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Acevedo-Sánchez Y, Woida PJ, Kraemer S, Lamason RL. An obligate intracellular bacterial pathogen forms a direct, interkingdom membrane contact site. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.05.543771. [PMID: 37333133 PMCID: PMC10274737 DOI: 10.1101/2023.06.05.543771] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Interorganelle communication regulates cellular homeostasis through the formation of tightly-associated membrane contact sites 1-3. Prior work has identified several ways that intracellular pathogens alter contacts between eukaryotic membranes 4-6, but there is no existing evidence for contact sites spanning eukaryotic and prokaryotic membranes. Here, using a combination of live-cell microscopy and transmission and focused-ion-beam scanning electron microscopy, we demonstrate that the intracellular bacterial pathogen Rickettsia parkeri forms a direct membrane contact site between its bacterial outer membrane and the rough endoplasmic reticulum (ER), with tethers that are approximately 55 nm apart. Depletion of the ER-specific tethers VAPA and VAPB reduced the frequency of rickettsia-ER contacts, suggesting these interactions mimic organelle-ER contacts. Overall, our findings illuminate a direct, interkingdom membrane contact site uniquely mediated by rickettsia that seems to mimic traditional host MCSs.
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Affiliation(s)
| | - Patrick J. Woida
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Stephan Kraemer
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA
| | - Rebecca L. Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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Silva-Ramos CR, Faccini-Martínez ÁA. Clinical, epidemiological, and laboratory features of Rickettsia africae infection, African tick-bite fever: A systematic review. LE INFEZIONI IN MEDICINA 2022; 29:366-377. [PMID: 35146341 DOI: 10.53854/liim-2903-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/27/2021] [Indexed: 11/03/2022]
Abstract
African tick-bite fever (ATBF), caused by Rickettsia africae, is the main tick-borne rickettsiosis and the second most frequent cause of fever after malaria in travelers returning from sub-Saharan Africa. General descriptions on ATBF were made in the first two decades after recognized as a new infectious entity, and since then, many authors have contributed to the knowledge of the disease by reporting clinical cases in scientific literature. We developed a systematic review that evaluated all available evidence in the literature regarding clinical, epidemiological, and laboratory features of confirmed R. africae rickettsiosis cases. We followed the recommendations made by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guide. A total of 48 scientific publications (108 confirmed cases) were analyzed in order to extract data for developing this review. Overall, our results show that R. africae rickettsiosis is more frequent in males in the age group of 18-64 years, more than 80% of the cases occurred in European travelers, South Africa was the country where most infections were acquired, and almost 40% of cases occurred in clusters. Clinically, more than 80% of the cases had fever and eschar (55% developed multiple eschars), rash was present in less than the half of cases, and lymphangitis was not a common sign (11%). Headache, myalgia and regional lymphadenopathy were predominant nonspecific clinical manifestation (mean of 60%, 49% and 51%, respectively). Our results show that at least 70% of R. africae cases had altered laboratory parameters, most often showing an increase in transaminases and C-reactive protein. Tetracycline-class antibiotics, as monotherapy, were used in most (>90%) of the patients. Overall, only 4% of cases had complications, 12% required hospitalization, and there was a 100% rate of clinical recovery.
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Affiliation(s)
- Carlos Ramiro Silva-Ramos
- Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Álvaro A Faccini-Martínez
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Committee of Tropical Medicine, Zoonoses and Travel Medicine, Asociación Colombiana de Infectología, Bogotá, Colombia
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Frean J, Grayson W. South African Tick Bite Fever: An Overview. Dermatopathology (Basel) 2019; 6:70-76. [PMID: 31700846 PMCID: PMC6827444 DOI: 10.1159/000495475] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 11/12/2018] [Indexed: 12/03/2022] Open
Abstract
The rickettsiae are a diverse group of vector-borne zoonotic bacterial pathogens. The two common spotted fever diseases in existence in southern Africa are boutonneuse fever-like tick bite fever (TBF), caused by Rickettsia conorii, and African TBF, caused by R. africae. This review addresses demographic, epidemiological, clinical, diagnostic, therapeutic, and preventive aspects of TBF in the southern African context, including a discussion of the dermatopathological findings and potential diagnostic pitfalls.
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Affiliation(s)
- John Frean
- Parasitology Reference Laboratory, Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa.,School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Wayne Grayson
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Ampath National Laboratories, Johannesburg, South Africa
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Dincy PC, Susanne PA, Leni G, T S, Meera T, Aj PJ. Clinicopathological study on rickettsial spotted fever from south India. Trop Doct 2018; 48:325-329. [PMID: 30139305 DOI: 10.1177/0049475518794580] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In a prospective study conducted between November 2006 and April 2008 of 35 patients (male:female ratio 2:1) with proven rickettsial spotted fever, a generalised rash with involvement of palms and soles were seen in 80% of patients. Vasculitis on histopathology of rash was seen in 54%.
