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1.
Transbound Emerg Dis ; 68(6): 3207-3216, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34387927

RESUMO

Leptospirosis is a zoonotic neglected disease of worldwide public health concern. Leptospira species can infect a wide range of wild and domestic mammals and lead to a spectrum of disease, including severe and fatal forms. Herein, we report for the first time a fatal Leptospira interrogans infection in a free-ranging nonhuman primate (NHP), a black-tufted marmoset. Icterus, pulmonary haemorrhage, interstitial nephritis, and hepatocellular dissociation were the main findings raising the suspicion of leptospirosis. Diagnostic confirmation was based on specific immunohistochemical and PCR assays for Leptospira species. Immunolocalization of leptospiral antigens and identification of pathogenic species (L. interrogans species) were important for better understanding the pathogenesis of the disease. One Health-related implications of free-ranging NHPs in anthropized areas and transmission dynamics of human and animal leptospirosis are discussed.


Assuntos
Leptospira interrogans , Leptospira , Leptospirose , Saúde Única , Animais , Brasil/epidemiologia , Callithrix , Leptospirose/epidemiologia , Leptospirose/veterinária
2.
Front Cell Infect Microbiol ; 11: 677999, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34249775

RESUMO

The exact global impact of leptospirosis is unknown due to inadequate surveillance systems in place in most low-income countries. In this study, we analyzed the differences in mouse inflammatory signatures involved in pathogenic versus non-pathogenic Leptospira recognition at 24h and 72h post infection. Injection of C3H-HeJ mice with non-pathogenic L. biflexa increased circulation of a few chemokines (5/21, 24%) without secretion of cytokines in blood that resulted in engagement of resident macrophages, dendritic cells, neutrophils and NK cells without engagement of T cells. In contrast, pathogenic L. interrogans induced circulation of a much higher panel of chemokines (18/21, 86%) and pro- and anti-inflammatory cytokines (11/19, 58%) in blood with a resulting signaling cascade leading to engagement of macrophages, dendritic cells, monocytes, NK cells and T cells without engagement of neutrophils. Although neutrophils do not appear to be engaged, a considerable number of chemokines that recruit other granulocytes such as eosinophils and basophils were also increased at 72h post infection with L. interrogans. Overall, the data suggest that prevention of dissemination of L. biflexa is associated with an early engagement of the innate immune response characterized by upregulation of a few chemokines that results in an efficacious phagocytic response without an overwhelming increase of pro-inflammatory cytokines. However, when macrophages fail to clear a pathogenic serovar such as L. interrogans, the adaptive response (T cells) is engaged to help out, but the resulting chemo-cytokine storm mediates a robust but non-resolving inflammatory response to pathogenic Leptospira that results in dissemination, kidney colonization, pathology and disease.


Assuntos
Leptospira interrogans , Leptospira , Leptospirose , Animais , Quimiocinas , Imunidade Inata , Camundongos , Camundongos Endogâmicos C3H
3.
Front Cell Infect Microbiol ; 11: 708739, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34277477

RESUMO

Leptospirosis is a neglected zoonosis, caused by pathogenic spirochetes bacteria of the genus Leptospira. The molecular mechanisms of leptospirosis infection are complex, and it is becoming clear that leptospires express several functionally redundant proteins to invade, disseminate, and escape the host's immune response. Here, we describe a novel leptospiral protein encoded by the gene LIC13086 as an outer membrane protein. The recombinant protein LIC13086 can interact with the extracellular matrix component laminin and bind plasminogen, thus possibly participating during the adhesion process and dissemination. Also, by interacting with fibrinogen and plasma fibronectin, the protein LIC13086 probably has an inhibitory effect in the fibrin clot formation during the infection process. The newly characterized protein can also bind molecules of the complement system and the regulator C4BP and, thus, might have a role in the evasion mechanism of Leptospira. Taken together, our results suggest that the protein LIC13086 may have a multifunctional role in leptospiral pathogenesis, participating in host invasion, dissemination, and immune evasion processes.


