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Blanton LS. Murine Typhus: A Review of a Reemerging Flea-Borne Rickettsiosis with Potential for Neurologic Manifestations and Sequalae. Infect Dis Rep 2023; 15:700-716. [PMID: 37987401 PMCID: PMC10660532 DOI: 10.3390/idr15060063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/24/2023] [Accepted: 10/24/2023] [Indexed: 11/22/2023] Open
Abstract
Murine typhus is an acute febrile illness caused by Rickettsia typhi, an obligately intracellular Gram-negative coccobacillus. Rats (Rattus species) and their fleas (Xenopsylla cheopis) serve as the reservoir and vector of R. typhi, respectively. Humans become infected when R. typhi-infected flea feces are rubbed into flea bite wounds or onto mucous membranes. The disease is endemic throughout much of the world, especially in tropical and subtropical seaboard regions where rats are common. Murine typhus is reemerging as an important cause of febrile illness in Texas and Southern California, where an alternate transmission cycle likely involves opossums (Didelphis virginiana) and cat fleas (Ctenocephalides felis). Although primarily an undifferentiated febrile illness, a range of neurologic manifestations may occur, especially when treatment is delayed. Serology is the mainstay of diagnostic testing, but confirmation usually requires demonstrating seroconversion or a fourfold increase in antibody titer from acute- and convalescent-phase sera (antibodies are seldom detectable in the first week of illness). Thus, early empiric treatment with doxycycline, the drug of choice, is imperative. The purpose of this review is to highlight murine typhus as an important emerging and reemerging infectious disease, review its neurologic manifestations, and discuss areas in need of further study.
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Affiliation(s)
- Lucas S Blanton
- Department Internal Medicine, Division of Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555, USA
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Rao RSP, Ghate SD, Shastry RP, Kurthkoti K, Suravajhala P, Patil P, Shetty P. Prevalence and heterogeneity of antibiotic resistance genes in Orientia tsutsugamushi and other rickettsial genomes. Microb Pathog 2023; 174:105953. [PMID: 36529286 DOI: 10.1016/j.micpath.2022.105953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/16/2022]
Abstract
Despite a million infections every year and an estimated one billion people at risk, scrub typhus is regarded as a neglected tropical disease. The causative bacterium Orientia tsutsugamushi, a member of rickettsiae, seems to be intrinsically resistant to several classes of antibiotics. The emergence of antibiotic-resistant scrub typhus is likely to become a global public health concern. Yet, it is unknown as to how common antibiotic resistance genes are in O. tsutsugamushi, and how variable these loci are among the genomes of rickettsiae. By using the comprehensive antibiotic resistance database, we explored 79 complete genomes from 24 species of rickettsiae for antibiotic resistance loci. There were 244 unique antibiotic resistance genes in rickettsiae. Both the total and unique antibiotic resistance genes in O. tsutsugamushi were significantly less compared to other members of rickettsiae. However, antibiotic resistance genes in O. tsutsugamushi genomes were more unique and highly variable. Many genes such as resistant variants of evgS, and vanS A/G were present in numerous copies. These results will have important implications in the context of antibiotic-resistant scrub typhus.
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Affiliation(s)
- R Shyama Prasad Rao
- Center for Bioinformatics, NITTE deemed to be University, Mangaluru, 575018, India.
| | - Sudeep D Ghate
- Center for Bioinformatics, NITTE deemed to be University, Mangaluru, 575018, India
| | - Rajesh P Shastry
- Division of Microbiology and Biotechnology, Yenepoya Research Center, Yenepoya deemed to be University, Mangaluru, 575018, India
| | - Krishna Kurthkoti
- Mycobacterium Research Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, 695014, India
| | - Prashanth Suravajhala
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Clappana PO, 690525, Kerala, India
| | - Prakash Patil
- Central Research Laboratory, KS Hegde Medical Academy (KSHEMA), NITTE deemed to be University, Mangaluru, 575018, India
| | - Praveenkumar Shetty
- Central Research Laboratory, KS Hegde Medical Academy (KSHEMA), NITTE deemed to be University, Mangaluru, 575018, India; Department of Biochemistry, KS Hegde Medical Academy (KSHEMA), NITTE deemed to be University, Mangaluru, 575018, India
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3
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Plant-mediated rifampicin treatment of Bemisia tabaci disrupts but does not eliminate endosymbionts. Sci Rep 2022; 12:20766. [PMID: 36456664 PMCID: PMC9715664 DOI: 10.1038/s41598-022-24788-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Whiteflies are among the most important global insect pests in agriculture; their sustainable control has proven challenging and new methods are needed. Bacterial symbionts of whiteflies are poorly understood potential target of novel whitefly control methods. Whiteflies harbour an obligatory bacterium, Candidatus Portiera aleyrodidarum, and a diverse set of facultative bacterial endosymbionts. Function of facultative microbial community is poorly understood largely due to the difficulty in their selective elimination without removal of the primary endosymbiont. Since the discovery of secondary endosymbionts, antibiotic rifampicin has emerged as the most used tool for their manipulation. Its effectiveness is however much less clear, with contrasting reports on its effects on the endosymbiont community. The present study builds upon most recent method of rifampicin application in whiteflies and evaluates its ability to eliminate obligatory Portiera and two facultative endosymbionts (Rickettsia and Arsenophnus). Our results show that rifampicin reduces but does not eliminate any of the three endosymbionts. Additionally, rifampicin causes direct negative effect on whiteflies, likely by disrupting mitochondria. Taken together, results signify the end of a rifampicin era in whitefly endosymbiont studies. Finally, we propose refinement of current quantification and data analysis methods which yields additional insights in cellular metabolic scaling.
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Together forever: Inseparable partners of the symbiotic system Paramecium multimicronucleatum/Ca. Trichorickettsia mobilis. Symbiosis 2022. [DOI: 10.1007/s13199-022-00854-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Zeng BS, Zeng BY, Hung CM, Kuo HC, Chen YW, Suen MW, Shiue YL, Tseng PT, Chen CH. The efficacy and tolerability of antibiotics in scrub typhus: An updated network meta-analysis of randomized controlled trials. Int J Infect Dis 2022; 122:461-468. [PMID: 35724826 DOI: 10.1016/j.ijid.2022.06.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/06/2022] [Accepted: 06/14/2022] [Indexed: 10/18/2022] Open
Abstract
INTRODUCTION Inadequate treatment of scrub typhus results in severe complications such as septic shock and is also associated with a high median mortality rate of 6%. However, there has been no conclusive evidence about the superiority of different antibiotics in managing scrub typhus in terms of efficacy and tolerability. METHODS The current network meta-analysis (NMA) was conducted using the frequentist method. The included participants were pediatric and adult patients infected with scrub typhus. The primary outcome was the cure rate in the patients included. The subgroup analysis was done according to pediatric or adult patients. RESULTS Overall, 14 randomized controlled trials (RCTs) with 1264 participants were included in this study. The NMA revealed that all the investigated antibiotics were associated with cure rates similar to those of doxycycline. The chloramphenicol and minocycline were ranked to be associated with the highest cure rate in the pediatric subgroup and adult subgroup, respectively. Second-generation quinolones, including ofloxacin and ciprofloxacin and chloramphenicol were associated with significantly lower adverse event rates than doxycycline. CONCLUSION The current update NMA provides evidence for the efficacy of chloramphenicol and minocycline in scrub typhus management. However, future large-scale RCTs with longer follow-up times are warranted. TRIAL REGISTRATION PROSPERO CRD42020222410. The current study was approved by the Institutional Review Board of the Tri-Service General Hospital, National Defense Medical Center (TSGHIRB No. B-109-29).
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Affiliation(s)
- Bing-Syuan Zeng
- Department of Internal Medicine, E-DA Cancer Hospital, Kaohsiung, Taiwan; Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Bing-Yan Zeng
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan; Department of Internal Medicine, E-DA Dachang Hospital, Kaohsiung, Taiwan
| | - Chao-Ming Hung
- Division of General Surgery, Department of Surgery, E-Da Cancer Hospital, Kaohsiung, Taiwan; School of Medicine, College of Medicine, I-Shou University, Kaohsiung, Taiwan
| | - Hung-Chang Kuo
- Department of Neurology, E-Da Cancer Hospital/School of Medicine, I-Shou University, Kaohsiung, Taiwan
| | - Yen-Wen Chen
- Prospect Clinic for Otorhinolaryngology & Neurology, Kaohsiung, Taiwan
| | - Mein-Woei Suen
- Department of Psychology, College of Medical and Health Science, Asia University, Taichung, Taiwan; Gender Equality Education and Research Center, Asia University, Taichung, Taiwan; Department of Medical Research, Asia University Hospital, Asia University, Taichung, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - Yow-Ling Shiue
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan.
| | - Ping-Tao Tseng
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan; Prospect Clinic for Otorhinolaryngology & Neurology, Kaohsiung, Taiwan; Department of Psychology, College of Medical and Health Science, Asia University, Taichung, Taiwan.
| | - Chang-Hua Chen
- Program in Translational Medicine, National Chung Hsing University, Taichung City, Taiwan; Rong Hsing Research Center For Translational Medicine, National Chung Hsing University, Taichung City, Taiwan; Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.
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Verhoeve VI, Fauntleroy TD, Risteen RG, Driscoll TP, Gillespie JJ. Cryptic Genes for Interbacterial Antagonism Distinguish Rickettsia Species Infecting Blacklegged Ticks From Other Rickettsia Pathogens. Front Cell Infect Microbiol 2022; 12:880813. [PMID: 35592653 PMCID: PMC9111745 DOI: 10.3389/fcimb.2022.880813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/04/2022] [Indexed: 01/28/2023] Open
Abstract
Background The genus Rickettsia (Alphaproteobacteria: Rickettsiales) encompasses numerous obligate intracellular species with predominantly ciliate and arthropod hosts. Notable species are pathogens transmitted to mammals by blood-feeding arthropods. Mammalian pathogenicity evolved from basal, non-pathogenic host-associations; however, some non-pathogens are closely related to pathogens. One such species, Rickettsia buchneri, is prevalent in the blacklegged tick, Ixodes scapularis. While I. scapularis transmits several pathogens to humans, it does not transmit Rickettsia pathogens. We hypothesize that R. buchneri established a mutualism with I. scapularis, blocking tick superinfection with Rickettsia pathogens. Methods To improve estimates for assessing R. buchneri infection frequency in blacklegged tick populations, we used comparative genomics to identify an R. buchneri gene (REIS_1424) not present in other Rickettsia species present throughout the I. scapularis geographic range. Bioinformatic and phylogenomics approaches were employed to propose a function for the hypothetical protein (263 aa) encoded by REIS_1424. Results REIS_1424 has few analogs in other Rickettsiales genomes and greatest similarity to non-Proteobacteria proteins. This cohort of proteins varies greatly in size and domain composition, possessing characteristics of Recombination hotspot (Rhs) and contact dependent growth inhibition (CDI) toxins, with similarity limited to proximal C-termini (~145 aa). This domain was named CDI-like/Rhs-like C-terminal toxin (CRCT). As such proteins are often found as toxin-antidote (TA) modules, we interrogated REIS_1423 (151 aa) as a putative antidote. Indeed, REIS_1423 is similar to proteins encoded upstream of CRCT domain-containing proteins. Accordingly, we named these proteins CDI-like/Rhs-like C-terminal toxin antidotes (CRCA). R. buchneri expressed both REIS_1423 and REIS_1424 in tick cell culture, and PCR assays showed specificity for R. buchneri over other rickettsiae and utility for positive detection in three tick populations. Finally, phylogenomics analyses uncovered divergent CRCT/CRCA modules in varying states of conservation; however, only R. buchneri and related Tamurae/Ixodes Group rickettsiae carry complete TA modules. Conclusion We hypothesize that Rickettsia CRCT/CRCA modules circulate in the Rickettsia mobile gene pool, arming rickettsiae for battle over arthropod colonization. While its functional significance remains to be tested, R. buchneri CRCT/CRCA serves as a marker to positively identify infection and begin deciphering the role this endosymbiont plays in the biology of the blacklegged tick.
