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Stone NE, Hamond C, Clegg J, McDonough RF, Bourgeois RM, Ballard R, Thornton NB, Nuttall M, Hertzel H, Anderson T, Whealy RN, Timm S, Roberts AK, Barragán V, Phipatanakul W, Leibler JH, Benson H, Specht A, White R, LeCount K, Furstenau TN, Galloway RL, Hill NJ, Madison JD, Fofanov VY, Pearson T, Sahl JW, Busch JD, Weiner Z, Nally JE, Wagner DM, Rosenbaum MH. Host population structure and rare dispersal events drive leptospirosis transmission patterns among Rattus norvegicus in Boston, Massachusetts, US. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598639. [PMID: 38915728 PMCID: PMC11195238 DOI: 10.1101/2024.06.12.598639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Leptospirosis (caused by pathogenic bacteria in the genus Leptospira ) is prevalent worldwide but more common in tropical and subtropical regions. Transmission can occur following direct exposure to infected urine from reservoir hosts, such as rats, or a urine-contaminated environment, which then can serve as an infection source for additional rats and other mammals, including humans. The brown rat, Rattus norvegicus , is an important reservoir of leptospirosis in urban settings. We investigated leptospirosis among brown rats in Boston, Massachusetts and hypothesized that rat dispersal in this urban setting influences the movement, persistence, and diversity of Leptospira . We analyzed DNA from 328 rat kidney samples collected from 17 sites in Boston over a seven-year period (2016-2022); 59 rats representing 12 of 17 sites were positive for Leptospira . We used 21 neutral microsatellite loci to genotype 311 rats and utilized the resulting data to investigate genetic connectivity among sampling sites. We generated whole genome sequences for 28 Leptospira isolates obtained from frozen and fresh tissue from some of the 59 Leptospira -positive rat kidneys. When isolates were not obtained, we attempted Leptospira genomic DNA capture and enrichment, which yielded 14 additional Leptospira genomes from rats. We also generated an enriched Leptospira genome from a 2018 human case in Boston. We found evidence of high genetic structure and limited dispersal among rat populations that is likely influenced by major roads and/or other unknown dispersal barriers, resulting in distinct rat population groups within the city; at certain sites these groups persisted for multiple years. We identified multiple distinct phylogenetic clades of L. interrogans among rats, with specific clades tightly linked to distinct rat populations. This pattern suggests L. interrogans persists in local rat populations and movement of leptospirosis in this urban rat community is driven by rat dispersal. Finally, our genomic analyses of the 2018 human leptospirosis case in Boston suggests a link to rats as the source. These findings will be useful for guiding rat control and human leptospirosis mitigation efforts in this and other urban settings.
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Kappagoda CN, Senevirathne R, Jayasundara D, Warnasekara Y, Srimantha L, De Silva L, Agampodi SB. The human Toll-like receptor 2 (TLR2) response during pathogenic Leptospira infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.16.567338. [PMID: 38014008 PMCID: PMC10680769 DOI: 10.1101/2023.11.16.567338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Background Human innate immune responses are triggered through the interaction of human pattern recognition receptors and pathogen-associated molecular patterns. The role of toll-like receptor2 (TLR2) in mice innate immune response to leptospirosis is well established, while human studies are limited. The present study aimed to determine the TLR2 response among confirmed cases of leptospirosis. Methodology/Principle findings The study has two components. Clinically suspected patients of leptospirosis were confirmed using a previously validated qPCR assay. Total RNA was extracted from patients' RNA-stabilized whole blood samples. Human TLR2 gene expression (RT-qPCR) analysis was carried out using an exon-exon spanning primer pair, using CFX Maestro™ software. The first set of patient samples was used to calculate the Relative Normalized Expression (ΔΔCq value) of the TLR2 gene in comparison to a healthy control sample and normalized by the reference gene GAPDH (Glyceraldehyde-3-phosphate dehydrogenase). Secondly, recruited patient samples were subjected to TLR2 gene expression analysis and compared to healthy controls and normalized by the reference genes Beta-2-microglobulin(B2M), Hypoxanthine phosphoribosyltransferase 1 (HPRT 1).In the initial cohort of 64 confirmed leptospirosis cases, 18 were selected for human TLR2 gene expression analysis based on criteria of leptospiremia and RNA yield. Within this group, one individual exhibited a down-regulation of TLR2 gene (Expression/ΔΔCq=0.01352), whereas the remaining subjects presented no significant change in gene expression. In a subsequent cohort of 23 confirmed cases, 13 were chosen for similar analysis. Among these, three patients demonstrated down-regulation of TLR2 gene expression, with Expression/ΔΔCq values of 0.86574, 0.47200, and 0.28579, respectively. No TLR2 gene expression was noted in the other patients within this second group. Conclusions Our investigation into the acute phase of leptospirosis using human clinical samples has revealed a downregulation of TLR2 gene expression. This observation contrasts to the upregulation commonly reported in the majority of in-vitro and in-vivo studies of Leptospira infection. These preliminary findings prompt a need for further research to explore the mechanisms underlying TLR2's role in the pathogenesis of leptospirosis, which may differ in clinical settings compared to laboratory models. Author Summary The human immune system employs pattern recognition receptors like toll-like receptor 2 (TLR2) to detect and combat infections such as leptospirosis. While TLR2's role is well-documented in mice, its function in the human response to leptospirosis remains unclear. Our study evaluated TLR2 activity in patients with confirmed leptospirosis. We conducted a genetic analysis of blood samples from these patients, comparing TLR2 gene activity against healthy individuals, with standard reference genes for accuracy. Contrary to expectations and existing laboratory data, we observed a decrease in TLR2 activity in some patients. This suggests that human TLR2 responses in actual infections may diverge from established laboratory models. These findings indicate a need for further study to understand the human immune response to leptospirosis, which may significantly differ from that observed in controlled experimental settings.
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Prevalence of Pathogenic Leptospira spp. in Non-Volant Small Mammals of Hutan Lipur Sekayu, Terengganu, Malaysia. Pathogens 2022; 11:pathogens11111300. [PMID: 36365051 PMCID: PMC9693538 DOI: 10.3390/pathogens11111300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/03/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
Leptospirosis is an important zoonotic disease that is transmitted worldwide through infected small mammals such as rodents. In Malaysia, there is a paucity of information on the animal reservoirs that are responsible for leptospirosis transmission, with only a few studies focusing on leptospirosis risk in recreational areas. Therefore, in this study we characterized the species composition and the prevalence of pathogenic Leptospira spp. in non-volant small mammals of Hutan Lipur Sekayu, Terengganu. We performed ten trapping sessions totaling 3000 trappings between September 2019 and October 2020. Kidney samples from captured individuals were extracted for the PCR detection of pathogenic Leptospira spp. Overall, we captured 45 individuals from 8 species (1.56% successful trapping effort), with 9 individuals testing positive for pathogenic Leptospira, that is, a 20% (n = 9/45) prevalence rate. Rattus tiomanicus (n = 22) was the most dominant captured species and had the highest positive individual with pathogenic Leptospira (44.4%, n = 4/9). Despite the low successful trapping effort in this study, the results show the high diversity of non-volant small mammals in Hutan Lipur Sekayu, and that they could also maintain and transmit pathogenic Leptospira.
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Gorman M, Xu R, Prakoso D, Salvador LCM, Rajeev S. Leptospira enrichment culture followed by ONT metagenomic sequencing allows better detection of Leptospira presence and diversity in water and soil samples. PLoS Negl Trop Dis 2022; 16:e0010589. [DOI: 10.1371/journal.pntd.0010589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/07/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
Background
Leptospirosis, a life-threatening disease in humans and animals, is one of the most widespread global zoonosis. Contaminated soil and water are the major transmission sources in humans and animals. Clusters of disease outbreaks are common during rainy seasons.
