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Short report: variation in the 56-kD type-specific antigen gene of Orientia tsutsugamushi isolated from patients in Thailand.

The sequences of a 300-base pair region of the 56-kD type-specific antigen gene from 12 Orientia tsutsugamushi isolates from Thailand were compared with isolates from other regions in Asia. A high degree of heterogeneity was found among the 12 Thai isolates, with the C3 strain most commonly found. The abundance of the C3 strain of O. tsutsugamushi is of particular concern because doxycycline and chloramphenicol resistance have previously been reported in this strain.

Genetic recombination of Orientia tsutsugamushi strains from scrub typhus patients in Guangxi, Southwest China, and the analysis of clinical features.

Three Orientia tsutsugamushi genotypic groups belonging to two prototypes (Gilliam and Karp) were identified in scrub typhus patients from Guangxi, Southwest China. Fever, headache, pneumonia, fatigue, chill, and anorexia were the most common clinical signs. Frequent recombination was observed for their 47-kDa gene compared to 56-kDa and 16S genes. Furthermore, patients infected with the Gilliam prototype represent a much higher proportion of pneumonia (6/6, 100%) than those infected with the Karp prototype (4/8, 50%) (p-value = 0.040). This discrepancy is consistent with recent animal tests o…

Use of chimeric antibodies as positive controls in an enzyme-linked immunosorbent assay for diagnosis of scrub typhus (infection by Orientia tsutsugamushi).

The use of human sera collected from individuals of known infected and noninfected status is necessary for the validation of diagnostic assa … ve investigated the potential use of chimeric IgG with specificity for the major surface antigen of Orientia tsutsugamushi as an alternative positive control for inclusion in a commercial enzyme-linked immunosorbent assay kit for the diagnosis of rickettsia scrub typhus (caused by infection with O. tsutsugamushi). Chimeric IgG was expressed in stably trans …

Correction: Orientia tsutsugamushi Stimulates an Original Gene Expression Program in Monocytes: Relationship with Gene Expression in Patients with Scrub Typhus.

[This corrects the article DOI: 10.1371/journal.pntd.0001028.].

A high-resolution nested PCR assay for genotyping Orientia tsutsugamushi based on a defined 700 bp segment of the TSA56 gene.

OBJECTIVES: To define a reproducibly specified TSA56 fragment that preserves genotype assignment relative to the full-length gene and to establish a standardized sequence-based genotyping workflow using nested PCR and phylogenetic assignment. METHODS: We screened 355 complete TSA56 sequences across the gene and designed nested primers to generate an ∼800-bp amplicon covering the selected segment. Analytical performance was assessed across 17 genotypes, clinical applicability was evaluated in 216 acute-phase blood samples, and interlaboratory agreement was assessed across three laboratories.

"Acute encephalitis syndrome in adults: Molecular and serological evidence of Orientia tsutsugamushi infection in Puducherry and neighboring districts of Tamil Nadu".

BACKGROUND: Scrub typhus has emerged as a prominent etiological agent of acute encephalitis syndrome (AES) in India. However, there is a dearth of information on its involvement in AES in South India. Knowing the specific etiology and its prevalence would help in the definitive management of patients, perhaps improving morbidity and mortality. METHODS: A cross-sectional descriptive study was performed in Pondicherry to determine the proportion of adult patients with Orientia tsutsugamushi infection causing AES between January 2020 and December 2021. Diagnosis was performed by a combination of…

Microbiome and mitogenomics of the chigger mite Pentidionis agamae: potential role as an Orientia vector and associations with divergent clades of Wolbachia and Borrelia.

BACKGROUND: Trombiculid mites are globally distributed, highly diverse arachnids that largely lack molecular resources such as whole mitogenomes for the elucidation of taxonomic relationships. Trombiculid larvae (chiggers) parasitise vertebrates and can transmit bacteria (Orientia spp.) responsible for scrub typhus, a zoonotic febrile illness. Orientia tsutsugamushi causes most cases of scrub typhus and is endemic to the Asia-Pacific Region, where it is transmitted by Leptotrombidium spp. chiggers. However, in Dubai, Candidatus Orientia chuto was isolated from a case of scrub typhus and is als…

Hosts and vectors of scrub typhus in Chile: epidemiological study and molecular analyses of Orientia infection in rodents and rodent-associated mites.

