RESUMEN

Research concerning leptospirosis in donkeys and mules has been neglected around the world. Therefore, the aim of this study was to investigate the epidemiological situation of the prevalence of anti-Leptospira spp. antibodies in donkeys and mules from the state of Minas Gerais, Brazil. Blood serum samples were collected from 180 animals (109 donkeys and 71 mules) in two rural properties from the state of Minas Gerais, Brazil, and then submitted to a microscopic agglutination test (MAT). Urea and creatinine values were also quantified. Epidemiological variables such as age, breeding system, contact with other animal species, source of water and food, vaccination against leptospirosis, presence of reproductive alterations, and rodent control were also investigated. From 180 samples collected, 39 (21.67%) showed positive results in the MAT, at a dilution ≥ 1:100. Some animals were reactive for more than one serovar. The serovar Tarassovi was the most frequent (14.07%), followed by Hardjo (11.85%) and Wolffi (11.11%). There was a statistically significant difference between animals from 0 to 3 years of age reactive in the MAT in comparison to the other age groups. Most of the animals had urea and creatinine concentrations within the acceptable reference limit; however, there was a significant increase in creatinine levels in some of the test animals. The studied properties showed differences in some epidemiological aspects such as vaccination of the animals, presence of reproductive problems in the herd, and rodent control. Such aspects pointed as risk factors that may influence the frequency of positive serological results in property 1. The present study demonstrated that the prevalence of leptospirosis in donkeys and mules is high and several serovars are being maintained by these animals, representing a potential public health risk.

Asunto(s)

Leptospira , Leptospirosis , Animales , Brasil/epidemiología , Equidae , Creatinina , Leptospirosis/epidemiología , Leptospirosis/veterinaria , Pruebas de Aglutinación/veterinaria , Anticuerpos Antibacterianos

RESUMEN

Bacillus subtilis (BS) has been used as an excellent probiotic; however, some BS strains seem to be opportunist pathogens or do not present inhibitory effects in the pathogenic bacteria, so the characterization of BS strains for use in animals is mandatory. This study aimed to select nonpathogenic strains of BS, which can inhibit Salmonella spp., avian pathogenic Escherichia coli (APEC), and Campylobacter jejuni (CJ) using a chicken embryo as a model. We tested nine (9) strains of BS isolated from several sources (named A to I) in in vitro by tests of mucin degradation activity, haemolytic activity, apoptosis, and necrosis in fibroblasts from chickens. After the in vitro test, we tested the remaining seven (7) strains (strains A to G) in a chicken embryo (CE) as an in vivo model and target animal. We inoculated 3 log CFU/CE of each strain via allantoic fluid at the 10th day postincubation (DPI). Each treatment group consisted of eight CEs. At the 17th DPI we checked CE mortality, gross lesions, CE weight, and whether BS strains were still viable. To perform the cytokine, total protein, albumin, and reactive C protein analysis, we collected the CE blood from the allantoic vessel and intestine fragments in the duodenum portion for histomorphometric analysis. After the results in CEs, we tested the inhibition capacity of the selected BS strains for diverse strains of Salmonella  Heidelberg (SH), S. Typhimurium (ST), S. Enteritidis (SE), S. Minnesota (SM), S. Infantis (SI), Salmonella var. monophasic (SVM), APEC and C. jejuni. After the in vitro trial (mucin degradation activity, haemolytic activity, apoptosis, and necrosis), we removed two (2) strains (H and I) that showed ß-haemolysis, mucin degradation, and/or high apoptosis and necrosis effects. Although all strains of BS were viable in CEs at the 17th DPI, we removed four (4) strains (A, B, D, F) once they led to the highest mortality in CEs or a high albumin/protein ratio. C. jejuni inoculated with strain G had greater weight than the commercial strain, which could be further used for egg inoculation with benefits to the CE. From the tests in CEs, we selected the strains C, E, and G for their ability to inhibit pathogenic strains of relevant foodborne pathogens. We found that the inhibition effect was strain dependent. In general, strains E and/or G presented better or similar results than commercial control strains in the inhibition of SH, ST, SI, APEC, and two (2) strains of CJ. In this study, we selected BS strains C, E and G due to their in vitro and in vivo safety and beneficial effects. In addition, we emphasize the value of CE as an in vivo experimental model for assessing BS's safety and possible benefits for poultry and other animals.

Asunto(s)

Campylobacter jejuni , Infecciones por Escherichia coli , Probióticos , Embrión de Pollo , Animales , Pollos/microbiología , Bacillus subtilis , Escherichia coli , Mucinas , Necrosis

RESUMEN

Erysipelas is a disease caused by the Erysipelothrix genus, whose main species is the E. rhusiopathiae, the causative agent of animal erysipelas and human erysipeloid. We isolated Erysipelothrix sp. strain 2 (ES2) from turkey's organs during an outbreak in Brazilian commercial and breeder flocks with sepsis and high mortality levels. We studied 18 flocks, accounting for 182 samples, being eight flocks (84 samples) as ES2 positive with individuals demonstrating clinical symptoms and high mortality. We obtained the genetic variability of 19 samples with PFGE and found two clones, both from the same flock but different samples, and two clusters. Interestingly, we found 15 strains with high genetic variability among and within flocks. We have found a positive association between the proximity of ES2 positive turkey flocks and commercial swine sites through epidemiological analysis. We infected Vero cells with two different isolates and three distinct concentrations of ES2. After performing the morphometry, we recorded enlargement of the nucleus and nucleolus. Moreover, we performed fluorescence assays that resulted in apoptotic and necrotic cells. We demonstrated that ES2 could multiply in the extracellular medium and invade and survive inside Vero cells. For the first time, our finds show that ES2 may have similar behavior as E. rhusiopathiae as a facultative intracellular microorganism, which may represent a hazard for humans.