The Experts below are selected from a list of 7464 Experts worldwide ranked by ideXlab platform
Philippe Parola - One of the best experts on this subject based on the ideXlab platform.
-
Cellulitis of the face associated with SENLAT caused by Rickettsia slovaca detected by qPCR on scalp Eschar swab sample: An unusual case report and review of literature
Ticks and Tick-borne Diseases, 2019Co-Authors: Marie Hocquart, Didier Raoult, Philippe Parola, Hortense Drouet, Paul Levet, Carole EldinAbstract:Background: Tick-borne rickettsioses are infectious diseases caused by obligate intracellular Gram-negative bacteria belonging to the spotted fever groupof Rickettsia. Methods: We describe an unusual case of SENLAT (Scalp Eschar and neck lymphadenopathy after tick bite), caused byRickettsia slovaca, associated with a cellulitis of the face in a 70-year-old woman, and diagnosed using qPCR on a scalp Eschar swab. We review the literature regarding cases of SENLAT-associated-cellulitis and case of SENLAT diagnosed by qPCR on scalp Eschar swabs. Results: We found only one previous report of SENLAT associated with a cellulitis of the face. It was a nine-year-old French girl diagnosed by seroconversion for Rickettsia sp. Our review of the literature showed that qPCR on Eschar swab samples is a less invasive method than performing cutaneous biopsy of the Eschar and has good sensitivity and specificity (90% and 100%, respectively). Conclusions: We report the second case of cellulitis of the face associated with the SENLAT syndrome. Detection of Rickettsia by qPCR on swab sample of the scalp Eschar is a simple, noninvasive technique allowing rapid diagnosis and treatment when SENLAT is suspected.
-
Dual Genotype Orientia tsutsugamushi Infection in Patient with Rash and Eschar, Vietnam, 2016
Emerging Infectious Diseases, 2018Co-Authors: Nhiem Le-viet, Duc-tuan Phan, Nho Le-viet, Sinh Trinh, Philippe ParolaAbstract:We report a dual genotype Orientia tsutsugamushi infection in Vietnam in 2016. The patient had fever, rash, and an Eschar. The Kawasaki genotype was identified in the Eschar specimen and Karp genotype in the whole blood specimen. The genotype co-infection rate for scrub typhus is unknown and should be further evaluated.
-
Use of Eschar swabbing for the molecular diagnosis and genotyping of Orientia tsutsugamushi causing scrub typhus in Quang Nam province, Vietnam
PLoS Neglected Tropical Diseases, 2017Co-Authors: Didier Raoult, Oleg Mediannikov, Nhiem Le Viet, Maureen Laroche, Hoa L. Thi Pham, Philippe ParolaAbstract: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 blood were obtained, 17 (85%) of the Eschar specimens and 5 (25%) of the whole blood specimens tested positive for O. tsutsugamushi. Genetic analysis of the 56-kDa TSA gene sequences demonstrated that the 14 sequences obtained in this study, including 12 Eschar swabs and 2 whole blood specimens, were related to 4 groups: Karp, Kawasaki, Gilliam (JG-v and TG-v) and TA716. The majority (9/14; 64.4%) of contemporary O. tsutsugamushi genotypes in Quang Nam province were related to the Karp group. Conclusions These results suggest that polyclonal antigen pools used for serological testing in the future should contain at least Karp, Kawasaki, Gilliam and TA716 antigens for Vietnamese patients, as well as patients who have traveled to Vietnam. qPCR after Eschar swabbing should be considered for molecular diagnosis of scrub typhus in endemic patients as well as in travelers, since it is easy to perform and appears very useful for the rapid detection of Orientia tsutsugamushi in the early phase of infection.
