Isolation and PCR detection of rickettsiae from clinical and rodent samples in Malaysia (original) (raw)
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Human Infection with Rickettsia honei , Thailand
Emerging Infectious Diseases, 2005
Human spotted fever rickettsiosis was detected molecularly by 2 real-time polymerase chain reaction (PCR) assays performed on DNA extracted from a Thai patient's serum sample. Sequences of PCR amplicons from 5 rickettsial genes used for multilocus sequence typing were 100% identical with those deposited with GenBank for Rickettsia honei TT-118.
Journal of Clinical Microbiology, 2003
A spotted fever rickettsia quantitative PCR assay (SQ-PCR) was developed for the detection and enumeration of Rickettsia rickettsii and other closely related spotted fever group rickettsiae. The assay is based on fluorescence detection of SYBR Green dye intercalation in a 154-bp fragment of the rOmpA gene during amplification by PCR. As few as 5 copies of the rOmpA gene of R. rickettsii can be detected. SQ-PCR is suitable for quantitation of R. rickettsii and 10 other genotypes of spotted fever group rickettsiae but not for R. akari, R. australis, R. bellii, or typhus group rickettsiae. The sensitivity of SQ-PCR was comparable to that of a plaque assay using centrifugation for inoculation. The SQ-PCR assay was applied successfully to the characterization of rickettsial stock cultures, the replication of rickettsiae in cell culture, the recovery of rickettsial DNA following different methods of extraction, and the quantitation of rickettsial loads in infected animal tissues, clinical samples, and ticks. on July 12, 2015 by guest http://jcm.asm.org/ Downloaded from on July 12, 2015 by guest http://jcm.asm.org/ Downloaded from 5472 EREMEEVA ET AL.
Identification of rickettsiae from wild rats and cat fleas in Malaysia
Rickettsioses are emerging zoonotic diseases reported worldwide. In spite of the serological evidence of spotted fever group rickettsioses in febrile patients in Malaysia, limited studies have been conducted to identify the animal reservoirs and vectors of rickettsioses. This study investigated the presence of rickettsiae in the tissue homogenates of 95 wild rats and 589 animal ectoparasites. Using PCR assays targeting the citrate synthase gene (gltA), rickettsial DNA was detected in the tissue homogenates of 13 (13.7%) wild rats. Sequence analysis of the gltA amplicons showed 98.6–100% similarity with those of Rickettsia honei/R. conorii/R. raoultii (Rickettsiales: Rickettsiaceae). Sequence analysis of outer membrane protein A gene (ompA) identified Rickettsia sp. TCM1 strain from two rats. No rickettsia was detected from Laelaps mites, Rhipicephalus sanguineus and Haemaphysalis bispinosa ticks, and Felicola subrostratus lice in this study. R. felis was identified from 32.2% of 177 Ctenocephalides felis fleas. Sequence analysis of the gltA amplicons revealed two genotypes of R. felis (Rf31 and RF2125) in the fleas. As wild rats and cat fleas play an important role in the enzoonotic maintenance of rickettsiae, control of rodent and flea populations may be able to reduce transmission of rickettsioses in the local setting.
Addition of monoclonal antibodies specific for Rickettsia akari to the rickettsial diagnostic panel
Journal of Clinical Microbiology, 1988
Monoclonal antibodies were produced from mice infected with Rickettsia akari (the etiologic agent of rickettsialpox) and evaluated for specificity in indirect fluorescent-antibody tests with 23 different rickettsial antigens. Of the nine antibodies that were evaluated, two were specific for R. akari and four reacted with R. akari and all other spotted fever group rickettsiae. The remaining three antibodies reacted with some, but not all, members of the spotted fever group. None of the antibodies reacted with typhus, scrub typhus, trench fever, or Q fever rickettsiae. Adding these antibodies to the list of available diagnostic reagents will facilitate identification of rickettsial diseases, particularly those caused by members of the spotted fever group, where the clinical presentations are similar and the etiologic agents are closely related antigenically.
