Design and Development of an Internationally Applicable Educational Video to Increase Community Awareness in Regions with High Prevalence of Melioidosis and Diabetes

Melioidosis is a neglected tropical disease that causes high morbidity and mortality. Public health awareness is essential for both prevention and early detection of the infection. This project aimed to develop an internationally applicable educational tool to increase community awareness in regions with high prevalence of diabetes and melioidosis. The animation was created with international collaboration. Sixty-four delegates from different cultural backgrounds participated in the survey to evaluate the animation. Feedback was positive, with 85% agreeing that they would use this video for public education and 82% agreeing that the video was culturally appropriate to them in the context of their region. The animation was refined after feedback. To supplement the 3-minute animation, a 13-minute film footage of interviews with clinicians, researchers and patients was also created. These materials have been made available online through the International Melioidosis Network and can be readily downloaded or subtitled in any language using publicly available software, demonstrating the utility of developing low-cost adaptable health education material targeted for widespread use internationally

Molecular characterisation and classification of Burkholderia pseudomallei

Melioidosis presents with a broad spectrum of clinical presentations. Discussions on the correlations of disease presentation and severity with factors such as isolate virulence, host status and geographical location have been long and many. Additional issues such as latency and disease relapse serve to further complicate the picture. Molecular typing methods have been used to support a number of theories relating to such questions. They have also provided data regarding the evolutionary origins of Burkholderia pseudomallei isolates, in addition to defining the degree of clonality of multiple isolates from individual patients. More recently, molecular technology has been used in the search for biomarkers, molecular fingerprints used as diagnostic indicators of disease.\ud © 2012 Elsevier B.V. All rights reserved

The effect of different Burkholderia pseudomallei isolates of varying levels of virulence on toll-like-receptor expression

The purpose of this investigation was to ascertain the degree of toll-like-receptor (TLR) activation by Burkholderia pseudomallei isolates with varying levels of virulence 2 h post infection. Standard antibiotic protection assays were performed on RAW 264.7 macrophages and peritoneal exudate cells (PEC) challenged with B. pseudomallei. Real-time PCR (RT-PCR) was performed to determine TLR2, TLR4, TLR5 and TLR9 expression. Internalization and killing of bacteria were determined 2h post infection. ELISAs were performed to determine the levels of TNF-α from cultured supernatants. Nitrate levels were determined by Griess assays. Up to 2h post infection, B. pseudomallei failed to significantly increase TLR4, TLR5 and TLR9 expression in both cell types. However, TLR2 expression was increased in RAW 264.7 macrophages, irrespective of isolate virulence. The levels of TNF-α and nitrate were significantly attenuated in RAW 264.7 macrophages, and no correlation was found between the level of virulence of the infecting strain and TLR expression, bacterial uptake, or killing. The ability of B. pseudomallei to evade detection by macrophages may in part be due to possible signal dampening of TLRs at very early stages of infection

Identification of defective early immune responses to Burkholderia pseudomallei infection in a diet-induced murine model of type 2 diabetes

Co-occurrence of bacterial infections with type 2 diabetes (T2D) is a global problem. Melioidosis caused by Burkholderia pseudomallei is 10 times more likely to occur in patients with T2D, than in normoglycemic individuals. Using an experimental model of T2D, we observed that greater susceptibility in T2D was due to differences in proportions of infiltrating leucocytes and reduced levels of MCP-1, IFN-γ and IL-12 at sites of infection within 24 h post-infection. However, by 72 h the levels of inflammatory cytokines and bacteria were markedly higher in visceral tissue and blood in T2D mice. In T2D, dysregulated early immune responses are responsible for the greater predisposition to B. pseudomallei infection

Burkholderia pseudomallei enhances maturation of bone marrow derived dendritic cells

T-cell activation is essential for protection against Burkholderia pseudomallei infection. Using bone marrow-derived dendritic cells (BMDC) isolated from partially resistant C57BL/6 and susceptible BALB/c mice, the degree of BMDC activation in the presence of B. pseudomallei was investigated. Maturation, cytokine production and internalization of B. pseudomallei by BMDC was assessed in response to infection with a highly virulent and a low-virulent clinical isolate. Maturation was determined by identifying the upregulation of cell-surface markers CD11c and CD86. IL-1b and IL-12p40 expression were assessed by reverse-transcriptase PCR. The uptake of B. pseudomallei by BMDC was measured using an internalization assay. This study demonstrated that B. pseudomallei isolates stimulate the maturation of BMDC to the same degree regardless of virulence. However, maturation of BMDC was significantly increased in BALB/c mice compared with C57BL/6 mice. Additionally, the uptake of B. pseudomallei by BMDC was significantly greater with the highly virulent isolate compared with the low-virulent isolate. Expression of\ud IL-12 and IL-1b following infection with B. pseudomallei was up-regulated. The differences observed may have implications in the development of an effective immune response to B. pseudomallei

