Statins increase rifampin mycobactericidal effect.

Mycobacterium leprae and Mycobacterium tuberculosis antimicrobial resistance has been followed with great concern during the last years, while the need for new drugs able to control leprosy and tuberculosis, mainly due to extensively drug-resistant tuberculosis (XDR-TB), is pressing. Our group recently showed that M. leprae is able to induce lipid body biogenesis and cholesterol accumulation in macrophages and Schwann cells, facilitating its viability and replication. Considering these previous results, we investigated the efficacies of two statins on the intracellular viability of mycobacteria within the macrophage, as well as the effect of atorvastatin on M. leprae infections in BALB/c mice. We observed that intracellular mycobacteria viability decreased markedly after incubation with both statins, but atorvastatin showed the best inhibitory effect when combined with rifampin. Using Shepard's model, we observed with atorvastatin an efficacy in controlling M. leprae and inflammatory infiltrate in the BALB/c footpad, in a serum cholesterol level-dependent way. We conclude that statins contribute to macrophage-bactericidal activity against Mycobacterium bovis, M. leprae, and M. tuberculosis. It is likely that the association of statins with the actual multidrug therapy effectively reduces mycobacterial viability and tissue lesion in leprosy and tuberculosis patients, although epidemiological studies are still needed for confirmation.

Optimized protocols for Mycobacterium leprae strain management: frozen stock preservation and maintenance in athymic nude mice.

Leprosy, caused by Mycobacterium leprae, is an important infectious disease that is still endemic in many countries around the world, including Brazil. There are currently no known methods for growing M. leprae in vitro, presenting a major obstacle in the study of this pathogen in the laboratory. Therefore, the maintenance and growth of M. leprae strains are preferably performed in athymic nude mice (NU-Foxn1(nu)). The laboratory conditions for using mice are readily available, easy to perform, and allow standardization and development of protocols for achieving reproducible results. In the present report, we describe a simple protocol for purification of bacilli from nude mouse footpads using trypsin, which yields a suspension with minimum cell debris and with high bacterial viability index, as determined by fluorescent microscopy. A modification to the standard method for bacillary counting by Ziehl-Neelsen staining and light microscopy is also demonstrated. Additionally, we describe a protocol for freezing and thawing bacillary stocks as an alternative protocol for maintenance and storage of M. leprae strains.

Detecção de Paracoccidioides brasiliensis em tatus (Dasypus novemcinctus) provenientes de uma reserva de Cerrado do Instituto Lauro de Souza Lima (Bauru, SP / Paracoccidoides brasiliensis detection in armadillos (Dasypus novemcinctus) from a Savanna reserve at the Lauro de Souza Lima Institute (Bauru, SP)

A constatação de que o tatu Dasypus novemcinctus infecta-se naturalmente pelo Paracoccidioides brasiliensis abriu perspectivas para estudos eco-epidemiológicos e de evolução deste patógeno. No presente estudo, foi investigada a ocorrência do P. brasiliensis em tatus capturados em uma reserva de Cerrado em Bauru, SP. Foram avaliados quatro animais (C1-C4), dos quais, após a eutanásia, foi feita a coleta de pulmão, fígado, baço e linfonodos mesentéricos para avaliação micológica e molecular. Fragmentos de DNA ribossomal foram amplificados por PCR e Nested-PCR utilizando primers específicos para P. brasiliensis. O isolamento fúngico foi positivo em três animais, nas amostras de linfonodo (C1), fígado (C4) e baço (C2 e C4). Amplicons de 387pb foram identificados em três amostras de tecido. A detecção de animais infectados na reserva de Cerrado aponta para a importância de utilizar esses animais como sinalizadores da presença do patógeno no ambiente, sendo esta uma avaliação inédita no município de Bauru, SP.