Leptospirosis: predictores de mala evolución clínica en pacientes hospitalizados, 25 años de experiencia / Leptospirosis: predictors of poor outcomes in hospitalized patients, 25 years of experience

Introducción: La leptospirosis es una zoonosis que cons-tituye un problema emergente de salud pública. La insufi-ciencia renal, plaquetopenia y compromiso respiratorio se describen como predictores de mortalidad.Objetivos: Describir características clínicas, radiológicas y de laboratorio de individuos hospitalizados por leptos-pirosis y evaluar los predictores de mala evolución clínica (MEC).Materiales y métodos: Estudio de cohorte de inclusión ambispectiva de pacientes con leptospirosis internados en un hospital de la ciudad de Santa Fe entre 1997 y 2022. Se definió MEC como la admisión a Unidad de Cuidados Intensivos (UCI), requerimiento de asistencia respiratoria mecánica (ARM) y/o muerte. Se utilizaron las pruebas de Chi2, test T de Student o la U de Mann-Whitney, según co-rrespondiera. Se construyó una regresión logística binaria con las variables con p<0,05.Resultados: 101 pacientes, 87,1% (n=88) hombres, media-na de edad de 29 (RIC 20-44) años. La fiebre fue el síntoma más frecuente [83,2% (n=84)], seguido del compromiso di-gestivo [62,4% (n=63)]. Las alteraciones de laboratorio más frecuentes fueron: eritrosedimentación elevada [91,9% (n=79)] y leucocitosis [61% (n=61)]. Se observó MEC en el 25,7% (n=26). El 25,7% (n=26) fue admitido en UCI, el 13,9% (n=14) requirió ARM y el 5% (n=5) falleció. La presencia de plaquetopenia (OR=13,3, IC95% 2-80), las alteraciones en la radiografía de tórax (OR=33,5, IC95% 5-225) y la ausencia de cefalea (OR=6,8, IC95% 1-32) fueron predictores inde-pendientes de MEC.Conclusiones: En concordancia con la bibliografía, la afec-tación pulmonar y plaquetopenia son factores de riesgo para la mala evolución clínica. En nuestra serie, la cefalea constituyó un síntoma protector

Introduction: Leptospirosis is an emerging zoonotic di-sease that poses a public health problem. Renal failu-re, thrombocytopenia, and respiratory involvement have been described as predictors of mortality.Objectives: To describe the clinical, radiological, and la-boratory characteristics of hospitalized individuals with leptospirosis and evaluate predictors of poor clinical outcomes (PCO).Materials and methods: A prospective cohort study was conducted including patients with leptospirosis admit-ted to a hospital in the city of Santa Fe between 1997 and 2022. PCO was defined as admission to the Intensive Care Unit (ICU), requirement for mechanical respiratory assistance (MRA), and/or death. The chi-square test, Student>s t-test, or Mann-Whitney U test were used as appropriate. A binary logistic regression was performed with variables having p<0.05.Results: Out of the 101 patients included, 87.1% (n=88) were male, with a median age of 29 (IQR 20-44) years. Fever was the most common symptom [83.2% (n=84)], followed by digestive involvement [62.4% (n=63)]. The most frequent laboratory abnormalities were elevated erythrocyte sedimentation rate [91.9% (n=79)] and leuko-cytosis [61% (n=61)]. PCO was observed in 25.7% (n=26) of patients, with 25.7% (n=26) admitted to the ICU, 13.9% (n=14) requiring MRA, and 5% (n=5) resulting in death. The presence of thrombocytopenia (OR=13.3, 95% CI 2-80), abnormalities in chest X-rays (OR=33.5, 95% CI 5-225), and absence of headache (OR=6.8, 95% CI 1-32) were predictors of PCO. Conclusions: Consistent with the literature, pulmonary involvement and thrombocytopenia are independent risk factors for poor clinical outcomes. In our series, the pre-sence of headache was a protective symptom

Molecular detection of leptosipira in synanthropic and wild rodents from Villavicencio municipality, Colombia / Detección molecular de leptospiras en roedores del municipio de Villavicencio, Colombia

Introduction: Rodents are potential transmitters of Leptospira spp. In the municipality of Villavicencio, Colombia, leptospirosis is a disease that, although notifiable, is still underreported. In this region, rodent species that can host pathogenic leptospira remain unknown. Objective: To detect the presence of Leptospira spp. through molecular analysis in rodents (Rodentia) from peri-urban and rural areas belonging to the municipality of Villavicencio in Colombia. Methods: Peri-urban and rural areas of the townships belonging to Villavicencio municipality were selected for sampling. These areas presented similar ecological conditions: they were near water bodies and peridomiciliary areas, and some of them included fields of agricultural crops. Rodents´ kidneys were removed and frozen in liquid nitrogen. DNA was extracted using a commercial kit and subsequently amplified through conventional polymerase chain reaction. Results: The rodent species collected were: Rattus rattus, Mus musculus, Zygodontomys brevicauda, Oligoryzomys sp, Hylaeamys (formerly Oryzomys) and Proechimys cf. oconnelli. Leptospira DNA was amplified in six rodents and the purified amplicons were sent to Macrogen Inc. (Seoul, Korea) for sequencing. The alignment analysis of the sequenced products demonstrated 98.64 percent of coverage and identity with Leptospira interrogans. Conclusions: This is the first study carried out on wild and synanthropic rodents in the municipality of Villavicencio. The incidence of leptospirosis raises the alarm due to the important role of these small mammals in the transmission of this zoonosis, which is considered the second cause, after dengue, of undifferentiated febrile illness in Villavicencio(AU)