-
Candidatus Coxiella massiliensis Infection
Emerging Infectious Diseases, 2016Co-Authors: Emmanouil Angelakis, Philippe Parola, Oleg Mediannikov, Sarah-lyne Jos, Jean-michel Berenger, Didier RaoultAbstract:Bacteria genetically related to Coxiella burnetii have been found in ticks. Using molecular techniques, we detected Coxiella-like bacteria, here named Candidatus Coxiella massiliensis, in skin biopsy samples and ticks removed from patients with an Eschar. This organism may be a common agent of scalp Eschar and neck lymphadenopathy after tick bite.
-
The use of Eschar swabs for the diagnosis of African tick-bite fever.
Ticks and tick-borne diseases, 2012Co-Authors: Cristina Socolovschi, Philippe Brouqui, Philippe Parola, Aurélie Renvoisé, Didier RaoultAbstract:African tick-bite fever (ATBF) caused by Rickettsia africae is a frequent cause of fever in returned travelers. Here, we used Eschar swabs and/or Eschar crust samples for the molecular diagnosis of ATBF in returned travelers. In 4 of 5 patients returning from South Africa, including 3 with negative serology, R. africae was identified by molecular tools targeting 2 different genes. The findings of this study highlight the usefulness of Eschar swabs and/or Eschar crust samples for the diagnosis of R. africae infection.
Didier Raoult - One of the best experts on this subject based on the ideXlab platform.
-
Cellulitis of the face associated with SENLAT caused by Rickettsia slovaca detected by qPCR on scalp Eschar swab sample: An unusual case report and review of literature
Ticks and Tick-borne Diseases, 2019Co-Authors: Marie Hocquart, Didier Raoult, Philippe Parola, Hortense Drouet, Paul Levet, Carole EldinAbstract:Background: Tick-borne rickettsioses are infectious diseases caused by obligate intracellular Gram-negative bacteria belonging to the spotted fever groupof Rickettsia. Methods: We describe an unusual case of SENLAT (Scalp Eschar and neck lymphadenopathy after tick bite), caused byRickettsia slovaca, associated with a cellulitis of the face in a 70-year-old woman, and diagnosed using qPCR on a scalp Eschar swab. We review the literature regarding cases of SENLAT-associated-cellulitis and case of SENLAT diagnosed by qPCR on scalp Eschar swabs. Results: We found only one previous report of SENLAT associated with a cellulitis of the face. It was a nine-year-old French girl diagnosed by seroconversion for Rickettsia sp. Our review of the literature showed that qPCR on Eschar swab samples is a less invasive method than performing cutaneous biopsy of the Eschar and has good sensitivity and specificity (90% and 100%, respectively). Conclusions: We report the second case of cellulitis of the face associated with the SENLAT syndrome. Detection of Rickettsia by qPCR on swab sample of the scalp Eschar is a simple, noninvasive technique allowing rapid diagnosis and treatment when SENLAT is suspected.
-
Use of Eschar swabbing for the molecular diagnosis and genotyping of Orientia tsutsugamushi causing scrub typhus in Quang Nam province, Vietnam
PLoS Neglected Tropical Diseases, 2017Co-Authors: Didier Raoult, Oleg Mediannikov, Nhiem Le Viet, Maureen Laroche, Hoa L. Thi Pham, Philippe ParolaAbstract: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 blood were obtained, 17 (85%) of the Eschar specimens and 5 (25%) of the whole blood specimens tested positive for O. tsutsugamushi. Genetic analysis of the 56-kDa TSA gene sequences demonstrated that the 14 sequences obtained in this study, including 12 Eschar swabs and 2 whole blood specimens, were related to 4 groups: Karp, Kawasaki, Gilliam (JG-v and TG-v) and TA716. The majority (9/14; 64.4%) of contemporary O. tsutsugamushi genotypes in Quang Nam province were related to the Karp group. Conclusions These results suggest that polyclonal antigen pools used for serological testing in the future should contain at least Karp, Kawasaki, Gilliam and TA716 antigens for Vietnamese patients, as well as patients who have traveled to Vietnam. qPCR after Eschar swabbing should be considered for molecular diagnosis of scrub typhus in endemic patients as well as in travelers, since it is easy to perform and appears very useful for the rapid detection of Orientia tsutsugamushi in the early phase of infection.