Assuntos
Leptospira interrogans , Leptospira , Leptospirose , Fibrina/metabolismo , Humanos , Leptospira interrogans/genética , Leptospira interrogans/metabolismo , Plasminogênio/metabolismo , Ligação Proteica
4.
J Med Case Rep ; 15(1): 358, 2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34294111

RESUMO

BACKGROUND: Leptospirosis is an underdiagnosed bacterial infection with nonspecific symptoms, hence, a diagnostic challenge. Identifying a case of leptospirosis in Switzerland is uncommon. Although kidney complications are frequent in severe forms, including tubular dysfunction, observing this complication is rare in our country. We report the case of a patient with leptospirosis and kidney dysfunction, which was notable for proximal tubulopathy. This case report describes the diagnosis and management of this patient's tubular dysfunction. CASE PRESENTATION: A 34-year-old Caucasian male known for alcohol and drug abuse presented to our emergency department suffering from severe pain in the lower limbs, jaundice, and fever with flu-like symptoms. Physical examination was not contributory. Blood tests showed cytopenia, elevated inflammatory markers, acute kidney injury, and altered liver function tests with predominant cholestasis. Urinalysis showed proteinuria and significant glycosuria without concomitant hyperglycemia. Leptospirosis was suspected and confirmed by both positive serum polymerase chain reaction and elevated immunoglobulin M for Leptospira interrogans. The patient was treated with intravenous amoxicillin-clavulanate and doxycycline for 7 days. After antibiotic treatment, symptoms disappeared, and kidney dysfunction completely resolved. CONCLUSION: Our case focuses on the description of leptospirosis-related acute kidney injury with proximal tubular dysfunction, which is a rare finding in Switzerland.


Assuntos
Injúria Renal Aguda , Síndrome de Fanconi , Leptospira interrogans , Leptospirose , Injúria Renal Aguda/diagnóstico , Injúria Renal Aguda/etiologia , Adulto , Síndrome de Fanconi/complicações , Síndrome de Fanconi/diagnóstico , Síndrome de Fanconi/tratamento farmacológico , Humanos , Leptospirose/complicações , Leptospirose/diagnóstico , Leptospirose/tratamento farmacológico , Masculino , Suíça
5.
BMC Vet Res ; 17(1): 221, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34154583

RESUMO

BACKGROUND: Leptospirosis is an endemic zoonosis in Brazil, with a great impact on human and animal health. Although dogs are frequently infected by pathogenic Leptospira, the current epidemiological understanding of canine leptospirosis is mainly based on serological tests that predict the infecting serogroup/serovar. Thus, the present study aimed at identifying the causative agent for severe cases of canine leptospirosis in a highly endemic area through the isolation and characterization of the isolated strains. RESULTS: Urine, serum and blood samples were collected from 31 dogs with suspected acute leptospirosis treated at the Veterinary Hospital Service of Santo Amaro University between 2018 and 2019. Acute infection was confirmed in 17 dogs (54.8%) by the associated use of Polymerase Chain Reaction (PCR), Microscopic Agglutination (MAT) and bacteriological culture. Eleven dogs (35.5%) had titers ≥800, with the most frequent serogroups being Autumnalis and Icterohaemorrhagiae (n = 4 each) and Canicola (n = 2). Leptospires were recovered from four dogs, and Multilocus Sequence Analysis (MLSA) revealed infection caused by L. interrogans, which were further characterized as serogroups Canicola (n = 1) and Icterohaemorrhagiae (n = 3). CONCLUSION: The identity of the isolates and serological pattern of MAT suggest that dogs are highly exposed to the serogroup Icterohaemorrhagiae and Canicola, also indicating possible circulation of serogroups not yet isolated in Brazil, notably serogroup Autumnalis. Our findings also reinforce the usefulness of using multiple diagnostic approaches to confirm acute canine leptospirosis.


