Phylogenetic Diversity of Orientia tsutsugamushi Isolates in Patients with Scrub Typhus in Bengaluru, India

Chunchanur, Sneha K; Venugopal, Senthil K.; Ambica, R.; Dakshayani, B

doi:10.4103/ijmm.ijmm_19_267

Cited by 9 publications

(9 citation statements)

References 15 publications

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“…Here, the possibility of one strain outgrowing other in cell culture is non-deniable. In accordance with the previous report ( Varghese et al, 2013 , 2015 ; Chunchanur et al, 2019 ; Kumar et al, 2019 ; Kannan et al, 2020 ; Behera et al, 2021 ), our study confirms the prevalence of Gilliam followed by Kato- and Karp-like strains. The prevalence of Gilliam strain was observed in four districts of UP, namely, Kushinagar, Gorakhpur, Basti, and Siddharthnagar.…”

Section: Discussionsupporting

confidence: 93%

“…A subsequent study found out the existence of antibodies against OT during AES epidemic period (July–November 2016) as well as during the lean period (December–June 2016), antibody titer being higher during the epidemic period ( Kamble et al, 2020 ). Apart from these studies, various other reports were based on either serological or molecular evidences but none involved isolation of pathogen in cell culture that is a definite method for diagnosis of any disease of unknown etiology ( Janardhanan et al, 2014 ; Varghese et al, 2015 ; Jain et al, 2017 ; Chunchanur et al, 2019 ; Kumar et al, 2019 ; Gupte et al, 2020 ; Kannan et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

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Genotypic Characterization of Orientia tsutsugamushi Isolated From Acute Encephalitis Syndrome and Acute Febrile Illness Cases in the Gorakhpur Area, Uttar Pradesh, India

Nanaware

Desai²,

Banerjee³

et al. 2022

Front. Microbiol.

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Scrub typhus infections caused by Orientiatsutsugamushi (OT), continue to remain underdiagnosed globally, due to the lack of distinctive symptoms. The elusive nature of the Acute Encephalitis Syndrome (AES) outbreak in Gorakhpur, Uttar Pradesh that claimed numerous pediatric lives was the driving force of this study which involved serological diagnosis (IgM–ELISA), isolation of OT in cell culture, confirmation by PCR, and characterization by Sanger sequencing. In total, 12 out of 36 patients were seropositive, of which 4 were positive by PCR. Upon enrichment in cell culture, additional 3 patients (including two seronegative) were detected positive by PCR. In total, three of these 7 patients were found to be infected with two strains of OT. Taken together, this study for the first time reports the occurrence of dual infections in addition to three circulating OT genotypes (Gilliam, Kato, and Karp-like) and highlights the significance of enriching OT in cell culture systems for efficient molecular detection.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Genotypic Characterization of Orientia tsutsugamushi Isolated From Acute Encephalitis Syndrome and Acute Febrile Illness Cases in the Gorakhpur Area, Uttar Pradesh, India

Nanaware

Desai²,

Banerjee³

et al. 2022

Front. Microbiol.

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“…During phylogenetic analysis, one of our isolates has formed a separate branch along with Ikeda like strain ( KT345167 ) reported by Koraluru et al, far from the original Ikeda prototype strain ( AF173033 ). In Bangalore, the predominance of strains similar to the Gilliam prototype were seen followed by Kato and Boryong-like isolates [ 13 ]. Though our study setting is close to Bangalore, none of the isolates in our study were similar to Boryong-like strains.…”

Section: Discussionmentioning

confidence: 99%

Clinical, laboratory, and molecular epidemiology of Orientia tsutsugamushi infection from Southwestern India

Chunduru¹,

Manoj²,

Poornima³

et al. 2023

PLoS ONE

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Scrub typhus is a vector borne disease which in a proportion of patients causes multiorgan involvement and death if untreated. Infecting genotype and virulence factors play a role in severity of infection and outcome. The current prospective cohort study was undertaken to elucidate the severity of illness in scrub typhus patients and to identify the circulating genotypes in Karnataka, India. A total of 214 patients of either gender from 9 districts of Karnataka and one patient each from Andhra Pradesh and Kerala, India were enrolled in the study. With a predefined severity criterion, 132 patients were segregated to the severe group. Multi organ involvement was seen in 59 (44.69%) patients. Phylogenetic analysis revealed JG-v like (48.97%), Karp-like (26.53%), JG-like (22.44%), and Kato-like (2.04%) strains in Karnataka. Patients infected with Orientia tsutsugamushi Karp-like strains had respiratory involvement (69.2%), cardiovascular involvement (46.2%) and thrombocytopenia (23.1%) and required higher hospital resource utilization.