Candidatus Orientia chiloensis causes scrub typhus over a wide geographical range in southern Chile. The life cycle, including vectors and reservoirs of this novel rickettsial pathogen, is incompletely understood. We analyzed rodent tissue and rodent-associated mite samples collected during a field study in six localities on Chiloé Island, where human scrub typhus cases have occurred. Using molecular methods, we detected Orientia DNA in 24.8% of rodents, belonging to five of seven captured species. Orientia-infection rates showed geographical variations, but were not influenced by rodent speci…

Detection of Immunoglobulin M and Immunoglobulin G Antibodies Against Orientia tsutsugamushi for Scrub Typhus Diagnosis and Serosurvey in Endemic Regions.

OBJECTIVE: To estimate the regional cutoff of optical density (OD) values for immuno-globulin M (IgM) antibodies against Orientia tsutsugamushi in serum and cerebrospinal fluid (CSF) for clinical diagnosis of scrub typhus and immunoglobulin G (IgG) antibodies in serum for sero-epidemiology in Gorakhpur, Uttar Pradesh, India. METHODS: We used data from a serological investigation of acute encephalitis syndrome patients (n=407) during the 2016 outbreak in Gorakhpur, India to determine the cutoff for OD values for IgM antibodies, and from community-based serosurveys (n=1991) to estimate the cuto…

Bacterial microbiome of the chigger mite Leptotrombidium imphalum varies by life stage and infection with the scrub typhus pathogen Orientia tsutsugamushi.

Scrub typhus is a mites-borne rickettsiosis caused by the obligate intracellular Gram-negative bacterium Orientia tsutsugamushi. The disease is potentially life threatening and is prevalent in tropical Asia, islands of the western Pacific Ocean and northern Australia where an estimated one million cases occur annually. Orientia tsutsugamushi is transmitted by the bite of larval mites in the genus Leptotrombidium. In the present study, the composition of the microbiome in larvae, deutonymphs and adult males and females from laboratory colonies of L. imphalum that were infected as well as uninfe…

Use of eschar swabbing for the molecular diagnosis and genotyping of Orientia tsutsugamushi causing scrub typhus in Quang Nam province, Vietnam.

BACKGROUND: Scrub typhus is a rickettsiosis which is caused by Orientia tsutsugamushi and occurs throughout the Asia-Pacific region. Molecular diagnosis of rickettsioses using eschar swabs has recently emerged, and may be very useful for the diagnosis of these diseases in tropical settings. METHODOLOGY/PRINCIPAL FINDINGS: Quantitative polymerase chain reaction (qPCR) was used to detect O. tsutsugamushi DNA in whole blood and eschar swab specimens of 67 patients who were clinically suspected of scrub typhus in Quang Nam province, Vietnam. Among the 20 patients for whom both eschar and whole bl…

A highly sensitive quantitative real-time PCR assay based on the groEL gene of contemporary Thai strains of Orientia tsutsugamushi.

Partial nucleotide sequences (459 bp) of the groEL gene (encoding the 60-kDa heat shock protein, HSP60) from 23 contemporary isolates of Orientia tsutsugamushi isolated from patients with acute scrub typhus in Thailand were compared with 16 reference strain sequences to evaluate the potential of groEL as a conserved and representative target for molecular diagnostics.. Overall nucleotide identity within all available O. tsutsugamushi isolates (n = 39) was 98.8% (range: 95.0-100), reflecting a high degree of conservation; nucleotide identities were 67.5% and 65.6%, respectively, when typhus and…

Восстановление и жизнеспособность цутсугамуши из упакованных красных клеток и опасность получения тифа от переливания крови.

Цель этого исследования состояла в том, чтобы определить, может ли инфекционный Ориентия цуцугамуши, этиологический агент скруба тифа, пережить обычные процедуры обработки и хранения крови. СТРАТЕГИЯ И МЕТОДЫ: Моноядерные клетки, изолированные от цельной крови при центрифуге плотности, были привиты при помощи штамма О. Цутсугамуши, штамма Карпа. Инфекция мононуклеарных клеток была подтверждена пятном Джимсы, прямым флуоресцирующим антителным анализом и цепной реакцией полимеразы с использованием демпферов, специфичных для оперона кристаллов О. Цутсугамуши. Количество рикетсиальных частиц в каж

Совпадение в аннотации оригинала
BACKGROUND: The purpose of this study was to determine whether infective Orientia tsutsugamushi, the etiologic agent of scrub typhus, could survive normal blood banking processing and storage procedures. STUDY DESIGN AND METHODS: Mononuclear cells isolated from whole blood by density gradient centrifugation were inoculated with O. tsutsugamushi, Karp strain…

A Compact Closed Genome of Orientia tsutsugamushi from Hainan Island, China Provides a TA763_A Reference and Reveals Repeat-Driven Remodeling.

