Culture and molecular identification of microorganisms from Digital Dermatitis lesions in dairy cattle: Leptospira, an unexpected finding / Cultivo e identificação molecular de microrganismos isolados de lesões de dermatite digital em bovinos leiteiros: Leptospira, um achado inesperado

Bovine digital dermatitis (BDD) is an infectious and contagious disease characterized by ulcerative and proliferative lesions affecting the skin on the bulbs of the heel or the interdigital cleft in dairy cattle, often associated with lameness. Evidences on the etiology of BDD indicate that it is multifactorial, involving environmental factors and multiple bacterial colonization. We isolated and identified microorganisms from BDD biopsy samples obtained from five Holstein Friesian and two Jersey cows by cultivation and molecular identification of bacterial isolates using 16S rRNA gene sequence analysis. We identified six bacterial species: Spirochetes as Treponema pedis and Leptospira broomi/L. fainei, L. licerasiae/L. wolffii; Corynebacterium appendicis, Cupriavidus gilardii and Enterococcus casseliflavus/E. gallinarum. It was quite surprising to have isolated and identified Leptospira species in three out of seven cultures, from different individual cows and two different farms. The species identified belong to the intermediate pathogenic clade, which is a group found to cause human and animal disease. Our findings indicate the need to further investigate the association of Leptospira of intermediate pathogenicity with BDD lesions and whether its presence would have any veterinary and medical significance both in Leptospirosis and with the pathogenesis of BDD lesions, especially in tropical countries.(AU)

Dermatite digital bovina (DDB) é uma doença infecciosa, contagiosa, caracterizada por lesões ulcerativas e proliferativas da região dos talões e/ou do espaço interdigital, frequentemente associada com claudicação. Evidências indicam que a etiologia da DDB é multifatorial, envolvendo fatores ambientais e colonização polimicrobiana. Relata-se aqui o isolamento e a identificação bacteriana em amostras de biópsias em lesões de DDB, obtidas de cinco vacas da raça Holandesa e duas da raça Jersey, por meio de cultivo e identificação molecular de isolados, com base na análise de sequências de genes 16S rRNA. São identificadas seis espécies bacterianas: as espiroquetas Treponema pedis e Leptospira broomi/L. fainei, L. licerasiae/L. wolffii; Corynebacterium appendicis, Cupriavidus gilardii e Enterococcus casseliflavus/E. gallinarum. O isolamento e a identificação de espécies de Leptospira surpreenderam, destacando-se sua presença em três dos sete cultivos obtidos em diferentes vacas, de duas fazendas distintas. As espécies identificadas pertencem ao grupo tipificado como de patogenicidade intermediária, causador de doenças em animais e no homem. Os resultados apresentados indicam a necessidade de maiores investigações sobre a associação entre Leptospira de patogenicidade intermediária e a patogênese das lesões DDB, investigando-se sua presença e significado nas medicinas veterinária e humana, especialmente em países tropicais.(AU)

In vitro activity of meglumine antimoniate, a pentavalent antimonial drug, on Leishmania promastigotes

The activity of a pentavalent antimonial drug glucantime on the growth of promastigote forms of Leishmania strains involved in South American cutaneous and mucocutaneous leishmaniasis was investigated. A marked difference in susceptibility to glucantime among four different strains and cloned lines obtained from a single strain was observed. For the sensitive strains (L.braziliensis M2903 and L. guyanensis M1176), the cell growth was reduced in a dose-dependent manner for drug concentrations at a range of 0.23 to 23 mM. However, despite the relative sensitivity of the assay, no significant increase of effect was observed in the presence of higher drug concentrations. For the resistant strains (L. amazonensis M10996 and L. braziliensis LYB259) a dose-response line is obtained at a higher concentration range (20 mM to mM). The influence of the drug on surface properties, respiratory activity and incorporation of radiolabelled leucine by a sensitive strain - L-guyanensis M1176-was studied as an approach to its site of action. Despite the increased intensity of self-aglutination for cells growing in the presence of glucantime, no significant change was observed in electrophoretic mobility or Concanavian A reactivity. Since the oxygen uptake of glucose-stimulated promastigotes was only slightly reduced in the presence of 23 mM glucantime at 28-C, the reduction was not sufficient to explain the total growth inhibition observed. A significant decrease of 14C-leucine incorporation into the cold TCA-insoluble fraction of drug-treated cells was observed within the same concentration range that reduces promastigote growth