Introducción: Los roedores son potenciales transmisores de Leptospira spp. En el municipio de Villavicencio, Colombia, la leptospirosis es una enfermedad que, aunque debe notificarse obligatoriamente, sigue subreportada. En esta región, algunas especies de roedores pueden ser reservorios de leptospiras patógenas, situación que se desconoce. Objetivo: Detectar la presencia de Leptospira spp. a través del análisis molecular en roedores (Rodentia) de áreas periurbanas y rurales del municipio de Villavicencio, Colombia. Métodos: Para el trampeo se seleccionaron áreas periurbanas y rurales de las veredas pertenecientes al municipio de Villavicencio. Las áreas escogidas presentaban condiciones ecológicas similares: cerca de cuerpos de agua y áreas peridomiciliarias; algunas de ellas localizadas en campos de cultivos de la agricultura. Se extirparon los riñones de los roedores y se conservaron en nitrógeno líquido. Se extrajo el ADN usando un estuche comercial y posteriormente se amplificó mediante reacción en cadena de la polimerasa convencional. Resultados: Las especies de roedores colectadas fueron: Rattus rattus, Mus musculus, Zygodontomys brevicauda, Oligoryzomys sp., Hylaeamys (ahora Oryzomys) y Proechimys oconnelli. El ADN de leptospira se amplificó en seis roedores y los amplicones purificados se enviaron a Macrogen Inc. (Seoul, Korea) para secuenciación. El análisis de alineamiento de los productos secuenciados demostró un 98,64 por ciento de cobertura e identidad con Leptospira interrogans. Conclusiones: Este es el primer estudio llevado a cabo en roedores silvestres y sinantrópicos en el municipio de Villavicencio. La incidencia de la leptospirosis genera una alarma con respecto a la importancia del papel de esos pequeños mamíferos en la transmisión de esta zoonosis, la cual es la segunda causa de los síndromes febriles indiferenciados en Villavicencio, después del dengue(AU)

Crosstalk between E-Cadherin/ß-Catenin and NF-κB Signaling Pathways: The Regulation of Host-Pathogen Interaction during Leptospirosis.

Approximately 1 million cases of leptospirosis, an emerging infectious zoonotic disease, are reported each year. Pathogenic Leptospira species express leucine-rich repeat (LRR) proteins that are rarely expressed in non-pathogenic Leptospira species. The LRR domain-containing protein family is vital for the virulence of pathogenic Leptospira species. In this study, the biological mechanisms of an essential LRR domain protein from pathogenic Leptospira were examined. The effects of Leptospira and recombinant LRR20 (rLRR20) on the expression levels of factors involved in signal transduction were examined using microarray, quantitative real-time polymerase chain reaction, and western blotting. The secreted biomarkers were measured using an enzyme-linked immunosorbent assay. rLRR20 colocalized with E-cadherin on the cell surface and activated the downstream transcription factor ß-catenin, which subsequently promoted the expression of MMP7, a kidney injury biomarker. Additionally, MMP7 inhibitors were used to demonstrate that the secreted MMP7 degrades surface E-cadherin. This feedback inhibition mechanism downregulated surface E-cadherin expression and inhibited the colonization of Leptospira. The degradation of surface E-cadherin activated the NF-κB signal transduction pathway. Leptospirosis-associated acute kidney injury is associated with the secretion of NGAL, a downstream upregulated biomarker of the NF-κB signal transduction pathway. A working model was proposed to illustrate the crosstalk between E-cadherin/ß-catenin and NF-κB signal transduction pathways during Leptospira infection. Thus, rLRR20 of Leptospira induces kidney injury in host cells and inhibits the adhesion and invasion of Leptospira through the upregulation of MMP7 and NGAL.

Deciphering the Role of Leptospira Surface Protein LigA in Modulating the Host Innate Immune Response.

