scholarly journals Evaluation of PCR-Based Assay for Diagnosis of Spotted Fever Group Rickettsiosis in Human Serum Samples

2005 ◽  
Vol 12 (6) ◽  
pp. 759-763 ◽  
Author(s):  
Yeon-Joo Choi ◽  
Seung-Hyun Lee ◽  
Kyung-Hee Park ◽  
Young-Sang Koh ◽  
Keun-Hwa Lee ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Bacterial Species ◽  
Immunoglobulin M ◽  
Rickettsia Conorii ◽  
Spotted Fever Group ◽  
Sequencing Analysis ◽  
Pcr Assay ◽  
Serum Samples ◽  
Dna Fragment ◽  
Sfg Rickettsia

ABSTRACT A nested PCR assay was developed for the detection of spotted fever group (SFG) rickettsiae in serum samples. The assay was based on specific primers derived from the rickettsial outer membrane protein B gene (rompB) of Rickettsia conorii. An SFG rickettsia-specific signal is obtained from R. akari, R. japonica, R. sibirica, and R. conorii. Other bacterial species tested did not generate any signal, attesting to the specificity of the assay. As few as seven copies of the rompB gene of R. conorii could be detected in 200 μl of serum sample. The assay was evaluated with a panel of sera obtained from patients with acute-phase febrile disease tested by immunofluorescent antibody assay (IFA). The SFG rickettsia-specific DNA fragment was detected in 71 out of 100 sera, which were proven to have immunoglobulin M antibodies against SFG rickettsial antigen by IFA. The results were further confirmed by restriction fragment length polymorphism and sequencing analysis of the DNA fragments. The results indicated that this PCR assay is suitable for the diagnosis of spotted fever group rickettsiosis in Korea.

scholarly journals The Rickettsia conorii Autotransporter Protein Sca1 Promotes Adherence to Nonphagocytic Mammalian Cells

2010 ◽  
Vol 78 (5) ◽  
pp. 1895-1904 ◽  
Author(s):  
Sean P. Riley ◽  
Kenneth C. Goh ◽  
Timothy M. Hermanas ◽  
Marissa M. Cardwell ◽  
Yvonne G. Y. Chan ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Spotted Fever ◽  
Expression System ◽  
Host Cells ◽  
Rickettsia Conorii ◽  
Spotted Fever Group ◽  
Gram Negative Bacteria ◽  
Heterologous Expression System ◽  
Cell Association ◽  
Sfg Rickettsia

ABSTRACT The pathogenesis of spotted fever group (SFG) Rickettsia species, including R. conorii and R. rickettsii, is acutely dependent on adherence to and invasion of host cells, including cells of the mammalian endothelial system. Bioinformatic analyses of several rickettsia genomes revealed the presence of a cohort of genes designated sca genes that are predicted to encode proteins with homology to autotransporter proteins of Gram-negative bacteria. Previous work demonstrated that three members of this family, rOmpA (Sca0), Sca2, and rOmpB (Sca5) are involved in the interaction with mammalian cells; however, very little was known about the function of other conserved rickettsial Sca proteins. Here we demonstrate that sca1, a gene present in nearly all SFG rickettsia genomes, is actively transcribed and expressed in R. conorii cells. Alignment of Sca1 sequences from geographically diverse SFG Rickettsia species showed that there are high degrees of sequence identity and conservation of these sequences, suggesting that Sca1 may have a conserved function. Using a heterologous expression system, we demonstrated that production of R. conorii Sca1 in the Escherichia coli outer membrane is sufficient to mediate attachment to but not invasion of a panel of cultured mammalian epithelial and endothelial cells. Furthermore, preincubation of a recombinant Sca1 peptide with host cells blocked R. conorii cell association. Together, these results demonstrate that attachment to mammalian cells can be uncoupled from the entry process and that Sca1 is involved in the adherence of R. conorii to host cells.