Methodology/Principal findings
In this study, to detect the presence of Leptospira, we applied PCR, direct metagenomic sequencing, and enrichment culture followed by PCR and metagenomic sequencing on water and soil samples. Direct sequencing and enrichment cultures followed by PCR or sequencing effectively detected pathogenic and nonpathogenic Leptospira compared to direct PCR and 16S amplification-based metagenomic sequencing in soil or water samples. Among multiple culture media evaluated, Ellinghausen-McCullough-Johnson-Harris (EMJH) media containing antimicrobial agents was superior in recovering and detecting Leptospira from the environmental samples. Our results show that enrichment culture followed by PCR can be used to confirm the presence of pathogenic Leptospira in environmental samples. Additionally, metagenomic sequencing on enrichment cultures effectively detects the abundance and diversity of Leptospira spp. from environmental samples.
Conclusions/Significance
The selection of methodology is critical when testing environmental samples for the presence of Leptospira. Selective enrichment culture improves Leptospira detection efficacy by PCR or metagenomic sequencing and can be used successfully to understand the presence and diversity of pathogenic Leptospira during environmental surveillance.
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Agampodi S, Warnasekara J, Siribaddana S, Kularatna SAM, Gamage C, Jayasundara D, Senevirathna I, Srimantha S, Kappagoda C, Weerawansa P, Pilapitiya S, Lokunarangoda N, Sarathchandra C, Senanayake H, Matthias M, Vinetz J. Demographic, exposure, clinical, biochemical and diagnostic data of febrile patients recruited for the largest field study on leptospirosis in Sri Lanka. Data Brief 2022; 43:108378. [PMID: 35770027 PMCID: PMC9234077 DOI: 10.1016/j.dib.2022.108378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/31/2022] [Accepted: 06/07/2022] [Indexed: 11/23/2022] Open
Abstract
This dataset includes data from febrile patients recruited for a large hospital-based study in Sri Lanka from 2016 to 2019. The variables include primary socio-demographic data, exposure data, clinical data, biochemical and investigation data. Some of these data are available as serial data from admission to discharge daily. Microscopic agglutination test, quantitative PCR of whole blood, urine and serum and culture isolation was performed to diagnose the patients with leptospirosis.
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Affiliation(s)
- Suneth Agampodi
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
- Corresponding author. @sunethagampodi
| | - Janith Warnasekara
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Sisira Siribaddana
- Department of Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - SAM Kularatna
- Department of Medicine, Faculty of Medicine, University of Peradeniya, Sri Lanka
| | - Chandika Gamage
- Department of Microbiology, Faculty of Medicine, University of Peradeniya, Sri Lanka
| | - Dinesha Jayasundara
- Department of Microbiology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Indika Senevirathna
- Department of Biochemistry, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Shalka Srimantha
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Chamila Kappagoda
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Prasanna Weerawansa
- Department of Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Senaka Pilapitiya
- Department of Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Niroshan Lokunarangoda
- Department of Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Chamara Sarathchandra
- Department of Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Hemal Senanayake
- Department of Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Michael Matthias
- Section of Infectious Diseases, Department of Internal Medicine, School of Medicine, Yale University, United States
| | - Joseph Vinetz
- Section of Infectious Diseases, Department of Internal Medicine, School of Medicine, Yale University, United States
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Othman S, Lee PY, Lam JY, Philip N, Azhari NN, Affendy NB, Masri SN, Neela VK, Mohd-Taib FS, Chee HY. A versatile isothermal amplification assay for the detection of leptospires from various sample types. PeerJ 2022; 10:e12850. [PMID: 35291487 PMCID: PMC8918162 DOI: 10.7717/peerj.12850] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/07/2022] [Indexed: 01/10/2023] Open
Abstract
Background Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira that affects both humans and animals worldwide. Early detection of the pathogen in humans is crucial for early intervention and control of the progression of the disease to a severe state. It is also vitally important to be able to detect the presence of the pathogen in carrier animals to control the spread of the disease from the environment. Here we developed a simple and rapid loop-mediated isothermal amplification (LAMP) assay targeting the leptospiral secY gene. Results Several reaction conditions of the LAMP reaction were optimized to ensure efficient amplification of the target DNA. The sensitivity of the developed LAMP assay obtained using a pure Leptospira culture was 2 × 104 copies of genomic DNA per reaction (equivalent to 0.1 ng) for a 40-minute reaction time. No cross-reactions were observed in the LAMP reaction against a series of non-leptospiral bacteria, indicating a specific reaction. The applicability of the LAMP assay was demonstrated on human blood and urine specimens collected from suspected leptospirosis patients and rat kidney specimens collected from suspected leptospirosis outbreak areas and high-risk areas. The developed LAMP assay demonstrated a higher detection rate for leptospiral DNA compared with the polymerase chain reaction (PCR) assay, possibly due to the presence of inhibitory substances, especially in rat kidney specimens, to which the PCR method is more susceptible. The present findings also highlight the importance of urine sample collection from patients for routine monitoring of the disease. Conclusions In short, the developed LAMP assay can serve as a feasible alternative tool for the diagnosis of leptospirosis and be used for epidemiological and environmental surveillance of the disease, considering its robustness, rapidity, sensitivity, and specificity, as demonstrated in this study.
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Affiliation(s)
- Shuhaidah Othman
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Pui-Yuei Lee
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Jia-Yong Lam
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Noraini Philip
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Nurul Natasya Azhari
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Norliza Bahtiar Affendy
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Siti Norbaya Masri
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Vasantha Kumari Neela
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Farah Shafawati Mohd-Taib
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Hui-Yee Chee
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
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Kakita T, Okano S, Kyan H, Miyahira M, Taira K, Kitashoji E, Koizumi N. Laboratory diagnostic, epidemiological, and clinical characteristics of human leptospirosis in Okinawa Prefecture, Japan, 2003-2020. PLoS Negl Trop Dis 2021; 15:e0009993. [PMID: 34905535 PMCID: PMC8670671 DOI: 10.1371/journal.pntd.0009993] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 11/12/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Leptospirosis is considered an endemic disease among agricultural workers in Okinawa Prefecture, which is the southernmost part of Japan and has a subtropical climate, but data on the current status and trend of this disease are scarce. METHODOLOGY/PRINCIPAL FINDINGS We conducted a retrospective study of clinically suspected leptospirosis patients whose sample and information were sent to the Okinawa Prefectural Institute of Health and Environment from November 2003 to December 2020. Laboratory diagnosis was established using culture, nested polymerase chain reaction (PCR), and/or microscopic agglutination test (MAT) with blood, cerebrospinal fluid, and/or urine samples. Statistical analyses were performed to compare the epidemiological information, clinical features, and sensitivities of diagnostic methods among laboratory-confirmed cases. Serogroups and the species of Leptospira isolates were determined by MAT using 13 antisera and flaB sequencing. A total of 531 clinically suspected patients were recruited, among whom 246 (46.3%) were laboratory confirmed to have leptospirosis. Among the confirmed cases, patients aged 20-29 years (22.4%) and male patients (85.7%) were the most common. The most common estimated sources of infection were recreation (44.5%) and labor (27.8%) in rivers. Approximately half of the isolates were of the L. interrogans serogroup Hebdomadis. The main clinical symptoms were fever (97.1%), myalgia (56.3%), and conjunctival hyperemia (52.2%). Headache occurred significantly more often in patients with Hebdomadis serogroup infections than those with other serogroup infections. The sensitivities of culture and PCR exceeded 65% during the first 6 days, while the sensitivity of MAT surpassed that of culture and PCR in the second week after onset. PCR using blood samples was a preferable method for the early diagnosis of leptospirosis. CONCLUSIONS/SIGNIFICANCE The results of this study will support clinicians in the diagnosis and treatment of undifferentiated febrile patients in Okinawa Prefecture as well as patients returning from Okinawa Prefecture.