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Affiliation(s)
- Victoria I. Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Tyesha D. Fauntleroy
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Riley G. Risteen
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Timothy P. Driscoll
- Department of Biology, West Virginia University, Morgantown, WV, United States
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
- *Correspondence: Joseph J. Gillespie,
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Dasch GA, Eremeeva ME, Zambrano ML, Premaratna R, Kularatne SAM, Jayanthe Rajapakse RPV. Molecular Characterization of Rickettsial Agents in Ticks (Acari: Ixodidae) from Sri Lanka. Am J Trop Med Hyg 2022; 106:tpmd210995. [PMID: 35405644 PMCID: PMC9209928 DOI: 10.4269/ajtmh.21-0995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/31/2022] [Indexed: 11/10/2022] Open
Abstract
Because the majority of spotted fever group rickettsiae are transmitted to humans by tick bites, it is important to understand which ticks might play a role in transmission of rickettsial pathogens in Sri Lanka. The purpose of our study was to conduct molecular surveillance of 847 ticks collected in different locations in central Sri Lanka to determine which were infected with Rickettsia and Anaplasmataceae. Molecular methods were used to identify the ticks and the agents detected. Most ticks (Amblyomma, Haemaphysalis, and Rhipicephalus) were collected by flagging, and lower number was collected from dogs, cattle, pigs, a pangolin, and tortoises. Five spotted fever genotypes were identified: a Rickettsia africae-like agent in Amblyomma larvae, Rhipicephalus massiliae and a related genotype identified in association with the tropical type of Rhipicephalus sanguineus from dogs and Rhipicephalus haemaphysaloides from dogs and cattle, and Candidatus R. kellyi and another novel genotype (SL94) in R. haemaphysaloides. Twenty-three ticks were positive for Anaplasmataceae, including one Anaplasma and two Ehrlichia genotypes. Because the sequence database for both ticks and rickettsial agents from Sri Lanka and southern India is not extensive, additional molecular characterization of the tick species of Sri Lanka and their rickettsial agents is required to understand their pathogenic potential more completely. However, several of the agents we identified in this survey may well be pathogenic for humans and domestic animals, and should be considered as a part of epidemiological surveillance and patient management.
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Affiliation(s)
- Gregory A. Dasch
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Marina E. Eremeeva
- Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, Georgia
| | - Maria L. Zambrano
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
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Chigwada AD, Mapholi NO, Ogola HJO, Mbizeni S, Masebe TM. Pathogenic and Endosymbiotic Bacteria and Their Associated Antibiotic Resistance Biomarkers in Amblyomma and Hyalomma Ticks Infesting Nguni Cattle (Bos spp.). Pathogens 2022; 11:pathogens11040432. [PMID: 35456107 PMCID: PMC9028808 DOI: 10.3390/pathogens11040432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/27/2022] [Accepted: 03/31/2022] [Indexed: 11/17/2022] Open
Abstract
Deciphering the interactions between ticks and their microbiome is key to revealing new insights on tick biology and pathogen transmission. However, knowledge on tick-borne microbiome diversity and their contribution to drug resistance is scarce in sub–Saharan Africa (SSA), despite endemism of ticks. In this study, high-throughput 16S rRNA amplicon sequencing and PICRUSt predictive function profiling were used to characterize the bacterial community structure and associated antibiotic resistance markers in Amblyomma variegatum, A. hebraeum, and Hyalomma truncatum ticks infesting Nguni cattle (Bos spp.). Twenty-one (seven families and fourteen genera) potentially pathogenic and endosymbiotic bacterial taxa were differentially enriched in two tick genera. In H. truncatum ticks, a higher abundance of Corynebacterium (35.6%), Porphyromonas (14.4%), Anaerococcus (11.1%), Trueperella (3.7%), and Helcococcus (4.7%) was detected. However, Rickettsia (38.6%), Escherichia (7%), and Coxiellaceae (2%) were the major differentially abundant taxa in A. variegatum and A. hebraeum. Further, an abundance of 50 distinct antibiotic resistance biomarkers relating to multidrug resistance (MDR) efflux pumps, drug detoxification enzymes, ribosomal protection proteins, and secretion systems, were inferred in the microbiome. This study provides theoretical insights on the microbiome and associated antibiotic resistance markers, important for the design of effective therapeutic and control decisions for tick-borne diseases in the SSA region.
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Affiliation(s)
- Aubrey Dickson Chigwada
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa (UNISA), Florida Campus, Roodepoort 1709, South Africa; (A.D.C.); (N.O.M.); (H.J.O.O.); (S.M.)
| | - Ntanganedzeni Olivia Mapholi
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa (UNISA), Florida Campus, Roodepoort 1709, South Africa; (A.D.C.); (N.O.M.); (H.J.O.O.); (S.M.)
| | - Henry Joseph Oduor Ogola
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa (UNISA), Florida Campus, Roodepoort 1709, South Africa; (A.D.C.); (N.O.M.); (H.J.O.O.); (S.M.)
- School of Agricultural and Food Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo P.O. Box 210-40601, Kenya
| | - Sikhumbuzo Mbizeni
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa (UNISA), Florida Campus, Roodepoort 1709, South Africa; (A.D.C.); (N.O.M.); (H.J.O.O.); (S.M.)
| | - Tracy Madimabi Masebe
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa (UNISA), Florida Campus, Roodepoort 1709, South Africa; (A.D.C.); (N.O.M.); (H.J.O.O.); (S.M.)
- Correspondence: ; Tel.: +27-11-471-2268
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Elelu N, Ola-Fadunsin SD, Bankole AA, Raji MA, Ogo NI, Cutler SJ. Prevalence of tick infestation and molecular characterization of spotted fever Rickettsia massiliae in Rhipicephalus species parasitizing domestic small ruminants in north-central Nigeria. PLoS One 2022; 17:e0263843. [PMID: 35157723 PMCID: PMC8843212 DOI: 10.1371/journal.pone.0263843] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/27/2022] [Indexed: 11/18/2022] Open
Abstract
Ticks are of great menace to animal and human health. They serve as vectors to both animals and human pathogens including Rickettsia species. Tick-borne rickettsiosis in West Africa remains incompletely understood. We determined the prevalence of tick infestation among small ruminants and molecularly described a clinically significant spotted fever Rickettsia massiliae from Rhipicephalus ticks collected from North-Central, Nigeria. A total of 352 small ruminants comprising of 152 sheep and 200 goats that were brought for slaughter at the major small ruminant slaughterhouse in Ilorin were examined for the presence of ticks. The collected Rhipicephalus species were subjected to molecular studies to detect and characterize Rickettsia massiliae. Of the small ruminants examined, 21 sheep and 46 goats were infested with ticks representing 13.82% and 23.00% respectively. Eight and nine different species of ticks were detected in sheep and goats respectively, with Rhipicephalus (Boophilus) decoloratus being the most prevalent tick species in both sheep and goats. There was a significant difference (p <0.01) in the prevalence of the different tick species collected in sheep and in goats. Based on the PCR amplification of the 23S-5S intergenic spacer (IGS), only 2 of the 142 Rhipicephalus tick samples screened for R. massiliae were positive (1.41%; 95% CI = 0.39-4.99). Rickettsia massiliae was detected from Rhipicephalus turanicus collected from sheep. Sequences obtained from the PCR carried out by amplifying Rickettsia 23S-5S IGS showed 99-100% close identity with members of the R. massiliae group. This study has for the first time confirmed the presence of spotted fever group Rickettsia massiliae from feeding ticks in Nigerian small ruminants. Further investigations to determine the possible pathogenic role of human R. massiliae infection in Nigeria would be beneficial.
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Affiliation(s)
- Nusirat Elelu
- Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, University of Ilorin, Ilorin, Nigeria
| | - Shola David Ola-Fadunsin
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Ilorin, Ilorin, Nigeria
- * E-mail:
| | | | - Mashood Abiola Raji
- Department of Veterinary Microbiology, Faculty of Veterinary Medicine, University of Ilorin, Ilorin, Nigeria
| | | | - Sally Jane Cutler
- School of Health, Sport and Bioscience, University of East London, London, United Kingdom
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Mileva R, Milanova A. Doxycycline pharmacokinetics in mammalian species of veterinary interest – an overview. BULGARIAN JOURNAL OF VETERINARY MEDICINE 2022. [DOI: 10.15547/bjvm.2321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Doxycycline is a broad-spectrum tetracycline antibiotic widely used in veterinary medicine. The current review aims to summarise the available data about pharmacokinetics in mammalian species of veterinary interest and to indicate the basic strategies for refining dosage regimens in order to use this antibiotic reasonably. Additionally, the available data about population pharmacokinetics are reviewed as this approach exhibits a number of benefits in terms of determination of drug pharmacokinetics, prediction of drug disposition and interpretation of the variations in the pharmacokinetic parameters. Further research with animal species of veterinary interest and pathogens causing diseases in animals is needed to clarify the pharmacokinetics and pharmacodynamics of doxycycline.
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Affiliation(s)
- R. Mileva
- Department of Pharmacology, Animal Physiology and Physiological Chemistry, Facul-ty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria
| | - A. Milanova
- Department of Pharmacology, Animal Physiology and Physiological Chemistry, Facul-ty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria
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Zhou C, Bei J, Qiu Y, Chang Q, Nyong E, Vasilakis N, Yang J, Krishnan B, Khanipov K, Jin Y, Fang X, Gaitas A, Gong B. Exosomally Targeting microRNA23a Ameliorates Microvascular Endothelial Barrier Dysfunction Following Rickettsial Infection. Front Immunol 2022; 13:904679. [PMID: 35812423 PMCID: PMC9260018 DOI: 10.3389/fimmu.2022.904679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/23/2022] [Indexed: 11/25/2022] Open
Abstract
Spotted fever group rickettsioses caused by Rickettsia (R) are devastating human infections, which mainly target microvascular endothelial cells (ECs) and can induce lethal EC barrier dysfunction in the brain and lungs. Our previous evidence reveals that exosomes (Exos) derived from rickettsial-infected ECs, namely R-ECExos, can induce disruption of the tight junctional (TJ) protein ZO-1 and barrier dysfunction of human normal recipient brain microvascular endothelial cells (BMECs). However, the underlying mechanism remains elusive. Given that we have observed that microRNA23a (miR23a), a negative regulator of endothelial ZO-1 mRNA, is selectively sorted into R-ECExos, the aim of the present study was to characterize the potential functional role of exosomal miR23a delivered by R-ECExos in normal recipient BMECs. We demonstrated that EC-derived Exos (ECExos) have the capacity to deliver oligonucleotide RNAs to normal recipient BMECs in an RNase-abundant environment. miR23a in ECExos impairs normal recipient BMEC barrier function, directly targeting TJ protein ZO-1 mRNAs. In separate studies using a traditional in vitro model and a novel single living-cell biomechanical assay, our group demonstrated that miR23a anti-sense oligonucleotide-enriched ECExos ameliorate R-ECExo-provoked recipient BMEC dysfunction in association with stabilization of ZO-1 in a dose-dependent manner. These results suggest that Exo-based therapy could potentially prove to be a promising strategy to improve vascular barrier function during bacterial infection and concomitant inflammation.
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Affiliation(s)
- Changcheng Zhou
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Jiani Bei
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Yuan Qiu
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Qing Chang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Emmanuel Nyong
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Nikos Vasilakis
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
- Department of Preventive Medicine and Population Health, The University of Texas Medical Branch, Galveston, TX, United States
- Center for Vector Borne and Zoonotic Diseases, University of Texas Medical Branch, Galveston, TX, United States
- The Center of Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX, United States
| | - Jun Yang
- Department of Internal Medicine, Endocrinology, University of Texas Medical Branch, Galveston, TX, United States
| | - Balaji Krishnan
- Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch, Galveston, TX, United States
| | - Kamil Khanipov
- Department of Pharmacology, University of Texas Medical Branch, Galveston, TX, United States
| | - Yang Jin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Boston University Medical Campus, Boston, MA, United States
| | - Xiang Fang
- Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch, Galveston, TX, United States
| | - Angelo Gaitas
- The Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Bin Gong
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
- Center for Vector Borne and Zoonotic Diseases, University of Texas Medical Branch, Galveston, TX, United States
- The Center of Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX, United States
- *Correspondence: Bin Gong,
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12
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Mediterranean Spotted Fever: Current Knowledge and Recent Advances. Trop Med Infect Dis 2021; 6:tropicalmed6040172. [PMID: 34698275 PMCID: PMC8544691 DOI: 10.3390/tropicalmed6040172] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/17/2021] [Accepted: 09/21/2021] [Indexed: 12/15/2022] Open
Abstract
Mediterranean spotted fever (MSF) is an emerging tick-borne rickettsiosis of the spotted fever group (SFG), endemic in the Mediterranean basin. By virtue of technological innovations in molecular genetics, it has been determined that the causative agent of MSF is Rickettsia conorii subspecies conorii. The arthropod vector of this bacterium is the brown dog tick Rhipicephalus sanguineus. The true nature of the reservoir of R. conorii conorii has not been completely deciphered yet, although many authors theorize that the canine population, other mammals, and the ticks themselves could potentially contribute as reservoirs. Typical symptoms of MSF include fever, maculopapular rash, and a characteristic eschar (“tache noire”). Atypical clinical features and severe multi-organ complications may also be present. All of these manifestations arise from the disseminated infection of the endothelium by R. conorii conorii. Several methods exist for the diagnosis of MSF. Serological tests are widely used and molecular techniques have become increasingly available. Doxycycline remains the treatment of choice, while preventive measures are focused on modification of human behavior and vector control strategies. The purpose of this review is to summarize the current knowledge on the epidemiology, pathogenesis, clinical features, diagnosis, and treatment of MSF.
