Splenic granuloma: Melioidosis or Tuberculosis?

Shared challenges to the control of complex intracellular neglected pathogens

The complex intracellular pathogens Mycobacterium tuberculosis, Mycobacterium leprae, Leishmania spp., and Burkholderia pseudomallei, which cause tuberculosis, leprosy, leishmaniasis, and melioidosis respectively, represent major health threats with a significant global burden concentrated in low- and middle-income countries. While these diseases vary in their aetiology, pathology and epidemiology, they share key similarities in the biological and sociodemographic factors influencing their incidence and impact worldwide. In particular, their occurrence in resource-limited settings has important implications for research and development, disease prevalence and associated risk factors, as well as access to diagnostics and therapeutics. In accordance with the vision of the VALIDATE (VAccine deveLopment for complex Intracellular neglecteD pAThogeEns) Network, we consider shared challenges to the effective prevention, diagnosis and treatment of these diseases as shaped by both biological and social factors, illustrating the importance of taking an interdisciplinary approach. We further highlight how a cross-pathogen perspective may provide valuable insights for understanding and addressing challenges to the control of all four pathogens.

The mystery behind a 1000 day fever in a young male

This case is of a 23 year old diabetic male who presented with fever and splenic lesions. He continued to have fever off and on over the next 3 years despite empirical antibiotics and anti-tubercular therapy. No definitive diagnosis could be made despite exhaustive investigations. Finally, a splenectomy resulted in sustained defervescence. The splenic histopathology showed caseating granulomas but aerobic cultures, Xpert MTB/Rif ULTRA, TB and fungal cultures were negative. A final diagnosis of splenic melioidosis was made based on the clinical features, radiology, histopathology, literature review and absence of an alternative diagnosis.

Tuberculosis and COVID-19 Co-infection: An Updated Review

Coronavirus disease (COVID 19) has involved millions of people all over the world. Tuberculosis (TB) continues to affect millions of people every year with high mortality. There is limited literature on the occurrence of COVID 19 in patients with TB. We reviewed the available data on various clinical details, management, and outcome among patients with COVID-19 and TB. 8 studies reported a total of 80 patients with this coinfection. These patients were reported from ten different countries, with Italy reporting the largest number of cases. Migrant, males constituted a major proportion of cases. Most reported patients were symptomatic. Fever, dry cough, and dyspnea were the most commonly reported symptoms. Bilateral ground glass opacities were more common in COVID 19 infection and cavitary lesions were more common in patients with TB. Most reported TB patients had been found to have mycobacterium tuberculosis from sputum culture in the background of pulmonary TB. Most patients of TB were treated with multidrug regimen antitubercular therapy. In all 8 studies, COVID 19 was treated as per the local protocol. Mortality was reported in more than 10% of patients. Mortality was higher in elderly patients (> 70 years) and amongst patient with multiple medical comorbidities.

Multinucleated Giant Cell Formation as a Portal to Chronic Bacterial Infections

This review provides a snapshot of chronic bacterial infections through the lens of Burkholderia pseudomallei and detailing its ability to establish multi-nucleated giant cells (MNGC) within the host, potentially leading to the formation of pyogranulomatous lesions. We explore the role of MNGC in melioidosis disease progression and pathology by comparing the similarities and differences of melioidosis to tuberculosis, outline the concerted events in pathogenesis that lead to MNGC formation, discuss the factors that influence MNGC formation, and consider how they fit into clinical findings reported in chronic cases. Finally, we speculate about future models and techniques that can be used to delineate the mechanisms of MNGC formation and function.