Scrub typhus, caused by the obligate intracellular bacterium Orientia tsutsugamushi (O. tsutsugamushi), remains a major public-health concern in the Asia-Pacific region. Genome-wide inference is complicated by extensive repetitive DNA and frequent genome rearrangement. We isolated O. tsutsugamushi HMU_001 from a scrub typhus patient on Hainan Island, China. Intracellular morphology was examined and replication was quantified in endothelial cells. Using long-read sequencing with short-read polishing, we generated a closed circular genome and performed standardized comparative analyses across al…

Complexity of type-specific 56 kDa antigen CD4 T-cell epitopes of Orientia tsutsugamushi strains causing scrub typhus in India.

Orientia tsutsugamushi (Ots) is an obligate, intracellular, mite-transmitted human pathogen which causes scrub typhus. Understanding the diversity of Ots antigens is essential for designing specific diagnostic assays and efficient vaccines. The protective immunodominant type-specific 56 kDa antigen (TSA) of Ots varies locally and across its geographic distribution. TSA contains four hypervariable domains. We bioinformatically analyzed 345 partial sequences of TSA available from India, most of which contain only the three variable domains (VDI-III) and three spacer conserved domains (SVDI, SVDI…

Cross-Regulation of Proinflammatory Cytokines by Interleukin-10 and miR-155 in Orientia tsutsugamushi-Infected Human Macrophages Prevents Cytokine Storm.

Scrub typhus is caused by the obligate intracellular bacterium Orientia tsutsugamushi. Macrophages are host cells for its replication and clearance. Severe complications in patients are mainly caused by a cytokine storm resulting from overproduction of proinflammatory cytokines; nevertheless, the molecular mechanism for the occurrence remains obscure. Herein, we investigate the interactive regulation of cytokines and micro-RNA (miR) in human macrophages infected with low and high doses of O. tsutsugamushi. During low dose infection, macrophages produce high levels of IL-10 through extracellula…

Orientia tsutsugamushi, agent of scrub typhus, displays a single metapopulation with maintenance of ancestral haplotypes throughout continental South East Asia.

Orientia tsutsugamushi is the causative agent of scrub typhus, a major cause of febrile illness in rural area of Asia-Pacific region. A multi-locus sequence typing (MLST) analysis was performed on strains isolated from human patients from 3 countries in Southeast Asia: Cambodia, Vietnam and Thailand. The phylogeny of the 56-kDa protein encoding gene was analyzed on the same strains and showed a structured topology with genetically distinct clusters. MLST analysis did not lead to the same conclusion. DNA polymorphism and phylogeny of individual gene loci indicated a significant level of recombi…

Diversity of the 47-kD HtrA nucleic acid and translated amino acid sequences from 17 recent human isolates of Orientia.

Orientia tsutsugamushi, the etiologic agent of potentially fatal scrub typhus, is characterized by a high antigenic diversity, which complicates the development of a broadly protective vaccine. Efficacy studies in murine and nonhuman primate models demonstrated the DNA vaccine candidate pKarp47, based upon the O. tsutsugamushi Karp 47-kD HtrA protein gene, to be a successful immunoprophylactic against scrub typhus. To characterize 47-kD HtrA protein diversity among human isolates of Orientia, we sequenced the full open reading frame (ORF) of the 47-kD HtrA gene and analyzed the translated amin…

[Sequence analysis subtyping of the 56-kDa protein-encoding gene of Karp-type Orientia tsutsugamushi isolated in scrub typhus cases].

To determine the Karp-type Orientia tsutsugamushi subtype in northern Japan, i.e., Yamagata, Niigata, and Akita Prefectures, we analyzed the partial nucleotide sequence of the 56-kDa protein-encoding gene of 30 isolates from scrub typhus cases. Based on sequencing results, we classified isolates into two groups of 27 and 3 isolates. Nucleotide sequences of 27 isolates were homologous to the yeo-joo strain, classified as a JP-1 subtype. The three isolates were each homologous to a stain of CMM1, KNP1, or KNP2, classified as JP-2 subtypes. Phylogenetic tree analysis showed the 27 isolates formin…