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13
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Allen PE, Noland RC, Martinez JJ. Rickettsia conorii survival in THP-1 macrophages involves host lipid droplet alterations and active rickettsial protein production. Cell Microbiol 2021; 23:e13390. [PMID: 34464019 DOI: 10.1111/cmi.13390] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 12/29/2022]
Abstract
Rickettsia conorii is a Gram-negative, cytosolic intracellular bacterium that has classically been investigated in terms of endothelial cell infection. However, R. conorii and other human pathogenic Rickettsia species have evolved mechanisms to grow in various cell types, including macrophages, during mammalian infection. During infection of these phagocytes, R. conorii shifts the host cell's overall metabolism towards an anti-inflammatory M2 response, metabolically defined by an increase in host lipid metabolism and oxidative phosphorylation. Lipid metabolism has more recently been identified as a key regulator of host homeostasis through modulation of immune signalling and metabolism. Intracellular pathogens have adapted mechanisms of hijacking host metabolic pathways including host lipid catabolic pathways for various functions required for growth and survival. In the present study, we hypothesised that alterations of host lipid droplets initiated by lipid catabolic pathways during R. conorii infection is important for bacterial survival in macrophages. Herein, we determined that host lipid droplet modulation is initiated early during R. conorii infection, and these alterations rely on active bacteria and lipid catabolic pathways. We also find that these lipid catabolic pathways are essential for efficient bacterial survival. Unlike the mechanisms used by other intracellular pathogens, the catabolism of lipid droplets induced by R. conorii infection is independent of upstream host peroxisome proliferator-activated receptor-alpha (PPARα) signalling. Inhibition of PPARɣ signalling and lipid droplet accumulation in host cells cause a significant decrease in R. conorii survival suggesting a negative correlation with lipid droplet production and R. conorii survival. Together, these results strongly suggest that the modulation of lipid droplets in macrophage cells infected by R. conorii is an important and underappreciated aspect of the infection process. TAKE AWAYS: Host lipid droplets are differentially altered in early and replicative stages of THP-1 macrophage infection with R. conorii. Lipid droplet alterations are initiated in a bacterial-dependent manner and do not require host peroxisome proliferator-activated receptors α or ɣ activation. Pharmacological inhibition of host lipid catabolic processes during R. conorii infection indicates a requirement of lipid catabolism for bacterial survival and initiation of lipid droplet modulation. A significant increase in host lipid droplets during infection has a negative impact on R. conorii survival in THP-1 macrophages.
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Affiliation(s)
- Paige E Allen
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, Louisiana, USA
| | - Robert C Noland
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
| | - Juan J Martinez
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, Louisiana, USA
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14
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In Vitro Susceptibility of Rickettsia Species to Eravacycline, Omadacycline, and Tigecycline. Antimicrob Agents Chemother 2021; 65:e0066521. [PMID: 34060898 DOI: 10.1128/aac.00665-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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15
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Caravedo Martinez MA, Ramírez-Hernández A, Blanton LS. Manifestations and Management of Flea-Borne Rickettsioses. Res Rep Trop Med 2021; 12:1-14. [PMID: 33574726 PMCID: PMC7873028 DOI: 10.2147/rrtm.s274724] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 01/26/2021] [Indexed: 12/16/2022] Open
Abstract
Murine typhus and flea-borne spotted fever are undifferentiated febrile illnesses caused by Rickettsia typhi and Rickettsia felis, respectively. These organisms are small obligately intracellular bacteria and are transmitted to humans by fleas. Murine typhus is endemic to coastal areas of the tropics and subtropics (especially port cities), where rats are the primary mammalian host and rat fleas (Xenopsylla cheopis) are the vector. In the United States, a cycle of transmission involving opossums and cat fleas (Ctenocephalides felis) are the presumed reservoir and vector, respectively. The incidence and distribution of murine typhus appear to be increasing in endemic areas of the US. Rickettsia felis has also been reported throughout the world and is found within the ubiquitous cat flea. Flea-borne rickettsioses manifest as an undifferentiated febrile illness. Headache, malaise, and myalgia are frequent symptoms that accompany fever. The incidence of rash is variable, so its absence should not dissuade the clinician to consider a rickettsial illness as part of the differential diagnosis. When present, the rash is usually macular or papular. Although not a feature of murine typhus, eschar has been found in 12% of those with flea-borne spotted fever. Confirmatory laboratory diagnosis is usually obtained by serology; the indirect immunofluorescence assay is the serologic test of choice. Antibodies are seldom present during the first few days of illness. Thus, the diagnosis requires acute- and convalescent-phase specimens to document seroconversion or a four-fold increase in antibody titer. Since laboratory diagnosis is usually retrospective, when a flea-borne rickettsiosis is considered, empiric treatment should be initiated. The treatment of choice for both children and adults is doxycycline, which results in a swift and effective response. The following review is aimed to summarize the key clinical, epidemiological, ecological, diagnostic, and treatment aspects of flea-borne rickettsioses.
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Affiliation(s)
- Maria A Caravedo Martinez
- Department of Internal Medicine – Division of Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA
| | | | - Lucas S Blanton
- Department of Internal Medicine – Division of Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA
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16
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Wangrangsimakul T, Phuklia W, Newton PN, Richards AL, Day NPJ. Scrub Typhus and the Misconception of Doxycycline Resistance. Clin Infect Dis 2021; 70:2444-2449. [PMID: 31570937 PMCID: PMC7245148 DOI: 10.1093/cid/ciz972] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/27/2019] [Indexed: 12/24/2022] Open
Abstract
Scrub typhus, a neglected infectious disease caused by the obligate intracellular bacterium Orientia tsutsugamushi, is a major cause of fever across the Asia Pacific region with more than a billion people at risk. Treatment with antibiotics such as doxycycline or chloramphenicol is effective for the majority of patients. In the 1990s, reports from northern Thailand raised a troubling observation; some scrub typhus patients responded poorly to doxycycline, which investigators attributed to doxycycline resistance. Despite the controversial nature of these reports, independent verification was neglected, with subsequent studies speculating on the role of doxycycline resistance in contributing to failure of treatment or prophylaxis. In this review, we have outlined the evidence for drug-resistant Orientia tsutsugamushi, assessed the evidence for doxycycline resistance, and highlight more recent findings unsupportive of doxycycline resistance. We conclude that doxycycline resistance is a misconception, with treatment outcome likely to be determined by other bacterial, host, and pharmacological factors.
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Affiliation(s)
- Tri Wangrangsimakul
- Mahidol -Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Weerawat Phuklia
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Paul N Newton
- Mahidol -Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Allen L Richards
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Nicholas P J Day
- Mahidol -Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
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17
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Mironov T, Sabaneyeva E. A Robust Symbiotic Relationship Between the Ciliate Paramecium multimicronucleatum and the Bacterium Ca. Trichorickettsia Mobilis. Front Microbiol 2020; 11:603335. [PMID: 33324385 PMCID: PMC7721670 DOI: 10.3389/fmicb.2020.603335] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 10/28/2020] [Indexed: 12/22/2022] Open
Abstract
Close reciprocal interactions in symbiotic systems have suggested the holobiont concept, in which the host and its microbiota are considered as a single entity. Ciliates are known for their ability to form symbiotic associations with prokaryotes. Relationships between the partners in such systems vary from mutualism to parasitism and differ significantly in their robustness. We assessed the viability of the ciliate Paramecium multimicronucleatum and its ability to maintain its intranuclear endosymbiont Ca. Trichorickettsia mobilis (Rickettsiaceae) after treatment with antibiotics characterized by different mode of action, such as ampicillin, streptomycin, chloramphenicol, tetracycline. The presence of endosymbionts in the host cell was determined by means of living cell observations made using differential interference contrast or fluorescence in situ hybridization with the species-specific oligonucleotide probe (FISH). Administration of antibiotics traditionally used in treatments of rickettsioses, tetracycline and chloramphenicol, depending on the concentration used and the ciliate strain treated, either caused death of both, infected and control cells, or did not affect the ability of the host to maintain the intranuclear endosymbiont. The surviving cells always manifested motile bacteria in the macronucleus. Streptomycin treatment never led to the loss of endosymbionts in any of the four infected strains, and nearly all ciliates remained viable. Ampicillin treatment never caused host cell death, but resulted in formation of filamentous and immobile oval bacterial forms. Under repeated ampicillin treatments, a part of endosymbionts was registered in the host cytoplasm, as evidenced both by FISH and transmission electron microscopy. Endosymbionts located in the host cytoplasm were enclosed in vacuoles, apparently, corresponding to autophagosomes. Nevertheless, the bacteria seemed to persist in this compartment and might cause relapse of the infection. Although the antibiotic sensitivity profile of Trichorickettsia seems to resemble that of other representatives of Rickettsiaceae, causative agents of severe diseases in humans, neither of the antibiotic treatments used in this study resulted in an aposymbiotic cell line, apparently, due to the protists’ sensitivity to tetracyclines, the drugs of preference in rickettsiosis treatment. The observed robustness of this symbiotic system makes it a good model for further elaboration of the holobiont concept.
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Affiliation(s)
- Timofey Mironov
- Department of Cytology and Histology, Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Elena Sabaneyeva
- Department of Cytology and Histology, Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
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18
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Blanda V, D’Agostino R, Giudice E, Randazzo K, La Russa F, Villari S, Vullo S, Torina A. New Real-Time PCRs to Differentiate Rickettsia spp. and Rickettsia conorii. Molecules 2020; 25:molecules25194431. [PMID: 32992475 PMCID: PMC7582818 DOI: 10.3390/molecules25194431] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/18/2020] [Accepted: 09/25/2020] [Indexed: 11/16/2022] Open
Abstract
Rickettsia species are an important cause of emerging infectious diseases in people and animals, and rickettsiosis is one of the oldest known vector-borne diseases. Laboratory diagnosis of Rickettsia is complex and time-consuming. This study was aimed at developing two quantitative real-time PCRs targeting ompB and ompA genes for the detection, respectively, of Rickettsia spp. and R. conorii DNA. Primers were designed following an analysis of Rickettsia gene sequences. The assays were optimized using SYBR Green and TaqMan methods and tested for sensitivity and specificity. This study allowed the development of powerful diagnostic methods, able to detect and quantify Rickettsia spp. DNA and differentiate R. conorii species.
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Affiliation(s)
- Valeria Blanda
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (V.B.); (R.D.); (K.R.); (S.V.); (S.V.); (A.T.)
| | - Rosalia D’Agostino
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (V.B.); (R.D.); (K.R.); (S.V.); (S.V.); (A.T.)
| | - Elisabetta Giudice
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, Università degli Studi di Messina, 98122 Messina, Italy;
| | - Kety Randazzo
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (V.B.); (R.D.); (K.R.); (S.V.); (S.V.); (A.T.)
| | - Francesco La Russa
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (V.B.); (R.D.); (K.R.); (S.V.); (S.V.); (A.T.)
- Correspondence:
| | - Sara Villari
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (V.B.); (R.D.); (K.R.); (S.V.); (S.V.); (A.T.)
| | - Stefano Vullo
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (V.B.); (R.D.); (K.R.); (S.V.); (S.V.); (A.T.)
| | - Alessandra Torina
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (V.B.); (R.D.); (K.R.); (S.V.); (S.V.); (A.T.)
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19
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Epidemiology, Clinical Aspects, Laboratory Diagnosis and Treatment of Rickettsial Diseases in the Mediterranean Area During COVID-19 Pandemic: A Review of the Literature. Mediterr J Hematol Infect Dis 2020; 12:e2020056. [PMID: 32952967 PMCID: PMC7485464 DOI: 10.4084/mjhid.2020.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/04/2020] [Indexed: 01/12/2023] Open
Abstract
The purpose of the present review is to give an update regarding the classification, epidemiology, clinical manifestation, diagnoses, and treatment of the Rickettsial diseases present in the Mediterranean area. We performed a comprehensive search, through electronic databases (Pubmed – MEDLINE) and search engines (Google Scholar), of peer-reviewed publications (articles, reviews, and books). The availability of new diagnostic tools, including Polymerase Chain Reaction and nucleotide sequencing has significantly modified the classification of intracellular bacteria, including the order Rickettsiales with more and more new Rickettsia species recognized as human pathogens. Furthermore, emerging Rickettsia species have been found in several countries and are often associated with unique clinical pictures that may challenge the physician in the early detection of the diseases. Rickettsial infections include a wide spectrum of clinical presentations ranging from a benign to a potentially life treating disease that requires prompt recognition and proper management. Recently, due to the spread of SARS-CoV-2 infection, the differential diagnosis with COVID-19 is of crucial importance. The correct understanding of the clinical features, diagnostic tools, and proper treatment can assist clinicians in the management of Rickettsioses in the Mediterranean area.