Leptospira, a zoonotic pathogen, is known to infect various hosts and can establish persistent infection. This remarkable ability of bacteria is attributed to its potential to modulate (activate or evade) the host immune response by exploiting its surface proteins. We have identified and characterized the domain of the variable region of Leptospira immunoglobulin-like protein A (LAV) involved in immune modulation. The 11th domain (A11) of the variable region of LigA (LAV) induces a strong TLR4 dependent innate response leading to subsequent induction of humoral and cellular immune responses in mice. A11 is also involved in acquiring complement regulator FH and binds to host protease Plasminogen (PLG), there by mediating functional activity to escape from complement-mediated killing. The deletion of A11 domain significantly impaired TLR4 signaling and subsequent reduction in the innate and adaptive immune response. It also inhibited the binding of FH and PLG thereby mediating killing of bacteria. Our study discovered an unprecedented role of LAV as a nuclease capable of degrading Neutrophil Extracellular Traps (NETs). This nuclease activity was primarily mediated by A11. These results highlighted the moonlighting function of LigA and demonstrated that a single domain of a surface protein is involved in modulating the host innate immune defenses, which might allow the persistence of Leptospira in different hosts for a long term without clearance.

Cross-sectional survey for canine leptospirosis in an Atlantic Rainforest area of the semiarid of Paraíba state, Northeastern Brazil / Estudo transversal para leptospirose canina em área de Mata Atlântica do semiárido da Paraíba, Nordeste do Brasil

Leptospirosis is a worldwide zoonosis caused by the bacteria Leptospira spp. that affects humans, domestic and wild animals. The present work aimed to conduct a cross-sectional survey for leptospirosis in the canine population of the Brejo Paraibano microregion, semiarid of Northeastern Brazil. From May to October 2017, blood samples from 414 dogs were collected in the counties of Alagoa Grande (n=100), Areia (n=79), Bananeiras (n=72), Alagoa Nova (n=73), Serrraria (n=25), Pilões (n=25), Borborema (n=20) and Matinhas (n=20). The tutors of the sampled dogs answered an epidemiological questionnaire, obtaining information about the animals, owner, residence and breeding of the dogs. Subsequently, the serum samples were subjected to the microscopic agglutination test (MAT), using a collection of 23 serovar pathogenic antigens and using the 1:50 dilution as the cutoff point. Of the 414 dogs analyzed 52 were seroreactive, resulting in an apparent prevalence of 12.6% and a real prevalence of 12.2%. Seroreactive dogs were found in the eight counties. Dogs were reactive for the serogroups Icterohaemorrhagiae (76.9%), Autumnalis (13.55%), Pomona (3.8%), Grippotyphosa (3.8%) and Serjoe (1.9%) Antibody titers ranged from 50 to 800. The statistical analysis (robust Poisson regression) detected six factors associated with seropositivity, including the rainy season (prevalence ratio; PR=1.94, P=0.013), male dogs (PR=2.10, P=0.005), animals with age greater than five years (PR=4.21, P=0.012), consumption of untreated water (PR=1.87, P=0.043), free access of dogs to street (PR=2.15, P=0.011) and contact with wildlife (PR=3.54, P=0.050). The serogroup Icterohaemorrhagiae has a high zoonotic potential and was the most frequent in seropositive animals. The high real prevalence of Leptospira spp. in a transmission region of the semiarid region of Paraíba and the occurrence of seroreactive animals in all the counties suggest wide distribution of the infection and reinforce the need for preventive measures to avoid infection in pets and, consequently, to humans. The analysis of factors associated with the prevalence suggest greater manegment cares with the dogs.(AU)

A leptospirose é uma zoonose mundial causada pela bactéria Leptospira spp. que afeta seres humanos, animais domésticos e selvagens. O presente trabalho teve como objetivo realizar um estudo transversal de leptospirose na população canina da microrregião Brejo Paraibano, semiárido do Nordeste do Brasil. No período de maio a outubro de 2017, amostras de sangue de 414 cães foram coletadas nas cidades de Alagoa Grande (n=100), Areia (n=79), Bananeiras (n=72), Alagoa Nova (n=73), Serraria (n=25), Pilões (n=25), Borborema (n=20) e Matinhas (n=20). Os tutores dos cães amostrados responderam a um questionário epidemiológico, sendo obtidas informações sobre os animais, proprietário, residência e criação dos cães. Posteriormente as amostras de soro foram submetidas à prova de soroaglutinação microscópica (SAM), utilizando-se uma coleção de 23 sorovares antígenos patogênicos e adotando como ponto de corte a diluição 1:50. Dos 414 cães analisados 52 foram sorreativos, resultando em uma prevalência aparente de 12.6% e uma prevalência real de 12,2%. Cães sororreativos foram encontrados nos oito municípios. Os cães foram reativos para o sorogrupo Icterohaemorrhagiae (76,9%), Autumnalis (13,55%), Pomona (3,8%), Grippotyphosa (3,8%) and Serjoe (1,9%) Os títulos de anticorpos variaram de 50 a 800. A análise estatística (regressão de Poisson robusta) detectou seis fatores associados à soropositividade, incluindo o período chuvoso (razão de prevalência - RP=1,94; P=0,013), cães machos (RP=2,10; P=0,005), animais com idade maior que cinco anos (RP=4,21; P=0,012), consumo de água não tratada (RP=1,87; P=0,043), cães com livre acesso à rua (RP=2,15; P=0,011) e contato com animais silvestres (RP=3,54; P=0,050). Os resultados desse estudo indicaram que há a exposição por Leptospira spp. em cães da microrregião do Brejo paraibano. O sorogrupo Icterohaemorrhagiae possui alto potencial zoonótico e foi o mais frequente nos animais soropositivos. A alta prevalência real de Leptospira spp. em uma região de transmissão da região semiárida da Paraíba e a ocorrência de animais sororreativos em todos os municípios sugerem uma ampla distribuição da infecção e reforçam a necessidade de medidas preventivas para evitar a infecção em animais de estimação e, consequentemente, em seres humanos. A análise dos fatores associados à prevalência sugere maior cuidado com os cães.(AU)

The Role of Properdin in Killing of Non-Pathogenic Leptospira biflexa.