Assuntos
Doenças do Cão/diagnóstico , Leptospira/isolamento & purificação , Leptospirose/veterinária , Testes de Aglutinação/veterinária , Animais , Brasil , Doenças do Cão/microbiologia , Cães , Leptospira/classificação , Leptospira/genética , Leptospira/imunologia , Leptospira interrogans/isolamento & purificação , Leptospirose/diagnóstico , Leptospirose/microbiologia , Tipagem de Sequências Multilocus/veterinária , Reação em Cadeia da Polimerase/veterinária , Sorogrupo
6.
PLoS Negl Trop Dis ; 15(6): e0009410, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34143778

RESUMO

BACKGROUND: Leptospirosis has been described as a biphasic disease consisting of hematogenous dissemination to major organs in the acute phase and asymptomatic renal colonization in the chronic phase. Several observational studies have suggested an association between leptospirosis and chronic kidney disease (CKD). We investigated the dynamics of leptospires and histopathological changes in the kidney to understand the relationship between them, and also investigated the extent of renal dysfunction in the acute and chronic phases of leptospirosis using a hamster model. FINDINGS: Hamsters (n = 68) were subcutaneously infected with 1 × 104 cells of the Leptospira interrogans serovar Manilae strain UP-MMC-SM. A total of 53 infected hamsters developed fatal acute leptospirosis, and the remaining 15 hamsters recovered from the acute phase, 13 of which showed Leptospira colonization in the kidneys in the chronic phase. Five asymptomatic hamsters also had renal colonization in the chronic phase. Immunofluorescence staining showed that leptospires were locally distributed in the renal interstitium in the early acute phase and then spread continuously into the surrounding interstitium. The kidneys of the surviving hamsters in the chronic phase showed patchy lesions of atrophic tubules, a finding of chronic tubulointerstitial nephritis, which were substantially consistent with the distribution of leptospires in the renal interstitium. The degree of atrophic tubules in kidney sections correlated statistically with the serum creatinine level in the chronic phase (rs = 0.78, p = 0.01). CONCLUSION: Subcutaneous infection with pathogenic leptospires could cause acute death or chronic leptospirosis in hamsters after surviving the acute phase. We suggest that the renal distribution of leptospires during the acute phase probably affected the extent of tubular atrophy, leading to CKD.


Assuntos
Rim/microbiologia , Leptospira interrogans , Leptospirose/microbiologia , Insuficiência Renal Crônica/microbiologia , Doença Aguda , Animais , Anticorpos Antibacterianos/sangue , Doença Crônica , Creatinina/sangue , Cricetinae , Leptospirose/complicações , Masculino , Mesocricetus
7.
Comp Immunol Microbiol Infect Dis ; 77: 101664, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34091280

RESUMO

Leptospirosis, a zoonotic disease with worldwide distribution, is caused by spirochetes of the genus Leptospira. In dogs, this disease is frequently misdiagnosed. Few studies have attempted to associate the detection of Leptospira spp. infection with clinicopathological and renal histopathological findings using a multidisciplinary approach. The present study isolated and characterized Leptospira spp. obtained from naturally infected dogs and described relevant clinical and histopathological findings. Blood and urine were collected from 57 dogs with clinical symptomatology suggestive of leptospirosis; 38 cases were confirmed by PCR in urine or by culture or microscopic agglutination testing (titers ≥800). A total of 12 strains of pathogenic Leptospira were isolated from the studied dogs (seven in blood, four in urine and one in both blood and urine samples). All isolates were characterized as Leptospira interrogans serogroup Icterohaemorrhagiae. Of the confirmed cases, almost one-third of the animals had been vaccinated. Our analysis of laboratory testing revealed that azotemia and proteinuria were statistically significant predictors of infection. The main histopathological findings seen in kidney tissues were necrosis, degeneration, tubular regeneration, mononuclear inflammatory infiltrate and congestion. A multidisciplinary approach involving clinicopathological and histopathological characterization of renal involvement can aid in the identification of acute leptospirosis infection.


Assuntos
Doenças do Cão , Leptospira interrogans , Leptospira , Leptospirose , Animais , Doenças do Cão/diagnóstico , Cães , Leptospira interrogans/genética , Leptospirose/diagnóstico , Leptospirose/veterinária , Estudos Prospectivos , Sorogrupo
8.
Int J Biol Macromol ; 182: 785-795, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33862076

RESUMO

In Leptospira interrogans serovar Copenhageni, the CRISPR-Cas I-B locus possesses a CRISPR array between the two independent cas-operons. Using the reverse transcription-PCR and the in vitro endoribonuclease assay with Cas6 of Leptospira (LinCas6), we account that the CRISPR is transcriptionally active and is conventionally processed. The LinCas6 specifically excises at one site within the synthetic cognate repeat RNA or the repeats of precursor-CRISPR RNA (pre-crRNA) in the sense direction. In contrast, the antisense repeat RNA is cleaved at multiple sites. LinCas6 functions as a single turnover endoribonuclease on its repeat RNA substrate, where substitution of one of predicted active site residues (His38) resulted in reduced activity. This study highlights the comprehensive understanding of the Leptospira CRISPR array transcription and its processing by LinCas6 that is central to RNA-mediated CRISPR-Cas I-B adaptive immunity.