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20
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Pasqualetti C, Szokoli F, Rindi L, Petroni G, Schrallhammer M. The Obligate Symbiont " Candidatus Megaira polyxenophila" Has Variable Effects on the Growth of Different Host Species. Front Microbiol 2020; 11:1425. [PMID: 32733401 PMCID: PMC7360802 DOI: 10.3389/fmicb.2020.01425] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 06/02/2020] [Indexed: 12/18/2022] Open
Abstract
"Candidatus Megaira polyxenophila" is a recently described member of Rickettsiaceae which comprises exclusively obligate intracellular bacteria. Interestingly, these bacteria can be found in a huge diversity of eukaryotic hosts (protist, green algae, metazoa) living in marine, brackish or freshwater habitats. Screening of amplicon datasets revealed a high frequency of these bacteria especially in freshwater environments, most likely associated to eukaryotic hosts. The relationship of "Ca. Megaira polyxenophila" with their hosts and their impact on host fitness have not been studied so far. Even less is known regarding the responses of these intracellular bacteria to potential stressors. In this study, we used two phylogenetically close species of the freshwater ciliate Paramecium, Paramecium primaurelia and Paramecium pentaurelia (Ciliophora, Oligohymenophorea) naturally infected by "Ca. Megaira polyxenophila". In order to analyze the effect of the symbiont on the fitness of these two species, we compared the growth performance of both infected and aposymbiotic paramecia at different salinity levels in the range of freshwater and oligohaline brackish water i.e., at 0, 2, and 4.5 ppt. For the elimination of "Ca. Megaira polyxenophila" we established an antibiotic treatment to obtain symbiont-free lines and confirmed its success by fluorescence in situ hybridization (FISH). The population and infection dynamics during the growth experiment were observed by cell density counts and FISH. Paramecia fitness was compared applying generalized additive mixed models. Surprisingly, both infected Paramecium species showed higher densities under all salinity concentrations. The tested salinity concentrations did not significantly affect the growth of any of the two species directly, but we observed the loss of the endosymbiont after prolonged exposure to higher salinity levels. This experimental data might explain the higher frequency of "Ca. M. polyxenophila" in freshwater habitats as observed from amplicon data.
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Affiliation(s)
- Chiara Pasqualetti
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy.,Mikrobiologie, Institut für Biologie II, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Franziska Szokoli
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy.,Institut für Hydrobiologie, Technische Universität Dresden, Dresden, Germany
| | - Luca Rindi
- Dipartimento di Biologia, CoNISMa, Università di Pisa, Pisa, Italy
| | - Giulio Petroni
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Martina Schrallhammer
- Mikrobiologie, Institut für Biologie II, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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21
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Rickettsial Diseases: Not Uncommon Causes of Acute Febrile Illness in India. Trop Med Infect Dis 2020; 5:tropicalmed5020059. [PMID: 32326477 PMCID: PMC7344935 DOI: 10.3390/tropicalmed5020059] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/09/2020] [Accepted: 04/13/2020] [Indexed: 12/22/2022] Open
Abstract
Rickettsial diseases (RDs) are major under-diagnosed causes of arthropod borne acute febrile illness (AFI) presenting with a range of symptoms from mild self-limiting fever to fatal sepsis. The spotted fever group (SFG) and typhus group (TG) are major RDs, which are commonly caused by Rickettsia conorii and Rickettsia typhi, respectively. The limited availability and role of serological tests in the acute phase of illness warrants rapid reliable molecular methods for diagnosis and epidemiological studies. Two hundred patients with AFI in whom the routine fever diagnostics were negative, were enrolled over a period of two months (April 2019 to May 2019). DNA was extracted and in-house nested PCR using primers specific for both SPG and TG pathogens was used. The positive amplified products were sequenced for species identification and phylogenetic analysis was performed using MEGA 7.0.14 software (iGEM, Temple University, Philadelphia, PA 19122, USA). The demographic details of the RD cases were documented. The prevalence of RD among AFI cases was 7% (14/200); SFG and TG were identified as the cause in 4% and 3% of AFI cases, respectively. The median age of the RD cases was 22 years (range 2–65). The median duration of fever was 3 days (range 1–12). The RD cases presented with respiratory symptoms or signs (44.44%), jaundice (22.22%), abdominal pain (22.22%), diarrhea (22.22), vesicular rash (11.11%), vomiting (11.11%), loss of appetite (11.11%), headache (11.11%), leukocytosis (88.88% with mean count 22,750/mm3), and thrombocytopenia (33.33%). The cases were treated empirically with piperacillin-tazobactam (66.66%), clindamycin (44.44%), cefotaxime (33.33%), meropenem (33.33%), metronidazole (33.33%), doxycycline (22.22%), azithromycin (22.22%), ceftriaxone (11.11%), and amoxicillin-clavulanic acid (11.11%). The mortality among the RD cases was 11.11%. The present pilot study shows that RD is not an uncommon cause of AFI in north India. The febrile episodes are usually transient, not severe and associated with heterogenous clinical presentation without documented history of tick exposure in the hospitalized patients. The transient, non-severe, febrile illness could be due to transient rickettsemia resulting from empirical antimicrobial therapy as the rickettsial organisms are expected to be more susceptible to higher doses of β-lactam antibiotics. The study emphasizes the molecular method as a useful tool to identify rickettsial etiology in AFI.
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22
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Blanton LS, Wilson NM, Quade BR, Walker DH. Susceptibility of Rickettsia rickettsii to Tigecycline in a Cell Culture Assay and Animal Model for Rocky Mountain Spotted Fever. Am J Trop Med Hyg 2020; 101:1091-1095. [PMID: 31516114 DOI: 10.4269/ajtmh.19-0445] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Rocky Mountain spotted fever (RMSF), caused by Rickettsia rickettsii, is a severe tick-borne infection endemic to the Americas. Oral doxycycline is effective, but during severe life-threatening disease, intravenous therapy is recommended. Unfortunately, intravenous formulations of doxycycline are not always available. Therefore, we aimed to determine the susceptibility of R. rickettsii to an alternative parenteral agent, tigecycline, in vitro and in vivo. To determine the minimum inhibitory concentration of tigecycline, R. rickettsii-inoculated Vero cells were incubated with medium containing tigecycline. At various time points, monolayers were collected and R. rickettsii was quantified via real-time polymerase chain reaction (PCR). The growth of R. rickettsii was inhibited in the presence of ≥ 0.5 µg/mL of tigecycline. To determine the effectiveness of tigecycline in vivo, guinea pigs were inoculated with R. rickettsii. Five days after inoculation, they were treated twice daily with subcutaneous tigecycline 3.75 mg/kg or subcutaneous doxycycline 5 mg/kg. Treated animals improved, whereas untreated controls remained ill. Tissues were collected for quantitative PCR-determined bacterial loads on day 8. Median bacterial loads in the tigecycline group were less than those in untreated animals: liver (0 versus 2.9 × 104 copies/mg), lung (0 versus 8.3 × 103 copies/mg), skin (2.6 × 102 versus 2.2 × 105 copies/mg), spleen (0 versus 1.3 × 104 copies/mg), and testes (0 versus 1.0 × 105 copies/mg, respectively). There were no significant differences in the bacterial loads between doxycycline-treated versus tigecycline-treated guinea pigs. These data indicate that tigecycline is effective against R. rickettsii in cell culture and in an animal model of RMSF.
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Affiliation(s)
- Lucas S Blanton
- Department of Internal Medicine-Infectious Diseases, University of Texas Medical Branch, Galveston, Texas
| | - Nicholas M Wilson
- School of Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Bethany R Quade
- Department of Internal Medicine-Infectious Diseases, University of Texas Medical Branch, Galveston, Texas
| | - David H Walker
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas
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23
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Phuklia W, Panyanivong P, Sengdetka D, Sonthayanon P, Newton PN, Paris DH, Day NPJ, Dittrich S. Novel high-throughput screening method using quantitative PCR to determine the antimicrobial susceptibility of Orientia tsutsugamushi clinical isolates. J Antimicrob Chemother 2020; 74:74-81. [PMID: 30295746 PMCID: PMC6293087 DOI: 10.1093/jac/dky402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/05/2018] [Indexed: 01/08/2023] Open
Abstract
Objectives To develop a method to enable the large-scale antimicrobial susceptibility screening of Orientia tsutsugamushi clinical isolates, using one timepoint and one concentration of antibiotics to considerably speed up the time to result. Methods Growth, harvesting, multiplicity of infection (moi) and the day to determine the MICs were optimized using five O. tsutsugamushi reference strains [susceptible (Karp, Kato and Gilliam) and putatively resistant (AFC-3 and AFSC-4)], one clinical isolate (UT76) and one rodent isolate (TA763). Subsequently, the MICs of azithromycin, chloramphenicol and doxycycline for these strains and 51 clinical isolates including AFSC-7 were determined. An optimal concentration was calculated using the epidemiological cut-off value. Results The conditions for O. tsutsugamushi infection, growth and harvesting were determined to be an moi of 100:1 and trypsinization with the peak growth on day 10. The resulting MICs were in line with previously published susceptibility data for all reference strains, except for Karp and AFSC-4, which showed azithromycin MICs of 0.0156 and 0.0313 mg/L, compared with 0.0078 and 0.0156 mg/L, respectively, in previous reports. The MIC of doxycycline for AFC-3 was 0.125 mg/L compared with >4 mg/L in earlier reports. The final single screening concentrations were identified as: azithromycin, 0.125 mg/L; chloramphenicol, 8 mg/L; and doxycycline, 1 mg/L. Conclusions This simplified procedure facilitates the simultaneous screening of 48 isolates for actively monitoring potential resistance of this important fever pathogen, with an 8-fold throughput improvement over early methods. The data do not support the existence of doxycycline- and chloramphenicol-resistant scrub typhus.
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Affiliation(s)
- Weerawat Phuklia
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Phonepasith Panyanivong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Davanh Sengdetka
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Piengchan Sonthayanon
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Daniel H Paris
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sabine Dittrich
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,FIND, Malaria & Fever Program, Geneva, Switzerland
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24
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A Metabolic Dependency for Host Isoprenoids in the Obligate Intracellular Pathogen Rickettsia parkeri Underlies a Sensitivity to the Statin Class of Host-Targeted Therapeutics. mSphere 2019; 4:4/6/e00536-19. [PMID: 31722991 PMCID: PMC6854040 DOI: 10.1128/msphere.00536-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Obligate intracellular pathogens, which include viruses as well as certain bacteria and eukaryotes, are a subset of infectious microbes that are metabolically dependent on and unable to grow outside an infected host cell because they have lost or lack essential biosynthetic pathways. In this study, we describe a metabolic dependency of the bacterial pathogen Rickettsia parkeri on host isoprenoid molecules that are used in the biosynthesis of downstream products, including cholesterol, steroid hormones, and heme. Bacteria make products from isoprenoids, such as an essential lipid carrier for making the bacterial cell wall. We show that bacterial metabolic dependency can represent a potential Achilles’ heel and that inhibiting host isoprenoid biosynthesis with the FDA-approved statin class of drugs inhibits bacterial growth by interfering with the integrity of the cell wall. This work supports the potential to treat infections by obligate intracellular pathogens through inhibition of host biosynthetic pathways that are susceptible to parasitism. Gram-negative bacteria in the order Rickettsiales have an obligate intracellular growth requirement, and some species cause human diseases such as typhus and spotted fever. The bacteria have evolved a dependence on essential nutrients and metabolites from the host cell as a consequence of extensive genome reduction. However, it remains largely unknown which nutrients they acquire and whether their metabolic dependency can be exploited therapeutically. Here, we describe a genetic rewiring of bacterial isoprenoid biosynthetic pathways in the Rickettsiales that has resulted from reductive genome evolution. Furthermore, we investigated whether the spotted fever group Rickettsia species Rickettsia parkeri scavenges isoprenoid precursors directly from the host. Using targeted mass spectrometry, we found that infection caused decreases in host isoprenoid products and concomitant increases in bacterial isoprenoid metabolites. Additionally, we report that treatment of infected cells with statins, which inhibit host isoprenoid synthesis, prohibited bacterial growth. We show that growth inhibition correlates with changes in bacterial size and shape that mimic those caused by antibiotics that inhibit peptidoglycan biosynthesis, suggesting that statins lead to an inhibition of cell wall synthesis. Altogether, our results describe a potential Achilles’ heel of obligate intracellular pathogens that can potentially be exploited with host-targeted therapeutics that interfere with metabolic pathways required for bacterial growth. IMPORTANCE Obligate intracellular pathogens, which include viruses as well as certain bacteria and eukaryotes, are a subset of infectious microbes that are metabolically dependent on and unable to grow outside an infected host cell because they have lost or lack essential biosynthetic pathways. In this study, we describe a metabolic dependency of the bacterial pathogen Rickettsia parkeri on host isoprenoid molecules that are used in the biosynthesis of downstream products, including cholesterol, steroid hormones, and heme. Bacteria make products from isoprenoids, such as an essential lipid carrier for making the bacterial cell wall. We show that bacterial metabolic dependency can represent a potential Achilles’ heel and that inhibiting host isoprenoid biosynthesis with the FDA-approved statin class of drugs inhibits bacterial growth by interfering with the integrity of the cell wall. This work supports the potential to treat infections by obligate intracellular pathogens through inhibition of host biosynthetic pathways that are susceptible to parasitism.