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Affiliation(s)
- Tetsuya Kakita
- Department of Biological Sciences, Okinawa Prefectural Institute of Health and Environment, Uruma, Okinawa, Japan
| | - Sho Okano
- Department of Biological Sciences, Okinawa Prefectural Institute of Health and Environment, Uruma, Okinawa, Japan
| | - Hisako Kyan
- Department of Biological Sciences, Okinawa Prefectural Institute of Health and Environment, Uruma, Okinawa, Japan
| | - Masato Miyahira
- Department of Biological Sciences, Okinawa Prefectural Institute of Health and Environment, Uruma, Okinawa, Japan
| | - Katsuya Taira
- Department of Biological Sciences, Okinawa Prefectural Institute of Health and Environment, Uruma, Okinawa, Japan
| | - Emi Kitashoji
- Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Nagasaki, Japan
| | - Nobuo Koizumi
- Department of Bacteriology I, National Institute of Infectious Disease, Shinjuku, Tokyo, Japan
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Braun P, Nguyen MDT, Walter MC, Grass G. Ultrasensitive Detection of Bacillus anthracis by Real-Time PCR Targeting a Polymorphism in Multi-Copy 16S rRNA Genes and Their Transcripts. Int J Mol Sci 2021; 22:12224. [PMID: 34830105 PMCID: PMC8618755 DOI: 10.3390/ijms222212224] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 02/03/2023] Open
Abstract
The anthrax pathogen Bacillus anthracis poses a significant threat to human health. Identification of B. anthracis is challenging because of the bacterium's close genetic relationship to other Bacillus cereus group species. Thus, molecular detection is founded on species-specific PCR targeting single-copy genes. Here, we validated a previously recognized multi-copy target, a species-specific single nucleotide polymorphism (SNP) present in 2-5 copies in every B. anthracis genome analyzed. For this, a hydrolysis probe-based real-time PCR assay was developed and rigorously tested. The assay was specific as only B. anthracis DNA yielded positive results, was linear over 9 log10 units, and was sensitive with a limit of detection (LoD) of 2.9 copies/reaction. Though not exhibiting a lower LoD than established single-copy PCR targets (dhp61 or PL3), the higher copy number of the B. anthracis-specific 16S rRNA gene alleles afforded ≤2 unit lower threshold (Ct) values. To push the detection limit even further, the assay was adapted for reverse transcription PCR on 16S rRNA transcripts. This RT-PCR assay was also linear over 9 log10 units and was sensitive with an LoD of 6.3 copies/reaction. In a dilution series of experiments, the 16S RT-PCR assay achieved a thousand-fold higher sensitivity than the DNA-targeting assays. For molecular diagnostics, we recommend a real-time RT-PCR assay variant in which both DNA and RNA serve as templates (thus, no requirement for DNase treatment). This can at least provide results equaling the DNA-based implementation if no RNA is present but is superior even at the lowest residual rRNA concentrations.
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Affiliation(s)
| | | | | | - Gregor Grass
- Bundeswehr Institute of Microbiology (IMB), 80937 Munich, Germany; (P.B.); (M.D.-T.N.); (M.C.W.)
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Mendoza MV, Rivera WL. Application of simplified MLST scheme for direct typing of clinical samples from human leptospirosis cases in a tertiary hospital in the Philippines. PLoS One 2021; 16:e0258891. [PMID: 34669742 PMCID: PMC8528318 DOI: 10.1371/journal.pone.0258891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 10/07/2021] [Indexed: 11/29/2022] Open
Abstract
Despite the major threat of leptospirosis to public health in the Philippines, its epidemiologic data remain scarce. Multilocus sequence typing (MLST) is a method often used for identification of circulating Leptospira species and disease surveillance. Unfortunately, molecular typing of Leptospira isolates is not routinely done in most hospital settings. A simplified MLST scheme targeting three loci (adk, lipL41, mreA) was performed for rapid direct typing of Leptospira in clinical specimens. Blood samples from suspected or clinically diagnosed cases (n = 50) were initially screened via polymerase chain reaction (PCR) targeting 23S rRNA, 16S rRNA (rrs2), and lipL32 genes. From the nine positives, seven had interpretable data from MLST. Allelic profiles identified L. interrogans in all positive samples. Six were assigned to ST12 of serovar Manilae (serogroup Pyrogenes) while one sample cannot be clearly differentiated between two serovars/serogroups, Bataviae/Losbanos (serogroup Bataviae) or Australis (serogroup Australis), indicating possibility of a new ST. Phylogenetic analysis confirmed that the application of simplified MLST scheme produces consistent results with the seven-loci genetic profile of published Leptospira MLST schemes. Reduced scheme addressed the challenges often encountered in the amplification of full MLST genetic profile of Leptospira. The approach is a potential alternative to serological tests for rapid typing of clinical specimens and can also aid in investigations on disease epidemiology specifically to monitor occurrence, pathogen transmission, host specificity and susceptibility, and other factors that could lead to potential outbreaks.
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Affiliation(s)
- Marjo V. Mendoza
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City, Philippines
| | - Windell L. Rivera
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City, Philippines
- Natural Sciences Research Institute, University of the Philippines Diliman, Quezon City, Philippines
- * E-mail:
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Highly multiplexed oligonucleotide probe-ligation testing enables efficient extraction-free SARS-CoV-2 detection and viral genotyping. Mod Pathol 2021; 34:1093-1103. [PMID: 33536572 PMCID: PMC7856856 DOI: 10.1038/s41379-020-00730-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/25/2020] [Accepted: 11/25/2020] [Indexed: 02/04/2023]
Abstract
There is an urgent and unprecedented need for sensitive and high-throughput molecular diagnostic tests to combat the SARS-CoV-2 pandemic. Here we present a generalized version of the RNA-mediated oligonucleotide Annealing Selection and Ligation with next generation DNA sequencing (RASL-seq) assay, called "capture RASL-seq" (cRASL-seq), which enables highly sensitive (down to ~1-100 pfu/ml or cfu/ml) and highly multiplexed (up to ~10,000 target sequences) detection of pathogens. Importantly, cRASL-seq analysis of COVID-19 patient nasopharyngeal (NP) swab specimens does not involve nucleic acid purification or reverse transcription, steps that have introduced supply bottlenecks into standard assay workflows. Our simplified protocol additionally enables the direct and efficient genotyping of selected, informative SARS-CoV-2 polymorphisms across the entire genome, which can be used for enhanced characterization of transmission chains at population scale and detection of viral clades with higher or lower virulence. Given its extremely low per-sample cost, simple and automatable protocol and analytics, probe panel modularity, and massive scalability, we propose that cRASL-seq testing is a powerful new technology with the potential to help mitigate the current pandemic and prevent similar public health crises.
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Gunasegar S, Neela VK. Evaluation of diagnostic accuracy of loop-mediated isothermal amplification method (LAMP) compared with polymerase chain reaction (PCR) for Leptospira spp. in clinical samples: a systematic review and meta-analysis. Diagn Microbiol Infect Dis 2021; 100:115369. [PMID: 33845305 DOI: 10.1016/j.diagmicrobio.2021.115369] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/20/2021] [Accepted: 03/06/2021] [Indexed: 12/29/2022]
Abstract
Loop-mediated isothermal amplification (LAMP) test is widely used in molecular diagnostics as a point-of-care technique alternative to traditional PCR especially in resource-limited countries. LAMP has been recently used to diagnose leptospirosis. Therefore, we undertook a systematic review and meta-analysis to compare the accuracy of LAMP with PCR in the diagnosis of leptospirosis. Sixty-one studies were extracted from three international databases and analyzed throughout using the PRISMA guideline. The pooled sensitivity of LAMP and PCR technique was 0.80 (95% CI: 0.58-0.90) and 0.54 (95% CI: 0.35-0.67) respectively indicating that LAMP is more sensitive than PCR. The Q* value of LAMP and PCR-based technique is 274.61 and 397.95, respectively. Among the analyzed studies, significant heterogeneity was observed where I2 is 90.90% for LAMP-based and 86.18% for PCR-based. Our study suggests that LAMP has better diagnostic accuracy than PCR. However, future work should be carried out to reduce heterogeneity as well as to improve and develop effective intervention strategies.