RETROSPECTIVE SEROLOGICAL DIAGNOSTICS OF SPOTTED FEVER GROUP RIKKETSIOSES IN HIGH RISK AREAS OF RICKETTSIA CONORII SUBSP. CASPIA INFECTION

2019 ◽  
Vol 64 (6) ◽  
pp. 354-359 ◽  
Author(s):  
T. A. Chekanova ◽  
S. Zh. Netalieva ◽  
S. N. Shpynov ◽  
M. A. Babaeva ◽  
A. V. Kostarnoy
Keyword(s):  
High Risk ◽  
Spotted Fever ◽  
Activity Period ◽  
Rickettsia Conorii ◽  
Spotted Fever Group ◽  
Adenovirus Infection ◽  
Risk Areas ◽  
Acute Respiratory Viral Infection ◽  
Serological Diagnostics ◽  
Sfg Rickettsia

723 blood sera from 537 patients of Regional Infectious Clinical Hospital, Astrakhan were obtained during high activity period of Rhipicephalus ticks (May-September 2015) and retrospectively studied for IgG/IgM to antigen of spotted fever group (SFG) Rickettsia. IgG and/or IgM to Rickettsia conorii were detected in 145 sera from 130 patients, and antibodies to R. sibirica (group-specific) were detected in 143 sera from 145. Antibodies to R. conorii were detected for 71,4% patients with Astrakhan spotted fever (ASF), for 28,4% patients with acute respiratory viral infection, for 19,1% patients with infection of unspecified etiology and for 40% patients having symptoms of a adenovirus infection. Acute rickettsiosis, provably ASF, is serologically validated for 71 patients. Dynamic of IgM/IgG to R. conorii in sera of patients having different preliminary diagnoses is discussed. IgM to R. conorii in sera of patients having adenovirus infection symptoms were detected at a later time as compared with others. For regions of high risk of R. conorii subsp. caspia infection the differentiation of diagnostic and anamnestic specific antibodies is very important. The absence of serological and molecular biological markers in third of patients with ASF symptoms is necessary to study. Preparations and algorithms for diagnosis of SFG rickettsioses are needed to improve.

scholarly journals Serological Evidence of Anaplasma phagocytophilum and Spotted Fever Group Rickettsia spp. Exposure in Horses from Central Italy

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 88 ◽  
Author(s):  
Valentina Virginia Ebani
Keyword(s):  
Anaplasma Phagocytophilum ◽  
Spotted Fever ◽  
Central Italy ◽  
Geographic Area ◽  
Spotted Fever Group ◽  
Serum Samples ◽  
Health Concept ◽  
Spotted Fever Group Rickettsia ◽  
The One ◽  
Sfg Rickettsia

Anaplasma phagocytophilum and Rickettsia spp. are tick-borne bacteria of veterinary and human concern. In view of the One-Health concept, the present study wanted to evaluate the spreading of these pathogens in horses living in central Italy. In particular, the aim of the investigation was to verify the exposure to A. phagocytophilum in order to update the prevalence of this pathogen in the equine population from this area, and to spotted fever group (SFG) Rickettsia spp. to evaluate a possible role of horses in the epidemiology of rickettsiosis. Indirect immunofluorescent assay was carried out to detect antibodies against A. phagocytophilum and SFG (spotted fever group) Rickettsia spp. in blood serum samples collected from 479 grazing horses living in central Italy during the period from 2013 to 2018. One hundred and nine (22.75%) horses were positive for A. phagocytophilum, 72 (15.03%) for SFG Rickettsia spp., and 19 (3.96%) for both antigens. The obtained results confirm the occurrence of A. phagocytophilum in equine populations, and also suggest the involvement of horses in the epidemiology of SFG rickettsiosis. In both cases, in view of the zoonotic aspect of these pathogens and the frequent contact between horses and humans, the monitoring of equine populations could be useful for indication about the spreading of the tick-borne pathogens in a certain geographic area.

scholarly journals Significant Growth by Rickettsia Species within Human Macrophage-Like Cells Is a Phenotype Correlated with the Ability to Cause Disease in Mammals

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 228
Author(s):  
M. Nathan Kristof ◽  
Paige E. Allen ◽  
Lane D. Yutzy ◽  
Brandon Thibodaux ◽  
Christopher D. Paddock ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Spotted Fever ◽  
Growth Characteristic ◽  
Human Macrophage ◽  
Rickettsia Conorii ◽  
Spotted Fever Group ◽  
Rocky Mountain Spotted Fever ◽  
Phagocytic Cells ◽  
Pathogenic Potential ◽  
Rickettsia Species