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25
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Abstract
Rickettsia are small, obligately intracellular, gram-negative bacilli. They are distributed among a variety of hematophagous arthropod vectors and cause illness throughout the world. Rickettsioses present as an acute undifferentiated febrile illness and are often accompanied by headache, myalgias, and malaise. Cutaneous manifestations include rash and eschar, which both occur at varying incidence depending on the infecting species. Serology is the mainstay of diagnosis, and the indirect immunofluorescence assay is the test of choice. Reactive antibodies are seldom present during early illness, so testing should be performed on both acute-phase and convalescent-phase sera. Doxycycline is the treatment of choice.
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Affiliation(s)
- Lucas S Blanton
- Department of Internal Medicine, Division of Infectious Diseases, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0435, USA.
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26
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Yaglom HD, Casal M, Carson S, O'Grady CL, Dominguez V, Singleton J, Chung I, Lodge H, Paddock CD. Expanding Recognition of Rickettsia parkeri Rickettsiosis in Southern Arizona, 2016-2017. Vector Borne Zoonotic Dis 2019; 20:82-87. [PMID: 31638478 DOI: 10.1089/vbz.2019.2491] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Rickettsia parkeri rickettsiosis is an emerging, tick-borne disease in the United States (US), transmitted by the bite of Amblyomma maculatum group ticks. Clinical manifestations include fever, headache, myalgia, maculopapular rash, and a characteristic eschar that forms at the site of the tick bite. Arizona's index case of R. parkeri rickettsiosis was reported in 2014. Seven additional confirmed and probable cases were identified during 2016-2017 through routine investigation of electronic laboratory reports and by self-reporting to public health authorities. Serum samples were evaluated for immunoglobulin G antibodies reactive with antigens of Rickettsia rickettsii (the agent of Rocky Mountain spotted fever [RMSF]) and R. parkeri using indirect immunofluorescence antibody tests. Eschar swab specimens were evaluated using Rickettsia genus-specific and R. parkeri-specific real-time PCR assays. Patients (six male, one female) ranged in age from 29 to 69 years (median of 41 years), and became ill between July 2016 and September 2017. Fever (6/7), myalgia (5/7), and arthralgia (5/7) were most commonly reported and 5/7 patients had a documented eschar. All patients reported a tick bite acquired in southern Arizona within 2-8 days before illness onset. Four patients worked as U.S. Border Patrol agents. Antibodies reactive to R. rickettsii, R. parkeri, or to both antigens were detected in all patients. Seroconversions between acute and convalescent-phase samples were identified for two patients and DNA of R. parkeri was identified in eschar swab samples from two patients. R. parkeri rickettsiosis is endemic to a region of the southwestern United States and presents an occupational risk that could be lessened by prevention messaging to Border Patrol agents. RMSF, a closely related and more severe spotted fever rickettsiosis, is also endemic to Arizona. Public health agencies can assist clinicians in distinguishing these two infections clinically through education and accessing species-specific diagnostic assays that can improve surveillance efforts for both diseases.
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Affiliation(s)
- Hayley D Yaglom
- Arizona Department of Health Services, Office of Infectious Disease Services, Phoenix, Arizona
| | - Mariana Casal
- Arizona Department of Health Services, Office of Border Health, Tucson, Arizona
| | | | | | | | - Joseph Singleton
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Ida Chung
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Heidi Lodge
- Copper Queen Medical Associates, Douglas, Arizona
| | - Christopher D Paddock
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
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27
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Sekeyová Z, Danchenko M, Filipčík P, Fournier PE. Rickettsial infections of the central nervous system. PLoS Negl Trop Dis 2019; 13:e0007469. [PMID: 31465452 PMCID: PMC6715168 DOI: 10.1371/journal.pntd.0007469] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
As a result of migrations and globalization, people may face a possible increase in the incidence of central nervous system rickettsial infections (CNS R). These diseases, caused by Rickettsia species and transmitted to humans by arthropod bites, are putatively lethal. However, the diagnosis of CNS R is challenging and often delayed due to their nonspecific clinical presentation and the strict intracellular nature of rickettsiae. Furthermore, transfer of rickettsiae to the brain parenchyma is not yet understood. The aim of this review is to analyze and summarize the features and correlated findings of CNS R in order to focus attention on these intriguing but frequently neglected illnesses. We also incorporated data on CNS infections caused by Rickettsia-related microorganisms.
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Affiliation(s)
- Zuzana Sekeyová
- Institute of Virology, Slovak Academy of Sciences, Dubravska cesta, Bratislava, Slovakia
| | - Monika Danchenko
- Institute of Virology, Slovak Academy of Sciences, Dubravska cesta, Bratislava, Slovakia
| | - Peter Filipčík
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta, Bratislava, Slovakia
| | - Pierre Edouard Fournier
- Aix-Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU Mediterranée-Infection, Marseille, France
- Centre National de Référence des Rickettsia, Coxiella et Bartonella, IHU Mediterranée-Infection, Marseille, France
- * E-mail:
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28
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Abstract
Nonribosomal peptides are assemblages, including antibiotics, of canonical amino acids and other molecules. β-lactam antibiotics act on bacterial cell walls and can be cleaved by β-lactamases. β-lactamase activity in humans has been neglected, even though eighteen enzymes have already been annotated such in human genome. Their hydrolysis activities on antibiotics have not been previously investigated. Here, we report that human cells were able to digest penicillin and this activity was inhibited by β-lactamase inhibitor, i.e. sulbactam. Penicillin degradation in human cells was microbiologically demonstrated on Pneumococcus. We expressed a MBLAC2 human β-lactamase, known as an exosome biogenesis enzyme. It cleaved penicillin and was inhibited by sulbactam. Finally, β-lactamases are widely distributed, archaic, and have wide spectrum, including digesting anticancer and β-lactams, that can be then used as nutriments. The evidence of the other MBLAC2 role as a bona fide β-lactamase allows for reassessment of β-lactams and β-lactamases role in humans.
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Tantibhedhyangkul W, Wongsawat E, Matamnan S, Inthasin N, Sueasuay J, Suputtamongkol Y. Anti-Mycoplasma Activity of Daptomycin and Its Use for Mycoplasma Elimination in Cell Cultures of Rickettsiae. Antibiotics (Basel) 2019; 8:antibiotics8030123. [PMID: 31438510 PMCID: PMC6784056 DOI: 10.3390/antibiotics8030123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/15/2019] [Accepted: 08/17/2019] [Indexed: 12/24/2022] Open
Abstract
Mycoplasma contamination detrimentally affects cellular functions and the growth of intracellular pathogens in cell cultures. Although several mycoplasmacidal agents are commercially available for sterile cell cultures, they are not applicable to rickettsia-infected cells. In our attempt to find an anti-mycoplasma drug for contaminated rickettsial cultures, we determined the susceptibilities of three common Mycoplasma species to daptomycin. Mycoplasma orale and M. arginini showed low-level resistance to daptomycin (minimum inhibitory concentration, MIC = 2 mg/L), whereas M. hyorhinis was high-level resistant (MIC = 32 mg/L). However, some Mycoplasma isolates developed higher resistance to daptomycin after failed treatments with inadequate doses or durations. An aminoglycoside (gentamicin) was still active against M. hyorhinis and could be used in Orientia cultures. For complete eradication of mycoplasmas in Rickettsia cultures, we recommend a 3-week treatment with daptomycin at 256 mg/L. In contaminated Orientia cultures, daptomycin at 32 mg/L was effective in eradicating M. orale, whereas either gentamicin or amikacin (100 mg/L) was effective in eradicating M. hyorhinis. Unlike each drug alone, the combinations of daptomycin plus clindamycin and/or quinupristin/dalfopristin proved effective in eradicating M. hyorhinis. In summary, our study demonstrated the in vitro anti-mycoplasma activity of daptomycin and its application as a new mycoplasma decontamination method for Rickettsia and Orientia cultures.
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Affiliation(s)
- Wiwit Tantibhedhyangkul
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Ekkarat Wongsawat
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Sutthicha Matamnan
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Naharuthai Inthasin
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jintapa Sueasuay
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Yupin Suputtamongkol
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
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30
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Satoh M, Kato H, Takayama-Ito M, Ogawa M, Ando S, Saijo M. In vitro evaluation of minimum inhibitory concentration of several antibacterial agents against Rickettsia japonica using a plaque reduction assay system. J Infect Chemother 2019; 25:917-919. [PMID: 31186196 DOI: 10.1016/j.jiac.2019.05.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/14/2019] [Accepted: 05/18/2019] [Indexed: 11/25/2022]
Abstract
The study was conducted to determine the minimum inhibitory concentrations (MICs) of several antibacterial agents against Rickettsia japonica, which causes Japanese spotted fever. A plaque reduction assay as an in vitro culture method was conducted to determine the MICs of antibacterial agents (4 types of tetracyclines: tetracycline, doxycycline, minocycline, and tigecycline; 3 types of quinolones: ciprofloxacin, ofloxacin, and levofloxacin; and 2 types of macrolides: azithromycin and clarythromycin) against R. japonica. R. japonica was sensitive to the antibacterial agents tested with MICs similar to those against other spotted fever rickettsia determined in previously described plaque reduction assays.
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Affiliation(s)
- Masaaki Satoh
- Department of Virology I, National Institute of Infectious Diseases, Japan
| | - Hirofumi Kato
- Department of Virology I, National Institute of Infectious Diseases, Japan
| | | | - Motohiko Ogawa
- Department of Virology I, National Institute of Infectious Diseases, Japan
| | - Shuji Ando
- Department of Virology I, National Institute of Infectious Diseases, Japan
| | - Masayuki Saijo
- Department of Virology I, National Institute of Infectious Diseases, Japan.
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31
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do Rosário CJRM, da Rocha CQ, de Aguiar DM, Lima CAA, Silveira DPB, Leite JAC, Coutinho DF, Melo FA. Anti-Ehrlichia properties of the essential oil of Ageratum conyzoides L. and its interaction with doxycycline. AMB Express 2019; 9:58. [PMID: 31037564 PMCID: PMC6488629 DOI: 10.1186/s13568-019-0780-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/16/2019] [Indexed: 11/10/2022] Open
Abstract
Canine Monocytic Ehrlichiosis (CME) is an infectious disease caused by the rickettsia organism Ehrlichia canis which is transmitted mainly the ixodid brown dog tick Rhipicephalus sanguineus. The prevalence of E. canis infection has been increasing in recent years. The World Health Organization has been warned about antibiotics resistance and one of the way to prevent this situation is found new compound with this property. Doxycycline is the treatment of choice for this tick-borne disease. Adverse effects are noted in dogs that are sensitive to this drug. Antibiotic resistance may also occur. The present study aimed to evaluate the anti-Ehrlichia properties of the essential oil of the aerial parts of Ageratum conyzoides L. in infected DH82 cells, as well as its anti-Ehrlichia activity associated with doxycycline using the checkerboard assay. A. conyzoides is a native plant from northeast Brazil with many reports of ethnopharmacological applications. The essential oil of A. conyzoides was extracted from the aerial parts of the plant using the hydrodistillation method. E. canis-infected DH82 cells were cultured in DMEM (Dulbecco’s Modified Eagle Medium), maintained at 37 °C and 5% CO2, and standardized at a 70% infection rate for the initiation of treatment protocols. The tests were first carried out with the aim of defining the IC50. The combined effect of doxycycline and A. conyzoides essential oil was then determined using the checkerboard dilution technique (checkerboard method) in which the IC50 was 200 µg/mL. The doxycycline reduction index from the combined effect was 4.90 times resulting in a synergistic effect. To the authors’ knowledge, this is the first alternative treatment (alternative therapy) based on bioactive molecules that have antibacterial activity against E. canis.