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Affiliation(s)
- Shan Gunasegar
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Vasantha Kumari Neela
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
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Abstract
The diagnosis of leptospirosis depends on specific laboratory tests because nonspecific and diverse clinical manifestations make clinical diagnosis difficult and it is easily confused with other infectious diseases in the tropics. Suitable laboratory diagnostic tests vary depending on the stage of the disease, requiring the combination of diagnostic tests using appropriate specimens at each disease stage.
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Affiliation(s)
- Nobuo Koizumi
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.
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Abstract
Abstract
Background
Leptospirosis, caused by pathogenic Leptospira spp., is a widespread zoonotic disease worldwide. Early diagnosis is required for proper patient management and reducing leptospirosis morbidity and mortality.
Objective
To summarize current literature regarding commonly used and new promising molecular approaches to Leptospira detection and diagnostic tests of human leptospirosis.
Method
The relevant articles in Leptospira and leptospirosis were retrieved from MEDLINE (PubMed) and Scopus.
Results
Several molecular techniques have been developed for diagnosis of human leptospirosis. Polymerase chain reaction-based techniques targeting on either lipL32 or 16S rRNA (rrs) gene are most commonly used to detect leptospiral DNA in various clinical specimens. Whole blood and urine are recommended specimens for suspected cases in the first (acute) and the second (immune) phases, respectively. Isothermal amplification with less expensive instrument is an alternative DNA detection technique that may be suitable for resource-limited laboratories.
Conclusion
Detection of leptospiral DNA in clinical specimens using molecular techniques enhances sensitivity for diagnosis of leptospirosis. The efficient and robust molecular detection especially in the early leptospiremic phase may prompt early and appropriate treatment leading to reduced morbidity and mortality of patients with leptospirosis.
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Affiliation(s)
- Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine , Chulalongkorn University , Bangkok 10330 , Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development , Chulalongkorn University , Bangkok 10330 , Thailand
| | - Kanitha Patarakul
- Department of Microbiology, Faculty of Medicine , Chulalongkorn University , Bangkok 10330 , Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development , Chulalongkorn University , Bangkok 10330 , Thailand
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Credle JJ, Robinson ML, Gunn J, Monaco D, Sie B, Tchir A, Hardick J, Zheng X, Shaw-Saliba K, Rothman RE, Eshleman SH, Pekosz A, Hansen K, Mostafa H, Steinegger M, Larman HB. Highly multiplexed oligonucleotide probe-ligation testing enables efficient extraction-free SARS-CoV-2 detection and viral genotyping. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.06.03.130591. [PMID: 32577648 PMCID: PMC7302202 DOI: 10.1101/2020.06.03.130591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The emergence of SARS-CoV-2 has caused the current COVID-19 pandemic with catastrophic societal impact. Because many individuals shed virus for days before symptom onset, and many show mild or no symptoms, an emergent and unprecedented need exists for development and deployment of sensitive and high throughput molecular diagnostic tests. RNA-mediated oligonucleotide Annealing Selection and Ligation with next generation DNA sequencing (RASL-seq) is a highly multiplexed technology for targeted analysis of polyadenylated mRNA, which incorporates sample barcoding for massively parallel analyses. Here we present a more generalized method, capture RASL-seq ("cRASL-seq"), which enables analysis of any targeted pathogen- (and/or host-) associated RNA molecules. cRASL-seq enables highly sensitive (down to ~1-100 pfu/ml or cfu/ml) and highly multiplexed (up to ~10,000 target sequences) detection of pathogens. Importantly, cRASL-seq analysis of COVID-19 patient nasopharyngeal (NP) swab specimens does not involve nucleic acid extraction or reverse transcription, steps that have caused testing bottlenecks associated with other assays. Our simplified workflow additionally enables the direct and efficient genotyping of selected, informative SARS-CoV-2 polymorphisms across the entire genome, which can be used for enhanced characterization of transmission chains at population scale and detection of viral clades with higher or lower virulence. Given its extremely low per-sample cost, simple and automatable protocol and analytics, probe panel modularity, and massive scalability, we propose that cRASL-seq testing is a powerful new surveillance technology with the potential to help mitigate the current pandemic and prevent similar public health crises.
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Affiliation(s)
- Joel J. Credle
- Institute for Cell Engineering, Immunology Division, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Matthew L Robinson
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jonathan Gunn
- Institute for Cell Engineering, Immunology Division, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Daniel Monaco
- Institute for Cell Engineering, Immunology Division, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Brandon Sie
- Institute for Cell Engineering, Immunology Division, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Alexandra Tchir
- Institute for Cell Engineering, Immunology Division, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Justin Hardick
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Emergency Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xuwen Zheng
- Institute for Cell Engineering, Immunology Division, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Kathryn Shaw-Saliba
- Department of Emergency Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Richard E. Rothman
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Emergency Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Susan H. Eshleman
- Division of Transfusion Medicine, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Andrew Pekosz
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Kasper Hansen
- Department of Biostatistics, Johns Hopkins University, Baltimore, MD, USA
| | - Heba Mostafa
- Division of Medical Microbiology, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Martin Steinegger
- Biological Sciences & Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - H. Benjamin Larman
- Institute for Cell Engineering, Immunology Division, Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
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Julio RGV, Agudelo-Flórez P, López JÁ, Sánchez RGP. New molecular target for the phylogenetic identification of Leptospira species directly from clinical samples: an alternative gene to 16S rRNA. Rev Soc Bras Med Trop 2020; 53:e20190333. [PMID: 32187337 PMCID: PMC7094048 DOI: 10.1590/0037-8682-0333-2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 09/06/2019] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION: Phylogenetic analysis of the 16S ribosomal gene initial region is used to
identify Leptospira isolates at the species level from
clinical samples. Unfortunately, this method cannot differentiate between
some intermediates and saprophytic species. METHODS: We used comparative genomic analysis between 35 Leptospira
species to find new molecular targets for Leptospira
species identification. RESULTS: We proposed the use of the rpoC gene, encoding the
DNA-directed RNA polymerase β-subunit, for identifying 35
Leptospira species. CONCLUSIONS: The rpoC gene can be a molecular target to identify the main
species of the Leptospira genus directly from clinical
samples.
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Affiliation(s)
| | - Piedad Agudelo-Flórez
- Basic Science Research Group, Graduates School - CES University. Medellín, Antioquia, Colombia
| | - Juan Álvaro López
- Microbiology School, Primary Immunodeficiencies Group, University of Antioquia. Medellín, Antioquia, Colombia
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16
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Lam JY, Low GKK, Chee HY. Diagnostic accuracy of genetic markers and nucleic acid techniques for the detection of Leptospira in clinical samples: A meta-analysis. PLoS Negl Trop Dis 2020; 14:e0008074. [PMID: 32049960 PMCID: PMC7041858 DOI: 10.1371/journal.pntd.0008074] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/25/2020] [Accepted: 01/18/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Leptospirosis is often difficult to diagnose because of its nonspecific symptoms. The drawbacks of direct isolation and serological tests have led to the increased development of nucleic acid-based assays, which are more rapid and accurate. A meta-analysis was performed to evaluate the diagnostic accuracy of genetic markers for the detection of Leptospira in clinical samples. METHODOLOGY AND PRINCIPLE FINDINGS A literature search was performed in Scopus, PubMed, MEDLINE and non-indexed citations (via Ovid) by using suitable keyword combinations. Studies evaluating the performance of nucleic acid assays targeting leptospire genes in human or animal clinical samples against a reference test were included. Of the 1645 articles identified, 42 eligible studies involving 7414 samples were included in the analysis. The diagnostic performance of nucleic acid assays targeting the rrs, lipL32, secY and flaB genes was pooled and analyzed. Among the genetic markers analyzed, the secY gene showed the highest diagnostic accuracy measures, with a pooled sensitivity of 0.56 (95% CI: 0.50-0.63), a specificity of 0.98 (95% CI: 0.97-0.98), a diagnostic odds ratio of 46.16 (95% CI: 6.20-343.49), and an area under the curve of summary receiver operating characteristics curves of 0.94. Nevertheless, a high degree of heterogeneity was observed in this meta-analysis. Therefore, the present findings here should be interpreted with caution. CONCLUSION The diagnostic accuracies of the studies examined for each genetic marker showed a significant heterogeneity. The secY gene exhibited higher diagnostic accuracy measures compared with other genetic markers, such as lipL32, flaB, and rrs, but the difference was not significant. Thus, these genetic markers had no significant difference in diagnostic accuracy for leptospirosis. Further research into these genetic markers is warranted.