Assuntos
Proteínas de Bactérias/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Endorribonucleases/metabolismo , Leptospira interrogans/genética , RNA Mensageiro/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Domínio Catalítico , Endorribonucleases/química , Endorribonucleases/genética , Leptospira interrogans/metabolismo , RNA Mensageiro/genética
9.
Microb Pathog ; 155: 104895, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33878396

RESUMO

To adapt into the host system from moist environment Leptospira alter their gene expression by inducing differential expression of the genes encoding virulence factors. Knowledge about the molecular pathogenesis and virulent evolution remains limited to Leptospira. The pathogenic organism sense the environmental changes mainly through their outer membrane proteins that in-turn activates the signal transduction pathways to overcome the stress to adaptation into host system and to evade immunity. In this present study, we analyzed the expression profile of virulence associated OMPs regulated under various stress conditions like temperatures, iron deprivation, osmotic stress and low to high passages in single scale and characterized the selected proteins by MALDI-TOF MS/MS and their role in pathogenesis were predicted by implying in-silico analysis. To identify differential expression profile, the extracted OMPs were resolved through 2DE and compared the OMPs profile from various in-vivo like conditions in single scale and found 61 upregulated OMPs and three potentially virulent proteins were earmarked for their significance in pathogenesis. Further, the in-silico analysis revealed that differentially expressed protein has MHC-I T-cell, MHC-II T-cell and B-cell epitopes which showed an interaction between human TLR2 proteins confirmed by CABS docking and interaction network unveiled to understand the leptospiral virulent mechanism and host adaptation.


Assuntos
Leptospira interrogans , Leptospira , Leptospirose , Proteínas da Membrana Bacteriana Externa/genética , Humanos , Peptídeos , Espectrometria de Massas em Tandem , Fatores de Virulência
10.
Sensors (Basel) ; 21(7)2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33917354

RESUMO

Leptospirosis is an underestimated tropical disease caused by the pathogenic Leptospira species and responsible for several serious health problems. Here, we aimed to develop an ultrasensitive DNA biosensor for the rapid and on-site detection of the Loa22 gene of Leptospira interrogans using a gold nanoparticle-carbon nanofiber composite (AuN/CNF)-based screen-printed electrode. Cyclic voltammetry and electrochemical impedance were performed for electrochemical analysis. The sensitivity of the sensor was 5431.74 µA/cm2/ng with a LOD (detection limit) of 0.0077 ng/µL using cyclic voltammetry. The developed DNA biosensor was found highly specific to the Loa22 gene of L. interrogans, with a storage stability at 4 °C for 180 days and a 6% loss of the initial response. This DNA-based sensor only takes 30 min for rapid detection of the pathogen, with a higher specificity and sensitivity. The promising results obtained suggest the application of the developed sensor as a point of care device for the diagnosis of leptospirosis.


Assuntos
Leptospira interrogans , Leptospirose , Nanopartículas Metálicas , Ouro , Humanos , Leptospira interrogans/genética , Leptospirose/diagnóstico , Proteínas de Membrana
11.
J Zoo Wildl Med ; 52(1): 38-48, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33827159