The double burden: a new-age pandemic meets an ancient infection

Tuberculosis is responsible for significant morbidity and mortality in the tropics. Active TB develops when host defences are impaired. Epidemiological evidence and studies addressing the double burden of communicable and non-communicable diseases demonstrate a clear association between diabetes and susceptibility to TB, treatment failure and complications. The immune mechanisms involved in host-pathogen interactions in co-morbid TB-diabetes are not well defined and require further investigation. This combined with the increase in diabetes predominately in low- and middle-income countries where TB is prevalent has major health implications

Altered macrophage function is associated with severe Burkholderia pseudomallei infection in a murine model of type 2 diabetes

This study used a murine model of type 2 diabetes (BKS.Cg-Dock7m +/+ Leprdb/J mice) to investigate the inflammatory and cellular mechanisms predisposing to Burkholderia pseudomallei infection and co-morbid diabetes. Homozygous db/db (diabetic) mice developed extreme obesity, dyslipidaemia and glucose intolerance leading to hyperglycaemia and overt type 2 diabetes. Compared to their heterozygous db/+ (non-diabetic) littermates, diabetic mice rapidly succumbed to subcutaneous B. pseudomallei infection, paralleled by severe hypoglycaemia and increased expression of the proinflammatory cytokines, tumour necrosis factor (TNF)-α and interleukin (IL)-1β, in the spleen, despite comparable bacterial loads in the spleen of non-diabetic mice. Neutrophil oxidative burst and dendritic cell uptake and killing of B. pseudomallei were similar between diabetic and non-diabetic mice. Compared to peritoneal macrophages from non-diabetic mice, macrophages from diabetic mice were unable to contain and kill B. pseudomallei. Functional differences between macrophages of diabetic and non-diabetic mice toward B. pseudomallei may contribute to rapid dissemination and more severe disease progression in hosts with co-morbid type 2 diabetes

Anti-streptococcal antibody and T-cell interactions with vascular endothelial cells initiate the development of rheumatic carditis

The role of group A streptococcal and Streptococcus dysgalactiae subspecies equisimilis M-protein specific Abs and T-cells in endothelial cell activation was investigated using cultured rat aortic endothelial cells, and in a rat model of autoimmune valvulitis. Heat inactivated serum and mononuclear cells from streptococcal M-protein immunized rats independently induced upregulation of the endothelial cell adhesion molecules, vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1 in cultured cells. We also observed T-cell migration across endothelial cell monolayers incubated with serum from M-protein-immunized rats. Furthermore, we observed VCAM-1 and ICAM-1 expression in the myocardium of rats injected with M-protein compared to control animals. These observations support the contention that initial interactions between streptococcal M-protein specific Abs and/or T-cells with the heart endothelium lead to endothelial cell activation followed by transmigration of M-protein specific T-cells into heart tissue leading to an inflammatory process that leads to carditis in rheumatic fever and rheumatic heart disease

Anti-streptococcal antibody and T-cell interactions with vascular endothelial cells initiate the development of rheumatic carditis

The role of group A streptococcal and Streptococcus dysgalactiae subspecies equisimilis M-protein specific Abs and T-cells in endothelial cell activation was investigated using cultured rat aortic endothelial cells, and in a rat model of autoimmune valvulitis. Heat inactivated serum and mononuclear cells from streptococcal M-protein immunized rats independently induced upregulation of the endothelial cell adhesion molecules, vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1 in cultured cells. We also observed T-cell migration across endothelial cell monolayers incubated with serum from M-protein-immunized rats. Furthermore, we observed VCAM-1 and ICAM-1 expression in the myocardium of rats injected with M-protein compared to control animals. These observations support the contention that initial interactions between streptococcal M-protein specific Abs and/or T-cells with the heart endothelium lead to endothelial cell activation followed by transmigration of M-protein specific T-cells into heart tissue leading to an inflammatory process that leads to carditis in rheumatic fever and rheumatic heart disease