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MSphere May 2021Species of (: ) are obligate intracellular parasites of a wide range of eukaryotes, with recognized arthropod-borne human pathogens belonging to the transitional group...
Species of (: ) are obligate intracellular parasites of a wide range of eukaryotes, with recognized arthropod-borne human pathogens belonging to the transitional group (TRG), typhus group (TG), and spotted fever group (SFG) rickettsiae. Growing in the host cytosol, rickettsiae pilfer numerous metabolites to make a typical Gram-negative bacterial cell envelope. The O-antigen of rickettsial lipopolysaccharide (LPS) is immunogenic and has been shown to tether the S-layer to the rickettsial surface; however, little is known about the structure and immunogenicity of the lipid A moiety. The structure of lipid A, the membrane anchor of LPS, affects the ability of this molecule to interact with components of the host innate immune system, specifically the MD-2/TLR4 receptor complex. To dissect the host responses that can occur during and infection, structural analysis of lipid A is needed. Lipid A was extracted from four species and structurally analyzed. (TRG), (TG), and (SFG) produced a similar structure, whereas (SFG) altered the length of a secondary acyl group. While all structures have longer acyl chains than known highly inflammatory hexa-acylated lipid A structures, the modification should differentially alter interactions with the hydrophobic internal pocket in MD2. The significance of these characteristics toward inflammatory potential as well as membrane dynamics between arthropod and vertebrate cellular environments warrants further investigation. Our work adds lipid A to the secretome and O-antigen as variable factors possibly correlating with phenotypically diverse rickettsioses. Spikes in rickettsioses occur as deforestation, urbanization, and homelessness increase human exposure to blood-feeding arthropods. Still, effective vaccines remain elusive. Recent studies have determined that lipopolysaccharide anchors the protective S-layer to the bacterial surface and elicits bactericidal antibodies. Furthermore, growing immunological evidence suggests vertebrate sensors (MD-2/TLR4 and noncanonical inflammasome) typically triggered by the lipid A portion of lipopolysaccharide are activated during infection. However, the immunopotency of lipid A is unknown due to poor appreciation for its structure. We determined lipid A structures for four distinct rickettsiae, revealing longer acyl chains relative to highly inflammatory bacterial lipid A. Surprisingly, lipid A of the Rocky Mountain spotted fever agent deviates in structure from other rickettsiae. Thus, lipid A divergence may contribute to variable disease phenotypes, sounding an alarm for determining its immunopotency and possible utility (i.e., as an adjuvant or anti-inflammatory) for development of more prudent rickettsiacidal therapies.
Topics: Humans; Lipid A; Rickettsia; Rickettsia Infections
PubMed: 33952661
DOI: 10.1128/mSphere.00184-21 -
Journal of Global Infectious Diseases 2022Co-infection with different agents such as bacterial, viral, and Rickettsia is being increasingly recognized due to greater availability and utilization of the...
INTRODUCTION
Co-infection with different agents such as bacterial, viral, and Rickettsia is being increasingly recognized due to greater availability and utilization of the diagnostic tests among malaria patients.
METHODS
Consecutive admitted malarial cases were included and were subjected to test for general investigations, bacteria, typhoid, dengue, chikungunya, and rest for specific diagnosis. All patients were followed up till discharge or death and appropriate statistical tests were performed.
RESULTS
A total of 152 malaria patients were recruited and 27 (18.8%) had concurrent infections. It included 40.7% dengue only, 18.7% pneumonia, 11.1% urinary tract infection (UTI), 7.4% enteric fever, 3.7% leptospirosis, chikungunya, and tuberculous meningitis each, and 3.7% each of dengue with pneumonia and UTI. The organisms isolated were and The mean duration of fever was 6.33 ± 3.63 days with a range of 3-20 days. Blood culture grew in 2 cases and Dengue co-infections had significantly higher clinical and laboratory features of dengue and complications such as bleeding, jaundice, and cholecystitis, whereas rest concurrent infections had a significantly higher proportion of nausea and vomiting, convulsion, altered sensorium, productive cough, urinary symptoms, shock, acute kidney injury, anemia, and mean neutrophil count. There was significantly higher mortality among malaria-dengue concurrent infection group with 2 (15.4%) than malaria mono-infection group 3 (2.4%).
CONCLUSION
Co-infections with malaria are not uncommon, especially dengue fever and other bacterial infections. The dominant clinical picture is of the superimposed infection. Decision should be clinically guided adjunct with specific diagnostic tests, and timely treatment has favorable outcome.