-
Candidatus Coxiella massiliensis Infection
Emerging Infectious Diseases, 2016Co-Authors: Emmanouil Angelakis, Philippe Parola, Oleg Mediannikov, Sarah-lyne Jos, Jean-michel Berenger, Didier RaoultAbstract:Bacteria genetically related to Coxiella burnetii have been found in ticks. Using molecular techniques, we detected Coxiella-like bacteria, here named Candidatus Coxiella massiliensis, in skin biopsy samples and ticks removed from patients with an Eschar. This organism may be a common agent of scalp Eschar and neck lymphadenopathy after tick bite.
-
Molecular Identification of Pathogenic Bacteria in Eschars from Acute Febrile Patients, Senegal
The American journal of tropical medicine and hygiene, 2014Co-Authors: Oleg Mediannikov, Cristina Socolovschi, Matthieu Million, Sokhna, Hubert Bassene, Georges Diatta, Florence Fenollar, Didier RaoultAbstract:Fever caused by Rickettsia felis was recently shown to play an important role in infectious diseases morbidity in sub-Saharan Africa. We collected 68 cotton swabs from fever-associated Eschars in four different regions of Senegal. In 5 of 68 Eschar samples (7.4%), we have identified DNA from R. felis. In 49 of 68 Eschar samples (72.1%), we have identified DNA from Staphylococcus aureus. In 35 of 68 Eschar samples (51.5%), we have identified DNA from Streptococcus pyogenes, and in 4 of 68 Eschar samples (5.9%), we have identified DNA from Streptococcus pneumoniae. In 34 cases, S. aureus was found together with S. pyogenes. DNA from R. felis was also found in swabs from the skin of the healthy Senegalese villagers (3 of 60; 5%) but not French urbanites. The presence of S. aureus and S. pyogenes was significantly associated with the presence of Eschars in febrile patients compared with the healthy skin from the control group. Finally, we confirmed that Senegal is an endemic region for R. felis, which is found in both Eschars and healthy skin swabs.
-
The use of Eschar swabs for the diagnosis of African tick-bite fever.
Ticks and tick-borne diseases, 2012Co-Authors: Cristina Socolovschi, Philippe Brouqui, Philippe Parola, Aurélie Renvoisé, Didier RaoultAbstract:African tick-bite fever (ATBF) caused by Rickettsia africae is a frequent cause of fever in returned travelers. Here, we used Eschar swabs and/or Eschar crust samples for the molecular diagnosis of ATBF in returned travelers. In 4 of 5 patients returning from South Africa, including 3 with negative serology, R. africae was identified by molecular tools targeting 2 different genes. The findings of this study highlight the usefulness of Eschar swabs and/or Eschar crust samples for the diagnosis of R. africae infection.
Seung Hyun Lee - One of the best experts on this subject based on the ideXlab platform.
-
Diagnosis of scrub typhus by immunohistochemical staining of Orientia tsutsugamushi in cutaneous lesions.