RESUMO

The spirochete bacterium Leptospira interrogans serovar Pomona is enzootic to California sea lions (CSL; Zalophus californianus) and causes periodic epizootics. Leptospirosis in CSL is associated with a high fatality rate in rehabilitation. Evidence-based tools for estimating prognosis and guiding early euthanasia of animals with a low probability of survival are critical to reducing the severity and duration of animal suffering. Classification and regression tree (CART) analysis of clinical data was used to predict survival outcomes of CSL with leptospirosis in rehabilitation. Classification tree outputs are binary decision trees that can be readily interpreted and applied by a clinician. Models were trained using data from cases treated from 2017 to 2018 at The Marine Mammal Center in Sausalito, CA, and tested against data from cases treated from 2010 to 2012. Two separate classification tree analyses were performed, one including and one excluding data from euthanized animals. When data from natural deaths and euthanasias were included in model-building, the best classification tree predicted outcomes correctly for 84.7% of cases based on four variables: appetite over the first 3 days in care, and blood urea nitrogen (BUN), creatinine, and sodium at admission. When only natural deaths were included, the best model predicted outcomes correctly for 87.6% of cases based on BUN and creatinine at admission. This study illustrates that CART analysis can be successfully applied to wildlife in rehabilitation to establish evidence-based euthanasia criteria with the goal of minimizing animal suffering. In the context of a large epizootic that challenges the limits of a facility's capacity for care, the models can assist in maximizing allocation of resources to those animals with the highest predicted probability of survival. This technique may be a useful tool for other diseases seen in wildlife rehabilitation.


Assuntos
Leptospirose/veterinária , Leões-Marinhos/microbiologia , Envelhecimento , Animais , Animais Selvagens , Surtos de Doenças , Rim/microbiologia , Leptospira interrogans/isolamento & purificação , Leptospirose/microbiologia , Leptospirose/patologia , Leptospirose/urina , Prognóstico , Análise de Regressão
12.
Trop Anim Health Prod ; 53(2): 194, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33666800

RESUMO

At present, little is known regarding the prevalence of buffalo leptospirosis worldwide, especially with respect to which Leptospira strains may infect this animal species. Furthermore, most investigations into this disease in buffaloes have only been performed with serological studies. In Brazil, particularly in the Amazon, buffalo production is growing and is just as important as cattle production, although few studies have been performed on buffalo compared to cattle. Thus, the aim of this study was to isolate and characterise Leptospira strains from river buffaloes raised in the Brazilian Amazon region. We collected 109 kidney samples from slaughtered buffaloes raised in the Amazon Delta region of Brazil. The samples were analysed by bacteriological culture for the isolation of leptospires, and the obtained isolates were serologically and molecularly characterised by microscopic agglutination test (MAT), DNA sequencing and multiple locus variable-number tandem repeat analysis (MLVA). Five isolates were obtained, and in serogrouping analyses, these isolates were only reactive for the Pomona serogroup, with an observed titre of 25,600. The DNA sequencing results revealed that all the isolates belonged to the species Leptospira interrogans, and the MLVA results showed that the VNTR loci 4, 7 and 10 profile of all the isolates was 4-1-10. In this study, we observed that Pomona serogroup strains circulate in buffaloes in the Amazon, showing that in Brazil, buffaloes can be affected by Leptospira strains other than the Sejroe group, which are adapted to cattle.


Assuntos
Búfalos/microbiologia , Leptospira interrogans/classificação , Leptospira interrogans/isolamento & purificação , Leptospirose/veterinária , Rios , Animais , Brasil/epidemiologia , Feminino , Leptospira interrogans/genética , Leptospirose/epidemiologia , Masculino
13.
PLoS Negl Trop Dis ; 15(3): e0008970, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33705392