PubMed: 35910822
DOI: 10.4103/jgid.jgid_279_21 -
Ticks and Tick-borne Diseases Mar 2023Rickettsioses are vector-borne zoonotic diseases whose etiological agents are bacteria of the genera Rickettsia and Orientia. In Colombia, literature published on...
Rickettsioses are vector-borne zoonotic diseases whose etiological agents are bacteria of the genera Rickettsia and Orientia. In Colombia, literature published on rickettsioses during the 20th century is limited and disperse; to date, there are no detailed publications that compile the affected regions or the involved Rickettsia species in each outbreak. Since early works of Luis Patiño-Camargo, the study of rickettsioses gained major importance with the subsequent description of significant outbreaks in some departments of the country. During the 1940s, many articles were published reporting outbreaks probably caused by Rickettsia rickettsii, Rickettsia typhi, and Rickettsia prowazekii, as well as studies on their diagnosis, vaccination, and prophylaxis. One of the most notorious works was published by Patiño-Camargo where he named the R. rickettsii rickettsiosis as "Tobia fever". However, in the subsequent decades, these entities entered a prolonged period of neglected research and surveillance, and just gained importance until the 21st century, when new fatal cases began to be reported in the country; thus, many questions remained unanswered during this overlooked period. The present work reviewed online databases, repositories, and libraries to compile literature related to rickettsioses in Colombia published during the 20th century. Gathered data show that typhus group rickettsioses (including infections by R. typhi and R. prowazekii) were broadly distributed in departments from the Andean and Caribbean regions, and that spotted fever group rickettsioses cases (including infections by R. rickettsii) were registered in other locations different from Tobia (Cundinamarca), like Atlántico, Bolivar, and Santander departments. These findings contribute to the knowledge of these diseases, their historical distribution, public health burden, and set new horizons for rickettsioses research in different Colombian locations.
Topics: Male; Humans; Colombia; Rickettsia Infections; Rickettsia; Rickettsia prowazekii; Rickettsia rickettsii
PubMed: 36628901
DOI: 10.1016/j.ttbdis.2022.102118 -
Molecular Genetics & Genomic Medicine Jun 2020Dental pulp with special structure has become a good reference sample in paleomicrobiology-related blood-borne diseases, many pathogens were detected by different... (Review)
Review
INTRODUCTION
Dental pulp with special structure has become a good reference sample in paleomicrobiology-related blood-borne diseases, many pathogens were detected by different methods based on the diagnosis of nucleic acids and proteins.
OBJECTIVES
This review aims to propose the preparation process from ancient teeth collection to organic molecule extraction of dental pulp and summary, analyze the methods that have been applied to detect septicemic pathogens through ancient dental pulps during the past 20 years following the first detection of an ancient microbe.
METHODS
The papers used in this review with two main objectives were obtained from PubMed and Google scholar with combining keywords: "ancient," "dental pulp," "teeth," "anatomy," "structure," "collection," "preservation," "selection," "photography," "radiography," "contamination," "decontamination," "DNA," "protein," "extraction," "bone," "paleomicrobiology," "bacteria," "virus," "pathogen," "molecular biology," "proteomics," "PCR," "MALDI-TOF," "LC/MS," "ELISA," "immunology," "immunochromatography," "genome," "microbiome," "metagenomics."
RESULTS
The analysis of ancient dental pulp should have a careful preparation process with many different steps to give highly accurate results, each step complies with the rules in archaeology and paleomicrobiology. After the collection of organic molecules from dental pulp, they were investigated for pathogen identification based on the analysis of DNA and protein. Actually, DNA approach takes a principal role in diagnosis while the protein approach is more and more used. A total of seven techniques was used and ten bacteria (Yersinia pestis, Bartonella quintana, Salmonella enterica serovar Typhi, Salmonella enterica serovar Paratyphi C, Mycobacterium leprae, Mycobacterium tuberculosis, Rickettsia prowazeki, Staphylococcus aureus, Borrelia recurrentis, Bartonella henselae) and one virus (Anelloviridae) were identified. Y. pestis had the most published in quantity and all methods were investigated for this pathogen, S. aureus and B. recurrentis were identified by three different methods and others only by one. The combining methods interestingly increase the positive rate with ELISA, PCR and iPCR in Yersinia pestis diagnosis. Twenty-seven ancient genomes of Y. pestis and one ancient genome of B. recurrentis were reconstructed. Comparing to the ancient bone, ancient teeth showed more advantage in septicemic diagnosis. Beside pathogen identification, ancient pulp help to distinguish species.