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32
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Newton PN, Keolouangkhot V, Lee SJ, Choumlivong K, Sisouphone S, Choumlivong K, Vongsouvath M, Mayxay M, Chansamouth V, Davong V, Phommasone K, Sirisouk J, Blacksell SD, Nawtaisong P, Moore CE, Castonguay-Vanier J, Dittrich S, Rattanavong S, Chang K, Darasavath C, Rattanavong O, Paris DH, Phetsouvanh R. A Prospective, Open-label, Randomized Trial of Doxycycline Versus Azithromycin for the Treatment of Uncomplicated Murine Typhus. Clin Infect Dis 2019; 68:738-747. [PMID: 30020447 PMCID: PMC6376095 DOI: 10.1093/cid/ciy563] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 07/07/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Murine typhus, or infection with Rickettsia typhi, is a global but neglected disease without randomized clinical trials to guide antibiotic therapy. METHODS A prospective, open, randomized trial was conducted in nonpregnant, consenting inpatient adults with rapid diagnostic test evidence of uncomplicated murine typhus at 2 hospitals in Vientiane, Laos. Patients were randomized to 7 days (D7) or 3 days (D3) of oral doxycycline or 3 days of oral azithromycin (A3). Primary outcome measures were fever clearance time and frequencies of treatment failure and relapse. RESULTS Between 2004 and 2009, the study enrolled 216 patients (72 per arm); 158 (73.2%) had serology/polymerase chain reaction (PCR)-confirmed murine typhus, and 52 (24.1%) were R. typhi PCR positive. The risk of treatment failure was greater for regimen A3 (22.5%; 16 of 71 patients) than for D3 (4.2%; 3 of 71) or D7 (1.4%; 1 of 71) (P < .001). Among R. typhi PCR-positive patients, the area under the time-temperature curve and the fever clearance time were significantly higher for A3 than for D3 (1.8- and 1.9-fold higher, respectively; P = .005) and D7 (1.5- and 1.6-fold higher; P = .02). No patients returned with PCR-confirmed R. typhi relapse. CONCLUSION In Lao adults, azithromycin is inferior to doxycycline as oral therapy for uncomplicated murine typhus. For doxycycline, 3- and 7-day regimens have similar efficacy. Azithromycin use in murine typhus should be reconsidered. Investigation of genomic and phenotypic markers of R. typhi azithromycin resistance is needed. CLINICAL TRIAL REGISTRATION ISRCTN47812566.
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Affiliation(s)
- Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine & Global Health, University of Oxford, United Kingdom
| | - Valy Keolouangkhot
- Adult Infectious Disease Ward, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Sue J Lee
- Centre for Tropical Medicine & Global Health, University of Oxford, United Kingdom
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Siho Sisouphone
- Adult Infectious Disease Ward, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | | | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine & Global Health, University of Oxford, United Kingdom
- Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao People's Democratic Republic
| | - Vilada Chansamouth
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Viengmon Davong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Joy Sirisouk
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Stuart D Blacksell
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine & Global Health, University of Oxford, United Kingdom
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pruksa Nawtaisong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Catrin E Moore
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine & Global Health, University of Oxford, United Kingdom
| | - Josée Castonguay-Vanier
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Sabine Dittrich
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine & Global Health, University of Oxford, United Kingdom
| | - Sayaphet Rattanavong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Ko Chang
- Adult Infectious Disease Ward, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Chirapha Darasavath
- Adult Infectious Disease Ward, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Oudayvone Rattanavong
- Adult Infectious Disease Ward, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Daniel H Paris
- Centre for Tropical Medicine & Global Health, University of Oxford, United Kingdom
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Medicine, Swiss Tropical and Public Health Institute, Switzerland
- Faculty of Medicine, University of Basel, Switzerland
| | - Rattanaphone Phetsouvanh
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine & Global Health, University of Oxford, United Kingdom
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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33
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Antimicrobial Resistance in Chlamydiales, Rickettsia, Coxiella, and Other Intracellular Pathogens. Microbiol Spectr 2018; 6. [PMID: 29651977 DOI: 10.1128/microbiolspec.arba-0003-2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
This article will provide current insights into antimicrobial susceptibilities and resistance of an important group of bacterial pathogens that are not phylogenetically related but share lifestyle similarities in that they are generally considered to be obligate intracellular microbes. As such, there are shared challenges regarding methods for their detection and subsequent clinical management. Similarly, from the laboratory perspective, susceptibility testing is rarely undertaken, though molecular approaches might provide new insights. One should also bear in mind that the highly specialized microbial lifestyle restricts the opportunity for lateral gene transfer and, consequently, acquisition of resistance.
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34
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Ocias LF, Dessau RB, Lebech AM, Jørgensen CS, Petersen RF, Krogfelt KA. Evidence of rickettsiae in Danish patients tested for Lyme neuroborreliosis: a retrospective study of archival samples. BMC Infect Dis 2018; 18:325. [PMID: 29996782 PMCID: PMC6042448 DOI: 10.1186/s12879-018-3210-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/26/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND With a prevalence of 4.7-13% in Danish Ixodes ricinus ticks, Rickettsia helvetica is one of the most frequently detected tick-borne organisms in Denmark. Most reports of human exposure have described asymptomatic seroconversion or a mild, self-limiting flu-like illness but it has also been implicated as a cause of subacute lymphocytic meningitis. Because Borrelia burgdorferi sensu lato (Bbsl) and R. helvetica are both found in the same tick species, potential co-transmission is a possibility. We examined 1) the seroprevalence of anti-rickettsia antibodies in patients investigated for Lyme neuroborreliosis (LNB), and 2) the cerebrospinal fluid (CSF) and sera of same patients for the presence of Rickettsia DNA. METHODS Ninety-nine sera and 87 CSF samples from patients with intrathecal synthesis of anti-Borrelia antibodies and 101 sera and 103 CSF samples from patients with no detectable intrathecal synthesis were retrospectively examined for this study. Sera were analyzed for antibodies against spotted fever group (SFG) rickettsiae and both the CSF and sera were tested for Rickettsia DNA using a genus-specific real-time PCR. RESULTS Of the patients tested for LNB, 32% (64/200) had IgG antibodies against SFG rickettsiae. Among patients with confirmed intrathecal synthesis of Borrelia-specific antibodies, 38% (38/99) exhibited IgG antibodies. None of these values were statistically significant when compared with sera from healthy blood donors (p = 0.7 and 0.19). Rickettsia DNA was found in the CSF of 4% (8/190) of patients. CONCLUSION No statistically significant difference was found in the seroprevalence of anti-rickettsia antibodies in patients tested for LNB and healthy blood donors, indicative of a low rate of exposure in this group of patients. Eight patients showed evidence of Rickettsia DNA in the CSF, five of whom had LNB. However, cycle threshold (Ct) values were high, indicating low concentrations of DNA, and no apparent alteration in the clinical manifestations of LNB were noted in the medical records of these patients.
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Affiliation(s)
- Lukas Frans Ocias
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Artillerivej 5, Copenhagen, Denmark. .,Department of Clinical Microbiology, Slagelse Hospital, Slagelse, Denmark.
| | - Ram Benny Dessau
- Department of Clinical Microbiology, Slagelse Hospital, Slagelse, Denmark
| | - Anne-Mette Lebech
- Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Charlotte Sværke Jørgensen
- Department of Virus and Microbiological Special Diagnostics, Statens Serum Institut, Copenhagen, Denmark
| | - Randi Føns Petersen
- Department of Virus and Microbiological Special Diagnostics, Statens Serum Institut, Copenhagen, Denmark
| | - Karen Angeliki Krogfelt
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Artillerivej 5, Copenhagen, Denmark
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Wangrangsimakul T, Althaus T, Mukaka M, Kantipong P, Wuthiekanun V, Chierakul W, Blacksell SD, Day NP, Laongnualpanich A, Paris DH. Causes of acute undifferentiated fever and the utility of biomarkers in Chiangrai, northern Thailand. PLoS Negl Trop Dis 2018; 12:e0006477. [PMID: 29852003 PMCID: PMC5978881 DOI: 10.1371/journal.pntd.0006477] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 04/24/2018] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Tropical infectious diseases like dengue, scrub typhus, murine typhus, leptospirosis, and enteric fever continue to contribute substantially to the febrile disease burden throughout Southeast Asia while malaria is declining. Recently, there has been increasing focus on biomarkers (i.e. C-reactive protein (CRP) and procalcitonin) in delineating bacterial from viral infections. METHODOLOGY/PRINCIPAL FINDINGS A prospective observational study was performed to investigate the causes of acute undifferentiated fever (AUF) in adults admitted to Chiangrai Prachanukroh hospital, northern Thailand, which included an evaluation of CRP and procalcitonin as diagnostic tools. In total, 200 patients with AUF were recruited. Scrub typhus was the leading bacterial cause of AUF (45/200, 22.5%) followed by leptospirosis (15/200, 7.5%) and murine typhus (7/200, 3.5%), while dengue was the leading viral cause (23/200, 11.5%). Bloodstream infections contributed to 7/200 (3.5%) of the study cohort. There were 9 deaths during this study (4.5%): 3 cases of scrub typhus, 2 with septicaemia (Talaromyces marneffei and Haemophilus influenzae), and 4 of unknown aetiologies. Rickettsioses, leptospirosis and culture-attributed bacterial infections, received a combination of 3rd generation cephalosporin plus a rickettsia-active drug in 53%, 73% and 67% of cases, respectively. Low CRP and white blood count were significant predictors of a viral infection (mainly dengue) while the presence of an eschar and elevated aspartate aminotransferase and alkaline phosphatase were important predictors of scrub typhus. INTERPRETATION Scrub typhus and dengue are the leading causes of AUF in Chiangrai, Thailand. Eschar, white blood count and CRP were beneficial in differentiating between bacterial and viral infections in this study. CRP outperformed procalcitonin although cut-offs for positivity require further assessment. The study provides evidence that accurate, pathogen-specific rapid diagnostic tests coupled with biomarker point-of-care tests such as CRP can inform the correct use of antibiotics and improve antimicrobial stewardship in this setting.
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Affiliation(s)
- Tri Wangrangsimakul
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Thomas Althaus
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Mavuto Mukaka
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Pacharee Kantipong
- Department of Medicine, Chiangrai Prachanukroh Hospital, Chiangrai, Thailand
| | - Vanaporn Wuthiekanun
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wirongrong Chierakul
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Stuart D. Blacksell
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas P. Day
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Daniel H. Paris
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
- Department of Medicine, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
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Torpiano P, Pace D. Clinically-diagnosed Mediterranean Spotted Fever in Malta. Travel Med Infect Dis 2018; 26:16-24. [PMID: 29462726 DOI: 10.1016/j.tmaid.2018.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 02/13/2018] [Accepted: 02/16/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND Mediterranean Spotted Fever (MSF) is a tick-borne zoonosis caused by Rickettsia conorii which is endemic in Malta, an island in the South Mediterranean that is a popular tourist destination. Diagnosis is frequently based on clinical manifestations as laboratory results are often limited to a retrospective diagnosis. We describe the clinical presentation, diagnosis and treatment of children <16 years who presented with MSF from 2011 to 2016. METHOD The demographics, clinical findings, laboratory results, management and outcome of all children hospitalised with suspected MSF based on the presence of fever and an eschar, were retrieved from their case notes. RESULTS Over the five-year study period six children, aged between 17 months and 15 years, were diagnosed with MSF. All children had contact with ticks and the majority presented in summer. Laboratory results were non-specific and included elevated inflammatory markers, lymphocytosis/lymphopenia and hyponatraemia. Serological and molecular techniques were used for diagnosis. Response to clarithromycin or doxycycline was immediate. CONCLUSION MSF should be included in the differential diagnosis of fever, rash and an eschar in children who travel to Malta. Despite advances in molecular diagnostics, clinical diagnosis remains important in the management of children with suspected MSF.