RESUMO

Leptospira interrogans is a pathogenic spirochete responsible for leptospirosis, a neglected, zoonotic reemerging disease. Humans are sensitive hosts and may develop severe disease. Some animal species, such as rats and mice can become asymptomatic renal carriers. More than 350 leptospiral serovars have been identified, classified on the basis of the antibody response directed against the lipopolysaccharide (LPS). Similarly to whole inactivated bacteria used as human vaccines, this response is believed to confer only short-term, serogroup-specific protection. The immune response of hosts against leptospires has not been thoroughly studied, which complicates the testing of vaccine candidates. In this work, we studied the immunoglobulin (Ig) profiles in mice infected with L. interrogans over time to determine whether this humoral response confers long-term protection after homologous challenge six months post-infection. Groups of mice were injected intraperitoneally with 2×107 leptospires of one of three pathogenic serovars (Manilae, Copenhageni or Icterohaemorrhagiae), attenuated mutants or heat-killed bacteria. Leptospira-specific immunoglobulin (IgA, IgM, IgG and 4 subclasses) produced in the first weeks up to 6 months post-infection were measured by ELISA. Strikingly, we found sustained high levels of IgM in mice infected with the pathogenic Manilae and Copenhageni strains, both colonizing the kidney. In contrast, the Icterohaemorrhagiae strain did not lead to kidney colonization, even at high dose, and triggered a classical IgM response that peaked at day 8 post-infection and disappeared. The virulent Manilae and Copenhageni serovars elicited high levels and similar profiles of IgG subclasses in contrast to Icterohaemorrhagiae strains that stimulated weaker antibody responses. Inactivated heat-killed Manilae strains elicited very low responses. However, all mice pre-injected with leptospires challenged with high doses of homologous bacteria did not develop acute leptospirosis, and all antibody responses were boosted after challenge. Furthermore, we showed that 2 months post-challenge, mice pre-infected with the attenuated M895 Manilae LPS mutant or heat-killed bacterin were completely protected against renal colonization. In conclusion, we observed a sustained IgM response potentially associated with chronic leptospiral renal infection. We also demonstrated in mice different profiles of protective and cross-reactive antibodies after L. interrogans infection, depending on the serovar and virulence of strains.


Assuntos
Anticorpos Antibacterianos/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Leptospira interrogans/imunologia , Leptospirose/imunologia , Leptospirose/prevenção & controle , Animais , Carga Bacteriana/imunologia , Reações Cruzadas/imunologia , Feminino , Imunoglobulina A/sangue , Rim/microbiologia , Leptospirose/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL
14.
Equine Vet J ; 53(4): 845-854, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33617667

RESUMO

BACKGROUND: Little information is available about experimental inoculation of leptospirosis in horses and the pathogenicity of Leptospira interrogans serovar Bratislava in this host. OBJECTIVES: To determine the serological, clinical, pathological and haematological responses of horses to L. interrogans serovar Bratislava strain PigK151. STUDY DESIGN: Randomised controlled in vivo experiment. METHODS: Ten seronegative female foals were divided into 2 groups, control (n = 4) and challenged (n = 6). The challenged group received 1 × 109 leptospires divided equally between topical ocular and intraperitoneal injections. Blood and urine samples were analysed. The temperature was recorded daily for the first 9 days, then weekly. Sera were tested by microscopic agglutination test (MAT). Automated complete blood count, differential and chemistry panel were performed. Histopathological analysis was performed on sections of liver, kidney, urinary bladder, uterine body and pineal gland. Sample culturing was performed from blood, urine, liver, kidney, reproductive tract and vitreous humour. RESULTS: No pyrexia was noted. PCR and culture were negative from all samples. Differences between groups were found in CBC, differential counts and serum biochemistry panel (or profile), suggesting that leptospiral challenge triggered an inflammatory response. No evidence of leptospirosis was found from histopathological analysis. All challenged foals developed a humoral response. The MAT allowed the confirmation of the infecting serovar at a later stage, but it also revealed cross-reactive results that were further explained by genomic analysis. MAIN LIMITATIONS: This experimental challenge had two main limitations: (a) the results might have varied if another strain from the same serovar had been used and (b) the use of another route of infection and a higher bacterial dose might have achieved colonisation. CONCLUSIONS: Based on these findings, it may suggest that L. interrogans serovar Bratislava is neither pathogenic nor host-adapted serovar for horses, although these results might have varied if another strain from the same serovar had been used instead.


Assuntos
Doenças dos Cavalos , Leptospira interrogans , Leptospira , Leptospirose , Animais , Anticorpos Antibacterianos , Feminino , Cavalos , Leptospirose/veterinária , Sorogrupo
15.
J Wildl Dis ; 57(1): 157-161, 2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33635995

RESUMO

Leptospira interrogans is one of the most important zoonotic pathogens globally. In urban settings, Norway rats (Rattus norvegicus) are important reservoirs of L. interrogans, but it is unclear how this bacterium is transmitted among rats. Both environmental features and rat population density may determine the prevalence of this pathogen in rat populations as well as the spillover risk to people. While these factors could play an important role in transmission between rats, it is unknown whether such factors influence prevalence among rats at a fine scale. Our objective was to determine if carriage of L. interrogans by rats could be explained by variation in the environment or in rat population density. Rats were live-trapped in a single neighborhood of Vancouver, Canada during two study periods (2011-12; 2016-17) and were tested for L. interrogans. The physical environment of each city block was recorded using a comprehensive, in-person environmental survey. Using generalized linear mixed modelling, we found no evidence of an association between carriage of L. interrogans and environmental features or rat population density, suggesting that these were not the primary drivers of its distribution among rats within this neighborhood. Understanding factors that promote L. interrogans transmission can be used to inform management approaches to minimize public health risks.


