Acute immune response to Mycobacterium massiliense in C57BL/6 and BALB/c mice.

Mycobacterium massiliense is an environmental opportunistic pathogen that has been associated with soft tissue infection after minor surgery. We studied the acute immune response of C57BL/6 and BALB/c mice infected intravenously with 10(6) CFU of an M. massiliense strain isolated from a nosocomial infection in Brazil. The results presented here show that M. massiliense is virulent and pathogenic to both C57BL/6 and BALB/c mice, inducing a granulomatous inflammatory reaction that involves the activation of macrophages, dendritic cells, and natural killer cells induced by gamma interferon and interleukin-17 (IL-17) in C57BL/6 mice and by IL-12 in BALB/c mice.

Emergence of nosocomial Mycobacterium massiliense infection in Goiás, Brazil.

A cluster of surgical site infection cases after arthroscopic and laparoscopic procedures occurred between 2005 and 2007 in Goiânia, in the central region of Brazil. Nontuberculous mycobacteria (NTM) were isolated from samples (exudates from cutaneous abscesses) from 18 patients of seven private hospitals. There were no reports of post-surgical arthroscopic and laparoscopic mycobacterial infections in Goiânia apart from this period. The 18 isolates were identified as Mycobacterium massiliense by PCR-restriction digestion of the hsp65 gene, pulsed-field gel electrophoresis (PFGE) comparisons, and rpoB partial gene sequencing. All isolates were typed as a single clone, indicating that they have the same origin, which suggests a common source of infection for all patients.

Effects of Terminalia catappa Linn. Extract on Candida albicans biofilms developed on denture acrylic resin discs.

BACKGROUND: Considering the prevalence of denture stomatitis and the challenge of controlling this pathology using conventional therapies, natural products have been suggested as important therapeutic alternatives due to their antifungal and anti-biofilm properties. Thus, this study investigated if immersion in Terminalia Catappa Linn. extract (TCE) affects Candida albicans biofilms developed on denture acrylic resin discs. MATERIAL AND METHODS: The minimal inhibitory and minimal fungicidal concentrations (MIC and MFC, respectively) tests were performed for TCE against suspensions of C. albicans. For the biofilm assay, discs (10 x 2 mm) were fabricated using a denture acrylic resin with surface roughness standardized. The biofilms were allowed to develop for 24 hours. Then, they were immersed in the following treatments overnight (8 hours): phosphate-buffered saline (PBS, control), TCE at MIC, 5XMIC or 10XMIC. The biofilms were analyzed for cell counts and microscopy. Data were analyzed by ANOVA followed by a Tukey test at a 5% significance level. RESULTS: The minimal concentration of TCE required to inhibit C. albicans was 6.25 mg/mL, while MFC was 12.5 mg/mL. Immersion in TCE at MIC was sufficient to reduce 80% of the biofilm viable cells compared to the control group (p< 0.001). Microscopic images confirm that immersion at 5XMIC and 10XMIC had a fungicidal activity with no significant differences between the concentrations regarding viable cells counts (p> 0.05). CONCLUSIONS: Within the limitations of this study, it was possible to conclude that immersion in TCE reduced the C. albicans biofilms cells developed on the denture acrylic surface. Key words:Terminalia catappa Linn, Biofilm, Candida albicans.

Cellular responses to MPT-51, GlcB and ESAT-6 among MDR-TB and active tuberculosis patients in Brazil.

Multi-drug resistant pulmonary tuberculosis (MDR-TB) may result from either insufficiency of the host cellular immune response or mycobacterial mechanisms of resistance. Mycobacterium tuberculosis-specific CD8+ and CD4+ T lymphocytes from MDR-TB patients are poorly studied. The aim of this study was to evaluate CD4+IFN-gamma+, CD4+IL-10+, CD8(+)IFN-gamma+ and CD8+IL-10+ cell populations by flow cytometry in non-resistant TB and multi-drug resistant tuberculosis (MDR-TB) patients from mid-central Brazil after stimulation with MPT-51, GlcB and ESAT-6 recombinant antigens from M. tuberculosis in comparison to tuberculin skin test negative (TST) healthy individuals. Non-resistant TB patients present specific cellular responses (CD4 and CD8, both IFN-gamma and IL-10) to GlcB, MPT-51 and ESAT-6; while MDR-TB patients present only CD8+IFN-gamma+ responses to ESAT-6 and CD8+IL-10+ responses to GlcB and ESAT-6. The results show that MDR-TB patients present impaired specific CD4 IFN-gamma and IL-10 responses and increased/normal specific CD8 IFN-gamma and IL-10 responses. This suggests an important role for CD8 function in these patients.