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Affiliation(s)
- Jia-Yong Lam
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Gary Kim-Kuan Low
- Clinical Research Team, Rapid Response Revival Research Ltd, Riverwood, Sydney, Australia
| | - Hui-Yee Chee
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
- * E-mail:
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Obusan MCM, Villanueva RMD, Siringan MAT, Rivera WL, Aragones LV. Leptospira spp. and Toxoplasma gondii in stranded representatives of wild cetaceans in the Philippines. BMC Vet Res 2019; 15:372. [PMID: 31655601 PMCID: PMC6815370 DOI: 10.1186/s12917-019-2112-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 09/24/2019] [Indexed: 01/26/2023] Open
Abstract
Background The stranding events of cetaceans in the Philippines provide opportunities for gathering biological information and specimens, especially from the pelagic forms. As part of an effort to monitor the health of wild cetaceans, this study detected Leptospira spp. and Toxoplasma gondii, causative agents of the emerging zoonotic diseases leptospirosis and toxoplasmosis respectively, in their stranded representatives. From October 2016–August 2018, 40 cetaceans (representing 14 species) that stranded nationwide were sampled for brain, cardiac muscle, skeletal muscle, kidney, and blood tissues, urine, and sera. These were subjected to molecular, serological, culture, and histopathological analyses to detect the target pathogens. Results T. gondii was detected in 20 (71%) of the 28 cetaceans with biological samples subjected to either molecular detection through RE gene amplification or IgG antibodies detection through agglutination-based serological assay. On the other hand, Leptospira was detected in 18 (64%) of 28 cetaceans with biological samples subjected to bacterial culture, molecular detection through 16S rDNA amplification, or IgM antibodies detection through ELISA-based serological assay. Conclusions There is the plausibility of toxoplasmosis and leptospirosis in cetacean populations found in the Philippines, however, acute or chronic phases of infections in sampled stranded individuals cannot be confirmed in the absence of supporting pathological observations and corroborating detection tests. Further studies should look for more evidences of pathogenicity, and explore the specific mechanisms by which pelagic cetacean species become infected by Leptospira spp. and T. gondii. As there is growing evidence on the role of cetaceans as sentinels of land-sea movement of emerging pathogens and the diseases they cause, any opportunity, such as their stranding events, should be maximized to investigate the health of their populations. Moreover, the role of leptospirosis or toxoplasmosis in these stranding events must be considered.
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Affiliation(s)
- Marie Christine M Obusan
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines. .,Natural Sciences Research Institute, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines.
| | - Ren Mark D Villanueva
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines.,Natural Sciences Research Institute, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines
| | - Maria Auxilia T Siringan
- Institute of Environmental Science and Meteorology, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines
| | - Windell L Rivera
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines.,Natural Sciences Research Institute, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines
| | - Lemnuel V Aragones
- Natural Sciences Research Institute, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines.,Institute of Environmental Science and Meteorology, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines
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18
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Sharma B, Thille K, Rametta N, Sharma R. Detection of Leptospira spp. using polymerase chain reaction technique from kidney of Rattus norvegicus from Grenada, West Indies. INTERNATIONAL JOURNAL OF ONE HEALTH 2019. [DOI: 10.14202/ijoh.2019.81-85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Aim: This study aimed to find out the prevalence of active infection of Leptospira spp. in Rattus norvegicus from Grenada, West Indies, through polymerase chain reaction (PCR). Materials and Methods: One hundred and forty-nine rats were trapped, anesthetized and their kidneys collected aseptically. DNA was extracted from the kidney tissue of each rat. PCR was performed targeting LipL32 gene. Eighteen PCR-positive amplicons for LipL32 gene segment were purified and sent for direct sequencing to the sequencing facility of MCLAB (South San Francisco, USA). Results of sequencing were read and interpreted. The prevalence of Leptospira spp. in relation to sex and age was also recorded. Results: All amplified sequences were compared to the sequences present in GenBank using basic local alignment search tool (BLAST) from the online website National Center for Biotechnology Information, the results revealed that six samples had similarity to Leptospira interrogans strain 1399/2016 and eight samples had similarity with Leptospira borgpetersenii serovar Hardjo-bovis strain L49. Of 149 kidney samples, only 14 were positive for Leptospira spp. by PCR giving an incidence of 9.3%. There was no significant difference found in relation to sex and age. Conclusion: This is the first report confirming active infection of Leptospira spp. in Rattus norvegicus in Grenada using PCR. The presence of active infection in rats can be considered as high risk for humans. Further research to understand the epidemiology of leptospirosis in Grenada is suggested.
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Affiliation(s)
- Bhumika Sharma
- Department of Pathobiology, School of Veterinary Medicine, St. George's University, Grenada, West Indies
| | - Katelyn Thille
- Department of Pathobiology, School of Veterinary Medicine, St. George's University, Grenada, West Indies
| | - Nia Rametta
- Department of Pathobiology, School of Veterinary Medicine, St. George's University, Grenada, West Indies
| | - Ravindra Sharma
- Department of Pathobiology, School of Veterinary Medicine, St. George's University, Grenada, West Indies
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Agampodi S, Warnasekara J, Jayasundara D, Senawirathna I, Gamage C, Kularatne S, Siribaddana S, Maththias M, Vinetz J. Study protocol: characterising the clinical, epidemiological and aetiological aspects of leptospirosis in Sri Lanka: a hospital based clinico-epidemiological study. BMJ Open 2019; 9:e027850. [PMID: 31511281 PMCID: PMC6738675 DOI: 10.1136/bmjopen-2018-027850] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 07/11/2019] [Accepted: 08/19/2019] [Indexed: 01/20/2023] Open
Abstract
INTRODUCTION Sri Lanka has one of the highest incidences of leptospirosis worldwide. We hypothesised that different geographical locations and patient context will have a distinct molecular epidemiology of leptospirosis, based on microgeographical characteristics related to regiona-specific Leptospira predominance. Our objective is to characterise the clinical, epidemiological and molecular aspects of leptospirosis in Sri Lanka to understand disease progression, risk factors and obtain isolates of Leptospira. METHODS AND ANALYSIS We designed a multicentre prospective study in Sri Lanka to recruit undifferentiated febrile patients and conduct follow-ups during hospital stays. Patients will be recruited from outpatient departments and medical wards. This study will be conducted at two main sites (Anuradhapura and Peradeniya) and several additional sites (Awissawella, Ratnapura and Polonnaruwa). Blood and urine will be collected from patients on the day of admission to the ward or presentation to the outpatient department. Bedside inoculation of 2-4 drops of venous blood will be performed with Ellinghausen-McCullough-Johnson-Harris (EMJH) semisolid media supplemented with antibiotics. Regionally optimised microscopic agglutination test, culture and qPCR-evidence will be performed to confirm the presence of Leptospira in blood which in turn will confirm the presence of disease. Whole genome sequencing will be carried out for all isolates recovered from patients. Multilocus sequence typing (MLST) will be used for the genotyping of new isolates. Sri Lankan isolates will be identified using three published MLST schemes for Leptospira. ETHICS AND DISSEMINATION Ethical clearance for the study was obtained from Ethics Review Committees (ERC), Medicine and Allied Sciences (FMAS), Rajarata University of Sri Lanka (RUSL) and University of Peradeniya. All genomic data generated through this project will be available at GenBank. Anonymised data will be deposited at the ERC, FMAS, RUSL.