Rickettsia are significant sources of tick-borne diseases in humans worldwide. In North America, two species in the spotted fever group of Rickettsia have been conclusively associated with disease of humans: Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, and Rickettsia parkeri, the cause of R. parkeri rickettsiosis. Previous work in our lab demonstrated non-endothelial parasitism by another pathogenic SFG Rickettsia species, Rickettsia conorii, within THP-1-derived macrophages, and we have hypothesized that this growth characteristic may be an underappreciated aspect of rickettsial pathogenesis in mammalian hosts. In this work, we demonstrated that multiple other recognized human pathogenic species of Rickettsia, including R. rickettsii, R. parkeri, Rickettsia africae, and Rickettsiaakari can grow within target endothelial cells as well as within PMA-differentiated THP-1 cells. In contrast, Rickettsia bellii, a Rickettsia species not associated with disease of humans, and R. rickettsii strain Iowa, an avirulent derivative of pathogenic R. rickettsii, could invade both cell types but proliferate only within endothelial cells. Further analysis revealed that similar to previous studies on R. conorii, other recognized pathogenic Rickettsia species could grow within the cytosol of THP-1-derived macrophages and avoided localization with two different markers of lysosomal compartments; LAMP-2 and cathepsin D. R. bellii, on the other hand, demonstrated significant co-localization with lysosomal compartments. Collectively, these findings suggest that the ability of pathogenic rickettsial species to establish a niche within macrophage-like cells could be an important factor in their ability to cause disease in mammals. These findings also suggest that analysis of growth within mammalian phagocytic cells may be useful to predict the pathogenic potential of newly isolated and identified Rickettsia species.

scholarly journals Evaluation of PCR-based assay in human serum samples for diagnosis of fatal cases of spotted fever group rickettsiosis

2009 ◽  
Vol 15 ◽  
pp. 232-234 ◽  
Author(s):  
E.M Mendes do Nascimento ◽  
S. Colombo ◽  
T.K. Nagasse-Sugahara ◽  
R.N. Angerami ◽  
M.R. Resende ◽  
...  
Keyword(s):  
Human Serum ◽  
Spotted Fever ◽  
Spotted Fever Group ◽  
Serum Samples ◽  
Human Serum Samples

scholarly journals Epidemiological aspects of the Brazilian spotted fever: serological survey of dogs and horses in an endemic area in the State of São Paulo, Brazil

1996 ◽  
Vol 38 (6) ◽  
pp. 427-430 ◽  
Author(s):  
Elba R.S. de Lemos ◽  
Raimundo D. Machado ◽  
José R. Coura ◽  
Maria A.A.M. Guimarães ◽  
Nelson Chagas
Keyword(s):  
Endemic Area ◽  
Spotted Fever ◽  
Domestic Animals ◽  
Sao Paulo ◽  
Spotted Fever Group ◽  
São Paulo ◽  
Serological Survey ◽  
Serum Samples ◽  
Blood Samples ◽  
Brazilian Spotted Fever

In order to obtain information on Brazilian spotted fever, a study in domestic animals was performed in the County of Pedreira, State of São Paulo, Brazil, where 17 human cases had been notified. Serum samples obtained from animals were tested by indirect immunofluorescence for detectable antibodies to spotted fever-group rickettsiae. Seropositivity was revealed in 12 (36.4%) of 33 dogs and seven (77.8%) of nine horses from the endemic area. For comparison, blood samples from dogs and horses from non endemic area were tested and four (12.9%) of 31 dogs and three (27.3%) of 11 horses were positive. The highest titers of antibodies by IFA (IgG > 1:1024) were found only in three dogs and six horses from endemic area. The results suggest that dogs as horses may serve as environmental sentinels for estabilishing the prevalence of foci of spotted fever in Brazil.

scholarly journals Isolation and Identification of Rickettsia massiliae from Rhipicephalus sanguineus Ticks Collected in Arizona

2006 ◽  
Vol 72 (8) ◽  
pp. 5569-5577 ◽  
Author(s):  
Marina E. Eremeeva ◽  
Elizabeth A. Bosserman ◽  
Linda J. Demma ◽  
Maria L. Zambrano ◽  
Dianna M. Blau ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Rhipicephalus Sanguineus ◽  
Vero Cells ◽  
The United States ◽  
Spotted Fever Group ◽  
Pcr Assay ◽  
Isolation And Identification ◽  
Cytotoxic Effects ◽  
Rickettsia Massiliae ◽  
Genotypic Characteristics