CONCLUSIONS
Dental pulp with specific tissue is a suitable sample for detection of the blood infection in the past through DNA and protein identification with the correct preparation process, furthermore, it helps to more understand the pathogens of historic diseases and epidemics.
Topics: Bacterial Infections; DNA, Ancient; Dental Pulp; Fossils; Humans; Metagenome; Microbiota
PubMed: 32233019
DOI: 10.1002/mgg3.1202 -
Socio-ecological determinants of rickettsial seroprevalence in a rural community of Yucatán, Mexico.Infection, Genetics and Evolution :... Aug 2022Rickettsial diseases have seen a re-emergence in the Americas in the last few decades, with concerning morbidity, mortality and economic implications that result from...
Rickettsial diseases have seen a re-emergence in the Americas in the last few decades, with concerning morbidity, mortality and economic implications that result from loss of productivity, income, curbs in liberal trade agreements, and reduction in agricultural practices. The aim of this study is to determine the socioecological determinants and seroprevalence for Rickettsia typhi and Rickettsia rickettsii among residents of Teabo, a rural community of Yucatán, Mexico. Sociodemographic data and serum samples were obtained from 180 consenting participants. Antibody titers for R. typhi and R. rickettsii were determined by indirect immunofluorescence assay (IFA). Participants also submitted tick samples collected from their residential area. We conducted logistic regression models to evaluate the association between exposure variables and seroprevalence. Rhipicephalus sanguineus s.l. (37%; n = 65), and Amblyomma cajennense Fabricius (17%; n = 29) were the predominant tick species in peri-domestic areas. Out of the 180 participants, there was significantly higher seroprevalence of R. typhi (n = 77; 46%) compared to R. rickettsii [n = 27, 15%, (p < 0.05)]. Pearson's chi-square test of independence revealed significant differences in R. rickettsii seroprevalence by gender (X [n = 175, df = 4, (p < 0.001)] = 180.26), level of education, (X [n = 180, df = 4, (p < 0.001)] = 44.0), and by tick species found in residential area, (X [n = 180, df = 4, (p = 0.050)] = 9.48). After adjusting for other variables in a logistic regression model, for each unit increase in the number of dogs present in the residential area, there was a 27% increase in the odds of human seroprevalence for R. typhi IgG (AOR = 1.27, 95% CI: 1.01-1.63). Compared to study participants living in residential areas with a 'low' height of vegetation, those living in residential areas with a 'medium' height of vegetation had 2.5 times greater odds of human seroprevalence for R. typhi IgG (AOR = 2.51, 95% CI: 1.19-5.40). Potentially modifiable existing factors in the peri-domestic area may constitute a high-risk source of seroprevalence for rickettsial antibodies among residents of the rural community of Teabo, Yucatán, Mexico.
Topics: Animals; Dog Diseases; Dogs; Humans; Immunoglobulin G; Mexico; Rhipicephalus sanguineus; Rickettsia; Rural Population; Seroepidemiologic Studies
PubMed: 35490957
DOI: 10.1016/j.meegid.2022.105291 -
Journal of Medical Entomology Mar 2022Rickettsioses are among emerging infectious diseases around the world. In Madagascar, little information is available regarding Rickettsia (Rickettsiales:...
Rickettsioses are among emerging infectious diseases around the world. In Madagascar, little information is available regarding Rickettsia (Rickettsiales: Rickettsiaceae) diversity and their potential impacts on public health. In fact, molecular screening of ectoparasites of mammals reported the presence of three species, Rickettsia africae, Rickettsia typhi, and Rickettsia felis. The present study aims to investigate the diversity of Rickettsia in small mammals and associated ectoparasites (fleas and ticks) using a molecular approach. In September and December 2016, fieldworks were undertaken in two districts of Madagascar to capture small mammals using standard traps (Tomahawk and Sherman traps) and collect associated ectoparasites. In total, 12 taxa of ectoparasites (5 flea and 7 tick species) were collected from 89 individuals of four species of terrestrial small mammals. Rickettsia spp. were molecularly identified in one specimen of Rattus rattus (Rodentia: Muridae), one specimen of Pulex irritans (Siphonaptera: Pulicidae) as well as four specimens of Ixodes cf. colasbelcouri (Ixodida: Ixodidae). This study showed the presence of three phylogenetically distinct taxa of Rickettsia in small mammals and their ectoparasites. The current study broadens our knowledge on the diversity of Rickettsia in the Central Highlands of Madagascar and highlights for the first time the presence of Ri. felis in R. rattus and in tick, I. cf. colasbelcouri in Madagascar. Additional studies are needed to have exhaustive information on Rickettsia in small mammals and their ectoparasites, to determine their pathogenicity as well as their potential effects on public health in order to update the national policy for the control of emerging infectious diseases in Madagascar.