Assuntos
Distribuição Animal , Demografia , Leptospira interrogans/fisiologia , Leptospirose/veterinária , Ratos/microbiologia , Doenças dos Roedores/microbiologia , Animais , Colúmbia Britânica/epidemiologia , Reservatórios de Doenças/veterinária , Leptospirose/epidemiologia , Leptospirose/microbiologia , Ratos/imunologia , Doenças dos Roedores/epidemiologia
16.
Lett Appl Microbiol ; 72(6): 730-740, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33590504

RESUMO

Leptospirosis is a re-emerging zoonotic disease of animals and humans caused by pathogenic Leptospira, which has major public health concerns. The study is aimed to express the recombinant outer membrane protein (OMP) A-like protein (rLoa22) and transmembrane (rOmpL37) protein of Leptospira interrogans serovar Hardjo in the Escherichia coli and their evaluation as a diagnostic antigen in the latex agglutination test (LAT) to detect anti-leptospiral antibodies in the sera of animals. The Loa22 and OmpL37 genes lacking signal peptide coding sequences were individually amplified (522 and 963 bp), by polymerase chain reaction, and directionally cloned into a pETite N-His Kan vector for expression. The expressed purified proteins were characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immunoblot, which confirmed leptospiral specific reactive protein with a molecular weight of ~19 and 36 kDa, respectively. The sensitized latex beads coated with these OM proteins separately were evaluated in LAT using cattle sera of microscopic agglutination test (MAT) confirmed positive (n = 53) and negative (n = 52) cases of leptospirosis. The rLoa22 LAT and rOmpL37 LAT revealed the relative diagnostic sensitivity of 94·34 and 96·23%, diagnostic specificity of 92·31 and 96·15% and accuracy of 93·33 and 96·19%, with the excellent agreement of Cohen's kappa value of 0·87 and 0·92, respectively. After extensive evaluation, this rapid recombinant protein-based field diagnostic test can be applied as a screening test for the detection of anti-leptospiral antibodies in the sera of animals in the field conditions.


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Testes de Fixação do Látex/veterinária , Leptospirose/diagnóstico , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antiprotozoários/imunologia , Antígenos de Bactérias/genética , Bovinos , Doenças dos Bovinos/diagnóstico , Doenças dos Bovinos/parasitologia , Eletroforese em Gel de Poliacrilamida , Immunoblotting , Testes de Fixação do Látex/métodos , Leptospira interrogans/imunologia , Leptospira interrogans/isolamento & purificação , Leptospirose/veterinária , Proteínas Recombinantes/genética , Testes Sorológicos/métodos , Zoonoses/diagnóstico , Zoonoses/parasitologia
17.
Microb Pathog ; 152: 104770, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33545326

RESUMO

Chronic leptospirosis usually occurs during sublethal doses infection of susceptible animal and reservoir host, which typical symptom is interstitial nephritis, and leptospira urine, contaminating the environment and threatening other susceptible animals and humans. Dipotassium glycyrrhizinate (DG) is a replacement for glycyrrhizic acid, which exhibits anti-inflammation, immunomodulation effects. This study is to investigate whether DG relieves leptospira-induced nephritis. In vitro, DG inhibited the leptospira-induced transcription levels of IL-1ß, IL-6, TNF-α, RANTES, MCP-1 and iNOS, and protein levels of IL-1ß and TNF-α, and downregulated NF-κB and MAPK pathway in TCMK-1 cells. In vivo, DG attenuated the kidney histopathological change and downregulated the expression of IL-1ß and TNF-α, as well as reduced kidney leptospiral burden. In summary, DG alleviated leptospira-induced inflammation through inhibitory NF-κB and MAPK pathway, and DG decreased the renal colonization of leptospires in mice.