Properdin (P) is a positive regulatory protein that stabilizes the C3 convertase and C5 convertase of the complement alternative pathway (AP). Several studies have suggested that properdin can bind directly to the surface of certain pathogens regardless of the presence of C3bBb. Saprophytic Leptospira are susceptible to complement-mediated killing, but the interaction of properdin with Leptospira spp. has not been evaluated so far. In this work, we demonstrate that properdin present in normal human serum, purified properdin, as well as properdin oligomers P2, P3, and P4, interact with Leptospira. Properdin can bind directly to the bacterial surface even in the absence of C3b. In line with our previous findings, AP activation was shown to be important for killing non-pathogenic L. biflexa, and properdin plays a key role in this process since this microorganism survives in P-depleted human serum and the addition of purified properdin to P-depleted human serum decreases the number of viable leptospires. A panel of pathogenic L.interrogans recombinant proteins was used to identify putative properdin targets. Lsa30, an outer membrane protein from L. interrogans, binds to unfractionated properdin and to a lesser extent to P2-P4 properdin oligomers. In conclusion, properdin plays an important role in limiting bacterial proliferation of non-pathogenic Leptospira species. Once bound to the leptospiral surface, this positive complement regulatory protein of the AP contributes to the formation of the C3 convertase on the leptospire surface even in the absence of prior addition of C3b.

High proportion of cattle and sheep seropositive and renal carriers of Leptospira sp. under semiarid conditions / Alta proporção de bovinos e ovinos soropositivos e portadores renais de Leptospira sp. em condições semiáridas

The aims of this study were to perform serological and molecular detection of Leptospira sp. infection in cattle and sheep under semiarid conditions. Based on a preliminary study performed in our research group, we selected six rural properties showing a positivity ≥ 60% for Sejroe serogroup with titer ≥ 200 measured in serological tests from cattle. In the present study, blood and urine samples were collected from 99 females of reproductive age (51 cattle and 48 sheep) for serological diagnosis, molecular detection and Leptospira sp. attempt to strain recovery. Of the 99 analyzed animals 38.4% (38/99) were positively reactive at the serological tests. Of them, 49% (25/51) were cattle and 27.1% (13/48) sheep. The serogroups detected in cattle were Sejroe (36.8%), Hebdomadis (26.3%), Australis (10.5%), Djasiman (10.5%), Ballum (5.3%), Pomona (5.3%), and Cynopteri (5.3%) with titers of 100­800. In sheep, the reactive serogroups were Australis (27.3%), Ballum (27.3%), Djasiman (18.1%), Tarassovi (9.1%), Icterohaemorrhagiae (9.1%), and Cynopteri (9.1%) with titers of 100­400.Leptospiral DNA was detected in nine urine samples, including five cattle and four sheep. Property 1 showed the highest serological positivity frequencies for both cattle (70.6%) and sheep (70.6%). Similarly, the highest frequency of DNA detection was also found (eight samples, 89%). In this property, we observed the existence of consorted rearing of cattle and sheep with close coexistence between these species. In semiarid conditions, transmission among animals of the same species seems to be the main form of Leptospira sp. dissemination in cattle and sheep herds. However, the contribution of other domestic and wild animals cannot be discarded. The practice of consorted rearing of cattle and sheep and their close coexistence may facilitate the spread of the pathogen in rural properties.