American journal of clinical pathology, 2008Co-Authors: Dong-min Kim, Won Jong Jang, Kyunghee Park, Chol-jin Park, Sung-chul Lim, Seung Hyun LeeAbstract:We assessed the clinical usefulness of immunohistochemical staining on skin biopsy specimens for the diagnosis of scrub typhus compared with indirect immunofluorescent antibody assay (IFA), the definitive diagnostic method for scrub typhus, in a prospective study of 125 patients with possible scrub typhus in 2005 and 2006. Skin biopsy specimens were obtained from 63 patients. To minimize the effects caused by antibiotics on immunohistochemical results, 46 patients were assessed before antibiotic administration (4 patients received antibiotic therapy before admission; 13 underwent skin biopsy after antibiotic administration at our hospital). Compared with IFA results, immunohistochemical results on maculopapular skin lesions demonstrated a sensitivity of 0.65 and a specificity of 1. Immunohistochemical results on Eschars demonstrated a sensitivity of 1 and a specificity of 1. For immunohistochemical staining performed on skin lesions within 3 or 4 days of administration of antibiotics that are effective for Rickettsia, the antibiotics did not greatly influence diagnostic sensitivity. Immunohistochemical staining of skin biopsy specimens, particularly that of Eschars, is sensitive and specific, and this technique can be reliable for confirming the diagnosis of scrub typhus. Scrub typhus is an acute febrile disease characterized by high fever, headache, and rash; these symptoms are caused by the intracellular gram-negative bacteria Orientia tsutsugamushi. It is a major febrile disease in Korea, Japan, China, Thailand, etc. The reservoir of O tsutsugamushi is wild rats, and chiggers are the vector. Bacterial infection happens when chiggers bearing O tsutsugamushi bite human beings and aspirate human tissue fluid. Eschars are formed on the sites bitten by the chiggers; fever, maculopapular rash, muscle ache, headache, anorexia, lymph node enlargement, and other signs and symptoms appear at the time of the formation of Eschar. The presence of Eschar has been reported to be an important finding for the diagnosis of rickettsialpox or scrub typhus. 1
-
distribution of Eschars on the body of scrub typhus patients a prospective study
American Journal of Tropical Medicine and Hygiene, 2007Co-Authors: Dong-min Kim, Seung Hyun Lee, Kyung Jun Won, Chiyoung Park, Hyong Sun Kim, Tae Young Yang, Ji Hyun Lee, Hyun Kuk Kim, Hyeonje Song, Ho ShinAbstract:Eschar is an important finding for the diagnosis of scrub typhus. The IFA test for possible scrub typhus was performed. The presence or absence of Eschar was thoroughly examined. Among the 176 scrub typhus cases confirmed by IFA, 162 (92.0%) cases had Eschar; 128 patients (79.5%) had Eschars on the front of the body. Eschars were primarily detected in males within 30 cm below the umbilicus (19 patients, 35.8%). Distributions on the lower extremities and the front chest above the umbilicus were 22.6% (12 patients) and 20.8% (11 patients), respectively. A different pattern was seen in females. The most prevalent area was the front chest above the umbilicus, which accounted for 40.7% (44 patients) of all the detected Eschars. Our study is the first report of a schematic diagram that shows the differences between the males and females with respect to Eschar location in scrub typhus patients.
-
clinical usefulness of Eschar polymerase chain reaction for the diagnosis of scrub typhus a prospective study
Clinical Infectious Diseases, 2006Co-Authors: Dong-min Kim, Chiyoung Park, Tae Young Yang, Ji Hyun Lee, Hyun Lee Kim, Jong Tae Yang, Sookyoung Shim, Seung Hyun LeeAbstract:BACKGROUND The aim of this study was to determine the diagnostic utility of performing Eschar polymerase chain reaction (PCR) for the diagnosis of scrub typhus through a prospective comparison of Eschar PCR results with indirect immunofluorescent antibody assay (IFA) results. METHODS We conducted a multicenter prospective study involving patients with possible scrub typhus. Whole-blood samples and Eschars were obtained for serological evaluation and PCR. A new crust was formed several days later at the site of the removed Eschar. The newly formed crust was taken for performance of the second Eschar PCR. Additional blood samples and Eschars were collected, if possible, at 1-week intervals for 1 month after antibiotic treatment. RESULTS We prospectively studied 135 patients with possible scrub typhus. Of these patients, 118 had scrub typhus confirmed on the basis of either a single indirect immunofluorescent specific immunoglobulin M titer against Orientia tsutsugamushi of > or = 1:10 or a > or = 4-fold increase in the follow-up titer. The results of nested PCR assay of the Eschars demonstrated a sensitivity of 0.86 (95% confidence interval, 0.78-0.92) and a specificity of 1 (95% confidence interval, 0.05-1). Among the 50 patients who showed positive results of Eschar PCR at admission, 46 (92%) also showed positive results for the follow-up PCR test of the newly formed Eschar after the treatment with antibiotics. CONCLUSIONS The Eschar PCR assay was useful as a rapid and reliable test to confirm the diagnosis of scrub typhus, even though the patients received treatment with appropriate antibiotics, such as macrolides, quinolones, and tetracycline, which are all active against Orientia and Rickettsia species.