Spotted Fever Group Rickettsioses and Murine Typhus in a Malaysian Teaching Hospital
The American journal of tropical medicine and hygiene, 2016
Limited information is available on the etiological agents of rickettsioses in southeast Asia. Herein, we report the molecular investigation of rickettsioses in four patients attending a teaching hospital in Malaysia. DNA of Rickettsia sp. RF2125, Rickettsia typhi, and a Rickettsia closely related to Rickettsia raoultii was detected in the blood samples of the patients. Spotted fever group rickettsioses and murine typhus should be considered in the diagnosis of patients with nonspecific febrile illness in this region.
PLOS Neglected Tropical Diseases, 2021
Background Current knowledge on Rickettsia felis infection in humans is based on sporadic case reports. Here we conducted a retrospective seroepidemiological survey of R. felis infection among febrile patients visiting a medical center in Taipei. Methodology/Principal findings A total of 122 patients with suspected rickettsioses presenting with fever of unknown origin (FUO) but tested negative for scrub typhus, murine typhus, or Q fever were retrospectively identified during 2009 to 2010. The archived serum samples were examined for the presence of antibodies against R. felis, Rickettsia japonica, and Rickettsia typhi using microimmunofluorescence (MIF) assay. Serological evidence of Rickettsia exposure was found in 23 (19%, 23/122) patients. Eight patients had antibodies reactive to R. felis, including four with current infection (a ≥4-fold increase in IgG titer between acute and convalescent sera). The clinical presentations of these four patients included fever, skin rash, lympha...
Study of rickettsia infection in patients suffering from fever of unknown origin
2021
Introduction: FUO/ PUO (Fever/Pyrexia of Unknown Origin) is referred to when temperature is observed above 38.30C (1010F) on many occasions over a period of > 3 weeks and unable to diagnose despite 1week of thorough investigations. Different studies reported diagnosis of malaria in 5 to 50% cases; leptospirosis in 3 to 10% cases and influenza in 8 to 12% cases Dengue fever and malaria are arthropod born diseases and endemic in many parts of India during the monsoon season. Leptospirosis and scrub typhus are zoonotic infections and are widely prevalent in areas with heavy monsoon and agrarian way of life. Aim : To evaluate the study of various Rickettsia infections in patients suffering from Fever Of Unknown Origin. Objectives: To understand the occurrence of infections caused by rickettsial species in suspected cases of FUO. To increase awareness and clinical suspicion among doctors for these infections. Materials and Methods: The assay was performed using P.vulgaris OX19, OX2, O...
Annals of the New York Academy of Sciences, 2006
Two strategies to improve the efficacy of the shell-vial method for Rickettsia were analyzed. Blood samples from 59 patients with Mediterranean spotted fever (MSF) were examined using the shellvial technique. (i) DNA from positive lenses was obtained when they were contaminated. (ii) Blood sample from one patient was cultured in 17 shell-vials. R. conorii was identified in four cases by polymerase chain reaction (PCR)-RFLP. Three of these were obtained from cells adherent to lenses and the fourth one by using total patient blood sample. Rickettsia isolation using all blood samples as well as DNA from shell-vial lenses could be useful in the study of rickettsial infections.
Vector-Borne and Zoonotic Diseases, 2014
Limited information is available on the presence of rickettsial infection in humans and animal reservoirs in Spain. Exposure to spotted fever group rickettsia in healthy humans and in farm and wild animals in the Province of Burgos, Spain, was examined by serological methods. Rickettsial DNA was also sought by PCR in animal samples. Of 102 human serum samples examined by indirect immunofluorescence assays (IFA), 5.88% were positive for antibodies against Rickettsia conorii (titers 1/128-1/512). Significant differences were detected in human seroprevalence with respect to age. In further IFAs, 102 out of 375 (27.2%) serum samples from the wild animals reacted with R. conorii antigens (titers 1/64-1/1024); 32 out of 281 (11.38%) samples from farm animals were also positive for R. conorii (titers 1/64-1/2048). The prevalence detected among total wild animals was significantly higher than among total farm animals. No rickettsial DNA was found by PCR in any farm or wild animal sample.