Os objetivos deste estudo foram realizar detecção sorológica e molecular da infecção por Leptospira sp. em bovinos e ovinos em condições semiáridas. Com base em estudo preliminar realizado em nosso grupo de pesquisa, foram selecionadas seis propriedades rurais com soropositividade ≥ 60% para o sorogrupo Sejroe com título ≥ 200 em bovinos. No presente estudo, amostras de sangue e urina foram coletadas de 99 fêmeas em idade reprodutiva (51 bovinos e 48 ovinos) para diagnóstico sorológico, detecção molecular e tentativa de recuperação de estirpesde Leptospira sp. Dos 99 animais analisados, 38,4% (38/99) foram sororeativos nos testes sorológicos. Destes, 49% (25/51) eram bovinos e 27,1% (13/48) ovinos. Os sorogrupos detectados em bovinos foram Sejroe (36,8%), Hebdomadis (26,3%), Australis (10,5%), Djasiman (10,5%), Ballum (5,3%), Pomona (5,3%) e Cynopteri (5,3%) com títulos de 100 a 800. Nos ovinos, os sorogrupos reativos foram Australis (27,3%), Ballum (27,3%), Djasiman (18,1%), Tarassovi (9,1%), Icterohaemorrhagiae (9,1%) e Cynopteri (9,1%) com títulos de 100-400. O DNA leptospiral foi detectado em nove amostras de urina, incluindo cinco bovinos e quatro ovinos. A propriedade 1 apresentou as maiores frequências de positividade sorológica para bovinos (70,6%) e ovinos (70,6%). Da mesma forma, a maior frequência de detecção de DNA também foi encontrada (oito amostras, 89%). Nesta propriedade observou-se a existência de criação consorciada de bovinos e ovinos com estreita convivência entre estas espécies. Em condições semiáridas, a transmissão entre animais da mesma espécie parece ser a principal forma de disseminação de Leptospira sp. em rebanhos bovinos e ovinos. No entanto, a contribuição de outros animais domésticos e selvagens não pode ser descartada. A prática de criação consorciada de bovinos e ovinos e sua estreita convivência podem facilitar a disseminação do patógeno em propriedades rurais.

Gene expression is associated with virulence in murine macrophages infected with Leptospira spp.

Leptospira genus contains species that affect human health with varying degrees of pathogenicity. In this context, we aimed to evaluate the differences in the modulation of host gene expression by strains of Leptospira varying in virulence. Our data showed a high number of differentially expressed transcripts in murine macrophages following 6h of infection. Leptospira infection modulated a set of genes independently of their degree of virulence. However, pathway analysis indicated that Apoptosis, ATM Signaling, and Cell Cycle: G2/M DNA Damage Checkpoint Regulation were exclusively regulated following infection with the virulent strain. Taken together, results demonstrated that species and virulence play a role during host response to Leptospira spp in murine macrophages, which could contribute to understanding the pathogenesis of leptospirosis.

The preventable efficacy of ß-glucan against leptospirosis.

Leptospirosis, caused by pathogenic Leptospira species, has emerged as an important neglected zoonotic disease. Few studies have reported the preventable effects of immunoregulators, except for antibiotics, against leptospirosis. Generally, immunostimulatory agents are considered effective for enhancing innate immune responses. Many studies have found that beta-glucan (ß-glucan) could be a potent and valuable immunostimulant for improving immune responses and controlling diseases. In this study, we investigated the preventable role of ß-glucan against Leptospira infection in hamsters. First, ß-glucan was administered 24 h prior to, during and after infection. The results showed that ß-glucan increased the survival rate to 100%, alleviated tissue injury, and decreased leptospire loads in target organs. Additionally, we found using quantitative real-time PCR that application of ß-glucan significantly enhanced the expression of Toll-like receptor (TLR) 2, interleukin (IL)-1ß and iNOS at 2 dpi (days post infection) and reduced the increase of TLR2, IL-1ß and iNOS induced by Leptospira at 5 dpi. Furthermore, to induce memory immunity, ß-glucan was administered 5 days prior to infection. ß-Glucan also significantly increased the survival rates and ameliorated pathological damage to organs. Moreover, we demonstrated that ß-glucan-trained macrophages exhibited elevated expression of proinflammatory cytokines (IL-1ß and IL-6) in vitro, indicating that ß-glucan induces an enhanced inflammatory response against Leptospira infection. These results indicate that administration of ß-glucan and other immunostimulants could be potential valuable options for the control of Leptospira infection.

Occurrence of antibodies against Leptospira spp. in donkeys of São Paulo state / Ocorrência de anticorpos contra Leptospira spp. em asininos no estado de São Paulo

Among the diseases that affect equines, bacterial diseases play an important role from a health and economic point of view, especially leptospirosis and brucellosis. The study aimed to provide information on the occurrence of anti-Leptospira spp. and anti-Brucella abortus antibodies in donkeys of São Paulo state. We found a frequency of 62.4% (53/85) antibodies against Leptospira spp. The donkeys were not seropositive for Brucella spp.(AU)

Entre as doenças que acometem os equídeos, as enfermidades bacterianas assumem um papel importante do ponto de vista sanitário e econômico, destacando-se a leptospirose e a brucelose. O estudo teve como objetivo fornecer informações sobre a ocorrência de anticorpos anti-Leptospira spp. e anti-Brucella abortus em jumentos no estado de São Paulo. Estimou-se que 62,4% (53/85) dos animais apresentavam anticorpos anti-Leptospira spp. Os jumentos estudados não foram sororreagentes contra a Brucella spp.(AU)

Characterization of the microtranscriptome of macrophages infected with virulent, attenuated and saprophyte strains of Leptospira spp.

Leptospirosis is a bacterial zoonosis, caused by Leptospira spp., that leads to significant morbidity and mortality worldwide. Despite considerable advances, much is yet to be discovered about disease pathogenicity. The influence of epigenetic mechanisms, particularly RNA-mediated post-transcriptional regulation of host immune response has been described following a variety of bacterial infections. The current study examined the microtranscriptome of macrophages J774A.1 following an 8h infection with virulent, attenuated and saprophyte strains of Leptospira. Microarray analysis revealed that 29 miRNAs were misregulated following leptospiral infection compared to control macrophages in a strain and virulence-specific manner. Pathway analysis for targets of these differentially expressed miRNAs suggests that several processes involved in immune response could be regulated by miRNAs. Our data provides the first evidence that host miRNAs are regulated by Leptospira infection in macrophages. A number of the identified miRNA targets participate in key immune response processes. We suggest that post-transcriptional regulation by miRNAs may play a role in host response to infection in leptospirosis.

Genome of Leptospira borgpetersenii strain 4E, a highly virulent isolate obtained from Mus musculus in southern Brazil

A previous study by our group reported the isolation and characterisation of Leptospira borgpetersenii serogroup Ballum strain 4E. This strain is of particular interest because it is highly virulent in the hamster model. In this study, we performed whole-genome shotgun genome sequencing of the strain using the SOLiD sequencing platform. By assembling and analysing the new genome, we were able to identify novel features that have been previously overlooked in genome annotations of other strains belonging to the same species.

High level of IL-10 expression in the blood of animal models possibly relates to resistance against leptospirosis.

Leptospirosis is a severe zoonosis which immunopathogenesis is poorly understood. We evaluated correlation between acute form of the disease and the ratio of the anti-inflammatory cytokine IL-10 to the pro-inflammatory TNF-α and IL-1ß expression during the early phase of infection comparing resistant mice and susceptible hamsters infected with two different species of virulent Leptospira. The IL-10/TNF-α and IL-10/IL-1ß expression ratios were higher in mouse compared to hamster independently of the Leptospira strain, suggesting a preponderant role of the host response and notably these cytokines in the clinical expression and survival to leptospirosis. Using an IL-10 neutralization strategy in Leptospira-infected mouse model, we also showed evidence of a possible role of this cytokine on host susceptibility, bacterial clearance and on regulation of cytokine gene expression.

Comparative genomic analysis of Brazilian Leptospira kirschneri serogroup Pomona serovar Mozdok

Leptospira kirschneri is one of the pathogenic species of the Leptospira genus. Human and animal infection from L. kirschneri gained further attention over the last few decades. Here we present the isolation and characterisation of Brazilian L. kirschneri serogroup Pomona serovar Mozdok strain M36/05 and the comparative genomic analysis with Brazilian human strain 61H. The M36/05 strain caused pulmonary hemorrhagic lesions in the hamster model, showing high virulence. The studied genomes presented high symmetrical identity and the in silico multilocus sequence typing analysis resulted in a new allelic profile (ST101) that so far has only been associated with the Brazilian L. kirschneri serogroup Pomona serovar Mozdok strains. Considering the environmental conditions and high genomic similarity observed between strains, we suggest the existence of a Brazilian L. kirschneri serogroup Pomona serovar Mozdok lineage that could represent a high public health risk; further studies are necessary to confirm the lineage significance and distribution.

Avaliação do padrão sazonal da infecção assintomática por leptospira spp e das formas grave da leptospirose / Evaluation of syndecan-4 expression and its role as biomarkers in chronic chagasic cardiomyopathy

INTRODUÇÃO E OBJETIVO: A leptospirose é uma zoonose, causada pela bactéria Leptospira, de ampla distribuição e elevado impacto à saúde humana. As epidemias de leptospirose no Brasil acontecem a cada ano em áreas urbanas durante o período de chuvas sazonais. Porém não existem estudos que avaliem se as formas assintomáticas e/ou subclínicas seguem este padrão estacional relacionado a precipitação. O objetivo deste trabalho é determinar a incidência de infecção assintomática e de leptospirose grave durante diferentes períodos de precipitação em Salvador. METODOLOGIA: Realizamos cinco inquéritos sorológicos estacionais em uma coorte com 3176 habitantes na comunidade de Pau da Lima, Salvador – Bahia, para identificar infecções assintomáticas por Leptospira spp (2013-2015)...

INTRODUCTION AND AIM: Introduction and aim: Leptospirosis is a zoonosis caused by Leptospira bacteria, and has a wide distribution with a high impact to human health. Outbreaks of leptospirosis in Brazil occur each year in urban areas during the rainy season. However, there are no studies to assess whether the asymptomatic and/or subclinical follow this seasonal pattern related to precipitation. The aim of this study is to determine the incidence of asymptomatic infection and severe leptospirosis. during different periods of rainfall in Salvador. METHODOLOGY: We conducted five seasonal serosurveys in a cohort of 3176 inhabitants in the community of Pau da Lima, Salvador-Bahia to identify asymptomatic infections by Leptospira (2013-2015)...

Leptospirosis among the self-supporting convicts of Andaman Island during the 1920s--the first report on pulmonary haemorrhage in leptospirosis?