Assuntos
Leptospira interrogans , Leptospira , Leptospirose , Nefrite , Animais , Ácido Glicirrízico/farmacologia , Leptospirose/tratamento farmacológico , Camundongos
18.
Int J Infect Dis ; 105: 135-140, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33556609

RESUMO

BACKGROUND: Leptospirosis is most often diagnosed clinically, and a laboratory test with high diagnostic accuracy is required. METHODS: IgM and IgG ELISAs using Leptospira antigens were established and evaluated in relation to the microscopic agglutination test (MAT). Antigen preparation consisted of saprophytic Leptospira biflexa to detect genus-specific antibodies (genus-specific ELISA) and a pool of the five most prevalent Leptospira interrogans serovars in Sri Lanka to detect serovar-specific antibodies (serovar-specific ELISA). IgM and IgG immune responses were studied in severe and mild leptospirosis patients (n = 100 in each group). RESULTS: The ELISAs showed high repeatability and reproducibility. The serovar-specific IgM-ELISA showed a sensitivity of 80.2% and specificity of 89%; the genus-specific IgM-ELISA showed a sensitivity of 83.3% and specificity of 91%. The serovar- and genus-specific IgG-ELISAs showed sensitivities of 73.3% and 81.7%, respectively, and specificities of 83.3% and 83.3%, respectively. The commercial IgM-ELISA showed a sensitivity of 79.2% and specificity of 93%. The commercial IgG-ELISA showed a sensitivity of 50% and specificity of 96.7%. IgM levels observed in mild and severe leptospirosis patients were significantly higher than in the healthy control group, with mean absorbance values of 0.770, 0.778, and 0.163, respectively. Severe leptospirosis patients had significantly higher mean anti-leptospiral IgG levels compared to both mild leptospirosis patients and healthy control group subjects (0.643, 0.358, and 0.116, respectively; ANOVA, p < 0.001). The presence of anti-leptospiral IgG above an optical density of 0.643 at 1:100 could predict a high risk of severe disease. CONCLUSION: The serovar-specific in-house ELISA could be used for the laboratory diagnosis of leptospirosis in endemic settings. The high levels of anti-leptospiral IgG observed suggest its value as a predictor of disease severity.


Assuntos
Anticorpos Antibacterianos/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Leptospirose/diagnóstico , Testes Sorológicos/métodos , Testes de Aglutinação , Antígenos de Bactérias/imunologia , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Leptospira interrogans/imunologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Sri Lanka/epidemiologia
19.
Sci Rep ; 11(1): 1768, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33469138

RESUMO

Leptospirosis is a neglected, widespread zoonosis caused by pathogenic species of the genus Leptospira, and is responsible for 60,000 deaths per year. Pathogenic mechanisms of leptospirosis remain poorly understood mainly because targeted mutations or gene silencing in pathogenic Leptospira continues to be inherently inefficient, laborious, costly and difficult to implement. In addition, pathogenic leptospires are highly fastidious and the selection of mutants on solid agar media can take up to 6 weeks. The catalytically inactive Cas9 (dCas9) is an RNA-guided DNA-binding protein from the Streptococcus pyogenes CRISPR/Cas system and can be used for gene silencing, in a strategy termed CRISPR interference (CRISPRi). Here, this technique was employed to silence genes encoding major outer membrane proteins of pathogenic L. interrogans. Conjugation protocols were optimized using the newly described HAN media modified for rapid mutant recovery at 37 °C in 3% CO2 within 8 days. Complete silencing of LipL32 and concomitant and complete silencing of both LigA and LigB outer membrane proteins were achieved, revealing for the first time that Lig proteins are involved in pathogenic Leptospira serum resistance. Gene silencing in pathogenic leptospires and rapid mutant recovery will facilitate novel studies to further evaluate and understand pathogenic mechanisms of leptospirosis.


Assuntos
Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/genética , Sistemas CRISPR-Cas/genética , Inativação Gênica , Leptospira interrogans/genética , Lipoproteínas/genética , Humanos , Leptospirose/microbiologia , Fenótipo , RNA Guia/genética
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