Dados do Trabalho

Título

Investigation of biofilm formation in the kidneys of chronically infected laboratory hamsters

Introdução

Pathogenic leptospires form biofilms in the environment, in vitro, and in the renal tubules of naturally infected rats (Rattus norvegicus) which act as persistently infected reservoir hosts of infection. Biofilms are a ubiquitous phenotype among bacteria and can act as a mechanism to enhance virulence during host infections.

Objetivo (s)

To investigate biofilm formation in the kidneys of experimentally infected hamsters for persistent renal leptospirosis.

Material e Métodos

Golden Syrian female hamsters were inoculated with 10^8 Leptospira borgpetersenii serovar Hardjo strain HB203 in 0.5 mL HAN media by intraperitoneal injection. Negative control hamsters received media only. Kidneys were harvested at 3 weeks post-infection, processed routinely, embedded in paraffin, cut into 4 µm serial sections and stained for 1) leptospires using the Steiner-Steiner Silver method, and 2) biofilms using Alcian blue pH 2.5 (stains for acidic carbohydrates). As a positive control for Alcian blue, intestinal tissue from dogs were used. Renal tubules positive for leptospires by silver staining were identified in serial sections to determine colocalization for biofilm staining with Alcian blue. All research involving animals were approved by the USDA National Animal Disease Center Animal Care and Use Committee.

Resultados e Conclusão

Kidneys from experimentally infected hamsters had renal tubules that were readily identified as positive for Leptospira by silver stain. On occasion, renal tubules that were positive for Leptospira were also identified on a serial section as positive for Alcian blue staining, suggesting the formation of biofilms during colonization. Conversely, renal tubules positive for Leptospira were also identified that were negative for Alcian blue. The extent of positive renal tubules for Leptospira biofilm was associated with agglomerated colonized tubules i.e., two or more colonized tubules in the same region. The identification of biofilms in persistently infected hosts enhances our understanding of pathogenic mechanisms of leptospirosis, and the transmission of this zoonotic disease. An animal model for the development of biofilm formation by leptospires during infection can facilitate novel approaches to further understand this phenotype.

Palavras-chave

Leptospirosis, Leptospira, Biofilms, Pathogenesis

Agradecimentos

National Council for Scientific and Technological Development (CNPq) and Coordination for the Improvement of Higher Education Personnel (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES).