Application of DNA sequence analysis based on five different conserved genes (16S rDNA, rpoB, gdh, est and pgm) for intra-species discrimination of Bacteroides fragilis.

In the past few years, many studies revealed a remarkable genetic variability in Bacteroides fragilis species, and the existence of two divisions was proposed according to presence or absence of the cfiA (metallo-ß-lactamase/carbapenemase) gene. The aim of this study was to evaluate the use of DNA sequence analysis for glutamate dehydrogenase (gdh), phosphoglucomutase (pgm) and esterase (est) metabolic genes, in comparison to RNA polymerase ß subunit (rpoB) and 16S ribosomal RNA (rrs) gene sequencing, to identify the presence of these two groups in seventeen B. fragilis strains. Based on phylogenetic trees, only the est gene sequences generated a classification similar to rrs- and rpoB-genes. On the other hand, the genes pgm and gdh did not allow the discrimination of these divisions. The est gene sequence can be suggested as an additional tool for differentiation of the two groups in B. fragilis, providing highly reproducible and reliable data in B. fragilis taxonomy.

An alternative for the preadsorption step in the paratuberculosis serodiagnosis: Mycobacterium fortuitum.

ELISAs for paratuberculosis employ a preadsorption step with Mycobacterium phlei to diminish unspecific reactions As M. fortuitum is one of the most frequent environmental mycobacteria, the purpose of this pilot study was to evaluate its use as an alternative for the preadsorption in ELISAs for paratuberculosis. Results suggest that M. fortuitum can be an alternative instead of or associated to M. phlei with comparable results (κ > 0.8) to conventional ELISAs using M. phlei as a preadsorption antigen.

A serological study on Brucella abortus, caprine arthritis-encephalitis virus and Leptospira in dairy goats in Rio de Janeiro, Brazil.

In spite of the large number of goats found in several developing tropical countries, milk production remains unsatisfactory. The occurrence of infectious diseases, such as leptospirosis, brucellosis and caprine arthritis-encephalitis (CAE) may in part be responsible for sub-optimal production. In this study, 1000 serum samples were tested for leptospirosis, 953 for brucellosis and 562 for CAE. All tested flocks presented at least one seroreactive animal for leptospirosis and for CAE. Reactivity to leptospirosis was 11.1%, and serovar hardjo was the most frequently found. Anti-B. abortus agglutinins were found in 0.5% of the samples presented and 14.1% were seroreactive to CAE. Leptospirosis was considered to represent the major infectious problem in the studied goat flocks. The occurrence of infectious diseases in the tested flocks may represent an important factor contributing to the decreased productivity of the animals. These findings may be similar to those observed in other developing countries and require further study to define the relationship between seropositivity and reduced production.

An alternative for the preadsorption step in the paratuberculosis serodiagnosis: Mycobacterium fortuitum / Mycobacterium fortuitum: uma alternativa para a etapa de pré-adsorção no sorodiagnóstico da paratuberculose

ELISAs for paratuberculosis employ a preadsorption step with Mycobacterium phlei to diminish unspecific reactions As M. fortuitum is one of the most frequent environmental mycobacteria, the purpose of this pilot study was to evaluate its use as an alternative for the preadsorption in ELISAs for paratuberculosis. Results suggest that M. fortuitum can be an alternative instead of or associated to M. phlei with comparable results (κ > 0.8) to conventional ELISAs using M. phlei as a preadsorption antigen.

Ensaios de sorodiagnóstico de paratuberculose (ELISA) utilizam Mycobacterium phlei na etapa de pré-adsorção para diminuir reações inespecíficas. Uma vez que M. fortuitum é uma das micobactérias atípicas mais isoladas no Brasil, o objetivo central deste estudo foi averiguar a possibilidade de sua utilização como antígeno da etapa de pré-adsorção destes testes. Os resultados sugerem que M. fortuitum apresentou resultados comparáveis (κ > 0.8) aos alcançados com M. phlei e que, portanto poderia ser uma alternativa ao invés ou associado a M. phlei na etapa de pré-adsorção de ELISAs para paratuberculose.