Topics: Animals; Communicable Diseases, Emerging; Ixodes; Madagascar; Mammals; Muridae; Rats; Rickettsia; Siphonaptera
PubMed: 34958102
DOI: 10.1093/jme/tjab207 -
The American Journal of Tropical... Jan 2024
Topics: Animals; Humans; Siphonaptera; Rickettsia typhi; Typhus, Endemic Flea-Borne; Rickettsia Infections; California; Rickettsia; Rickettsia felis
PubMed: 38109770
DOI: 10.4269/ajtmh.23-0742 -
Revista Peruana de Medicina... 2022
Topics: Humans; Mexico; Rickettsia; Rickettsia rickettsii; Rickettsia typhi; Rural Population
PubMed: 35766733
DOI: 10.17843/rpmesp.2022.391.10519 -
Frontiers in Cellular and Infection... 2022Rickettsia is a genus of nonmotile, Gram-negative, non-spore-forming, highly pleomorphic bacteria that cause severe epidemic rickettsioses. The spotted fever group and... (Review)
Review
Rickettsia is a genus of nonmotile, Gram-negative, non-spore-forming, highly pleomorphic bacteria that cause severe epidemic rickettsioses. The spotted fever group and typhi group are major members of the genus Rickettsia. Rickettsial species from the two groups subvert diverse host cellular processes, including membrane dynamics, actin cytoskeleton dynamics, phosphoinositide metabolism, intracellular trafficking, and immune defense, to promote their host colonization and intercellular transmission through secreted effectors (virulence factors). However, lineage-specific rickettsiae have exploited divergent strategies to accomplish such challenging tasks and these elaborated strategies focus on distinct host cell processes. In the present review, we summarized current understandings of how different rickettsial species employ their effectors' arsenal to affect host cellular processes in order to promote their own replication or to avoid destruction.
Topics: Humans; Rickettsia; Rickettsia Infections; Signal Transduction
PubMed: 36389139
DOI: 10.3389/fcimb.2022.995933 -
Vector Borne and Zoonotic Diseases... Aug 2019and are flea-borne pathogens, which cause murine typhus and flea-borne spotted fever, respectively. Recently, two other flea-borne rickettsiae (phylogenetically...
and are flea-borne pathogens, which cause murine typhus and flea-borne spotted fever, respectively. Recently, two other flea-borne rickettsiae (phylogenetically similar to ) have been discovered- and Rickettsia senegalensis. Currently, species-specific identification of detected organisms requires sequencing- or probe-based PCR assays. Our aim was to develop an efficient and inexpensive method to differentiate and -like organisms through restriction fragment length polymorphism (RFLP) analysis. Outer membrane protein B sequences of the aforementioned flea-borne rickettsiae were analyzed using DNASTAR Lasergene Core software to focus on the region amplified by the primers 120.2788 and 120.3599. Restriction enzyme digestion sites were identified, and digestions of each species were compared through simulated agarose gels. The enzyme IV was determined to be the most effective at creating a unique banding pattern within the area of interest. To confirm the predicted performance of IV digestion, we tested the DNA of known PCR positive fleas collected from cats and opossums within Galveston, Texas. DNA from these fleas was amplified using the primer set 120.2788 and 120.3599. The PCR products were then digested with IV, subjected to polyacrylamide gel electrophoresis, and visualized through ethidium bromide staining. The banding patterns were then compared with the computer-generated digestion patterns. All samples demonstrated a banding pattern consistent with the predicted pattern for the known species, as confirmed by previous sequencing. This RFLP assay was developed to be an efficient and cost-effective method to screen samples for , and R. senegalensis. We believe this assay can aid in the epidemiological and ecological studies of flea-borne rickettsiae.
Topics: Animals; Cats; Ctenocephalides; DNA, Bacterial; Didelphis; Electrophoresis, Polyacrylamide Gel; Flea Infestations; Insect Vectors; Polymorphism, Restriction Fragment Length; Rickettsia; Rickettsia Infections; Rickettsia felis; Texas
PubMed: 31021302
DOI: 10.1089/vbz.2018.2428