-
Usefulness of Eschar PCR for Diagnosis of Scrub Typhus
Journal of clinical microbiology, 2006Co-Authors: Seung Hyun Lee, Dong-min Kim, Young Shin Cho, Sung Ho Yoon, Sookyoung ShimAbstract:We report here on the case of a child who was infected with scrub typhus, and we made the diagnosis according to the serology and by performing PCRs on the child's Eschar. The patient was treated with azithromycin, and he did not experience any complications. Performing nested PCR on the Eschar might be both a rapid diagnostic test for scrub typhus in the early acute stage and a differential test as to whether or not a scab is a scrub typhus Eschar.
Dong-min Kim - One of the best experts on this subject based on the ideXlab platform.
-
Diagnosis of scrub typhus by immunohistochemical staining of Orientia tsutsugamushi in cutaneous lesions.
American journal of clinical pathology, 2008Co-Authors: Dong-min Kim, Won Jong Jang, Kyunghee Park, Chol-jin Park, Sung-chul Lim, Seung Hyun LeeAbstract:We assessed the clinical usefulness of immunohistochemical staining on skin biopsy specimens for the diagnosis of scrub typhus compared with indirect immunofluorescent antibody assay (IFA), the definitive diagnostic method for scrub typhus, in a prospective study of 125 patients with possible scrub typhus in 2005 and 2006. Skin biopsy specimens were obtained from 63 patients. To minimize the effects caused by antibiotics on immunohistochemical results, 46 patients were assessed before antibiotic administration (4 patients received antibiotic therapy before admission; 13 underwent skin biopsy after antibiotic administration at our hospital). Compared with IFA results, immunohistochemical results on maculopapular skin lesions demonstrated a sensitivity of 0.65 and a specificity of 1. Immunohistochemical results on Eschars demonstrated a sensitivity of 1 and a specificity of 1. For immunohistochemical staining performed on skin lesions within 3 or 4 days of administration of antibiotics that are effective for Rickettsia, the antibiotics did not greatly influence diagnostic sensitivity. Immunohistochemical staining of skin biopsy specimens, particularly that of Eschars, is sensitive and specific, and this technique can be reliable for confirming the diagnosis of scrub typhus. Scrub typhus is an acute febrile disease characterized by high fever, headache, and rash; these symptoms are caused by the intracellular gram-negative bacteria Orientia tsutsugamushi. It is a major febrile disease in Korea, Japan, China, Thailand, etc. The reservoir of O tsutsugamushi is wild rats, and chiggers are the vector. Bacterial infection happens when chiggers bearing O tsutsugamushi bite human beings and aspirate human tissue fluid. Eschars are formed on the sites bitten by the chiggers; fever, maculopapular rash, muscle ache, headache, anorexia, lymph node enlargement, and other signs and symptoms appear at the time of the formation of Eschar. The presence of Eschar has been reported to be an important finding for the diagnosis of rickettsialpox or scrub typhus. 1
-
distribution of Eschars on the body of scrub typhus patients a prospective study
American Journal of Tropical Medicine and Hygiene, 2007Co-Authors: Dong-min Kim, Seung Hyun Lee, Kyung Jun Won, Chiyoung Park, Hyong Sun Kim, Tae Young Yang, Ji Hyun Lee, Hyun Kuk Kim, Hyeonje Song, Ho ShinAbstract:Eschar is an important finding for the diagnosis of scrub typhus. The IFA test for possible scrub typhus was performed. The presence or absence of Eschar was thoroughly examined. Among the 176 scrub typhus cases confirmed by IFA, 162 (92.0%) cases had Eschar; 128 patients (79.5%) had Eschars on the front of the body. Eschars were primarily detected in males within 30 cm below the umbilicus (19 patients, 35.8%). Distributions on the lower extremities and the front chest above the umbilicus were 22.6% (12 patients) and 20.8% (11 patients), respectively. A different pattern was seen in females. The most prevalent area was the front chest above the umbilicus, which accounted for 40.7% (44 patients) of all the detected Eschars. Our study is the first report of a schematic diagram that shows the differences between the males and females with respect to Eschar location in scrub typhus patients.
