Scrub Typhus in South America
Journal
Frontiers in Medicine
ISSN
2296-858X
Date Issued
2022
Author(s)
Ju Jiang
Constanza Martínez-Valdebenito
Christina M. Farris
Gerardo Acosta-Jamett
Katia Abarca
Allen L. Richards
Type
Resource Types::text::journal::journal article
URL Institutional Repository
Abstract
<jats:p>Scrub typhus is a potentially severe rickettsiosis, caused by <jats:italic>Orientia tsutsugamushi</jats:italic> in the Asia-Pacific region. Recently, however, two distinct pathogens, “<jats:italic>Candidatus</jats:italic> Orientia chuto” and “<jats:italic>Candidatus</jats:italic> Orientia chiloensis”, have been discovered in the Middle East and South America, respectively. Since the novel pathogens differ significantly from <jats:italic>O. tsutsugamushi</jats:italic>, many established diagnostic methods are unreliable. This work describes the development and validation of a new quantitative real-time PCR (qPCR) assay (Orien16S) for the detection of all known <jats:italic>Orientia</jats:italic> species. Based on a 94 bp sequence of the 16S rRNA gene (<jats:italic>rrs</jats:italic>), Orien16S recognized DNA samples from <jats:italic>O. tsutsugamushi</jats:italic> (<jats:italic>n</jats:italic> = 41), <jats:italic>Ca.</jats:italic> O. chiloensis (<jats:italic>n</jats:italic> = 5), and <jats:italic>Ca.</jats:italic> O. chuto (<jats:italic>n</jats:italic> = 1), but was negative for DNA preparations from closely related rickettsiae and other members of the order Rickettsiales (<jats:italic>n</jats:italic> = 22) as well as unrelated bacterial species (<jats:italic>n</jats:italic> = 11). After its implementation in Chile, the assay was verified, correctly identifying all tested eschar and buffy coat samples (<jats:italic>n</jats:italic> = 28) of clinical suspected cases. Furthermore, Orien16S detected <jats:italic>Orientia</jats:italic> DNA in trombiculid mites collected in endemic regions in southern Chile. The presented novel qPCR assay provides a useful tool for detecting <jats:italic>Orientia</jats:italic> and diagnosing scrub typhus from all geographical regions.</jats:p>
Cite this document
Jiang, J., Martínez-Valdebenito, C., Weitzel, T., Farris, C. M., Acosta-Jamett, G., Abarca, K., & Richards, A. L. (2022). Development of a new genus-specific quantitative real-time pcr assay for the diagnosis of scrub typhus in south america. Frontiers in Medicine, 9, 831045. https://doi.org/10.3389/fmed.2022.831045
Subjects
orientia
;
identification
;
rickettsiae