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Affiliation(s)
- Suneth Agampodi
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka
| | - Janith Warnasekara
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka
| | - Dinesha Jayasundara
- Department of Microbiology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka
| | - Indika Senawirathna
- Department of Biochemistry, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka
| | - Chandika Gamage
- Department of Microbiology, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
| | - Senanayake Kularatne
- Department of Medicine, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
| | - Sisira Siribaddana
- Department of Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka
| | | | - Joseph Vinetz
- Yale University School of Medicine, New Haven, Connecticut, USA
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Yang B, de Vries SG, Ahmed A, Visser BJ, Nagel IM, Spijker R, Grobusch MP, Hartskeerl RA, Goris MGA, Leeflang MMG. Nucleic acid and antigen detection tests for leptospirosis. Cochrane Database Syst Rev 2019; 8:CD011871. [PMID: 31425612 PMCID: PMC6699653 DOI: 10.1002/14651858.cd011871.pub2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Early diagnosis of leptospirosis may contribute to the effectiveness of antimicrobial therapy and early outbreak recognition. Nucleic acid and antigen detection tests have the potential for early diagnosis of leptospirosis. With this systematic review, we assessed the sensitivity and specificity of nucleic acid and antigen detection tests. OBJECTIVES To determine the diagnostic test accuracy of nucleic acid and antigen detection tests for the diagnosis of human symptomatic leptospirosis. SEARCH METHODS We searched electronic databases including MEDLINE, Embase, the Cochrane Library, and regional databases from inception to 6 July 2018. We did not apply restrictions to language or time of publication. SELECTION CRITERIA We included diagnostic cross-sectional studies and case-control studies of tests that made use of nucleic acid and antigen detection methods in people suspected of systemic leptospirosis. As reference standards, we considered the microscopic agglutination test alone (which detects antibodies against leptospirosis) or in a composite reference standard with culturing or other serological tests. Studies were excluded when the controls were healthy individuals or when there were insufficient data to calculate sensitivity and specificity. DATA COLLECTION AND ANALYSIS At least two review authors independently extracted data from each study. We used the revised Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2) to assess risk of bias. We calculated study-specific values for sensitivity and specificity with 95% confidence intervals (CI) and pooled the results in a meta-analysis when appropriate. We used the bivariate model for index tests with one positivity threshold, and we used the hierarchical summary receiver operating characteristic model for index tests with multiple positivity thresholds. As possible sources of heterogeneity, we explored: timing of index test, disease prevalence, blood sample type, primers or target genes, and the real-time polymerase chain reaction (PCR) visualisation method. These were added as covariates to the meta-regression models. MAIN RESULTS We included 41 studies evaluating nine index tests (conventional PCR (in short: PCR), real-time PCR, nested PCR, PCR performed twice, loop-mediated isothermal amplification, enzyme-linked immunosorbent assay (ELISA), dot-ELISA, immunochromatography-based lateral flow assay, and dipstick assay) with 5981 participants (1834 with and 4147 without leptospirosis). Methodological quality criteria were often not reported, and the risk of bias of the reference standard was generally considered high. The applicability of findings was limited by the frequent use of frozen samples. We conducted meta-analyses for the PCR and the real-time PCR on blood products.The pooled sensitivity of the PCR was 70% (95% CI 37% to 90%) and the pooled specificity was 95% (95% CI 75% to 99%). When studies with a high risk of bias in the reference standard domain were excluded, the pooled sensitivity was 87% (95% CI 44% to 98%) and the pooled specificity was 97% (95% CI 60% to 100%). For the real-time PCR, we estimated a summary receiver operating characteristic curve. To illustrate, a point on the curve with 85% specificity had a sensitivity of 49% (95% CI 30% to 68%). Likewise, at 90% specificity, sensitivity was 40% (95% CI 24% to 59%) and at 95% specificity, sensitivity was 29% (95% CI 15% to 49%). The median specificity of real-time PCR on blood products was 92%. We did not formally compare the diagnostic test accuracy of PCR and real-time PCR, as direct comparison studies were lacking. Three of 15 studies analysing PCR on blood products reported the timing of sample collection in the studies included in the meta-analyses (range 1 to 7 days postonset of symptoms), and nine out of 16 studies analysing real-time PCR on blood products (range 1 to 19 days postonset of symptoms). In PCR studies, specificity was lower in settings with high leptospirosis prevalence. Other investigations of heterogeneity did not identify statistically significant associations. Two studies suggested that PCR and real-time PCR may be more sensitive on blood samples collected early in the disease stage. Results of other index tests were described narratively. AUTHORS' CONCLUSIONS The validity of review findings are limited and should be interpreted with caution. There is a substantial between-study variability in the accuracy of PCR and real-time PCR, as well as a substantial variability in the prevalence of leptospirosis. Consequently, the position of PCR and real-time PCR in the clinical pathway depends on regional considerations such as disease prevalence, factors that are likely to influence accuracy, and downstream consequences of test results. There is insufficient evidence to conclude which of the nucleic acid and antigen detection tests is the most accurate. There is preliminary evidence that PCR and real-time PCR are more sensitive on blood samples collected early in the disease stage, but this needs to be confirmed in future studies.
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Affiliation(s)
- Bada Yang
- Amsterdam University Medical Centers, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsMeibergdreef 9AmsterdamNoord‐HollandNetherlands1105 AZ
| | - Sophia G de Vries
- Amsterdam University Medical Centers, location AMC, University of AmsterdamCenter of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal MedicineMeibergdreef 9AmsterdamNoord‐HollandNetherlands1105 AZ
| | - Ahmed Ahmed
- Academic Medical Centre (AMC), University of AmsterdamMedical Microbiology, OIE and National Collaborating Centre for Reference and Research on LeptospirosisMeibergdreef 39AmsterdamNetherlands1105 AZ
| | - Benjamin J Visser
- Amsterdam University Medical Centers, location AMC, University of AmsterdamCenter of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal MedicineMeibergdreef 9AmsterdamNoord‐HollandNetherlands1105 AZ
| | - Ingeborg M Nagel
- Amsterdam UMC, University of AmsterdamMedical LibraryMeibergdreef 9AmsterdamNetherlands1105 AZ
| | - René Spijker
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht UniversityCochrane NetherlandsRoom Str. 6.127P.O. Box 85500UtrechtNetherlands3508 GA
- Amsterdam UMC, University of Amsterdam, Amsterdam Public HealthMedical LibraryMeibergdreef 9AmsterdamNetherlands
| | - Martin P Grobusch
- Amsterdam University Medical Centers, location AMC, University of AmsterdamCenter of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal MedicineMeibergdreef 9AmsterdamNoord‐HollandNetherlands1105 AZ
| | - Rudy A Hartskeerl
- OIE and National Collaborating Centre for Reference and Research on LeptospirosisMeibergdreef 39AmsterdamNetherlands1105 AZ
| | - Marga GA Goris
- Academic Medical Centre (AMC), University of AmsterdamMedical Microbiology, OIE and National Collaborating Centre for Reference and Research on LeptospirosisMeibergdreef 39AmsterdamNetherlands1105 AZ
| | - Mariska MG Leeflang
- Amsterdam University Medical Centers, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsMeibergdreef 9AmsterdamNoord‐HollandNetherlands1105 AZ
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Karan L, Makenov M, Kolyasnikova N, Stukolova O, Toporkova M, Olenkova O. Dynamics of Spirochetemia and Early PCR Detection of Borrelia miyamotoi. Emerg Infect Dis 2019; 24:860-867. [PMID: 29664394 PMCID: PMC5938775 DOI: 10.3201/eid2405.170829] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We investigated whether Borrelia miyamotoi disease can be detected in its early stage by using PCR for borrelial 16S rRNA, which molecule (DNA or RNA) is the best choice for this test, and whether spirochetes are present in blood during the acute phase of B. miyamotoi disease. A total of 473 patients with a suspected tickborne infection in Yekaterinburg, Russia, in 2009, 2010, and 2015 were enrolled in this study. Blood samples were analyzed by using quantitative PCR or ELISA, and a diagnosis of borreliosis was confirmed for 310 patients. For patients with erythema migrans, 5 (3%) of 167 were positive for B. miyamotoi by PCR; for patients without erythema migrans, 65 (45%) of 143 were positive for B. miyamotoi by PCR. The median concentration for RNA was 3.8 times that for DNA. Median time for detection of B. miyamotoi in blood was 4 days.