Several researchers had carried out investigations on the possibility of existence of Weil's disease in Andaman Islands during early 20 th century. The first report of a series of confirmed cases of leptospirosis that occurred during 1929 was published in 1931.There were several reports during 1995 to 2009 that described detailed account of leptospirosis including various clinical syndromes. The possibility of pulmonary involvement in leptospirosis being a manifestation historically overlooked rather than newly emerged during the past two decades is examined in this review in the context of Andaman Islands. Two case series of leptospirosis, one occurred in 1929 and the other in 1996-1997 were reviewed with special emphasis on pulmonary involvement and haemorrhagic manifestations. The similarities and differences in the clinical profile of patients of the two case series were analysed. The review shows that respiratory system involvement and pulmonary haemorrhage as evidenced by presence of haemoptysis as a complication of leptospirosis was occurring during 1920s in Andaman Islands. The incidence of pulmonary involvement, however, rose from 9.4 per cent during 1929 to 52 per cent in 1996-1997. The case fatality ratio in patients with pulmonary involvement, which was 50 per cent during 1929 and 42.9 per cent during 1996-1997, was higher than that in cases without pulmonary involvement.Fever, conjunctival congestion, jaundice, vomiting, diarrhoea, hepatomagaly, haemoptysis, haematemesis and subconjunctival haemorrhage were common in both series. The case series in Andaman Islands in 1929 was probably the first report of pulmonary haemorrhage as a manifestation of leptospirosis. The increase in the incidence of pulmonary involvement in leptospirosis in the recent past is probably due to the increase in the density and diversity of its animal vectors,the broadening of the range of circulating serovars and the interactions between the vector and the agent. An increased virulence of Leptospira through gene acquisition and loss on an evolutionary time scale and the resulting change in the gene content, gene order and gene expression cannot be ruled out.

Occurrence of antibodies against Leptospira spp. in free-ranging wild canids from the Brazilian savanna / Ocorrência de anticorpos contra Leptospira spp. em canídeos selvagens de vida livre do cerrado brasileiro

The Brazilian savanna, also known as Cerrado, is one of the world's richest and most ecologically invaluable tropical savanna regions. There are few studies in Brazil about the diseases that affect the wild canids of this biome, which may be harmful to wildlife populations and public health. The aim of this study was to evaluate the occurrence of antibodies against Leptospira spp. in three Cerrado wild canids species using the microscopic agglutination test (MAT). Serum samples were tested from 19 crab-eating foxes (Cerdocyon thous), 14 maned wolves (Chrysocyon brachyurus), and seven hoary foxes (Lycalopex vetulus), all free-ranging animals found in the municipalities of Araguari and Uberlândia, Minas Gerais State, and Cumari, Goiás State, Brazil. Fourteen (35%) of these samples were seropositive. The most frequent serovars detected in the samples were Copenhageni and Hardjo, but reactions to the serovars Autumnalis, Grippotyphosa, Hebdomadis, Wolffi, and Icterohaemorrhagiae also occurred. Notwithstanding other reported results, this study is the first to report the presence of antibodies against Leptospira spp. in L. vetulus. The three species of wild canids examined may act as potential hosts for several serovars of leptospira in Brazil's savanna environment...

O cerrado é a mais diversificada savana tropical do mundo e constitui grande importância ecológica. Ainda assim, são poucos os estudos realizados no Brasil a respeito das doenças que acometem os canídeos desse bioma, o que causa prejuízos à população de animais selvagens e à saúde pública. Essa pesquisa foi realizada com o objetivo de avaliar a ocorrência de anticorpos contra Leptospira spp. em três espécies de canídeos selvagens do cerrado brasileiro utilizando o teste de soroaglutinação microscópica (SAM). Foram testadas amostras de soro sanguíneo de 19 cachorros-do-mato (Cerdocyon thous), 14 lobos guarás (Chrysocyon brachyurus) e sete raposas-do-campo (Lycalopex vetulus) de vida livre das regiões de cerrado de Araguari e Uberlândia, MG, e Cumari, GO. Dessas 40 amostras, 14 (35%) foram soropositivas. Os sorovares detectados com maior frequência foram Copenhageni e Hardjo, porém evidenciou-se também reação aos sorovares Autumnalis, Grippotyphosa, Hbedomadis, Wolffi e Icterohaemorrhagiae. Esse trabalho foi o primeiro a relatar a presença de anticorpos anti-Leptospira spp. em L. vetulus e verificou-se que as três espécies de canídeos utilizadas nessa pesquisa podem atuar como possíveis hospedeiros de diversos sorovares de leptospiras no ambiente de cerrado...

Markers of endothelial cell activation and immune activation are increased in patients with severe leptospirosis and associated with disease severity.

