No abstract

Abstract. Our aim was to evaluate the pulmonary changes induced by Leptospira interrogans infection in hamsters, and the gene expression of endogenous mediators in lung fragments during 28 days of observation. The animals were euthanized on days 4, 7, 14, 21, and 28 post-inoculation. Histopathologic lung analysis showed hemorrhage, pneumonia, alveolar congestion, and infiltrated cellular areas, with increasing severity until day 21 post-inoculation. Tumor necrosis factor (TNF)-a mRNA expression enhanced in first days with peak on day 4 and slightly decreased in the final phase. The interleukin (IL)-10 remained relatively constant throughout the period, with the exceptions of days 4 and 14. The endothelial nitric-oxide synthesis (eNOS) showed an increased expression on day 4, followed by an augment on days 7 and 14, and remaining constant up to day 28 post-infection. Our results demonstrate that inoculation of L. interrogans sorovar Icterohaemorrhagiae induced pulmonary lesions, including pulmonary hemorrhage, supporting that the lung is a target organ.

Objetivo: Identificar os microrganismos da conjuntiva ocular de cães clinicamente sadios na região de Araçatuba (SP), no verão e no inverno. Métodos: Foram utilizados quarenta cães, machos e fêmeas, com idade variando entre 2 e 5 anos. Após limpeza ocular com água tratada, foram realizadas colheitas de material do saco conjuntival inferior com auxílio de "swabs" estéreis, para posterior isolamento e identificação de bactérias aeróbicas, anaeróbicas e fungos. Resultados: As bactérias de maior ocorrência foram o Staphylococcus aureus e o Staphylococcus β-haemolyticus. O fungo de maior ocorrência foi Penicilium sp. Conclusão: Pôde-se concluir que houve variação da microbiota conjuntival normal em função da estação do ano. Dos microrganismos isolados, o único que apresentou diferença estatística significativa quanto à incidência sazonal foi o Staphylococcus β-haemolyticus, que foi isolado apenas no inverno.

The aim of the present study was to investigate the kinetics of humoral and cellular responses during leptospirosis. We observed that the presence of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) was associated with antibody production and bacterial recovery, and the compromising of both TNF-alpha and IL-6 in the immunopathogenesis of leptospirosis during an experimental infection of BALB/c mice inoculated with Leptospira interrogans serovar Canicola was verified. Results showed higher levels of TNF-alpha and IL-6 in the initial phase of infection, in which the greatest bacterial clearance was observed. However, when the bacterial recovery was compared with the kinetics of the production of antibodies, the results revealed a kinetics proportionally inverted to antibody production. This fact may be related to some inhibitory factor which could be responsible for the selective suppression of the cellular immune response. We concluded that during leptospirosis there was a greater mobilization of the cellular immune response activity, mainly in the initial phase of the infectious process, for posterior involvement of the humoral response, and that both TNF-alpha and IL-6 could be associated with the immunopathogenesis of the disease

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.

Antimicrobial resistance (AR) is a public health issue since it limits the choices to treat infections by Escherichia coli in humans and animals. In Brazil, the ovine meat market has grown in recent years, but studies about AR in sheep are still scarce. Thus, this study aims to investigate the presence of AR in E. coli isolated from lambs during feedlot. To this end, feces from 112 lambs with 2 months of age, after weaning, were collected on the first day of the animals in the feedlot (day 0), and on the last day before slaughtering (day 42). Isolates were selected in MacConkey agar supplemented with 4 mg/L of ceftiofur and identified by biochemical methods. Isolates were submitted to an antimicrobial susceptibility test by disc-diffusion and PCR to investigate genes for phylogenetic group, virulence determinants and resistance to the several antimicrobial classes tested. The genetic localization of the bla genes detected was elucidated by S1-PFGE followed by Southern blot-hybridizations. The isolates were typed by XbaI-PFGE and MLST methods. Seventy-eight E. coli were isolated from 8/112 (7.1%) animals on day 0, and from 55/112 (49.1%) animals on day 42. Since only fimH was present in almost all E. coli (97.4%) as a virulence gene, and also 88.5% belonged to phylogroups B1 or A, we consider that isolates represent intestinal commensal bacteria. The dendrogram separated the 78 non-virulent isolates in seven clusters, two of which comprised 50 E. coli belonging to ST/CC 1727/446 or ST 3994 recovered on day 42 commonly harboring the genotype bla CMY−2-aac(3)-IIa-tetA-sul1-sul2-floR-cmlA. Special attention should be given to the presence of bla CTX−M−15 , a worldwide gene spread, and bla CTX−M−14 , a hitherto undetected gene in Enterobacteriaceae from foodproducing animals in Brazil. Importantly, E. coli lineages and plasmids carrying bla genes detected here have already been reported as sources of infection in humans either from animals, food, or the environment, which raises public health concerns. Hence, two types of commensal E. coli carrying important AR genes clearly prevailed during feedlot, but lambs are also reservoirs of bacteria carrying important AR genes such as bla CTX−M−14 and bla CTX−M−15 , mostly related to antimicrobial treatment failure.

Os morcegos são hospedeiros de uma rica diversidade de microrganismos. Muitos trabalhos apontam uma estreita ligação entre quirópteros e fungos com potencial patogênico, principalmente por habitarem ambientes como cavernas, grutas e ocos de árvores, favoráveis à manutenção e propagação dos fungos. O objetivo do trabalho foi estudar a microbiota fúngica gastrintestinal de morcegos. Das 98 amostras pertencentes a 11 espécies de morcegos procedentes de 15 cidades estudadas, 20% são da espécie Carollia perspicillata, 19% Artibeus lituratus, 17% Molossus rufus, 13% Glossophaga soricina, 9% Nyctinomops macrotis, 8% Molossus molossus, 7% Desmodus rotundus, 2% Lasiurus ega, e 1% Eptesicus furinalis, Myotis nigricans e Tadarida brasiliensis. O gênero Aspergillus sp. foi isolado de 29% das amostras, seguidos por 6% Microsporum sp. e Penicillium sp., 4% Tricophyton sp. e zigomicetos e 2% Fusarium sp. Das espécies de leveduras, 14% foram de Rhodotorula sp., 10% Candida sp. e 2% Cryptococcus sp., 22% dos isolados permaneceram sem identificação. Todos os 82 cultivos de vísceras foram negativos para Histoplasma capsulatum. Houve associação estatística significativa entre os resultados do cultivo microbiológico e as espécies de morcegos (p < 0,05). Concluímos que os morcegos podem atuar como agentes veiculadores de fungos com potencial patogênico, entretanto outros trabalhos devem ser realizados a fim de estabelecer estratégias que permitam identificar os principais fatores correlacionados com o crescimento e a disseminação dos microrganismos na natureza e qual a implicação dos quirópteros no ciclo epidemiológico.

The datasets reported herein provide information about microarray experiment of macrophage cell line J774A.1 infected with three different strains of Leptospira spp. Transcriptomic profiles were generated using Affymetrix® Mouse Gene 2.1 ST Array Strip. Data was normalized and statically process, p-value < 0.01, FDR < 0.05 and log2 fold change (± 2). The microarray raw data are available in Gene Expression Omnibus (GEO) under accession number GSE105141.