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Affiliation(s)
- Paul Torpiano
- Department of Paediatrics, Mater Dei Hospital, Tal-Qroqq, Msida, MSD 2090, Malta.
| | - David Pace
- Department of Paediatrics, Mater Dei Hospital, Tal-Qroqq, Msida, MSD 2090, Malta
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Speck S, Kern T, Aistleitner K, Dilcher M, Dobler G, Essbauer S. In vitro studies of Rickettsia-host cell interactions: Confocal laser scanning microscopy of Rickettsia helvetica-infected eukaryotic cell lines. PLoS Negl Trop Dis 2018; 12:e0006151. [PMID: 29432420 PMCID: PMC5825168 DOI: 10.1371/journal.pntd.0006151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 02/23/2018] [Accepted: 12/04/2017] [Indexed: 11/19/2022] Open
Abstract
Rickettsia (R.) helvetica is the most prevalent rickettsia found in Ixodes ricinus ticks in Germany. Several studies reported antibodies against R. helvetica up to 12.5% in humans investigated, however, fulminant clinical cases are rare indicating a rather low pathogenicity compared to other rickettsiae. We investigated growth characteristics of R. helvetica isolate AS819 in two different eukaryotic cell lines with focus on ultra-structural changes of host cells during infection determined by confocal laser scanning microscopy. Further investigations included partially sequencing of rickA, sca4 and sca2 genes, which have been reported to encode proteins involved in cell-to-cell spread and virulence in some rickettsiae. R. helvetica grew constantly but slowly in both cell lines used. Confocal laser scanning microscopy revealed that the dissemination of R. helvetica AS819 in both cell lines was rather mediated by cell break-down and bacterial release than cell-to-cell spread. The cytoskeleton of both investigated eukaryotic cell lines was not altered. R. helvetica possesses rickA, but its expression is not sufficient to promote actin-based motility as demonstrated by confocal laser scanning microscopy. Hypothetical Sca2 and Sca4 proteins were deduced from nucleotide gene sequences but the predicted amino acid sequences were disrupted or truncated compared to other rickettsiae most likely resulting in non-functional proteins. Taken together, these results might give a first hint to the underlying causes of the reduced virulence and pathogenicity of R. helvetica.
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Affiliation(s)
- Stephanie Speck
- Bundeswehr Institute of Microbiology, German Center of Infection Research DZIF Partner, Munich, Bavaria, Germany
| | - Tanja Kern
- Bundeswehr Institute of Microbiology, German Center of Infection Research DZIF Partner, Munich, Bavaria, Germany
| | - Karin Aistleitner
- Bundeswehr Institute of Microbiology, German Center of Infection Research DZIF Partner, Munich, Bavaria, Germany
| | - Meik Dilcher
- University Medical Center Göttingen, Department of Virology, Göttingen, Lower Saxony, Germany
| | - Gerhard Dobler
- Bundeswehr Institute of Microbiology, German Center of Infection Research DZIF Partner, Munich, Bavaria, Germany
| | - Sandra Essbauer
- Bundeswehr Institute of Microbiology, German Center of Infection Research DZIF Partner, Munich, Bavaria, Germany
- * E-mail:
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Strand A, Paddock CD, Rinehart AR, Condit ME, Marus JR, Gillani S, Chung IH, Fowler VG. African Tick Bite Fever Treated Successfully With Rifampin in a Patient With Doxycycline Intolerance. Clin Infect Dis 2017; 65:1582-1584. [PMID: 28505276 PMCID: PMC5850440 DOI: 10.1093/cid/cix363] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/10/2017] [Indexed: 11/12/2022] Open
Abstract
African tick bite fever is the most commonly encountered travel-associated rickettsiosis, occurring in as many as 5% of travelers returning from rural subequatorial Africa. This case report illustrates that rifampin represents an effective alternative to doxycycline for treatment of African tick bite fever in some selective situations.
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Affiliation(s)
- Andrew Strand
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina
| | - Christopher D Paddock
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; and
| | | | - Marah E Condit
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; and
| | - Jessica R Marus
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; and
| | - Shezeen Gillani
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; and
| | - Ida H Chung
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; and
| | - Vance G Fowler
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina
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Portillo A, de Sousa R, Santibáñez S, Duarte A, Edouard S, Fonseca IP, Marques C, Novakova M, Palomar AM, Santos M, Silaghi C, Tomassone L, Zúquete S, Oteo JA. Guidelines for the Detection of Rickettsia spp. Vector Borne Zoonotic Dis 2017; 17:23-32. [PMID: 28055574 DOI: 10.1089/vbz.2016.1966] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The genus Rickettsia (Rickettsiales: Rickettsiaceae) includes Gram-negative, small, obligate intracellular, nonmotile, pleomorphic coccobacilli bacteria transmitted by arthropods. Some of them cause human and probably also animal disease (life threatening in some patients). In these guidelines, we give clinical practice advices (microscopy, serology, molecular tools, and culture) for the microbiological study of these microorganisms in clinical samples. Since in our environment rickettsioses are mainly transmitted by ticks, practical information for the identification of these arthropods and for the study of Rickettsia infections in ticks has also been added.
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Affiliation(s)
- Aránzazu Portillo
- 1 Center of Rickettsiosis and Arthropod-Borne Diseases , Hospital San Pedro-CIBIR, Logroño, Spain
| | - Rita de Sousa
- 2 National Institute of Health Dr. Ricardo Jorge , Águas de Moura, Portugal
| | - Sonia Santibáñez
- 1 Center of Rickettsiosis and Arthropod-Borne Diseases , Hospital San Pedro-CIBIR, Logroño, Spain
| | - Ana Duarte
- 3 Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon , Lisbon, Portugal
| | - Sophie Edouard
- 4 Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Institut Hospitalo-Universitaire Méditerranée-Infection , Marseille, France
| | - Isabel P Fonseca
- 3 Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon , Lisbon, Portugal
| | - Cátia Marques
- 3 Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon , Lisbon, Portugal
| | - Marketa Novakova
- 5 Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno , Brno, Czech Republic .,6 CEITEC VFU, University of Veterinary and Pharmaceutical Sciences Brno , Brno, Czech Republic
| | - Ana M Palomar
- 1 Center of Rickettsiosis and Arthropod-Borne Diseases , Hospital San Pedro-CIBIR, Logroño, Spain
| | - Marcos Santos
- 3 Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon , Lisbon, Portugal
| | - Cornelia Silaghi
- 7 National Centre for Vector Entomology, Institute of Parasitology, University of Zurich , Zurich, Switzerland
| | - Laura Tomassone
- 8 Department of Veterinary Sciences, University of Torino , Grugliasco, Italy
| | - Sara Zúquete
- 3 Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon , Lisbon, Portugal
| | - José A Oteo
- 1 Center of Rickettsiosis and Arthropod-Borne Diseases , Hospital San Pedro-CIBIR, Logroño, Spain
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Abstract
With advances in molecular genetics, more pathogenic rickettsial species have been identified. Pathogenic rickettsiae are transmitted by vectors, such as arthropods, into the patient's skin and then spread into the microvascular endothelial cells. Clinical manifestations are characterized by fever with headache and myalgias, followed by rash 3 to 5 days later. The undifferentiated nature of clinical symptoms, knowledge of the epidemiology, and the patient's history of travel and exposure to arthropod vectors are critical to the empiric administration of antimicrobial therapy. Doxycycline is currently the most effective antibiotic for treatment of all spotted fever group and typhus group rickettsioses.
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Affiliation(s)
- Rong Fang
- Department of Pathology, The University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555-0609, USA
| | - Lucas S Blanton
- Infectious Diseases, Department of Internal Medicine, The University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555-0435, USA
| | - David H Walker
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, The University of Texas Medical Branch, 301 University Boulevard, Keiller Building, Galveston, TX 77555-0609, USA.
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GFPuv-Expressing Recombinant Rickettsia typhi: a Useful Tool for the Study of Pathogenesis and CD8 + T Cell Immunology in R. typhi Infection. Infect Immun 2017; 85:IAI.00156-17. [PMID: 28289147 PMCID: PMC5442613 DOI: 10.1128/iai.00156-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 03/06/2017] [Indexed: 11/20/2022] Open
Abstract
Rickettsia typhi is the causative agent of endemic typhus, a disease with increasing incidence worldwide that can be fatal. Because of its obligate intracellular life style, genetic manipulation of the pathogen is difficult. Nonetheless, in recent years, genetic manipulation tools have been successfully applied to rickettsiae. We describe here for the first time the transformation of R. typhi with the pRAM18dRGA plasmid that originally derives from Rickettsia amblyommatis and encodes the expression of GFPuv (green fluorescent protein with maximal fluorescence when excited by UV light). Transformed R. typhi (R. typhiGFPuv) bacteria are viable, replicate with kinetics similar to those of wild-type R. typhi in cell culture, and stably maintain the plasmid and GFPuv expression under antibiotic treatment in vitro and in vivo during infection of mice. CB17 SCID mice infected with R. typhiGFPuv succumb to the infection with kinetics similar to those for animals infected with wild-type R. typhi and develop comparable pathology and bacterial loads in the organs, demonstrating that the plasmid does not influence pathogenicity. In the spleen and liver of infected CB17 SCID mice, the bacteria are detectable by immunofluorescence microscopy in neutrophils and macrophages by histological staining. Finally, we show for the first time that transformed rickettsiae can be used for the detection of CD8+ T cell responses. GFP-specific restimulation of spleen cells from R. typhiGFPuv-infected BALB/c mice elicits gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), and interleukin 2 (IL-2) secretion by CD8+ T cells. Thus, R. typhiGFPuv bacteria are a novel, potent tool to study infection with the pathogen in vitro and in vivo and the immune response to these bacteria.
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Biggs HM, Behravesh CB, Bradley KK, Dahlgren FS, Drexler NA, Dumler JS, Folk SM, Kato CY, Lash RR, Levin ML, Massung RF, Nadelman RB, Nicholson WL, Paddock CD, Pritt BS, Traeger MS. Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis - United States. MMWR Recomm Rep 2016; 65:1-44. [PMID: 27172113 DOI: 10.15585/mmwr.rr6502a1] [Citation(s) in RCA: 286] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Tickborne rickettsial diseases continue to cause severe illness and death in otherwise healthy adults and children, despite the availability of low-cost, effective antibacterial therapy. Recognition early in the clinical course is critical because this is the period when antibacterial therapy is most effective. Early signs and symptoms of these illnesses are nonspecific or mimic other illnesses, which can make diagnosis challenging. Previously undescribed tickborne rickettsial diseases continue to be recognized, and since 2004, three additional agents have been described as causes of human disease in the United States: Rickettsia parkeri, Ehrlichia muris-like agent, and Rickettsia species 364D. This report updates the 2006 CDC recommendations on the diagnosis and management of tickborne rickettsial diseases in the United States and includes information on the practical aspects of epidemiology, clinical assessment, treatment, laboratory diagnosis, and prevention of tickborne rickettsial diseases. The CDC Rickettsial Zoonoses Branch, in consultation with external clinical and academic specialists and public health professionals, developed this report to assist health care providers and public health professionals to 1) recognize key epidemiologic features and clinical manifestations of tickborne rickettsial diseases, 2) recognize that doxycycline is the treatment of choice for suspected tickborne rickettsial diseases in adults and children, 3) understand that early empiric antibacterial therapy can prevent severe disease and death, 4) request the appropriate confirmatory diagnostic tests and understand their usefulness and limitations, and 5) report probable and confirmed cases of tickborne rickettsial diseases to public health authorities.
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Affiliation(s)
- Holly M Biggs
- National Center for Emerging and Zoonotic Infectious Diseases, CDC, Atlanta, Georgia
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Blanton LS, Walker DH. Treatment of Tropical and Travel Related Rickettsioses. CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES 2016. [DOI: 10.1007/s40506-016-0070-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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A Rare Case of Mediterranean Spotted Fever and Encephalitis. Case Rep Infect Dis 2016; 2016:2421540. [PMID: 28053795 PMCID: PMC5174160 DOI: 10.1155/2016/2421540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/07/2016] [Accepted: 11/22/2016] [Indexed: 11/18/2022] Open
Abstract
Mediterranean spotted fever is a tick-borne zoonotic disease caused by Rickettsia conorii. It is transmitted by the dog tick Rhipicephalus sanguineus. It usually presents as a benign self-limited disease characterized by a skin rash, high fever, and, sometimes, a characteristic ulcer at the tick bite site called tache noir. The course of this disease is usually benign, although severe manifestations have been previously described, mainly in adults. Neurological manifestations are very unusual. We present a case of Mediterranean spotted fever with encephalitis to highlight the importance of clinical suspicion, mainly in endemic areas, the potential severity of this disease, and the need of early initiation of therapy in order to prevent severe complications.