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Affiliation(s)
- Peter Cv Dincy
- 1 Department of Dermatology, Venereology and Leprosy, Christian Medical College, Vellore, Tamil Nadu, India
| | - Pulimood A Susanne
- 1 Department of Dermatology, Venereology and Leprosy, Christian Medical College, Vellore, Tamil Nadu, India
| | - George Leni
- 1 Department of Dermatology, Venereology and Leprosy, Christian Medical College, Vellore, Tamil Nadu, India
| | - Sohanlal T
- 2 Department of Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Thomas Meera
- 3 Department of Pathology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Prakash John Aj
- 2 Department of Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
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Baltadzhiev IG, Pavlov PI. T-Lymphocyte Subset Absolute Counts in the Peripheral Blood of Mediterranean Spotted Fever Patients: Relations to Disease Severity. Folia Med (Plovdiv) 2016; 57:93-103. [PMID: 26933778 DOI: 10.1515/folmed-2015-0026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 02/18/2015] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION Mediterranean spotted fever (MSF) in Bulgaria is caused by Rickettsia conorii conorii. AIM This study aims at investigating the absolute counts of T-lymphocyte subsets in the peripheral blood of patients with MSF in order to establish relationships with disease severity. MATERIALS AND METHODS The absolute counts of T-lymphocyte subsets were tested in the blood of 62 patients in the acute stage of MSF. They were assigned into three age and sex matched groups, based on the severity of disease - with mild, moderate or severe forms. Controls were 32 age and sex matched healthy individuals. The diagnosis was confirmed by an immunofluorescence assay. Immunophenotyping was performed using Epics XL-MCL Coulter, USA flow-cytometer. RESULTS The absolute counts of immune competent (CD3+) cells, as well as the counts of helper/inducer (CD3+ CD4+) and suppressor/ cytotoxic (CD3+ CD8+) T-cell subsets decreased in parallel with disease severity. Naïve (CD4+ CD45RA+) and activated memory (CD4+ CD45RO+) T-cell subsets were reduced, particularly in severe MSF. Taken as a whole, the counts of activated (CD3+ HLA-DR+) and that of presenting accessory (CD28+) or stimulatory (CD38+) molecules Т-cell subsets was increased, but in the first two subsets the trend from mild to severe forms of the disease was descending. CONCLUSION Reduced T-lymphocyte subset counts are likely related to trans-migration into perivascular inflammatory foci. The increased number of T-lymphocytes bearing activation molecules reflects a mobilization of the cell-mediated immune response. An important issue of this study is the possible prognostic value of T-cell subsets counting, predicting the evolution of a clinical condition to clinical forms, according to the disease severity.
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Affiliation(s)
| | - Pavel I Pavlov
- Department of Clinical Laboratory, Faculty of Pharmacy, St. George University Hospital, Medical University, Plovdiv, Bulgaria
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Immunohistochemistry in the diagnosis of cutaneous bacterial infections. Am J Dermatopathol 2015; 37:179-93; quiz 194-6. [PMID: 25699977 DOI: 10.1097/dad.0000000000000227] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The identification of pathogens is of vital importance for the adequate treatment of infections. During the past 2 decades, the approach to histopathologic diagnosis has been dramatically transformed by immunohistochemistry (IHC) specifically in the diagnosis and classification of tumors and more recently in the diagnosis of infectious diseases in tissue samples. The main goals of this article were to: (1) identify by IHC the cutaneous structures where bacterial pathogens are expressed in the course of infection, (2) identify the specific cells in which bacterial pathogens are expressed in positive cases, and (3) describe the pattern of distribution of the bacterial antigens within these cells (nuclear, cytoplasmatic, or membranous). This article is an up-to-date overview of the potential uses and limitations of IHC in the histopathologic diagnosis of cutaneous bacterial infections. In conclusion, IHC is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, culture is not possible, or exhibit an atypical morphology.
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Abstract
The vascular endothelium is the main target of a limited number of infectious agents, Rickettsia, Ehrlichia ruminantium, and Orientia tsutsugamushi are among them. These arthropod-transmitted obligately-intracellular bacteria cause serious systemic diseases that are not infrequently lethal. In this review, we discuss the bacterial biology, vector biology, and clinical aspects of these conditions with particular emphasis on the interactions of these bacteria with the vascular endothelium and how it responds to intracellular infection. The study of these bacteria in relevant in vivo models is likely to offer new insights into the physiology of the endothelium that have not been revealed by other models.
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Affiliation(s)
- Gustavo Valbuena
- Department of Pathology and Center for Biodefense and Emerging Infectious Diseases, The University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-0609, USA.
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Valbuena G, Walker DH. The endothelium as a target for infections. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2007; 1:171-98. [PMID: 18039112 DOI: 10.1146/annurev.pathol.1.110304.100031] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The endothelial cells lining vascular and lymphatic vessels are targets of several infectious agents, including viruses and bacteria, that lead to dramatic changes in their functions. Understanding the pathophysiological mechanisms that cause the clinical manifestations of those infections has been advanced through the use of animal models and in vitro systems; however, there are also abundant studies that explore the consequences of endothelial infection in vitro without supporting evidence that endothelial cells are actual in vivo targets of infection in human diseases. This article defines criteria for considering an infection as truly endothelium-targeted and reviews the literature that offers insights into the pathogenesis of human endothelial-target infections.
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