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Detección molecular de leptospiras patógenas en roedores sinantrópicos y silvestres capturados en Yucatán, México. BIOMEDICA 2018; 38:51-58. [DOI: 10.7705/biomedica.v38i3.3938] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/28/2017] [Indexed: 11/21/2022]
Abstract
Introducción. La leptospirosis es una enfermedad zoonótica endémica en México, ocasionada por la bacteria del género Leptospira, la cual constituye un problema de salud pública y veterinaria. Los roedores son los reservorios más relevantes de Leptospira spp., debido a que la bacteria se establece y se reproduce en su tejido renal y es excretada por la orina.Objetivo. Identificar la presencia de Leptospira spp. en tejido renal de roedores capturados en Yucatán, México.Materiales y métodos. Se capturaron roedores sinantrópicos y silvestres en el municipio rural de Cenotillo, Yucatán, México. Se tomó un riñón de cada roedor y se extrajo el ADN total. La identificación de Leptospira spp. se hizo mediante la detección de dos fragmentos del gen 16S rRNA con una reacción en cadena de la polimerasa (PCR) de punto final. Los productos positivos se secuenciaron y se analizaron con herramientas de alineamiento.Resultados. Se capturaron 92 roedores pertenecientes a siete especies distintas. La PCR arrojó 5,4 % (5/92) de positividad global. El análisis del alineamiento de los aislamientos de los roedores infectados demostró 100 % de cobertura e identidad con la especie Leptospira interrogans. Esta es la primera evidencia molecular de la circulación de Leptospira spp. en Heteromys gaumeri capturados en Yucatán, México.Conclusión. Se evidenció que los roedores de Yucatán, México, son reservorios de Leptospira spp. y participan en el ciclo de infección de la leptospirosis en la región.
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Diagnosis of Human Leptospirosis in a Clinical Setting: Real-Time PCR High Resolution Melting Analysis for Detection of Leptospira at the Onset of Disease. Sci Rep 2018; 8:9213. [PMID: 29907838 PMCID: PMC6003994 DOI: 10.1038/s41598-018-27555-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 06/03/2018] [Indexed: 12/12/2022] Open
Abstract
Currently, direct detection of Leptospira can be done in clinical laboratories by conventional and by real-time PCR (qRT-PCR). We tested a biobank of paired samples of serum and urine from the same patient (202 patients) presenting at the hospital in an area endemic for leptospirosis using qRT-PCR followed by high resolution melting (HRM) analysis. The results were compared with those obtained by conventional nested PCR and with the serologic gold standard microscopic agglutination test (MAT). Differences were resolved by sequencing. qRT-PCR-HRM was positive for 46 of the 202 patients (22.7%, accuracy 100%) which is consistent with known prevalence of leptospirosis in the Azores. MAT results were positive for 3 of the 46 patients (6.5%). Analysis of paired samples allowed us to identify the illness point at which patients presented at the hospital: onset, dissemination or excretion. The melting curve analysis of Leptospira species revealed that 60.9% (28/46) of patients were infected with L. interrogans and 39.1% (18/46) were infected with L. borgpetersenii, both endemic to the Azores. We validated the use of qRT-PCR-HRM for diagnosis of leptospirosis and for identification of the Leptospira species at the earliest onset of infection in a clinical setting, in less than 2 hours.
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Abstract
PURPOSE OF REVIEW The definitive diagnosis of leptospirosis, which results from infection with spirochetes of the genus Leptospira, currently relies on the use of culture, serological testing (microscopic agglutination testing), and molecular detection. The purpose of this review is to describe new molecular diagnostics for Leptospira and discuss advancements in the use of available methods. RECENT FINDINGS Efforts have been focused on improving the clinical sensitivity of Leptospira detection using molecular methods. In this review, we describe a reoptimized pathogenic species-specific real-time PCR (targeting lipL32) that has demonstrated improved sensitivity, findings by two groups that real-time reverse-transcription PCR assays targeting the 16S rrs gene can improve detection, and two new loop-mediated amplification techniques. Quantitation of leptospiremia, detection in different specimen types, and the complementary roles played by molecular detection and microscopic agglutination testing will be discussed. Finally, a protocol for Leptospira strain subtyping using variable number tandem repeat targets and high-resolution melting will be described. SUMMARY Molecular diagnostics have an established role for the diagnosis of leptospirosis and provide an actionable diagnosis in the acute setting. The use of real-time reverse-transcription PCR for testing serum/plasma and cerebrospinal fluid, when available, may improve the detection of Leptospira without decreasing clinical specificity.
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Thirumalairaj J, Sivasankari K, Natarajaseenivasan K, Balagurunathan R. Potential anti-leptospiral compound, leptomycin B from marine Streptomyces indiaensis MSU5: taxonomy, fermentation, compound isolation, in vitro and in vivo efficacy. World J Microbiol Biotechnol 2017; 33:187. [PMID: 28956236 DOI: 10.1007/s11274-017-2351-1] [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: 04/07/2017] [Accepted: 09/21/2017] [Indexed: 11/30/2022]
Abstract
Leptospirosis is a worldwide reemerging tropical zoonotic disease with symptoms of mild febrile illness to more severe multiple organ failure caused by pathogenic leptospiral strains. There was no effective antibiotic for treating leptospirosis. Here, the anti-leptospiral potential of marine actinobacterial compound from Streptomyces indiaensis MSU5 isolated from Manakudy marine sediment, Tamil Nadu, India was evaluated. The potential actinobacterial strain was identified by phenotypic, cell wall, 16S rRNA gene sequence and phylogenetic analysis. In vitro anti-leptospiral activity of the actinobacterial compound was determined using broth microdilution test against various serovars of Leptospira with different concentration ranging from 15.625 to 500 µg/ml. Mass production of anti-leptospiral compound was carried out in agar surface fermentation with optimized condition and purified by preparative TLC. The purified fraction of anti-leptospiral compound named as MSU5-1, and it was confirmed by microdilution test. Remarkably, the compound MSU5-1 showed minimum inhibitory concentration of 62.5 µg/ml and minimum bactericidal concentration of 125 µg/ml against human pathogenic leptospiral isolate strain N2. The structural elucidation of purified compound was carried out using UV, FT-IR, NMR and LC-MS analysis. The compound MSU5-1 was tentatively identified as leptomycin B (C33H48O6) with molecular weight 541.1 g/mol. Anti-leptospiral activity of compound MSU5-1 exhibited 80% of survival rate in mice model, further it was confirmed by Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) analysis. From the available literature, this is the first report on the marine actinobacterial compound for evaluating both in vitro and in vivo leptospiricidal activity.