ABSTRACT Twenty Rhipicephalus sanguineus ticks collected in eastern Arizona were tested by PCR assay to establish their infection rate with spotted fever group rickettsiae. With a nested PCR assay which detects a fragment of the Rickettsia genus-specific 17-kDa antigen gene (htrA), five ticks (25%) were found to contain rickettsial DNA. One rickettsial isolate was obtained from these ticks by inoculating a suspension of a triturated tick into monolayers of Vero E6 monkey kidney cells and XTC-2 clawed toad cells, and its cell culture and genotypic characteristics were determined. Fragments of the 16S rRNA, GltA, rOmpA, rOmpB, and Sca4 genes had 100%, 100%, 99%, 99%, and 99%, respectively, nucleotide similarity to Rickettsia massiliae strain Bar29, previously isolated from R. sanguineus in Catalonia, Spain (L. Beati et al., J. Clin. Microbiol. 34:2688-2694, 1996). The new isolate, AZT80, does not elicit cytotoxic effects in Vero cells and causes a persistent infection in XTC-2 cells. The AZT80 strain is susceptible to doxycycline but resistant to rifampin and erythromycin. Whether R. massiliae AZT80 is pathogenic or infectious for dogs and humans or can cause seroconversion to spotted fever group antigens in the United States is unknown.

scholarly journals Occurrence of Ehrlichia canis and Hepatozoon canis and probable exposure to Rickettsia amblyommatis in dogs and cats in Natal, RN

2019 ◽  
Vol 28 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Marcos Gomes Lopes ◽  
Felipe da Silva Krawczak ◽  
Julia Teresa Ribeiro de Lima ◽  
Gislene Fatima da Silva Rocha Fournier ◽  
Igor da Cunha Lima Acosta ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Immunofluorescence Assay ◽  
Ehrlichia Canis ◽  
Hepatozoon Canis ◽  
Spotted Fever Group ◽  
Accession Number ◽  
Serum Samples ◽  
Control Center ◽  
Related Genotype ◽  
Babesia Spp

Abstract Occurrence of infection or exposure to Ehrlichia canis, Hepatozoon canis and Rickettsia spp. was detected in feral cats living in two fragments from Atlantic rainforest, in Natal, RN, Brazil, and in dogs living around the parks. While serum samples were collected from 155 animals (53 cats living in the parks; 29 dogs living in human homes around the parks; and 73 dogs living at an animal control center - ACC), spleen samples were collected from 20 dogs that were euthanized at ACC. Serum samples were analyzed to Rickettsia spp. and E. canis antibodies using the indirect immunofluorescence assay. Seventeen of the 102 dogs (17%) had E. canis antibodies and 13% (20/155) of all dogs and cats (i.e. 3% (3/102) of the dogs and 32% (17/53) of the cats) were seropositive for Rickettsia spp. antigens. The animals were therefore been exposed to R. amblyommatis or by a very closely related genotype. Among the 20 dog spleen samples analyzed, eight were PCR positive for E. canis and two for H. canis (GenBank accession number MG772657 and MG772658, respectively). In none of the spleen samples were obtained amplicons for Babesia spp. through PCR. This study provided the first evidence that Rickettsia of the spotted fever group is circulating among dogs and cats in Natal.

scholarly journals Characterization of Mutations in therpoB Gene in Naturally Rifampin-ResistantRickettsia Species

1999 ◽  
Vol 43 (10) ◽  
pp. 2400-2403 ◽  
Author(s):  
Michel Drancourt ◽  
Didier Raoult
Keyword(s):  
Spotted Fever ◽  
Single Point ◽  
Experimental Studies ◽  
Single Point Mutation ◽  
Rickettsia Conorii ◽  
Spotted Fever Group ◽  
Resistant Species ◽  
Encoding Gene ◽  
Group Species

ABSTRACT Rickettsiae are gram-negative, obligately intracellular bacteria responsible for arthropod-borne spotted fevers and typhus. Experimental studies have delineated a cluster of naturally rifampin-resistant spotted fever group species. We sequenced the 4,122- to 4,125-bp RNA polymerase β-subunit-encoding gene (rpoB) from typhus and spotted fever group representatives and obtained partial sequences for all naturally rifampin-resistant species. A single point mutation resulting in a phenylalanine-to-leucine change at position 973 of theRickettsia conorii rpoB sequence and present in all the rifampin-resistant species was absent in all the rifampin-susceptible species. rpoB-based phylogenetic relationships among these rickettsial species yielded topologies which were in accordance with previously published phylogenies.

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