OBJECTIVES: Previous studies concluded that haemorrhage is one of the most accurate prognostic factors of mortality in leptospirosis. Therefore, endothelial cell activation was investigated in relation to disease severity in severe leptospirosis. METHODS: Prospective cohort study of severe leptospirosis patients. Plasma levels of sE-selectin and Von Willebrand factor (VWF) were determined. Consequently, an in vitro endothelial cell model was used to assess endothelial activation after exposure to virulent Leptospira. Finally, immune activation, as a potential contributing factor to endothelial cell activation, was determined by soluble IL2-receptor (sIL-2r) and soluble Fas-ligand (sFasL) levels. RESULTS: Plasma levels of sE-selectin and VWF strongly increased in patients compared to healthy controls. Furthermore, sE-selectin was significantly elevated (203 ng/ml vs. 157 ng/ml, p < 0.05) in survivors compared to non-survivors. Endothelial cells exposed to virulent Leptospira showed increased VWF expression. E-selectin and ICAM-1 expression did not change. Immunohistochemistry revealed the presence of intracellular Leptospira and qPCR suggested replication. In vivo analysis showed that increased levels of sFasL and sIL-2r were both strongly associated with mortality. Furthermore sIL-2r levels were increased in patients that developed bleeding and significantly correlated to duration of hospital stay. DISCUSSION: Markers of endothelial activation and immune activation were associated with disease severity in leptospirosis patients.

WC1 is a hybrid γδ TCR coreceptor and pattern recognition receptor for pathogenic bacteria.

WC1 proteins are uniquely expressed on γδ T cells and belong to the scavenger receptor cysteine-rich (SRCR) superfamily. While present in variable, and sometimes high, numbers in the genomes of mammals and birds, in cattle there are 13 distinct genes (WC1-1 to WC1-13). All bovine WC1 proteins can serve as coreceptors for the TCR in a tyrosine phosphorylation dependent manner, and some are required for the γδ T cell response to Leptospira. We hypothesized that individual WC1 receptors encode Ag specificity via coligation of bacteria with the γδ TCR. SRCR domain binding was directly correlated with γδ T cell response, as WC1-3 SRCR domains from Leptospira-responsive cells, but not WC1-4 SRCR domains from Leptospira-nonresponsive cells, bound to multiple serovars of two Leptospira species, L. borgpetersenii, and L. interrogans. Three to five of eleven WC1-3 SRCR domains, but none of the eleven WC1-4 SRCR domains, interacted with Leptospira spp. and Borrelia burgdorferi, but not with Escherichia coli or Staphylococcus aureus. Mutational analysis indicated that the active site for bacterial binding in one of the SRCR domains is composed of amino acids in three discontinuous regions. Recombinant WC1 SRCR domains with the ability to bind leptospires inhibited Leptospira growth. Our data suggest that WC1 gene arrays play a multifaceted role in the γδ T cell response to bacteria, including acting as hybrid pattern recognition receptors and TCR coreceptors, and they may function as antimicrobials.

Leptospira interrogans sorovar Copenhageni e Icterohaemorrhagiae: relação evolutiva, diferenças genéticas e associação com desfecho clínico / Leptospira interrogans serovar Copenhageni and Icterohaemorrhagiae: evolutionary relationship, genetic differences and association with clinical outcome

A leptospirose é a zoonose mais disseminada mundialmente por infectar diversas espécies diferentes de animais mamíferos. Apresenta 22 espécies identificadas, sendo dez patogênicas, cinco intermediarias e sete saprofiticas, além de apresentar mais de 250 sorovares diferentes. Em Salvador, Leptospira interrogans sorovar Copenhageni é a causadora da epidemia urbana na cidade e apresenta ratos como seu hospedeiro reservatório. As formas clínicas da leptospirose podem variar de assintomática a formas graves. As manifestações clínicas mais graves envolve o desenvolvimento da síndrome Hemorrágica pulmonar severa, e óbito do paciente. Estudos para entender as diferenças genéticas entre as diferentes espécies e sorovares é de extrema importância para identificar fatores de virulência da bactéria, genes que possam está associado aos diferentes formas clinicas, e sua capacidade de se adaptar aos diferentes ambientes. Neste trabalho foi estudado o genoma de dois importantes serovares de L. interrogans, o sorovar Copenhageni e o serovar Icterohaemorrhagiae, e suas diferenças genéticas e associação com dados clínicos e epidemiológicos. Um total de 141 isolados...

There are 22 different species of Leptospira spp. in which 10 are pathogenic, 5 intermediate and 7 saprophytic species. In Salvador the Leptospira interrogans sorovar Copenhageni is the main serovar detected, responsible for the urban epidemics, and has rats as their main host. The clinical manifestations of leptospirosis can vary from asymptomatic form to severe disease like pulmonary hemorrhagic syndrome, and death. Studies to understand de genetic differences among the species and serovars are of great importance to identify virulence factors, genes that could be related to the different clinical manifestations and its capacity to adapt in different environments. Here, the genome of two epidemiologically important serovar of the L. interrogans, the serovar Copenhageni and serovar Icterohaemorrhagiae, and their genetic differences and the association of these differences with epidemiological and clinical data were studied. A total of 141 strains...