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“…The variations in these four domains has led to the observation of various of genotypes like Karp, Kato, Gilliam, Boryong, Kawasaki, Shimokoshi, TA763 and TA686 (10,12,13). Data on the complete TSA 56 gene is available from Thailand, Laos, South Korea, Malaysia, Taiwan, China, Japan, Vietnam, Myanmar, Cambodia and New Guinea (10,(14)(15)(16).…”

Section: Introductionmentioning

confidence: 99%

“…A study on chiggers collected from Hosur and Vellore, identified TA716 and Kato genotype based on Horinouchi protocol (13). Chunchanur et al, (2019) found Gilliam strain in Karnataka, India (14). Studies from Andhra Pradesh, Madhya Pradesh and Uttar Pradesh also showed Karp as the predominant genotype (15)(16)(17).…”

Section: Introductionmentioning

confidence: 99%

Genotyping ofOrientia tsutsugamushicirculating in and around Vellore (South India) using TSA 56 gene

Janaki

Govindasamy

Lakshmisurya

et al. 2023

Preprint

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The immunodominant TSA 56 gene of Orientia tsutsugamushi, (scrub typhus agent) has four variable regions (VD-I to VD-IV) making it useful for genotyping. As of date the genotyping data from India is based on partial 56kDa gene sequence analysis. The complete TSA 56 gene sequence is important for knowing the circulating strains and for designing region specific diagnostics and vaccines. This study was undertaken to determine Orientia tsutsugamushi genotypes circulating in and around Vellore using complete and partial TSA 56 gene. Of the 379 whole blood samples from suspected scrub typhus patients, 162 were positive by 47 kDa qPCR. Long protocol to amplify the complete TSA 56 gene (≈1605 bp) was performed on 21 samples. On the same 21 samples the partial gene sequence was also amplified using the Horinouchi (≈650bp) and the Furuya (≈480 bp) protocol. Using a combination of Sanger and Nanopore technology complete sequence was obtained for 9 and near complete (1551 to 1596 bp) for 4 respectively. As Furuya protocol gave multiple bands we obtained 480 bp sequences from the 13 complete gene sequences by in silico analysis. In contrast, 650bp sequences were obtained for 11 samples while for the remaining two we derived the 650 bp sequences from the complete gene sequences (Long protocol). Phylogenetic analysis of the complete gene (Long protocol) which includes VD-I to VD-IV region and partial gene (Horinouchi) which amplifies the VD-I to VD-III regions showed identical genotypes. Twelve belonged to TA763 genotype and one belongs to Karp genotype. The Furuya sequence (in silico) correctly identified the Karp genotype and 10 of the TA763 genotypes. Two TA763 genotypes (identified by complete and 650 bp partial gene analysis) were misidentified by Furuya sequence analysis as Karp genotype. The limited analysis showed the commonest Orientia tsutsugamushi genotypes circulating in and around Vellore is TA763 and that the 650 bp (Sanger) sequencing could be a cost effective method for identifying the scrub typhus genotypes. However, these results need to be validated by larger prospective multi-centric studies.

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Phylogenetic Diversity of Orientia tsutsugamushi Isolates in Patients with Scrub Typhus in Bengaluru, India

Cited by 9 publications

References 15 publications

Genotypic Characterization of Orientia tsutsugamushi Isolated From Acute Encephalitis Syndrome and Acute Febrile Illness Cases in the Gorakhpur Area, Uttar Pradesh, India

Genotypic Characterization of Orientia tsutsugamushi Isolated From Acute Encephalitis Syndrome and Acute Febrile Illness Cases in the Gorakhpur Area, Uttar Pradesh, India

Clinical, laboratory, and molecular epidemiology of Orientia tsutsugamushi infection from Southwestern India

Genotyping ofOrientia tsutsugamushicirculating in and around Vellore (South India) using TSA 56 gene

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