-
clinical usefulness of Eschar polymerase chain reaction for the diagnosis of scrub typhus a prospective study
Clinical Infectious Diseases, 2006Co-Authors: Dong-min Kim, Chiyoung Park, Tae Young Yang, Ji Hyun Lee, Hyun Lee Kim, Jong Tae Yang, Sookyoung Shim, Seung Hyun LeeAbstract:BACKGROUND The aim of this study was to determine the diagnostic utility of performing Eschar polymerase chain reaction (PCR) for the diagnosis of scrub typhus through a prospective comparison of Eschar PCR results with indirect immunofluorescent antibody assay (IFA) results. METHODS We conducted a multicenter prospective study involving patients with possible scrub typhus. Whole-blood samples and Eschars were obtained for serological evaluation and PCR. A new crust was formed several days later at the site of the removed Eschar. The newly formed crust was taken for performance of the second Eschar PCR. Additional blood samples and Eschars were collected, if possible, at 1-week intervals for 1 month after antibiotic treatment. RESULTS We prospectively studied 135 patients with possible scrub typhus. Of these patients, 118 had scrub typhus confirmed on the basis of either a single indirect immunofluorescent specific immunoglobulin M titer against Orientia tsutsugamushi of > or = 1:10 or a > or = 4-fold increase in the follow-up titer. The results of nested PCR assay of the Eschars demonstrated a sensitivity of 0.86 (95% confidence interval, 0.78-0.92) and a specificity of 1 (95% confidence interval, 0.05-1). Among the 50 patients who showed positive results of Eschar PCR at admission, 46 (92%) also showed positive results for the follow-up PCR test of the newly formed Eschar after the treatment with antibiotics. CONCLUSIONS The Eschar PCR assay was useful as a rapid and reliable test to confirm the diagnosis of scrub typhus, even though the patients received treatment with appropriate antibiotics, such as macrolides, quinolones, and tetracycline, which are all active against Orientia and Rickettsia species.
-
Usefulness of Eschar PCR for Diagnosis of Scrub Typhus
Journal of clinical microbiology, 2006Co-Authors: Seung Hyun Lee, Dong-min Kim, Young Shin Cho, Sung Ho Yoon, Sookyoung ShimAbstract:We report here on the case of a child who was infected with scrub typhus, and we made the diagnosis according to the serology and by performing PCRs on the child's Eschar. The patient was treated with azithromycin, and he did not experience any complications. Performing nested PCR on the Eschar might be both a rapid diagnostic test for scrub typhus in the early acute stage and a differential test as to whether or not a scab is a scrub typhus Eschar.
H.j. De Silva - One of the best experts on this subject based on the ideXlab platform.