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Affiliation(s)
- Jeyaraman Thirumalairaj
- Actinobacterial Research Laboratory, Department of Microbiology, Periyar University, Salem, Tamil Nadu, 636 011, India
| | - Karikalacholan Sivasankari
- Medical Microbiology Laboratory, Department of Microbiology, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620 024, India
| | - Kalimuthusamy Natarajaseenivasan
- Medical Microbiology Laboratory, Department of Microbiology, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620 024, India
| | - Ramasamy Balagurunathan
- Actinobacterial Research Laboratory, Department of Microbiology, Periyar University, Salem, Tamil Nadu, 636 011, India.
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Robinson ML, Manabe YC. Reducing Uncertainty for Acute Febrile Illness in Resource-Limited Settings: The Current Diagnostic Landscape. Am J Trop Med Hyg 2017; 96:1285-1295. [PMID: 28719277 DOI: 10.4269/ajtmh.16-0667] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
AbstractDiagnosing the cause of acute febrile illness in resource-limited settings is important-to give the correct antimicrobials to patients who need them, to prevent unnecessary antimicrobial use, to detect emerging infectious diseases early, and to guide vaccine deployment. A variety of approaches are yielding more rapid and accurate tests that can detect more pathogens in a wider variety of settings. After decades of slow progress in diagnostics for acute febrile illness in resource-limited settings, a wave of converging advancements will enable clinicians in resource-limited settings to reduce uncertainty for the diagnosis of acute febrile illness.
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Affiliation(s)
- Matthew L Robinson
- Division of Infectious Disease, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Yukari C Manabe
- Division of Infectious Disease, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
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Guernier V, Richard V, Nhan T, Rouault E, Tessier A, Musso D. Leptospira diversity in animals and humans in Tahiti, French Polynesia. PLoS Negl Trop Dis 2017; 11:e0005676. [PMID: 28658269 PMCID: PMC5507467 DOI: 10.1371/journal.pntd.0005676] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 07/11/2017] [Accepted: 06/02/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Leptospirosis is a highly endemic bacterial zoonosis in French Polynesia (FP). Nevertheless, data on the epidemiology of leptospirosis in FP are scarce. We conducted molecular studies on Leptospira isolated from humans and the potential main animal reservoirs in order to identify the most likely sources for human infection. METHODOLOGY/PRINCIPAL FINDINGS Wild rats (n = 113), farm pigs (n = 181) and domestic dogs (n = 4) were screened for Leptospira infection in Tahiti, the most populated island in FP. Positive samples were genotyped and compared to Leptospira isolated from human cases throughout FP (n = 51), using secY, 16S and LipL32 sequencing, and MLST analysis. Leptospira DNA was detected in 20.4% of rats and 26.5% of pigs. We identified two Leptospira species and three sequence types (STs) in animals and humans: Leptospira interrogans ST140 in pigs only and L. interrogans ST17 and Leptospira borgpetersenii ST149 in humans and rats. Overall, L. interrogans was the dominant species and grouped into four clades: one clade including a human case only, two clades including human cases and dogs, and one clade including human cases and rats. All except one pig sample showed a unique L. interrogans (secY) genotype distinct from those isolated from humans, rats and dogs. Moreover, LipL32 sequencing allowed the detection of an additional Leptospira genotype in pigs, clearly distinct from the previous ones. CONCLUSIONS/SIGNIFICANCE Our data confirm rats as a major potential source for human leptospirosis in FP. By contrast to what was expected, farm pigs did not seem to be a major reservoir for the Leptospira genotypes identified in human patients. Thus, further investigations will be required to determine their significance in leptospirosis transmission in FP.
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Affiliation(s)
- Vanina Guernier
- Institut Louis Malardé, Papeete, Tahiti, French Polynesia
- Australian Institute for Tropical Health and Medicine (AITHM), JCU, Townsville, Australia
| | - Vaea Richard
- Institut Louis Malardé, Papeete, Tahiti, French Polynesia
| | - Tuxuan Nhan
- Institut Louis Malardé, Papeete, Tahiti, French Polynesia
| | - Eline Rouault
- Institut Louis Malardé, Papeete, Tahiti, French Polynesia
| | - Anita Tessier
- Institut Louis Malardé, Papeete, Tahiti, French Polynesia
| | - Didier Musso
- Institut Louis Malardé, Papeete, Tahiti, French Polynesia
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Ilangovan A, Sakthivel P, Sivasankari K, Mercy CSA, Natarajaseenivasan K. Discovery of 6,7-dihydro-3H-pyrano[4,3-c]isoxazol-3-ones as a new class of pathogen specific anti-leptospiral agents. Eur J Med Chem 2017; 125:29-40. [PMID: 27643561 DOI: 10.1016/j.ejmech.2016.09.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/06/2016] [Accepted: 09/07/2016] [Indexed: 11/30/2022]
Abstract
A simple and efficient method for the synthesis of a series of 6,7-dihydro-3H-pyrano[4,3-c]isoxazol-3-one derivatives starting from 5-carboalkoxy-2,3-dihydropyranone (5-CDHPs) has been developed. Pyranoisoxazolones 10a-j, dihydronaphthopyran-4-one (DHNPs) class of natural product 12b and 12c and its analogues 12a and 13a-c were preliminarily screened against pathogenic leptospiral serovar Autumnalis strain N2 at various concentrations. Six pyranoisoxazolones, 10b, 10d, 10f, 10g, 10i and 10j which displayed very good anti-leptospiral activity was taken for secondary screening against twelve strains of pathogenic and one non-pathogenic leptospiral serovars. While all the compounds displayed significant anti-leptospiral activity against the pathogenic serovars at MIC of 62.5-500 μg/mL. Compounds 10d, 10g and 10j did not show any significant effect on non-pathogenic serovar. Inhibition of leptospires at a significant level by pyranoisoxazolone 10g was confirmed using RT-qPCR assay. In vivo treatment of BALB/c mice with compound 10g revealed that, it has 95% survivability against the pathogenic strain Canicola and also showed inhibition of renal colonization of leptospires. Compound 10g was found to show cytotoxicity against THP-1 cells only at higher concentration (≥75 μg/mL). Effective binding of compound 10g with leptospiral outer membrane protein LipL32 observed via in silico molecular docking provided a suitable explanation for pathogen specificity of compound 10g. Antibiotics acting against leptospirosis in human are very few. The results obtained from in vitro, in vivo and in silico study reveals that 6,7-dihydro-3H-pyrano[4,3-c]isoxazol-3-ones class of compounds are lead molecules for further development as pathogen specific anti-leptospiral agents.
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Affiliation(s)
- Andivelu Ilangovan
- School of Chemistry, Bharathidasan University, Tiruchirappalli, 620 024, Tamil Nadu, India.
| | - Palaniappan Sakthivel
- School of Chemistry, Bharathidasan University, Tiruchirappalli, 620 024, Tamil Nadu, India
| | - Karikalacholan Sivasankari
- Medical Microbiology Laboratory, Department of Microbiology, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620024, India
| | - Charles Solomon Akino Mercy
- Medical Microbiology Laboratory, Department of Microbiology, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620024, India
| | - Kalimuthusamy Natarajaseenivasan
- Medical Microbiology Laboratory, Department of Microbiology, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620024, India
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Chiani Y, Jacob P, Varni V, Landolt N, Schmeling MF, Pujato N, Caimi K, Vanasco B. Isolation and clinical sample typing of human leptospirosis cases in Argentina. INFECTION GENETICS AND EVOLUTION 2016; 37:245-51. [DOI: 10.1016/j.meegid.2015.11.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/26/2015] [Accepted: 11/29/2015] [Indexed: 11/29/2022]
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