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Current and past strategies for bacterial culture in clinical microbiology. Clin Microbiol Rev 2015; 28:208-36. [PMID: 25567228 DOI: 10.1128/cmr.00110-14] [Citation(s) in RCA: 281] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A pure bacterial culture remains essential for the study of its virulence, its antibiotic susceptibility, and its genome sequence in order to facilitate the understanding and treatment of caused diseases. The first culture conditions empirically varied incubation time, nutrients, atmosphere, and temperature; culture was then gradually abandoned in favor of molecular methods. The rebirth of culture in clinical microbiology was prompted by microbiologists specializing in intracellular bacteria. The shell vial procedure allowed the culture of new species of Rickettsia. The design of axenic media for growing fastidious bacteria such as Tropheryma whipplei and Coxiella burnetii and the ability of amoebal coculture to discover new bacteria constituted major advances. Strong efforts associating optimized culture media, detection methods, and a microaerophilic atmosphere allowed a dramatic decrease of the time of Mycobacterium tuberculosis culture. The use of a new versatile medium allowed an extension of the repertoire of archaea. Finally, to optimize the culture of anaerobes in routine bacteriology laboratories, the addition of antioxidants in culture media under an aerobic atmosphere allowed the growth of strictly anaerobic species. Nevertheless, among usual bacterial pathogens, the development of axenic media for the culture of Treponema pallidum or Mycobacterium leprae remains an important challenge that the patience and innovations of cultivators will enable them to overcome.
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Rubach MP, Maro VP, Bartlett JA, Crump JA. Etiologies of illness among patients meeting integrated management of adolescent and adult illness district clinician manual criteria for severe infections in northern Tanzania: implications for empiric antimicrobial therapy. Am J Trop Med Hyg 2014; 92:454-62. [PMID: 25385866 DOI: 10.4269/ajtmh.14-0496] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We describe the laboratory-confirmed etiologies of illness among participants in a hospital-based febrile illness cohort study in northern Tanzania who retrospectively met Integrated Management of Adolescent and Adult Illness District Clinician Manual (IMAI) criteria for septic shock, severe respiratory distress without shock, and severe pneumonia, and compare these etiologies against commonly used antimicrobials, including IMAI recommendations for emergency antibacterials (ceftriaxone or ampicillin plus gentamicin) and IMAI first-line recommendations for severe pneumonia (ceftriaxone and a macrolide). Among 423 participants hospitalized with febrile illness, there were 25 septic shock, 37 severe respiratory distress without shock, and 109 severe pneumonia cases. Ceftriaxone had the highest potential utility of all antimicrobials assessed, with responsive etiologies in 12 (48%) septic shock, 5 (14%) severe respiratory distress without shock, and 19 (17%) severe pneumonia illnesses. For each syndrome 17-27% of participants had etiologic diagnoses that would be non-responsive to ceftriaxone, but responsive to other available antimicrobial regimens including amphotericin for cryptococcosis and histoplasmosis; anti-tuberculosis therapy for bacteremic disseminated tuberculosis; or tetracycline therapy for rickettsioses and Q fever. We conclude that although empiric ceftriaxone is appropriate in our setting, etiologies not explicitly addressed in IMAI guidance for these syndromes, such as cryptococcosis, histoplasmosis, and tetracycline-responsive bacterial infections, were common.
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Affiliation(s)
- Matthew P Rubach
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University, Durham, North Carolina; Department of Medicine, Kilimanjaro Christian Medical Centre, Moshi, Tanzania; Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania; Duke Global Health Institute, Duke University, Durham, North Carolina; Centre for International Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Venance P Maro
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University, Durham, North Carolina; Department of Medicine, Kilimanjaro Christian Medical Centre, Moshi, Tanzania; Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania; Duke Global Health Institute, Duke University, Durham, North Carolina; Centre for International Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - John A Bartlett
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University, Durham, North Carolina; Department of Medicine, Kilimanjaro Christian Medical Centre, Moshi, Tanzania; Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania; Duke Global Health Institute, Duke University, Durham, North Carolina; Centre for International Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - John A Crump
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University, Durham, North Carolina; Department of Medicine, Kilimanjaro Christian Medical Centre, Moshi, Tanzania; Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania; Duke Global Health Institute, Duke University, Durham, North Carolina; Centre for International Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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Kurlovs AH, Li J, Cheng D, Zhong J. Ixodes pacificus ticks maintain embryogenesis and egg hatching after antibiotic treatment of Rickettsia endosymbiont. PLoS One 2014; 9:e104815. [PMID: 25105893 PMCID: PMC4126787 DOI: 10.1371/journal.pone.0104815] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/17/2014] [Indexed: 01/20/2023] Open
Abstract
Rickettsia is a genus of intracellular bacteria that causes a variety of diseases in humans and other mammals and associates with a diverse group of arthropods. Although Rickettsia appears to be common in ticks, most Rickettsia-tick relationships remain generally uncharacterized. The most intimate of these associations is Rickettsia species phylotype G021, a maternally and transstadially transmitted endosymbiont that resides in 100% of I. pacificus in California. We investigated the effects of this Rickettsia phylotype on I. pacificus reproductive fitness using selective antibiotic treatment. Ciprofloxacin was 10-fold more effective than tetracycline in eliminating Rickettsia from I. pacificus, and quantitative PCR results showed that eggs from the ciprofloxacin-treated ticks contained an average of 0.02 Rickettsia per egg cell as opposed to the average of 0.2 in the tetracycline-treated ticks. Ampicillin did not significantly affect the number of Rickettsia per tick cell in adults or eggs compared to the water-injected control ticks. We found no relationship between tick embryogenesis and rickettsial density in engorged I. pacificus females. Tetracycline treatment significantly delayed oviposition of I. pacificus ticks, but the antibiotic's effect was unlikely related to Rickettsia. We also demonstrated that Rickettsia-free eggs could successfully develop into larvae without any significant decrease in hatching compared to eggs containing Rickettsia. No significant differences in the incubation period, egg hatching rate, and the number of larvae were found between any of the antibiotic-treated groups and the water-injected tick control. We concluded that Rickettsia species phylotype G021 does not have an apparent effect on embryogenesis, oviposition, and egg hatching of I. pacificus.
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Affiliation(s)
- Andre H. Kurlovs
- Department of Biological Sciences, Humboldt State University, Arcata, California, United States of America
| | - Jinze Li
- Department of Biological Sciences, Humboldt State University, Arcata, California, United States of America
| | - Du Cheng
- Department of Biological Sciences, Humboldt State University, Arcata, California, United States of America
| | - Jianmin Zhong
- Department of Biological Sciences, Humboldt State University, Arcata, California, United States of America
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48
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Duan C, Xiong X, Qi Y, Gong W, Jiao J, Wen B. Genomic and comparative genomic analyses of Rickettsia heilongjiangensis provide insight into its evolution and pathogenesis. INFECTION GENETICS AND EVOLUTION 2014; 26:274-82. [PMID: 24924907 DOI: 10.1016/j.meegid.2014.05.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 11/28/2022]
Abstract
Rickettsia heilongjiangensis, the causative agent of far eastern spotted fever, is an obligate intracellular gram-negative bacterium that belongs to the spotted fever group rickettsiae. To understand the evolution and pathogenesis of R. heilongjiangensis, we analyzed its genome and compared it with other rickettsial genomes available in GenBank. The R. heilongjiangensis chromosome contains 1333 genes, including 1297 protein coding genes and 36 RNA coding genes. The genome also contains 121 pseudogenes, 54 insertion sequences, and 39 tandem repeats. Sixteen genes encoding the major components of the type IV secretion systems were identified in the R. heilongjiangensis genome. In total, 37 β-barrel outer membrane proteins were predicted in the genome, eight of which have been previously confirmed to be outer membrane proteins. In addition, 266 potential virulence factor genes, seven partially deleted antibiotic resistance genes, and a genomic island were identified in the genome. The codon usage in the genome is compatible with its low GC content, and the amino acid usage shows apparent bias. A comparative genomic analysis showed that R. heilongjiangensis and R. japonica share one unique fragment that may be a target sequence for a diagnostic assay. The orthologs of 37 genes of R. heilongjiangensis were found in pathogenic R. rickettsii str. Sheila Smith but not in non-pathogenic R. rickettsii str. Iowa, which may explain why R. heilongjiangensis is pathogenic. Pan-genome analysis showed that R. heilongjiangensis and 42 other rickettsiae strains share 693 core genes with a pan-genome size of 4837 genes. The pan-genome-based phylogeny showed that R. heilongjiangensis was closely related to R. japonica.
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Affiliation(s)
- Changsong Duan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
| | - Xiaolu Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
| | - Yong Qi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
| | - Wenping Gong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
| | - Jun Jiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
| | - Bohai Wen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
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49
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Edouard S, Raoult D. Use of the plaque assay for testing the antibiotic susceptibility of intracellular bacteria. Future Microbiol 2014; 8:1301-16. [PMID: 24059920 DOI: 10.2217/fmb.13.98] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The plaque assay was first described for titration of bacterial inoculums and clonal isolation, and was later adapted for testing antibiotics susceptibility and to study virulence factors and motility of bacteria. Over time, the sensitivity and reproducibility of the technique has been improved. Usually, the number of plaques is counted; however, the recent development of informatics tools has stimulated interest in the quantification of plaque size. Owing to this new approach, the plaque assay has been used to characterize the host cell response when infected cells are treated with antimicrobial agents. It was found that statins prevented cell lesions following rickettsial infection; in other studies, some antibiotics were found to cause apoptosis of host cells, suggesting a toxic activity. Here, we present an overview of the plaque assay as it has been used to investigate intracellular bacteria.
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Affiliation(s)
- Sophie Edouard
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD198, Inserm 1, 95, 13005 Marseille, France
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50
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Sutera V, Caspar Y, Boisset S, Maurin M. A new dye uptake assay to test the activity of antibiotics against intracellular Francisella tularensis. Front Cell Infect Microbiol 2014; 4:36. [PMID: 24672776 PMCID: PMC3957058 DOI: 10.3389/fcimb.2014.00036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 02/24/2014] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis, a facultative intracellular bacterium, is the aetiological agent of tularaemia. Antibiotic treatment of this zoonosis is based on the administration of a fluoroquinolone or a tetracycline for cases with mild to moderate severity, whereas an aminoglycoside (streptomycin or gentamicin) is advocated for severe cases. However, treatment failures and relapses remain frequent, especially in patients suffering from chronic lymph node suppuration. Therefore, new treatment alternatives are needed. We have developed a dye uptake assay for determination of minimal inhibitory extracellular concentrations (MIECs) of antibiotics against intracellular F. tularensis, and validated the method by comparing the results obtained using a CFU-enumerating method. We also compared MIECs with MICs of the same compounds determined using a CLSI broth microdilution method. We tested the activity of 11 antibiotics against two clinical strains of F. tularensis subsp. holarctica isolated in France. Both strains displayed low MICs (≤1 μg/mL) to fluoroquinolones (ciprofloxacin, levofloxacin and moxifloxacin), gentamicin, doxycycline and rifampicin. Higher MICs (≥8 μg/mL) were found for carbapenems (imipenem and meropenem), daptomycin and linezolid. Erythromycin MICs were 4.0 and 16.0 μg/mL, respectively, for the two clinical strains. MIECs were almost the same with the two methods used. They were concordant with MICs, except for erythromycin and linezolid (respectively, four and eight times more active against intracellular F. tularensis) and gentamicin (four to eight times less active against intracellular F. tularensis). This study validated the dye uptake assay as a new tool for determination of the activity of a large panel of antibiotics against intracellular F. tularensis. This test confirmed the intracellular activity of first-line antibiotics used for tularaemia treatment, but also revealed significant activity of linezolid against intracellular F. tularensis.
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Affiliation(s)
- Vivien Sutera
- Laboratoire de Bactériologie, Département des Agents Infectieux, Institut de Biologie et de Pathologie, Centre Hospitalier Universitaire Grenoble Grenoble, France ; Laboratoire Adaptation et Pathogénie des Micro-Organismes, Université Joseph Fourier-Grenoble 1 Grenoble Cedex 9, France ; CNRS, UMR 5163 Grenoble, France
| | - Yvan Caspar
- Laboratoire de Bactériologie, Département des Agents Infectieux, Institut de Biologie et de Pathologie, Centre Hospitalier Universitaire Grenoble Grenoble, France ; Laboratoire Adaptation et Pathogénie des Micro-Organismes, Université Joseph Fourier-Grenoble 1 Grenoble Cedex 9, France ; CNRS, UMR 5163 Grenoble, France
| | - Sandrine Boisset
- Laboratoire de Bactériologie, Département des Agents Infectieux, Institut de Biologie et de Pathologie, Centre Hospitalier Universitaire Grenoble Grenoble, France ; Laboratoire Adaptation et Pathogénie des Micro-Organismes, Université Joseph Fourier-Grenoble 1 Grenoble Cedex 9, France ; CNRS, UMR 5163 Grenoble, France
| | - Max Maurin
- Laboratoire de Bactériologie, Département des Agents Infectieux, Institut de Biologie et de Pathologie, Centre Hospitalier Universitaire Grenoble Grenoble, France ; Laboratoire Adaptation et Pathogénie des Micro-Organismes, Université Joseph Fourier-Grenoble 1 Grenoble Cedex 9, France ; CNRS, UMR 5163 Grenoble, France
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