-
Genotypic characterization of Orientia tsutsugamushi from patients in two geographical locations in Sri Lanka
BMC infectious diseases, 2017Co-Authors: Ranjan Premaratna, David H. Walker, Lucas S. Blanton, Dilhar N. Samaraweera, G. Nalika N. De Silva, Nilmini Chandrasena, H.j. De SilvaAbstract:To date more than 20 antigenically distinct strains of Orientia tsutsugamushi (OT) reported within the tsutsugamushi triangle that cause an undifferentiated acute febrile illness in humans. Genotypic characterization of OT in different geographic regions or within the same country, is important in order to establish effective diagnostics, clinical management and to develop effective vaccines. Genetic and antigenic characterization of OT causing human disease in OT-endemic regions is not known for Sri Lanka. Adult patients and children who were admitted with an acute febrile illness and presumed to having acute scrub typhus based on presence of an Eschar and other supporting clinical features were recruited. Eschar biopsies and buffy coat samples collected from patients who were confirmed having OT by IFA were further studied by real time PCR (Orientia 47 kD) and nested PCR (Orientia 56 kD) amplification. DNA sequences were obtained for 56 kD gene amplicons and phylogenetic comparisons were analyzed using currently available data in GenBank [Neucleotide substitution per 100 residues, 1000 Bootstrap Trials]. Twenty Eschar biopsies (Location1,19, Location 2,1) and eight buffy coat samples (Location1,6, Location2,2) examined by real time PCR revealed Orientia amplicons in 16 samples. DNA sequences were obtained for the 56 kD gene amplicons in 12 Eschars and 4 buffy coat samples. The genotypes of the Location1 samples revealed that, 7 exhibiting close homology with JP1 [distantly related to UT177 Thai (Karp related)], five had close homology with Kato strain, two had close homology with JGv and JG AF [Distantly related to Kawasaki M63383] and one had close homology with Gilliam strain. The Location 2 strain was closely related to Kuroki-Boryong L04956, the genotype which is distributed in far eastern Asia. Similar to other patients in the cohort this patient also had never travelled out of Sri Lanka. We observed all three main OT genotypes in Sri Lanka, and the majority fell into Thai Karp related clade. These results demonstrate great antigenic diversity of OT in the studied areas of Sri Lanka.
-
Genotypic characterization of Orientia tsutsugamushi from patients in two geographical locations in Sri Lanka
BMC Infectious Diseases, 2017Co-Authors: Ranjan Premaratna, David H. Walker, Lucas S. Blanton, Dilhar N. Samaraweera, G. Nalika N. De Silva, Nilmini Chandrasena, H.j. De SilvaAbstract:Background To date more than 20 antigenically distinct strains of Orientia tsutsugamushi (OT) reported within the tsutsugamushi triangle that cause an undifferentiated acute febrile illness in humans. Genotypic characterization of OT in different geographic regions or within the same country, is important in order to establish effective diagnostics, clinical management and to develop effective vaccines. Genetic and antigenic characterization of OT causing human disease in OT-endemic regions is not known for Sri Lanka. Methods Adult patients and children who were admitted with an acute febrile illness and presumed to having acute scrub typhus based on presence of an Eschar and other supporting clinical features were recruited. Eschar biopsies and buffy coat samples collected from patients who were confirmed having OT by IFA were further studied by real time PCR (Orientia 47 kD) and nested PCR (Orientia 56 kD) amplification. DNA sequences were obtained for 56 kD gene amplicons and phylogenetic comparisons were analyzed using currently available data in GenBank [Neucleotide substitution per 100 residues, 1000 Bootstrap Trials]. Results Twenty Eschar biopsies (Location1,19, Location 2,1) and eight buffy coat samples (Location1,6, Location2,2) examined by real time PCR revealed Orientia amplicons in 16 samples. DNA sequences were obtained for the 56 kD gene amplicons in 12 Eschars and 4 buffy coat samples. The genotypes of the Location1 samples revealed that, 7 exhibiting close homology with JP1 [distantly related to UT177 Thai (Karp related)], five had close homology with Kato strain, two had close homology with JGv and JG AF [Distantly related to Kawasaki M63383] and one had close homology with Gilliam strain. The Location 2 strain was closely related to Kuroki-Boryong L04956, the genotype which is distributed in far eastern Asia. Similar to other patients in the cohort this patient also had never travelled out of Sri Lanka. Conclusions We observed all three main OT genotypes in Sri Lanka, and the majority fell into Thai Karp related clade. These results demonstrate great antigenic diversity of OT in the studied areas of Sri Lanka.
